1. The document provides information on the anatomy of various cranial nerves and related structures in the skull base region. It includes images and descriptions of cranial nerves III through XII in different segments as they pass through the skull base.
2. Key areas discussed include the cisterns and foramina through which cranial nerves pass, as well as their spatial relationships in the internal acoustic meatus, cerebellopontine angle, and fundus of the internal auditory canal.
3. Potential locations of the facial nerve in relation to acoustic neuromas during different surgical approaches are illustrated and described.
This document provides information on part 2 of a presentation titled "SKULL BASE 360°". It includes detailed descriptions of various parts of the skull base, including the orbit, cavernous sinus, internal carotid artery, petrous carotid artery, inferior petrosal sinus, jugular foramen, and cranial nerves 3 and 7. Links are provided for downloading additional presentations on the skull base from the website skullbase360.in. The presenter is Dr. N. Murali Chand who specializes in ENT.
1. The document discusses various anatomical structures related to the skull base, including the inferior petrosal sinus and its relationship to surrounding nerves and vessels.
2. Different surgical approaches are described that provide exposure to the ventral brainstem, including the anterior petrosectomy, transcochlear, and infratemporal fossa approaches.
3. Key anatomical landmarks are highlighted, such as the jugular tubercle, occipital condyle, and their proximity to the lower cranial nerves. Maintaining awareness of these structures is important to avoid injury during skull base surgery.
1. The document describes the anatomy of the pituitary gland and surrounding structures, making numerous comparisons to a jackfruit.
2. Key structures mentioned include the pituitary capsule, pituitary ligaments, layers of the dura mater including the periosteal and meningeal layers, cranial venous sinuses, and the relationships between these structures.
3. Details are provided on the vascular supply to the pituitary gland from arteries such as the superior and inferior hypophyseal arteries.
This document provides information about various surgical approaches to the skull base, including the translabyrinthine, transpetrous, and middle cranial fossa approaches. Diagrams and photos show the structures of the internal auditory canal and how different types of bone removal are used in each approach. References are made to books and authors that provide further details. The document states that additional powerpoint presentations on skull base surgery can be accessed online.
The document provides information about the anterior cranial fossa and related anatomy. It begins with an overview of the carotid artery as it passes through the nasopharynx, petrous bone, and cavernous sinus before entering the anterior cranial fossa and giving off branches. It then describes relationships between the frontal sinus and cribriform plate. The rest of the document discusses various arteries including the fronto-polar artery and anterior and posterior ethmoidal arteries, and provides images from cadaver dissections to illustrate the described anatomy.
This document discusses the anatomy of the carotid artery, including its segments and relationships to surrounding structures in the skull base. It describes the parapharyngeal segment of the carotid artery and how looping can cause it to extend anteriorly into the prestyloid compartment. Several surgical approaches are discussed, including how the infratemporal fossa approach allows exposure of the intratemporal carotid artery. Key anatomical structures that relate to the carotid artery are also shown, such as the paraclival segment, the trigeminal ganglion, and the abducent nerve's crossing of the carotid. Surgical techniques like subperiosteal dissection to remove tumors attached to the carotid are also summarized.
Dr. B.D. Chaurasia was a renowned Indian anatomist whose textbooks inspired the author to pursue a career in surgery. His line diagrams simplified human anatomy. He provided web links to purchase his books and view additional presentations on topics like the skull base. The document then describes anatomy of the orbit, pterygopalatine fossa, infratemporal fossa, and various cranial nerves in both anterior and lateral views of the skull base. Diagrams and photographs supplement the anatomical descriptions.
This document discusses the anatomy of the vertebral artery and surrounding structures at the craniocervical junction. It includes labeled images showing the vertebral artery, foramen magnum, atlas, axis, and surrounding muscles, nerves, and bones. The document also provides information on approaches for further viewing these structures and notes that additional presentations on "Skull base 360" will be continuously updated on the provided website.
This document provides information on part 2 of a presentation titled "SKULL BASE 360°". It includes detailed descriptions of various parts of the skull base, including the orbit, cavernous sinus, internal carotid artery, petrous carotid artery, inferior petrosal sinus, jugular foramen, and cranial nerves 3 and 7. Links are provided for downloading additional presentations on the skull base from the website skullbase360.in. The presenter is Dr. N. Murali Chand who specializes in ENT.
1. The document discusses various anatomical structures related to the skull base, including the inferior petrosal sinus and its relationship to surrounding nerves and vessels.
2. Different surgical approaches are described that provide exposure to the ventral brainstem, including the anterior petrosectomy, transcochlear, and infratemporal fossa approaches.
3. Key anatomical landmarks are highlighted, such as the jugular tubercle, occipital condyle, and their proximity to the lower cranial nerves. Maintaining awareness of these structures is important to avoid injury during skull base surgery.
1. The document describes the anatomy of the pituitary gland and surrounding structures, making numerous comparisons to a jackfruit.
2. Key structures mentioned include the pituitary capsule, pituitary ligaments, layers of the dura mater including the periosteal and meningeal layers, cranial venous sinuses, and the relationships between these structures.
3. Details are provided on the vascular supply to the pituitary gland from arteries such as the superior and inferior hypophyseal arteries.
This document provides information about various surgical approaches to the skull base, including the translabyrinthine, transpetrous, and middle cranial fossa approaches. Diagrams and photos show the structures of the internal auditory canal and how different types of bone removal are used in each approach. References are made to books and authors that provide further details. The document states that additional powerpoint presentations on skull base surgery can be accessed online.
The document provides information about the anterior cranial fossa and related anatomy. It begins with an overview of the carotid artery as it passes through the nasopharynx, petrous bone, and cavernous sinus before entering the anterior cranial fossa and giving off branches. It then describes relationships between the frontal sinus and cribriform plate. The rest of the document discusses various arteries including the fronto-polar artery and anterior and posterior ethmoidal arteries, and provides images from cadaver dissections to illustrate the described anatomy.
This document discusses the anatomy of the carotid artery, including its segments and relationships to surrounding structures in the skull base. It describes the parapharyngeal segment of the carotid artery and how looping can cause it to extend anteriorly into the prestyloid compartment. Several surgical approaches are discussed, including how the infratemporal fossa approach allows exposure of the intratemporal carotid artery. Key anatomical structures that relate to the carotid artery are also shown, such as the paraclival segment, the trigeminal ganglion, and the abducent nerve's crossing of the carotid. Surgical techniques like subperiosteal dissection to remove tumors attached to the carotid are also summarized.
Dr. B.D. Chaurasia was a renowned Indian anatomist whose textbooks inspired the author to pursue a career in surgery. His line diagrams simplified human anatomy. He provided web links to purchase his books and view additional presentations on topics like the skull base. The document then describes anatomy of the orbit, pterygopalatine fossa, infratemporal fossa, and various cranial nerves in both anterior and lateral views of the skull base. Diagrams and photographs supplement the anatomical descriptions.
This document discusses the anatomy of the vertebral artery and surrounding structures at the craniocervical junction. It includes labeled images showing the vertebral artery, foramen magnum, atlas, axis, and surrounding muscles, nerves, and bones. The document also provides information on approaches for further viewing these structures and notes that additional presentations on "Skull base 360" will be continuously updated on the provided website.
1. The document provides information on skull base anatomy relevant for endoscopic sinus surgeons, including relationships between vital structures like the carotid artery and cranial nerves.
2. Key areas discussed include the pterygoid recess, pterygopalatine fossa, cavernous sinus compartments, orbital apex, and superior orbital fissure. Potential sites of iatrogenic carotid injury are also identified.
3. Understanding these complex anatomic relationships is important for safely performing endoscopic sinus surgery near the skull base.
This document provides an overview of skull base reconstruction techniques with figures and references from various sources. It discusses endoscopic pericranial flaps, split temporalis muscle flaps, fascia lata grafts, and pedicled flaps for skull base reconstruction. The document is a work in progress presentation on skull base reconstruction from multiple experts in the field, with the goal of continuous updates as more information is collected.
1. The document provides detailed anatomical descriptions and diagrams of the craniovertebral junction and foramen magnum region. It describes key landmarks such as the hypoglossal canal, jugular tubercle, pharyngeal tubercle, and their relationships to surrounding structures.
2. Surgical approaches to this region are discussed, including a transoral approach where the soft palate and portions of bone can be removed to fully expose the clivus, atlas, and axis.
3. Important vascular structures like the vertebral artery and its relation to nearby muscles are depicted. The document serves as a comprehensive reference for the intricate anatomy of the lower skull base.
This document discusses the anatomy of the orbit and skull base. It describes the layers of the orbital fascia including the periorbita, bulbar fascia, and its components. It details the anatomy of the superior orbital fissure and how it relates to the anterior lateral sellar compartment and orbital apex. Different types of optic nerve configurations are shown along with examples of pneumatization of the anterior clinoid process and sphenoid sinus. Clinical implications for endoscopic skull base surgery are discussed.
The document describes various anatomical structures related to the cochlea and cochlear implant surgery, including:
1. Diagrams of the cochlear anatomy including the oval window, round window, helicotrema, and divisions of the cochlear scalae.
2. Descriptions of different approaches for cochleostomy including anterior-inferior, inferior, superior, and others.
3. Identification of anatomical landmarks like the fustis that can help locate the round window.
4. Explanations of dangerous areas like Parisier's triangle that contain the labyrinthine facial nerve.
5. Discussions of anatomical variations like exostoses and dehis
This document provides information on transoral and transorbital approaches to the skull base from multiple experts. It begins with an overview of transoral approaches to the infratemporal fossa and parapharyngeal space, identifying important anatomical structures like the medial and lateral pterygoid muscles. It then discusses the transoral endoscopic view of these regions and landmarks like the internal carotid artery. Finally, it briefly mentions a transorbital endoscopic approach to the anterior cranial fossa that will be covered in more detail in a referenced book.
Dr. B.D. Chaurasia was a renowned Indian anatomist whose textbooks inspired the author to pursue a career in surgery. His line diagrams helped simplify anatomy. He produced line diagrams of skull base anatomy, including the 360° view of the skull base in Part 2. The document discusses cranial nerve anatomy in the skull base and relationships between nerves and vessels.
1. The document provides detailed anatomical views and descriptions of the structures within the cerebellopontine angle (CPA), including the trigeminal, acousticofacial, lower cranial, and foramen magnum areas.
2. Images show the cranial nerves and vascular structures within each area, along with their relationships to each other. Descriptions provide the landmarks and key clinical references.
3. The document is intended as an educational reference for neurosurgical approaches to the CPA, with a focus on endoscopic techniques. It updates an online resource on the skull base with new images and information.
The document discusses various cranial nerves and their anatomical relationships. It provides detailed images and descriptions of cranial nerves 1 through 4 within the skull base. Key points include:
- The optic nerve has several classification types depending on its relationship to the sphenoid sinus.
- The oculomotor nerve is sandwiched between the posterior cerebral artery and superior cerebellar artery.
- The posterior communicating artery has variable relationships with the oculomotor nerve, either running parallel or crossing.
- The trochlear nerve enters the cavernous sinus roof in 80% of cases or the lower tuberculum sellae surface in 20% of cases.
This document describes various approaches to the petrous apex, including the middle cranial fossa transpetrous approach. It discusses the landmarks and surgical anatomy relevant to this approach, including exposing the internal auditory canal and petrous apex by drilling bone. It also mentions combining the frontotemporal orbitozygomatic approach with the Kawase approach to access the middle and posterior cranial fossae. Several references are provided with links to videos and papers on these techniques.
This document provides information about a presentation on the skull base titled "SKULL BASE 360°-Part 1". It includes links to Part 2 of the presentation and the presenter's website for other skull base presentations. The document discusses various approaches to the skull base, including endoscopic, open, and combined approaches. Anatomical structures of the skull base are described such as nerves, blood vessels, and bones. Approaches covered include transmaxillary, translabyrinthine, and retrosigmoid approaches.
This document discusses various approaches for skull base surgery, including combined approaches. It provides examples of combining the anterior skull base approach with lateral skull base approaches like the neurosurgical or trans-temporal approaches. Another combined approach discussed is the frontotemporal orbitozygomatic (FTOZ) approach combined with transpetrous approaches to provide control of the middle and posterior cranial fossae. Neurosurgeons may also combine the FTOZ approach with the Kawase approach for control of the middle and posterior fossae. Videos and links are provided as examples of these combined approaches.
This document discusses the anatomy of the skull base triangles. It begins by naming the 10 triangles, which are divided into 4 cavernous sinus triangles and 6 middle fossa triangles. Each triangle is then defined by its borders and contents. Key structures discussed include the anterior clinoid process, carotid oculomotor membrane, cavernous segment of the internal carotid artery, and cranial nerves III, IV, V and VI. The relationships between these structures are illustrated in several diagrams. Videos are also provided that demonstrate anterior clinoid drilling techniques.
This document discusses lateral temporal bone resection for tumors. It provides details on:
1. Performing a piecemeal resection including subtotal temporal bone resection, infratemporal fossa type A approach, and superficial parotidectomy to spare the facial nerve.
2. The importance of performing superficial parotidectomy to remove first level draining lymph nodes.
3. Exposing and transposing the facial nerve from the mastoid segment to the parotid segment during the surgery.
4. The dangers of removing tumors at Parisier's triangle, which contains the labyrinthine part of the facial nerve. Care must be taken to avoid injuring the nerve.
The document provides information about the anatomy of the cavernous sinus from multiple perspectives. It discusses the medial wall, lateral wall, and roof of the cavernous sinus. It highlights key anatomical structures like the interclinoid ligaments, carotid oculomotor membrane, and cranial nerves that relate to approaches to the cavernous sinus from different angles. The document contains several images from cadaver dissections and endoscopic views that illustrate relationships between blood vessels and cranial nerves in the cavernous sinus region.
This document provides a summary of the anatomy and surgical implications of the round window niche and membrane. It discusses the various structures associated with the round window, including the fustis, crista semilunaris, and subcochlear canaliculus. It also describes different types of round window shapes that can be encountered surgically, such as high arched and parabolic. The summary highlights the importance of the round window niche for procedures like cochlear implantation and treatments for conditions like Meniere's disease.
1. The document provides information on the anatomy of the infratemporal fossa and related structures. It includes diagrams, descriptions, and links to video resources.
2. Key structures discussed include the pterygopalatine fossa, foramen ovale, foramen rotundum, vidian nerve, trigeminal ganglion, internal carotid artery, and the lower cranial nerves including their relationships.
3. Approaches to the infratemporal fossa are described including the infratemporal fossa approaches A through D. Muscles such as the medial and lateral pterygoid are also discussed in relation to protecting vascular structures.
This document provides an overview of skull base anatomy and imaging of skull base pathology. It begins with a description of the bones that make up the skull base and key anatomical structures like foramina and sinuses. Common pathologies are then discussed, including tumors originating from within the skull base (intra-axial) or adjacent structures outside the skull base (extra-axial). Example cases of chordoma and glomus tumor are presented with imaging findings. Finally, some hints and tips for skull base MRI interpretation are provided.
The skull base forms the floor of the cranial cavity and separates the brain from facial structures. It is a complex region made up of 5 bones - ethmoid, sphenoid, occipital, and paired temporal and frontal bones. It has three areas - anterior, middle, and posterior. The anterior area contains openings for vessels and nerves like the cribriform plate and optic canal. The middle area contains the cavernous sinus and openings like the superior orbital fissure. The posterior area borders the occipital bone and contains structures like the jugular foramen. A thorough understanding of the anatomy in this region is important for surgical planning and understanding pathologies.
1. The document discusses the anatomy of the superior orbital fissure (SOF) and related structures.
2. The SOF is located between two bony structures - superiorly the optic strut and inferiorly the maxillary strut.
3. The SOF contains important neurovascular structures including divisions of the oculomotor nerve and the abducens nerve.
1. The document discusses the anatomy of the clivus, dividing it into upper, middle, and lower thirds. The middle clivus is defined as the region from the floor of the sella to the floor of the sphenoid sinus.
2. Key surgical landmarks for the middle clivus include the paraclival carotid arteries and the carotid-clival window, which provides access to the petrous apex via an infrapetrous approach.
3. Cadaver dissections and endoscopic views are presented to illustrate anatomical structures in the upper and middle clivus.
Presentation1.pptx, radiological anatomy of the orbits, pns and petrous bone.Abdellah Nazeer
This document discusses radiological imaging of the orbit, paranasal sinuses, and petrous bone. It begins with an overview of orbit anatomy including contents, bones, communications, and measurements. Next, it describes radiological views used to image the orbit and adjacent structures like the Waters, Caldwell, and lateral projections. Ultrasound anatomy of the eye and orbit is also outlined. The document then discusses paranasal sinus anatomy and the osteomeatal complex. Computed tomography is described as the preferred method for evaluating the paranasal sinuses due to its ability to depict soft tissues and bone detail.
1. The document provides information on skull base anatomy relevant for endoscopic sinus surgeons, including relationships between vital structures like the carotid artery and cranial nerves.
2. Key areas discussed include the pterygoid recess, pterygopalatine fossa, cavernous sinus compartments, orbital apex, and superior orbital fissure. Potential sites of iatrogenic carotid injury are also identified.
3. Understanding these complex anatomic relationships is important for safely performing endoscopic sinus surgery near the skull base.
This document provides an overview of skull base reconstruction techniques with figures and references from various sources. It discusses endoscopic pericranial flaps, split temporalis muscle flaps, fascia lata grafts, and pedicled flaps for skull base reconstruction. The document is a work in progress presentation on skull base reconstruction from multiple experts in the field, with the goal of continuous updates as more information is collected.
1. The document provides detailed anatomical descriptions and diagrams of the craniovertebral junction and foramen magnum region. It describes key landmarks such as the hypoglossal canal, jugular tubercle, pharyngeal tubercle, and their relationships to surrounding structures.
2. Surgical approaches to this region are discussed, including a transoral approach where the soft palate and portions of bone can be removed to fully expose the clivus, atlas, and axis.
3. Important vascular structures like the vertebral artery and its relation to nearby muscles are depicted. The document serves as a comprehensive reference for the intricate anatomy of the lower skull base.
This document discusses the anatomy of the orbit and skull base. It describes the layers of the orbital fascia including the periorbita, bulbar fascia, and its components. It details the anatomy of the superior orbital fissure and how it relates to the anterior lateral sellar compartment and orbital apex. Different types of optic nerve configurations are shown along with examples of pneumatization of the anterior clinoid process and sphenoid sinus. Clinical implications for endoscopic skull base surgery are discussed.
The document describes various anatomical structures related to the cochlea and cochlear implant surgery, including:
1. Diagrams of the cochlear anatomy including the oval window, round window, helicotrema, and divisions of the cochlear scalae.
2. Descriptions of different approaches for cochleostomy including anterior-inferior, inferior, superior, and others.
3. Identification of anatomical landmarks like the fustis that can help locate the round window.
4. Explanations of dangerous areas like Parisier's triangle that contain the labyrinthine facial nerve.
5. Discussions of anatomical variations like exostoses and dehis
This document provides information on transoral and transorbital approaches to the skull base from multiple experts. It begins with an overview of transoral approaches to the infratemporal fossa and parapharyngeal space, identifying important anatomical structures like the medial and lateral pterygoid muscles. It then discusses the transoral endoscopic view of these regions and landmarks like the internal carotid artery. Finally, it briefly mentions a transorbital endoscopic approach to the anterior cranial fossa that will be covered in more detail in a referenced book.
Dr. B.D. Chaurasia was a renowned Indian anatomist whose textbooks inspired the author to pursue a career in surgery. His line diagrams helped simplify anatomy. He produced line diagrams of skull base anatomy, including the 360° view of the skull base in Part 2. The document discusses cranial nerve anatomy in the skull base and relationships between nerves and vessels.
1. The document provides detailed anatomical views and descriptions of the structures within the cerebellopontine angle (CPA), including the trigeminal, acousticofacial, lower cranial, and foramen magnum areas.
2. Images show the cranial nerves and vascular structures within each area, along with their relationships to each other. Descriptions provide the landmarks and key clinical references.
3. The document is intended as an educational reference for neurosurgical approaches to the CPA, with a focus on endoscopic techniques. It updates an online resource on the skull base with new images and information.
The document discusses various cranial nerves and their anatomical relationships. It provides detailed images and descriptions of cranial nerves 1 through 4 within the skull base. Key points include:
- The optic nerve has several classification types depending on its relationship to the sphenoid sinus.
- The oculomotor nerve is sandwiched between the posterior cerebral artery and superior cerebellar artery.
- The posterior communicating artery has variable relationships with the oculomotor nerve, either running parallel or crossing.
- The trochlear nerve enters the cavernous sinus roof in 80% of cases or the lower tuberculum sellae surface in 20% of cases.
This document describes various approaches to the petrous apex, including the middle cranial fossa transpetrous approach. It discusses the landmarks and surgical anatomy relevant to this approach, including exposing the internal auditory canal and petrous apex by drilling bone. It also mentions combining the frontotemporal orbitozygomatic approach with the Kawase approach to access the middle and posterior cranial fossae. Several references are provided with links to videos and papers on these techniques.
This document provides information about a presentation on the skull base titled "SKULL BASE 360°-Part 1". It includes links to Part 2 of the presentation and the presenter's website for other skull base presentations. The document discusses various approaches to the skull base, including endoscopic, open, and combined approaches. Anatomical structures of the skull base are described such as nerves, blood vessels, and bones. Approaches covered include transmaxillary, translabyrinthine, and retrosigmoid approaches.
This document discusses various approaches for skull base surgery, including combined approaches. It provides examples of combining the anterior skull base approach with lateral skull base approaches like the neurosurgical or trans-temporal approaches. Another combined approach discussed is the frontotemporal orbitozygomatic (FTOZ) approach combined with transpetrous approaches to provide control of the middle and posterior cranial fossae. Neurosurgeons may also combine the FTOZ approach with the Kawase approach for control of the middle and posterior fossae. Videos and links are provided as examples of these combined approaches.
This document discusses the anatomy of the skull base triangles. It begins by naming the 10 triangles, which are divided into 4 cavernous sinus triangles and 6 middle fossa triangles. Each triangle is then defined by its borders and contents. Key structures discussed include the anterior clinoid process, carotid oculomotor membrane, cavernous segment of the internal carotid artery, and cranial nerves III, IV, V and VI. The relationships between these structures are illustrated in several diagrams. Videos are also provided that demonstrate anterior clinoid drilling techniques.
This document discusses lateral temporal bone resection for tumors. It provides details on:
1. Performing a piecemeal resection including subtotal temporal bone resection, infratemporal fossa type A approach, and superficial parotidectomy to spare the facial nerve.
2. The importance of performing superficial parotidectomy to remove first level draining lymph nodes.
3. Exposing and transposing the facial nerve from the mastoid segment to the parotid segment during the surgery.
4. The dangers of removing tumors at Parisier's triangle, which contains the labyrinthine part of the facial nerve. Care must be taken to avoid injuring the nerve.
The document provides information about the anatomy of the cavernous sinus from multiple perspectives. It discusses the medial wall, lateral wall, and roof of the cavernous sinus. It highlights key anatomical structures like the interclinoid ligaments, carotid oculomotor membrane, and cranial nerves that relate to approaches to the cavernous sinus from different angles. The document contains several images from cadaver dissections and endoscopic views that illustrate relationships between blood vessels and cranial nerves in the cavernous sinus region.
This document provides a summary of the anatomy and surgical implications of the round window niche and membrane. It discusses the various structures associated with the round window, including the fustis, crista semilunaris, and subcochlear canaliculus. It also describes different types of round window shapes that can be encountered surgically, such as high arched and parabolic. The summary highlights the importance of the round window niche for procedures like cochlear implantation and treatments for conditions like Meniere's disease.
1. The document provides information on the anatomy of the infratemporal fossa and related structures. It includes diagrams, descriptions, and links to video resources.
2. Key structures discussed include the pterygopalatine fossa, foramen ovale, foramen rotundum, vidian nerve, trigeminal ganglion, internal carotid artery, and the lower cranial nerves including their relationships.
3. Approaches to the infratemporal fossa are described including the infratemporal fossa approaches A through D. Muscles such as the medial and lateral pterygoid are also discussed in relation to protecting vascular structures.
This document provides an overview of skull base anatomy and imaging of skull base pathology. It begins with a description of the bones that make up the skull base and key anatomical structures like foramina and sinuses. Common pathologies are then discussed, including tumors originating from within the skull base (intra-axial) or adjacent structures outside the skull base (extra-axial). Example cases of chordoma and glomus tumor are presented with imaging findings. Finally, some hints and tips for skull base MRI interpretation are provided.
The skull base forms the floor of the cranial cavity and separates the brain from facial structures. It is a complex region made up of 5 bones - ethmoid, sphenoid, occipital, and paired temporal and frontal bones. It has three areas - anterior, middle, and posterior. The anterior area contains openings for vessels and nerves like the cribriform plate and optic canal. The middle area contains the cavernous sinus and openings like the superior orbital fissure. The posterior area borders the occipital bone and contains structures like the jugular foramen. A thorough understanding of the anatomy in this region is important for surgical planning and understanding pathologies.
1. The document discusses the anatomy of the superior orbital fissure (SOF) and related structures.
2. The SOF is located between two bony structures - superiorly the optic strut and inferiorly the maxillary strut.
3. The SOF contains important neurovascular structures including divisions of the oculomotor nerve and the abducens nerve.
1. The document discusses the anatomy of the clivus, dividing it into upper, middle, and lower thirds. The middle clivus is defined as the region from the floor of the sella to the floor of the sphenoid sinus.
2. Key surgical landmarks for the middle clivus include the paraclival carotid arteries and the carotid-clival window, which provides access to the petrous apex via an infrapetrous approach.
3. Cadaver dissections and endoscopic views are presented to illustrate anatomical structures in the upper and middle clivus.
Presentation1.pptx, radiological anatomy of the orbits, pns and petrous bone.Abdellah Nazeer
This document discusses radiological imaging of the orbit, paranasal sinuses, and petrous bone. It begins with an overview of orbit anatomy including contents, bones, communications, and measurements. Next, it describes radiological views used to image the orbit and adjacent structures like the Waters, Caldwell, and lateral projections. Ultrasound anatomy of the eye and orbit is also outlined. The document then discusses paranasal sinus anatomy and the osteomeatal complex. Computed tomography is described as the preferred method for evaluating the paranasal sinuses due to its ability to depict soft tissues and bone detail.
This document discusses different approaches and considerations for resection of craniopharyngiomas. It provides links to several papers on microscopic and endoscopic resection techniques, and classifies craniopharyngiomas into four types based on their location relative to key anatomical structures like the infundibulum. It also discusses the anatomy of vessels like the superior hypophyseal artery that are important to preserve during endoscopic resection of these tumors.
1. The document describes the anatomical relationships between various structures in the nasal cavity, paranasal sinuses, orbits, and anterior cranial fossa as seen from endonasal and intracranial perspectives.
2. Dissections of the nasal cavity, paranasal sinuses, orbits, pterygopalatine fossa, cavernous sinus, and sellar region are shown along with corresponding intracranial views to illustrate these relationships.
3. Key landmarks such as the optic nerve, internal carotid artery, pituitary gland, cranial nerves, dural layers, and vascular structures are identified in both endonasal and intracranial views.
The key arteries supplying the visual pathway include the internal carotid artery, posterior cerebral artery, anterior cerebral artery, ophthalmic artery, and posterior ciliary arteries. The central retinal artery supplies the retina. The optic nerve receives blood supply from the posterior ciliary arteries and branches of the ophthalmic artery. The optic chiasm, tract, lateral geniculate body, and visual cortex are supplied by branches of the internal carotid, anterior cerebral, and posterior cerebral arteries. Venous drainage is primarily through the central retinal vein, ophthalmic veins, basal veins and internal cerebral veins.
The cranial nerves have both motor and sensory functions and nuclei in the brainstem. They are arranged into 7 columns - general somatic efferent, special visceral efferent, general visceral efferent, general visceral afferent, special visceral afferent, general somatic afferent, and special somatic afferent. The document then describes the individual cranial nerves III, IV, VI, V, and their functions, origins, courses, and relations. It discusses how the oculomotor, trochlear, abducent nerves originate in the midbrain and pons, pass through the cavernous sinus and orbit, and innervate different extraocular muscles. It also covers the
The vitreous body pushes the retina into place. If it shrinks due to dehydration, the retina can detach from the eye wall, damaging vision. The optic disc is a blind spot where the optic nerve and blood vessels exit the retina. The macula lutea contains the highest concentration of cones, providing sharp central vision. Fibers from the nasal retina cross at the optic chiasm, while temporal fibers remain uncrossed. The lateral geniculate body relays visual information to the visual cortex.
Anatomy of visual pathway and its lesions.Ruchi Pherwani
1) The visual pathway begins with photoreceptors in the retina which transmit visual information via the optic nerve and optic chiasm to the lateral geniculate nucleus. It then continues via the optic radiations to the primary visual cortex.
2) Lesions along the visual pathway can cause different types of visual field defects, including complete blindness from optic nerve lesions, bitemporal hemianopia from chiasmal lesions, and homonymous hemianopia from lesions of the optic tract or beyond.
3) The document discusses the anatomy and blood supply of structures in the visual pathway like the optic nerve, chiasm, tract, lateral geniculate nucleus and visual cortex. It also describes various causes and characteristics
The document discusses the craniovertebral junction (CVJ) including its embryology, anatomy, and radiology. Regarding embryology, the CVJ develops from the occipital somites which form parts of the occiput, atlas, and axis. Anatomically, the CVJ includes synovial joints between the occiput-atlas and atlas-axis that allow rotation. It is stabilized by ligaments like the transverse ligament. Radiologically, plain films and CT are used to assess the CVJ. Measurements like the Chamberlain's line evaluate for abnormalities like basilar invagination.
This document discusses the anatomy of the sellar region. It describes the structures below and above the sella turcica such as the nasal cavity, sphenoid bone, pituitary fossa, and suprasellar region. It details the pituitary gland, diaphragma sellae, intercavernous connections, and the ventricular and arterial relationships above the sella. The sphenoid sinus, carotid prominences, and lateral wall are also examined. Neurovascular structures like the optic chiasm, oculomotor nerve, arteries, and veins are mapped in relation to the sellar region.
Brachial plexus block by PNS and ultrasound guided blockZIKRULLAH MALLICK
This document provides an overview of brachial plexus anatomy and techniques for brachial plexus nerve blocks. It begins with a description of the brachial plexus formation from cervical and thoracic nerve roots and its branching pattern. Four main approaches for brachial plexus nerve blocks are described: interscalene, supraclavicular, infraclavicular, and axillary. Details are provided on the anatomy and techniques for performing interscalene and supraclavicular brachial plexus blocks. Ultrasound guidance is discussed as an advancement which allows real-time visualization of needle and nerve. Complications are also summarized.
this prsentation incluses HRCT temportal bone cross sectional anatomy images axial saggital and coronal with labelled diagram. This presentation help alot for radiology resident. Thanks.
The document describes the anatomy of the anterior and posterior triangles of the neck. It details the bones, muscles, blood vessels, nerves and other structures found in each triangle. Key structures mentioned include the cervical vertebrae, carotid artery, thyroid gland, larynx, and various nerves such as the hypoglossal and recurrent laryngeal nerves. The triangles described are the submandibular, submental and carotid triangles located in the anterior neck region.
Skull base anatomy by Dr. Aditya TiwariAditya Tiwari
The document discusses the anatomy and embryology of the skull base. It describes the various bones that make up the skull base, including the sphenoid, occipital and temporal bones. It outlines the boundaries and contents of the different cranial fossae: anterior, middle, and posterior. It also details important anatomical structures in the skull base like the cavernous sinus, foramina, and various nerves and vessels that pass through the skull base. Comprehensive knowledge of the skull base anatomy is important for understanding pathologies and surgical planning.
This document provides an overview of imaging modalities used in evaluating the ear, nose, and paranasal sinuses. It discusses plain radiography views including lateral, Caldwell, Waters, and submentovertex views. CT imaging of the nose and paranasal sinuses is described as the gold standard, with details on interpreting coronal and axial cuts. Key anatomical structures like the frontal sinus, ethmoid air cells, and sphenoid sinus are identified on various imaging views.
The document provides details on the anatomy of the orbit including its borders, contents, neurovascular structures, and surgical approaches. It describes the bones that form the borders of the orbit, as well as the contents such as the eyeball, muscles, nerves, vessels, and fatty tissue. Various surgical approaches for orbital tumors are summarized, including extracranial and transcranial methods, as well as endoscopic endonasal approaches.
Presentation1.pptx, radiological anatomy of the brain and pituitary glandAbdellah Nazeer
The document summarizes the normal radiological anatomy of the brain and pituitary gland as seen on computed tomography (CT) and magnetic resonance imaging (MRI). It describes the overall structure of the brain, including the cerebrum, cerebellum, brainstem, and four ventricles. It details the anatomy of the lateral, third, and fourth ventricles. It then outlines the major lobes and gyri of the cerebral hemispheres, including important motor and sensory areas. The document concludes by reviewing sectional anatomy as seen on axial CT and MRI scans.
This document provides an overview of orbital and ocular anatomy. It describes the bones that make up the orbit, including the frontal, zygomatic, maxillary, ethmoidal, sphenoid, lacrimal and palatine bones. It details the structures within the orbit, including the extraocular muscles, optic nerve, blood vessels and cranial nerves involved in vision. The anatomy of the eyeball is also summarized, including the cornea, as well as the pathways of the visual system from the retina to the visual cortex.
Embryology development of central nervous systemMBBS IMS MSU
The document summarizes the embryological development of the central nervous system. It begins with the formation of the neural plate and tube from ectoderm. The neural tube develops three primary brain vesicles - the prosencephalon (forebrain), mesencephalon (midbrain), and rhombencephalon (hindbrain). Neuroepithelial cells form the neural tube wall and generate neuroblasts that migrate inward to form the mantle layer and later differentiate into neurons and glial cells. Neural crest cells emerge along the neural folds and contribute to peripheral ganglia.
This presentation summarizes several papers on endoscopic orbital surgery and includes videos demonstrating minimally invasive endoscopic orbital surgery techniques. It provides links to access the full papers and videos. The document lists various endoscopic approaches to the orbit described in the literature, including transnasal, transorbital, and superior eyelid approaches. It also notes several domains that can be used to access papers and articles for free by entering a paper's digital objective indicator.
Cochlear implant systems involve implantable devices with electrode arrays and sound processors. There are various implant options from manufacturers like Cochlear, Advanced Bionics, and Med-El. The surgeon must consider the patient's condition and available implants to design the best implantation approach. Cochlear's Nucleus implant features a removable magnet for MRI safety and various electrode designs like the Contour Advance perimodiolar electrode or CI422 straight electrode to suit different surgical approaches and patient needs. Proper electrode placement is important for optimal hearing outcomes.
This document discusses electro-acoustic stimulation (EAS), which combines cochlear implantation for high frequencies with acoustic amplification for low frequencies. EAS aims to restore hearing in both high and low frequencies by using electric stimulation to improve hearing in high frequencies and acoustic amplification to improve residual hearing in low frequencies. Studies have found that EAS users score significantly higher on speech tests compared to users of hearing aids alone. The document discusses various EAS devices and features that aim to preserve residual hearing, such as shorter or thinner electrodes. It also covers aspects of the surgery and post-operative programming to optimize the benefits of combined electric and acoustic stimulation.
This document discusses techniques for cochlear implantation through the middle cranial fossa approach. It describes performing a superior cochleostomy just below the origin of the greater superficial petrosal nerve. It cautions not to fear injury to the carotid artery, which is 1 cm anterior. It also details identifying structures like the facial nerve and drilling the internal auditory canal from medial to lateral to avoid injuring the cochlea. Electrodes are described being placed in the basal, middle, and apical turns of the cochlea. Facial nerve stimulation is a risk if electrodes contact the labyrinthine segment, so selective deactivation may be needed. The document emphasizes the importance of anatomical landmarks and
1. Pre-operative imaging such as HRCT and MRI are important for cochlear implantation to evaluate anatomical variations and identify any contraindications.
2. Key factors assessed on imaging include the size of the internal auditory meatus, status of the cochlear nerve, and presence of any neurovascular anomalies which could increase surgical risk.
3. Congenital anomalies of the bony labyrinth or membranous structures detected on pre-operative imaging may influence the surgical approach and expectations of device insertion and outcome.
This document discusses several topics related to cochlear implant (CI) programs and accessibility in India, with a focus on the state of Andhra Pradesh. It raises questions about:
1) Whether there are enough CI surgeons and centers to meet demand, especially in rural/peripheral areas.
2) How to increase the number of CI surgeons through fellowship programs and allowing other specialists like DLOs to perform CI surgery with proper training.
3) Addressing high dropout rates from auditory verbal therapy (AVT) due to costs and long travel distances to urban centers.
4) The potential for tele-rehabilitation and other solutions to improve access to follow-up care like AVT in
1. The document describes various anatomical features of the round window membrane, including its shape, thickness, layers, and surgical implications.
2. It notes that the round window membrane is a neglected part of otological surgery but gaining more attention for procedures like cochlear implants.
3. Key structures that support the round window membrane are described, such as the fustis, a bony column that regulates sound wave flow and pressure differences.
1) The document discusses decision making approaches for tumors of the anterior and lateral skull base. It considers factors such as carotid control, nerve preservation, and minimizing brain retraction.
2) Key skull base surgeons like Kassam, Liu, Sanna, Sekhar, and Dugani provide expertise on various approaches and how the decision making has evolved over time with new techniques.
3) Carotid injury management is a critical topic, discussing options like covered stents, clamping, coiling, and the importance of revascularization when tumor resection jeopardizes the carotid artery.
The document discusses various options for managing carotid artery injury during anterior skull base surgery. It notes that covered stents, clamping, and coiling are the main options to cover a ruptured carotid. It emphasizes assessing collateral circulation with a balloon occlusion test preoperatively and considering pre-operative coiling for high-risk cases. Revascularization with a bypass is generally recommended if resection would jeopardize the carotid artery.
This document discusses various "rules" related to anatomical structures and distances in the temporal bone that are useful for ear surgeons. It provides measurements of important distances that are mostly less than 10mm. For example, it states that the distance between the tip of the incus and facial nerve is 2.36mm, and between structures in the semicircular canals is typically 4mm. Following these rules helps surgeons identify structures and avoid injuries when operating with drill burrs. Images and diagrams are provided to illustrate some of the rules.
The document discusses endoscopic transglabellar and supraorbital approaches for skull base surgery. It provides information on using these approaches to remove large macroadenomas and craniopharyngiomas. Giant craniopharyngiomas may require a combination of endoscopic transnasal and frontal or supraorbital approaches. The endoscopic supraorbital approach involves making a small incision in the eyebrow and keyhole opening to access the anterior cranial fossa.
This document provides links to videos about skull base surgery on a YouTube channel. It encourages visiting www.skullbase360.in for powerpoint presentations and more videos. Links are included for videos of various skull base surgeries, anatomy, debates on approaches, and dissection videos totaling 3 hours by Dr. Satish Jain. The links are intended to provide education on the skull base through video content.
This document provides information about various cisterns in the skull base region. It discusses the oculomotor cistern, lamina terminalis cistern, chiasmatic cistern, interpeduncular cistern, carotid cistern and others. Images are included showing endoscopic views of these cisterns and their anatomical relationships. The document recommends approaches such as retrolabyrinthine to access the prepontine cistern without doing a posterior clinoidectomy or pituitary transposition. It provides links to additional resources on endoscopic skull base surgery.
This document provides information about open skull base approaches and craniofacial surgeries. It lists several professors and their work in this area. It also provides links to videos and papers on different surgical techniques for the skull base, including subcranial approaches, facial translocation, bicoronal approaches, mandibulotomy, and preauricular approaches. The document encourages accessing papers and videos to continue learning about these surgical procedures and approaches.
Integrating Ayurveda into Parkinson’s Management: A Holistic ApproachAyurveda ForAll
Explore the benefits of combining Ayurveda with conventional Parkinson's treatments. Learn how a holistic approach can manage symptoms, enhance well-being, and balance body energies. Discover the steps to safely integrate Ayurvedic practices into your Parkinson’s care plan, including expert guidance on diet, herbal remedies, and lifestyle modifications.
Our backs are like superheroes, holding us up and helping us move around. But sometimes, even superheroes can get hurt. That’s where slip discs come in.
Local Advanced Lung Cancer: Artificial Intelligence, Synergetics, Complex Sys...Oleg Kshivets
Overall life span (LS) was 1671.7±1721.6 days and cumulative 5YS reached 62.4%, 10 years – 50.4%, 20 years – 44.6%. 94 LCP lived more than 5 years without cancer (LS=2958.6±1723.6 days), 22 – more than 10 years (LS=5571±1841.8 days). 67 LCP died because of LC (LS=471.9±344 days). AT significantly improved 5YS (68% vs. 53.7%) (P=0.028 by log-rank test). Cox modeling displayed that 5YS of LCP significantly depended on: N0-N12, T3-4, blood cell circuit, cell ratio factors (ratio between cancer cells-CC and blood cells subpopulations), LC cell dynamics, recalcification time, heparin tolerance, prothrombin index, protein, AT, procedure type (P=0.000-0.031). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and N0-12 (rank=1), thrombocytes/CC (rank=2), segmented neutrophils/CC (3), eosinophils/CC (4), erythrocytes/CC (5), healthy cells/CC (6), lymphocytes/CC (7), stick neutrophils/CC (8), leucocytes/CC (9), monocytes/CC (10). Correct prediction of 5YS was 100% by neural networks computing (error=0.000; area under ROC curve=1.0).
- Video recording of this lecture in English language: https://youtu.be/kqbnxVAZs-0
- Video recording of this lecture in Arabic language: https://youtu.be/SINlygW1Mpc
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
Rasamanikya is a excellent preparation in the field of Rasashastra, it is used in various Kushtha Roga, Shwasa, Vicharchika, Bhagandara, Vatarakta, and Phiranga Roga. In this article Preparation& Comparative analytical profile for both Formulationon i.e Rasamanikya prepared by Kushmanda swarasa & Churnodhaka Shodita Haratala. The study aims to provide insights into the comparative efficacy and analytical aspects of these formulations for enhanced therapeutic outcomes.
Cell Therapy Expansion and Challenges in Autoimmune DiseaseHealth Advances
There is increasing confidence that cell therapies will soon play a role in the treatment of autoimmune disorders, but the extent of this impact remains to be seen. Early readouts on autologous CAR-Ts in lupus are encouraging, but manufacturing and cost limitations are likely to restrict access to highly refractory patients. Allogeneic CAR-Ts have the potential to broaden access to earlier lines of treatment due to their inherent cost benefits, however they will need to demonstrate comparable or improved efficacy to established modalities.
In addition to infrastructure and capacity constraints, CAR-Ts face a very different risk-benefit dynamic in autoimmune compared to oncology, highlighting the need for tolerable therapies with low adverse event risk. CAR-NK and Treg-based therapies are also being developed in certain autoimmune disorders and may demonstrate favorable safety profiles. Several novel non-cell therapies such as bispecific antibodies, nanobodies, and RNAi drugs, may also offer future alternative competitive solutions with variable value propositions.
Widespread adoption of cell therapies will not only require strong efficacy and safety data, but also adapted pricing and access strategies. At oncology-based price points, CAR-Ts are unlikely to achieve broad market access in autoimmune disorders, with eligible patient populations that are potentially orders of magnitude greater than the number of currently addressable cancer patients. Developers have made strides towards reducing cell therapy COGS while improving manufacturing efficiency, but payors will inevitably restrict access until more sustainable pricing is achieved.
Despite these headwinds, industry leaders and investors remain confident that cell therapies are poised to address significant unmet need in patients suffering from autoimmune disorders. However, the extent of this impact on the treatment landscape remains to be seen, as the industry rapidly approaches an inflection point.
Histololgy of Female Reproductive System.pptxAyeshaZaid1
Dive into an in-depth exploration of the histological structure of female reproductive system with this comprehensive lecture. Presented by Dr. Ayesha Irfan, Assistant Professor of Anatomy, this presentation covers the Gross anatomy and functional histology of the female reproductive organs. Ideal for students, educators, and anyone interested in medical science, this lecture provides clear explanations, detailed diagrams, and valuable insights into female reproductive system. Enhance your knowledge and understanding of this essential aspect of human biology.
Muktapishti is a traditional Ayurvedic preparation made from Shoditha Mukta (Purified Pearl), is believed to help regulate thyroid function and reduce symptoms of hyperthyroidism due to its cooling and balancing properties. Clinical evidence on its efficacy remains limited, necessitating further research to validate its therapeutic benefits.
These lecture slides, by Dr Sidra Arshad, offer a simplified look into the mechanisms involved in the regulation of respiration:
Learning objectives:
1. Describe the organisation of respiratory center
2. Describe the nervous control of inspiration and respiratory rhythm
3. Describe the functions of the dorsal and respiratory groups of neurons
4. Describe the influences of the Pneumotaxic and Apneustic centers
5. Explain the role of Hering-Breur inflation reflex in regulation of inspiration
6. Explain the role of central chemoreceptors in regulation of respiration
7. Explain the role of peripheral chemoreceptors in regulation of respiration
8. Explain the regulation of respiration during exercise
9. Integrate the respiratory regulatory mechanisms
10. Describe the Cheyne-Stokes breathing
Study Resources:
1. Chapter 42, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 36, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 13, Human Physiology by Lauralee Sherwood, 9th edition
2. Great teachers – All this is their work .
I am just the reader of their books .
Prof. Paolo castelnuovo
Prof. Aldo Stamm Prof. Mario Sanna
Prof. Magnan
3. For Other powerpoint presentatioins
of
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I will update continuosly with date tag at the end as I am
getting more & more information
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www.skullbase360.in
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account after clicking www.skullbase360.in
12. Roof - two triangles:
1. clinoid (anterior)
2. oculomotor (posterior)
ACP anterior clinoid process, APCF anterior petroclinoid fold, DS dorsum sellae, ICF interclinoid
fold, PF pituitary fossa, PLL petrolingual ligament (inferior sphenopetrosal ligament),
PPCF posterior petroclinoid fold, PS planum sphenoidale, SSPL superior sphenopetrosal
ligament (Gruber’s ligament), TS tuberculum sellae, black asterisk middle clinoid process , CSR
cavernous sinus roof , white asterisk oculomotor nerve
If the Gruber’s ligament is ossificated it is called Wegener’s
bridge.
13. Oculomotor cistern
Cranial nerve III enters the roof included in its own cistern
(oculomotor cistern).
Oculomotor cistern goes upto
anterior clinoid tip
15. Endoscopic lateral skull base – 4th
coming from posteriorly over the
superior cerebellar artery [ in this
picture has 2 branches
16. The superior cerebellar artery (SCA) and the trochlear nerve (IV)
are well observed superior to the trigeminal nerve (V) – in
accoustic neroma surgery by translabyrinthine approach
17. 4th nerve under tentorium in subtemporal approach after cutting the
tentorium & lifting it , you are seeing 4th nerve insertion [ yellow arrow = REZ
of 4th nerve ]
18. The trochlear nerve is divided into 5 segments: cisternal, tentorial,
cavernous, fissural ( in superior orbital fissure ) and orbital.
The cisternal segment exits the midbrain and courses through the
quadrigeminal and ambiens cisterns towards the TC. The tentorial segment
starts when the nerve pierces the TC, usually posterior to the postero-lateral
margin of the oculomotor triangle. This segment ends at the level of the
anterior petroclinoid fold. This portion is in close relationship with the
spheno-petro-clival venous gulf and the petrous apex (Iaconetta et al. 2012 ).
19. Cadaveric dissection image taken
with a 30-degree endoscope
following removal of the superior
third of the clivus, visualizing the
small trochlear nerve seen running
along the tentorial membrane edge.
Posterior view of the left CPA with a 30° angled
endoscope gives a view of CPA contents and
permitsobservation of the blind spots by “looking
around the corner.” V indicates trigeminal nerve; VI,
abducens nerve; IV, trochlear nerve; VII, facial nerve
anteriorly hidden by VIII; VIII, vestibulocochlear
nerve; IX, glossopharyngeal nerve; X, vagusnerve;
XI, spinal accessory nerve; XII, hypoglossal nerve;
aica, anterior-inferior cerebellar artery; DV, Dandy’s
vein or superior petrosal vein; SPS, superior
petrosal sinus; Tent, tentorium.
20. Trochlear nerve. Lateral view of the right parasellar area. A triangular piece of the tentorium has been
removed while preserving the tentorial edge to expose the site at which the trochlear nerve pierces the
lower margin of tentorium. The trochlear nerve courses medial to the tentorial edge. It is the longest and
thinnest cranial nerve. It ia the only nerve to arise from the dorsal aspect of the brain stem. The trochlear
nerve arises from the midbrain below the infe- rior colliculi and passes around the brain stem near the
junction of the midbrain and pons to reach the lower margin of the tentorial edge. The trochlear nerve
pierces the tentorial edge (arrow) just behind the anterior attachment of the tentorium. and passes forward
in the lateral wall of the cavernous sinus below the oculomotor nerve. The upper edge of the posterior root
of the trigeminal nerve is in the lower margin of the exposure.
23. With 30 degree scope - The major sensory root and minor motor root
within the Meckel cavity This close-up view allows visualisation of the
roof and the bifurcation at the bottom of the Meckel cavity.
24. 6th nerve (the snake nerve)
6th nerve originates above the VBJ [
vertebro-basillar junction ] – Prof.
Amin Kassam
25. 6th nerve origin is above or below AICA or has two
rootlets of origin
26. After removal of the anterior component of the tumor Trans-labyrinthine
approach , the basilar artery (BA) is clearly visible, as well as the abducent
nerve (VI) and the origin of the anteroinferior cerebellar artery (AICA).
27. Closer view of the inferior area of the left CPA, with
tip of the endoscope between the acousticofacial nerve bundle and lower cranial nerves. PICA
originating from the vertebral arterycan be seen forming a loop near the REZ of the facial nerve.
AICA arises from the more medial basilar artery and traverses under the acousticofacial nerve
bundle to supply the anterior surface of cerebellum. Abducens nerve (VI) is occasionally formed
by two different nerve bundles as seen here.
28. Cadaveric dissection image demonstrating structures seen
following dissection of the lower third of the clivus. Note how
the basilar arteries and vertebral arteries can be extremely
tortuous in their course.
29. Pontomedullary junction = Vertebro-basillar junction
= Junction of Mid clivus & Lower clivus
The pontomedullary junction. The vertebral artery junction is at the level of
the junction of the inferior and midclivus. The basilar artery runs in a straight
line on the surface of the pons. The exit zones of the hypoglossal and
abducent nerves are at the same level. The abducent nerve exits from the
pontomedullary junction, and ascends in a rostral and lateral direction toward
the clivus.
The abducent nerve (VI) is seen in the prepontine
cistern after accoustic neuroma removal in close proximity
with the basilar artery. BA, basilar artery; BS,b rainstem.
30. The pontomedullary junction.
1. The exit zones of the hypoglossal and abducent nerves are at
the same level [ same vertical line when view from Transclival
approah ( through lower clivus ) ]
2. The abducent nerve exits from the pontomedullary junction, and ascends
in a rostral and lateral direction toward the clivus.
6th nerve originates above the
VBJ [ vertebro-basillar junction ]
– Prof. Amin Kassam
32. Gulfar segment of 6th nerve (GS in left picture ) ( gVIcn in right picture ) - The
gulfar segment can be identified at the intersection of the sellar floor and the
proximal parasellar internal carotid artery (ICA) (Barges-Coll et al. 2010 ).
6th nerve enters dorello’s canal between
the meningeal layer of dura and the
periosteal layer of dura (POD).
33. (Left ear) Difference between the conventional 180° translabyrinthine
approach and the 320° transapical extension in the surgical view. The
dashed line demonstrates the working area for extended bone removal. After
this bone work is completed, the important structures can be controlled. AICA,
anterior inferior cerebellar artery; BA, basilar artery; V, trigeminal nerve; VI, abducent nerve.
40. Closer view of the inferior area of the left CPA, with
tip of the endoscope between the acousticofacial nerve bundle and lower cranial nerves. PICA
originating from the vertebral arterycan be seen forming a loop near the REZ of the facial nerve.
AICA arises from the more medial basilar artery and traverses under the acousticofacial nerve
bundle to supply the anterior surface of cerebellum. Abducens nerve (VI) is occasionally formed
by two different nerve bundles as seen here.
41. Intraoperative endoscopic picture
in a patient with right hemifacial
spasm showing PICA having
perpendicular contact with VII at
REZ
Intraoperative endoscopic picture
in a patient with right hemifacial
spasm after “decompression” of
VII at REZ by mobilizing PICA and
interposition of Teflon insulation
42. Microscopic view of the foramen of Luschka on an injected specimen.
ChP, choroid plexus; VII, facial nerve; VIII, vestibulocochlear nerve; LCN,
lower cranial nerves; LF, foramen of Luschka.
43. a Microscopic view of the foramen of Luschka (arrow). b At higher
magnification, the bulbopontine junction is clearly appreciated. AICA, anterior
inferior cerebellar artery; PV, plexus of veins; VI, abducent nerve; VII, facial
nerve; VIII, vestibulocochlear nerve.
44. a Landmarks for identifying the
foramen of Luschka. The choroid
plexus (CP) exits the foramen. AICA,
anterior inferior cerebellar artery;
Fl, flocculus; VI, abducent nerve; VII,
facial nerve; VIII, vestibulocochlear
nerve; IX, glossopharyngeal nerve.
Anatomy of the fourth ventricle and
the lateral recess and the location of
the cochlear nucleus. This illustration
shows an ideal placement of an array
of electrodes. Cbl, cerebellum; CP,
choroid plexus; d, dorsal cochlear
nucleus; Fl, flocculus; SS, sigmoid
sinus; v, ventral cochlear nucleus;
VII, facial nerve; VIII, stump of the
vestibulocochlear nerve.
46. Left Ménière disease: In around 40% of cases,
the anterior inferior cerebellar artery (aica)
forms a vascular
loop running toward the porus acusticus,
usually inferior to the
vestibulocochlear nerve bundle. Within the
vestibulocochlear nerve,
the vestibular fibers (Ve) are more superior
(rostral) and close to the
trigeminal nerve, and the cochlear nerve (Co)
is inferior (caudal)
and close to the lower cranial nerves (LCN).
Left Ménière disease: A small
dissector is inserted
into the inter-vestibulocochlear
cleavage plane to divide the
vestibulocochlear nerve into its
two parts.
47. Mneumonic is Circle inspector of Police [ CI ] – Cochlear nerve is inferior
In cisternal AFB cochlear nerve is
inferior to vestibular nerve
In IAC cochlear nerve is anterio-
inferior quadrant
At the end of tumor
removal, the most
lateral fundus part
of the internal
auditory meatus is
checked with an
endoscope. Often
there is residual
tumor (T) in the
fundus. Fn indicates
facial nerve; Cn,
cochlear nerve; Vn,
residual vestibular
nerve.
48. Vestibular neurotomy is
progressively performed with
microsurgical scissors.
Left endoscopic vestibular
neurotomy is complete.
The facial nerve located
anteroinferior to the vestibular nerve
is now
visible.
49. Left microsurgical vestibular neurotomy with terminal
fibers being dissected by blunt probe. co indicates the cochlear
nerve; ve, sectioned vestibular nerve; aica, anterior inferior
cerebellar artery.
50. The anterior inferior cerebellar artery, lying between
the auditory and facial nerves, is found in 38% of cases. –
5 Trigeminal nerve , 7 Facial nerve , 8 Vestibulocochlear nerve
51. Artist’s renderings showing posterior view of
the left IAM. ( a ) Subarcuate artery penetrates the dura of
the subarcuate fossa near the IAM. The labyrinthine artery
enters the meatus with the vestibulocochlear and the facial
nerves. ( b ) Laterally convex loop of the AICA is embedded
in the dura covering the subarcuate fossa, where it
gives off the subarcuate artery. ( c ) AICA loop is embedded
in the dura and bone ( arrow ) surrounding the subarcuate
52. fossa. ( d ) Dura over the subarcuate fossa has been incised,
and the dura with the adherent loop is dissected free from
the subarcuate fossa in preparation for opening the IAM.
( e ) Dura over the subarcuate fossa has been incised and
remains attached to the artery. The bone surrounding the
embedded AICA loop is removed with a 2-mm diamond
drill to displace the artery medially for exposure of the
IAM (From Tanriover and Rhoton [ 50 ] )
56. The posterior wall of the internal
acoustic meatus has been
removed. The cleavage plane
between the superior and inferior
vestibular nerves is especially
prominent.
The dura lining the internal
acoustic meatus has been
opened. The transverse crest
separates the superior vestibular
and facial nerves above from the
inferior vestibular and cochlear
nerves below.
57. Enlarged view of the nerves
within the meatus. The cochlear
nerve is partially hidden anterior
to the inferior vestibular nerve.
The cleavage plane between the
superior and inferior vestibular
and cochlear nerves has been
started laterally and extended
medially to expose the individual
nerve bundles
58. In Left Trans-labyrinthine Accoustic neuroma surgery - Possible
locations of the facial nerve (FN) in relation to the tumor are
shown. C, cochlear nerve; ant., anterior; post., posterior; sup.,
superior.
59. Possible locations of the facial nerve
(FN) in relation to the tumor are shown. C, cochlear
nerve; ant., anterior; post., posterior; sup., superior.
60. a The effect of tumor size on the facial nerve (FN). Note that as the
tumor grows in size the facial nerve becomes thinner and more fragile
(splayed). b With tumor dissected away, the splayed nerve can be better
visualized.
61. The various locations of the facial nerve (FN). a Superiorly pushed
facial nerve (left ear). b Inferiorly pushed facial nerve (left ear). c Posteriorly
pushed facial nerve (left ear). T, tumor.
62. a ) Normal neural
relationships with the eighth nerve dividing into its
three parts in the lateral meatus. The facial and
superior
vestibular nerves are above the transverse crest and
the
cochlear and inferior vestibular nerves are below.
The facial
nerve occupies the anterosuperior quadrant of the
lateral meatus.
( b ) The facial nerve is displaced
directly anteriorly.
This is a frequent direction of
displacement with
acoustic neuroma.
In Retrosigmoid approach
63. ( c ) Another frequent direction of
displacement
of the facial nerve is anterior and
superior.
( d )The facial nerve is displaced
anteriorly and inferiorly by
tumor, which erodes the superior
wall of the meatus above
the nerves and grows into the
area above the nerves, displacing
them inferiorly
65. 7up- 7th is above
Coca cola – cochlear n. is cola[=lower]
66. FN & SVN converge as they pass toward the fundus , while the CN & IVN can
be seen diverging from each other as they pass laterally to the fundus - ---
Basal turn of cochlea pushing away IVN from CN
See the cochlea in below photo
67.
68. Translabyrinthine
approach – at fundus
Detachment of the superior vestibular nerve
(SVN). The facial nerve (FN) is clearly seen.
Arrows point at the canal where the superior
ampullary nerve was running.
69. While the dissection of the vestibular nerves is carried on further medially, adhesions (AD) between the facial nerve (FN) and the
vestibular nerves begin to be encountered. At this point careful, delicate dissectionshould be performed in order not to injure the
facial nerve. CN, cochlear While the dissection of the vestibular nerves is carried onfurther medially, adhesions (AD) between the
facial nerve (FN) and the vestibularnerves begin to be encountered. At this point careful, delicate dissectionshould be performed
in order not to injure the facial nerve. CN, cochlear
70. In some cases, the dissection of the adhesion bands will result in
bleeding, obscuring the plane of dissection. CN, cochlear nerve;
FN, facial nerve.
71. Identification of the facial nerve (FN) at the fundus of the internal auditory
canal is easier. TC, transverse crest; IVN, inferior vestibular nerve; SVN,
superior vestibular nerve.
72. Wrong technique for identifying the internal
auditory canal. Note that the posterior wall of
the canal is completely removed, while the superior
and inferior walls have not been drilled. The correct
way is to leave a thin shell over the dura of the
internal auditory canal until the two troughs are
created.
73. Identify the superior ampullary nerve first and then find the facial nerve
(F) after eliminating this nerve and the superior vestibular nerve (Vs).
74. middle cranial fossa photos
Fig. 5.30 A simple middle cranial fossa
approach has been established, and the
internal auditory canal dura has been
opened. A Anterior, B Bill’s bar, FN Facial
nerve, P Posterior, SSC Superior
semicircular canal, SV Superior vestibular
nerve
The acousticofacial bundle components have been
separated. Both the facial nerve (FN) cochlear nerve (CN)
can now be seen. AICA Anterior inferior cerebellar artery
75. The dura of the internal auditory canal
has been further removed. At
the level of the fundus, Bill’s bar (BB)
can be seen. AE, arcuate eminence; C,
cochlea; FN, facial nerve within the
internal auditory canal; GPN, greater
petrosal nerve; L, labyrinthine segment
of the facial nerve; SVN, superior
vestibular nerve.
At higher magnification, the
relationship at the fundus can be better
appreciated. AE, arcuate eminence; BB,
Bill’s bar; C, cochlea; FN(iac), internal
auditory canal segment of the facial
nerve; GG, geniculate ganglion; GPN,
greater petrosal nerve; L, labyrinthine
segment of the facial nerve; SVN,
superior vestibular nerve.
78. Exocranial & Endocranial views of Jugular Foramen : Within the JF area 2
venous compartement can be identified: a large postero-lateral_SIGMOID_venous channel and
a small antero-medial_PETROSAL_venous channel which can receive the drainage of the
inferior petrosal sinus (IPS). An intermediary neural compartment is located
between the venous ones and houses lower cranial nerves (IX, X, XI).
CC carotid canal, CR carotid ridge, ESF endolymphatic sac fossa, FS foramen spinosum, IAM internal acoustic
meatus, JT jugular tubercle, OC occipital condyle, PCF petroclival fi ssure, SAF subarcuate fossa, SP styloid
process, SSG sigmoid sinus groove, TB tympanic bone, VPTB vaginal process of the tympanic bone, white
arrow intrajugular process of the temporal bone, red arrow external ori fi ce of the hypoglossal canal, violet
arrow petroclival fi ssure, blue-sky arrow tubal isthmus, black arrow endocranial orifice of the hypoglossal
canal, orange arrow trigeminal impression, green arrow pyramidal fossa, black asterisks intrajugular ridge,
black circle intrajugularprocess of the occipital bone
79. FCB & JT & LCNs are at same level from anterior
to posterior
FCB = Fibrocartilago basalis , JT = Jugular tubercle , LCNs
Lower cranial nerves ( = 9th , 10th, 11th )
80. In Far lateral approach -- The lower cranial nerves have an intimate relationship with the
jugular tubercle (three black arrows). When the occipital bone and jugular tubercle are being drilled,
careful attention should be paid to avoiding damage to the lower cranial nerves. , Cbl cerebellum , ICA
internal carotid artery , OC occipital condyle , TP transverse process of the C1 vertebra , VA vertebral artery
, VIII cochleovestibular nerve , IX glossopharyngeal nerve , XI spinal accessory nerve
81. The right side of the
bulbomedullary junction. It is the
lowermost and narrowest part of
the posterior fossa. This area
requires special dissection prior
to endoscopic investigation
between the pontomedullary
stem and the jugular foramen.
82. The root fibers of the spinal
accessory nerve and the fibers of C1
and C2. The entrance of the vertebral
artery is the boundary between the
foramen magnum and the spinal part
of the accessory nerve.
A 30° endoscope provides an
overview of the medullary canal,
83. 11th nerve behind left vertebral artery at cervico-medullary junction – listen
lecture at 23.25 min in this Prof. Amin Kassam video
https://www.youtube.com/watch?v=QoMCqwJ6Ke0
Through anterior skull base
approach
Through endoscopic lateral skull
base approach – The entrance of
the vertebral artery is the
boundary between the foramen
magnum and the spinal part of
the accessory nerve.
84. The accessory nerve (XI) is closely related to the vertebral artery (VA) at the point of
dural entrance. Note the dura attached to the artery at this level.
Endoscopic lateral skull base
approach
85. The accessory nerve (XI) is closely related to the vertebral artery (VA) at the
point of dural entrance. Note the dura attached to the artery at this level.
86. Intracranial hypoglossal region. Anterior endoscopic transnasal-transclival vision is
compared with a posterior retrosigmoid endoscopic one
JF jugular foramen, JT jugular tubercle, IO inferior olive, PICA posteroinferior cerebellar artery, VA vertebral artery, IXcn
glossopharygeal nerve, Xcn vagus nerve, XIcnCR cervical roots of accessory nerve, XIcnSR spinal roots of accessory nerve,
XIIcn hypoglossal nerve
Cranial nerves IX and X present a close relationship with the fi rst portion of the PICA. They are protected by the arachnoid
membrane (Roche et al. 2008 ) . The roots of cranial nerve XIcn from the spine pass through the foramen magnum posterior
to the vertebral artery. Within the hypoglossal canal, XIIcn is surrounded by a venous plexus and dural and arachnoid
sheets. Branches of the ascending pharyngeal artery coursing through the hypoglossal canal are seen in about 50 % of cases
(Lang 1995 ) . Also branches from the posterior meningeal artery have been described (Janfaza and Nadol 2001 ). The
transcisternal vein to the area of the JF can be seen. Also, veins to the hypoglossal canal can be present. The hypoglossal
nerve do not exit with VA. It can have maximum 3 outlets. On the contrary, C1 roots exit with the VA.
87. Left side. The lower cranial
nerves, with the poste-rior
inferior cerebellar artery
arising from the vertebral
artery in the background.
Neurovascular relationships
between the exit zone of the root
fiber bundles of the eleventh and
twelfth nerves, the posterior
inferior cerebellar and vertebral
arteries. Fibrous tissue is seen
around the vertebral artery.
88. The facial nerve can be clearly seen
in the middle part of the approach
after retracting the posteriorly lying
cochlear nerve. Separation of the
glossopharyngeal nerve (IX) from the
vagus (X) and accessory (XI) nerves
at the medial aspect of the jugular
foramen.
Further inferiorly, the ninth (IX),
tenth (X), and eleventh (XI) cranial
nerves can be seen exiting the skull
through the jugular foramen
89. Right side. The root fibers of the hypoglossal nerve (12) collect in two
bundles, which pierce the dura in two dural pori. The hypoglossal nerve
is situated more anteriorly and medially than the root fibers of the
lower cranial nerves. The arterial relationship is the vertebral artery,
with perforating arteries to the brain stem. The curved vertebral artery
displaces and stretches the hypoglossal nerve fibers.
90. A closer view of the anterior border
of the pontomedullary
stem and the vertebral artery
junction and origin
of the basilar artery. Perforating
arteries arise from the vertebral
and basilar arteries.
The endoscope is focusing on the
hypoglossal nerve
area. The posterior inferior
cerebellar artery arises from the
vertebral artery in the
background, and runs between
the two
bundles of the hypoglossal nerve.
91. PICA passes between two bundles of 12th nerve & between
two roots of 11th nerve – retrosigmoid endoscopic approach
The endoscope is focusing on the
hypoglossal nerve area. The posterior
inferior cerebellar artery arises from the
vertebral artery in the background, and
runs between the two bundles of the
hypoglossal nerve.
The posterior inferior cerebellar
artery travels through the nerve
fiber roots of the accessory nerve
92. PICA passes between two bundles of 12th nerve & between
two roots of 11th nerve – anterior skull base endoscopic
approach
Endoscopic Far-medial
approach PICA passes through 12th
nerve – retrosigmoid
endoscopic approach
PICA passes through
11th nerve –
retrosigmoid
endoscopic approach
93. The posterior inferior cerebellar artery travels
through the nerve fiber roots of the accessory
nerve and
encircles the brain stem. The course of the
vertebral artery is
inferior and anterior to the lower cranial nerves
and the
hypoglossal nerve. Fibrous tissue surrounds the
entrance of
the vertebral artery into the CPA.
9 Glossopharyngeal nerve
10 Vagus nerve
11 Accessory nerve
12 Hypoglossal nerve
PICA Posterior inferior cerebellar
artery
Vert. A Vertebral artery
94.
95. A closer view of the pars nervosa
of the jugular foramen. The
glossopharyngeal nerve has its
own dural porus, which is
situated 0-3 mm upwards from
the dural porus of the tenth
cranial nerve. The vagus and the
accessory nerve exit the
posterior fossa together in a
sleeve of dura through the
jugular foramen.
Left side. The 30° angled endoscope
provides an overview of the inferior
part of the CPA. On the right lies the
acousticofacial nerve bundle, with
the anterior inferior cerebellar
artery; the glossopharyngeal nerve
and the vagus nerve, as multiple
filaments, form three to five major
nerve bundles and the accessory
nerve.
96. Relationship between the cochlear aqueduct and the lower cranial nerves. After rerouting of the facial nerve
and drilling away of the fallopian canal of the left temporal bone, the cochlear aqueduct (CA) has been
opened. The proximity of the glossopharyngeal nerve (IX) can be well appreciated. Since the nerve lies just
inferior to the cochlear aqueduct, the latter is used as a landmark to the nerve in the translabyrinthine
approach [ after drilling cochlea inferiorly ] , indicating the lower limit of drilling to avoid injury to the
glossopharyngeal nerve. ICA internal carotid artery , JB jugular bulb , SMF stylomastoid foramen
97. The glossopharyngeal nerve has its
own dural porus, which is situated
0-3 mm upwards from the dural
porus of the tenth cranial nerve. The
vagus and the accessory nerve exit
the posterior fossa together in a
sleeve of dura through the jugular
foramen.
98. The glossopharyngeal and vagus nerves are well
identified in the cerebellomedullary cistern before
entering the jugular foramen.
99. Cadaveric dissection with image taken just above the skeletonized hypoglossal canal
(HC) at the cerebellopontine angle. The anterior inferior cerebellar artery (AICA) can
be seen intimately associated with the vestibulocochlear nerve (CN VIII), facial nerve
(CN VII), and the nervus intermedius (NI). The posterior inferior cerebellar artery
(PICA) can be seen running between the vagus (CN X) and spinal and cranial portions
of the accessory nerves (CN XI – S, CN XI – C).
103. 1. The HC divides the condylar region into the tubercular compartment
(superior) and the condylar compartment (inferior).
Tubercular compartment contains LPT lateral pharyngeal tubercle, PT
pharyngeal tubercle,
2. The SCG [Supracondylar groove] represents a reliable landmark for hypoglossal canal (HC) identification
(red arrow) (Morera et al. 2010 ) .
104. The tubercular compartment corresponds to the Jugular tubercle ( JT )
Line along the lateral pharyngeal tubercle [ LPT ] passes through
Jugular tubercle [ JT ] – so when you are drilling LPT in anterior skull
base you will land up on JT .
LPT lateral pharyngeal tubercle, OC
occipital condyle, PT pharyngeal
tubercle, SCG supracondylar groove
Jugular tubercle ( JT )
105. Line along the lateral pharyngeal tubercle [ LPT ] passes through Jugular tubercle [ JT
] – so when you are drilling LPT in anterior skull base you will land up on JT .
Red rings = hypoglossal canals , yellow
ring = pharyngeal tubercle [ PT ] , blue
rings = lateral pharyngeal tubercle [
LPT]
106. The condylar emissary canal is visible superior
to the right occipital condyle within the supracondylar fossa (small arrow). The left
hypoglossal canal can be seen through this oblique view being located below the
jugular tubercle (large arrow).
107. Line along the lateral pharyngeal tubercle [ LPT ] passes through Jugular
tubercle [ JT ] – so when you are drilling LPT in anterior skull base you will
land up on JT .
yellow ring = pharyngeal tubercle [ PT ] , blue rings = lateral pharyngeal
tubercle [ LPT] , green ring = Jugular tubercle
108. JT = Jugular Tubercle – Below this
tubercle is hypoglossal canal & above
is Internal Jugular foramen
109. The pontomedullary junction.
1. The exit zones of the hypoglossal and abducent nerves are at
the same level [ same vertical line when view from Transclival
approah ( through lower clivus ) ]
2. The abducent nerve exits from the pontomedullary junction, and ascends
in a rostral and lateral direction toward the clivus.
110. Two cerebellar lobes and the
medullary stem. The
posterior inferior cerebellar artery
encircles the medullary
stem. The opposite vertebral artery
exits from the dural porus
and raises the hypoglossal nerve.
The pontomedullary junction. The vertebral
artery junction is at the level of the junction
of the inferior and midclivus. The basilar
artery runs in a straight line on the surface
of the pons. The exit zones of the hypoglossal
and abducent nerves are at the same level.
The abducent nerve exits from
the pontomedullary junction, and ascends in
a rostral and lateral direction toward the
clivus.
111. A closer view of the anterior
border of the pontomedullary
stem and the vertebral artery
junction and origin
of the basilar artery.
Perforating arteries arise from
the vertebral and basilar
arteries.
The endoscope is focusing on
the hypoglossal nerve area.
The posterior inferior
cerebellar artery arises from
the vertebral artery in the
background, and runs
between the two bundles of
the hypoglossal nerve.
112. The PICA runs between the two
bundles of the hypoglossal nerve.
At a higher magnification, the nerves IX−XI
are seen coursing toward the jugular
foramen. The two bundles of the
hypoglossal nerve(XII) are closely related
to the vertebral artery (VA) before they
unite to course in the hypoglossal canal in
the partially drilled occipital condyle (OC).
XIs, spinal accessory nerve.
113. Right side. The root fibers of the hypoglossal nerve (12) collect in two
bundles, which pierce the dura in two dural pori. The hypoglossal nerve
is situated more anteriorly and medially than the root fibers of the
lower cranial nerves. The arterial relationship is the vertebral artery,
with perforating arteries to the brain stem. The curved vertebral artery
displaces and stretches the hypoglossal nerve fibers.
114. The root fibers of the hypoglossal nerve (12) collect in two
bundles
Cadaveric dissection image showing the hypoglossal nerve
exiting the hypoglossal foramen with its corresponding vein that
communicates the internal jugular vein with the basilar plexus.
HC, hypoglossal canal; CN XII, hypoglossal nerve and rootlets;
FM, foramen magnum; VA, vertebral artery; PICA, posterior
inferior cerebellar artery; BA, basilar artery; CN X, vagus nerve.
115. Through endoscopic lateral skull
base - The curved vertebral
artery displaces and stretches
the hypoglossal nerve fibers.
Through anterior skull base
116. Through lateral skull base - The curved
vertebral artery displaces and stretches the
hypoglossal nerve fibers.
Through lateral skull base - The opposite
vertebral artery exits from the dural porus
and stretches /raises the hypoglossal nerve.
117. Cadaveric dissection image taken following dissection of the right lower third of the
clivus. As the posterior inferior cerebellar artery (PICA) courses from the vertebral
artery (VA) it frequently runs through the rootlets that make up the hypoglossal nerve
(CN XII). It may tent these rootlets as it courses to the cerebellomedullary fissure to
run intimately with the cranial nerves IX – XI. CN X, vagus nerve; HC, hypoglossal canal;
IPS, inferior petrosal sinus; BA, basilar artery; FM, foramen magnum; A. AOM, anterior
atlanto-occipital membrane.
118. Cadaveric dissection image showing the hypoglossal nerve
exiting the hypoglossal foramen with its corresponding vein that
communicates the internal jugular vein with the basilar plexus.
HC, hypoglossal canal; CN XII, hypoglossal nerve and rootlets;
FM, foramen magnum; VA, vertebral artery; PICA, posterior
inferior cerebellar artery; BA, basilar artery; CN X, vagus nerve.
119. The hypoglossal nerve do not exit with VA. It can have maximum
3 outlets. On the contrary, C1 roots exit with the VA.
121. Closer view of the inferior area of the left CPA, with
tip of the endoscope between the acousticofacial nerve bundle and lower cranial nerves. PICA
originating from the vertebral arterycan be seen forming a loop near the REZ of the facial nerve.
AICA arises from the more medial basilar artery and traverses under the acousticofacial nerve
bundle to supply the anterior surface of cerebellum. Abducens nerve (VI) is occasionally formed
by two different nerve bundles as seen here.
122. The facial nerve can be clearly seen
in the middle part of the approach
after retracting the posteriorly lying
cochlear nerve. Separation of the
glossopharyngeal nerve (IX) from the
vagus (X) and accessory (XI) nerves
at the medial aspect of the jugular
foramen.
Further inferiorly, the ninth (IX),
tenth (X), and eleventh (XI) cranial
nerves can be seen exiting the skull
through the jugular foramen
123. At the inferior part of the
approach the lower cranial nerves
can be appreciated.
The relation between the inferior
petrosal sinus (ips) and the lower
cranial nerves.
124. The origin of the hypoglossal nerve (XII).
.
The drilled occipital condyle (OC) and
the hypoglossal canal (HC).
125. Posterior cranial fossa (jugular and hypoglossal areas); vision obtained with a 45° endoscope
through a clival window
AICA anteroinferior cerebellar artery, BA basilar artery, IO inferior olive, LA labyrinthine artery, PCA posterior cerebral artery, PcomA
posterior communicating artery, PICA posteroinferior cerebellar artery, POV preolivary vein, RPA recurrent perforating artery, SCA
superior cerebellar artery, SPV superior petrosal vein, VA vertebral artery, IIIcn oculomotor nerve, Vcn trigeminal nerve, VIcn abducens
nerve, VIIcn facial nerve, VIIIcn vestiboloacoustic (statoacoustic) nerve, IXcn glossopharyngeal nerve, Xcn vagus nerve, XIIcn hypoglossal
nerve
The LA usually originates from the AICA, rarely directly from the BA. It feeds the inner ear. AICA and SCA course through the
cerebellopontine cistern. AICA enters the lower part of cerebellopontine cistern and it usually bifurcates into its rostral and caudal trunks
within the cistern. PICA origins from the VA, near the inferior olive, and passes posteriorly around the medulla. It could pass rostral, caudal
or even between the rootlets of the hypoglossal nerve. RPA(s) are arteries that present a recurrent course and reach the root entry zone of
the VII and VIII cns. They send branches to these nerves and to the brainsterm around the root entry zone.
126. Intracranial hypoglossal region. Anterior endoscopic transnasal-transclival vision is
compared with a posterior retrosigmoid endoscopic one
JF jugular foramen, JT jugular tubercle, IO inferior olive, PICA posteroinferior cerebellar artery, VA vertebral artery, IXcn
glossopharygeal nerve, Xcn vagus nerve, XIcnCR cervical roots of accessory nerve, XIcnSR spinal roots of accessory nerve,
XIIcn hypoglossal nerve
Cranial nerves IX and X present a close relationship with the fi rst portion of the PICA. They are protected by the arachnoid
membrane (Roche et al. 2008 ) . The roots of cranial nerve XIcn from the spine pass through the foramen magnum posterior
to the vertebral artery. Within the hypoglossal canal, XIIcn is surrounded by a venous plexus and dural and arachnoid
sheets. Branches of the ascending pharyngeal artery coursing through the hypoglossal canal are seen in about 50 % of cases
(Lang 1995 ) . Also branches from the posterior meningeal artery have been described (Janfaza and Nadol 2001 ). The
transcisternal vein to the area of the JF can be seen. Also, veins to the hypoglossal canal can be present. The hypoglossal
nerve do not exit with VA. It can have maximum 3 outlets. On the contrary, C1 roots exit with the VA.
127. Nerves and vessels of the posterior cranial fossa. (a) Basilar tip region, endoscopic view (b) Right cerebellopontine angle, endoscopic view from
anterior. (c) Right laterobulbar region, endoscopic intracranial view. (d) Three-dimensional reconstruction of the posterior cranial fossa. AICA,
anteroinferior cerebellar artery; BA, basilar artery; DV, Dandy’s vein; Fl, flocculus; IIIcn (CS), intracavernous portion of the oculomotor nerve; IIIcn,
oculomotor nerve; IO, inferior olive; IXcn, glossopharyngeal nerve; IX–X, glossopharyngeal and vagus nerves; LA, labyrinthic artery; LPMVN,
lateropontomesencephalic vein network; P1, posterior cerebral artery (first segment); P2, posterior cerebral artery (second segment); PcomA,
posterior communicating artery; PICA, posteroinferior cerebellar artery; POV, preolivary vein; PV, peduncular vein; RPA, recurrent perforating
artery; SCA, superior cerebellar artery; SPV, superior petrosal vein; TGAs, thalamogeniculate arteries; TPAs, thalamoperforating arteries; VA,
vertebral artery; Vcn, trigeminal nerve; VIcn, abducens nerve;
VII–VIIIcn, facial nerve and vestibuloacoustic nerve; VIIcn, facial nerve; VIIIcn, vestibuloacoustic nerve; X/XIcn, vagus and accessory nerves; XIcn,
accessory nerve; XIIcn, hypoglossal nerve.
129. Hypoglossal is just behind the upper end of
parapharyngel carotid – very easy way to
identify 12th nerve in paraphayrngeal space
– Dr.Satish jain
130. The hypoglossal nerve exits from the hypoglossal canal medial to the ICAp. It lies posteriorly to
the vagus nerve and passes laterally between the internal jugular vein and ICAp.
The hypoglossal nerve is usually accompained, within the hypoglossal canal, by an emissary vein and arterial
branches from ascending pharyngeal artery and occipital artery.
C1 atlas, Cl clivus, CS cavernous sinus, CV condylar vein, FCB fi brocartilago basalis, HC hypoglossal canal,
ICAc cavernous portion of the internal carotid artery, ICAp parapharyngeal portion of the internal carotid
artery, JT jugular tubercle, OC occipital condyle, XIIcn hypoglossal nerve, violet arrow atlanto-occipital
joint
131. Endoscopic endonasal view of a cadaveric dissection showing transection of the right eustachian tube (ET)
attachment to foramen lacerum (FL). The hypoglossal nerve (XII) enters the hypoglossal canal just deep to
the ET and separates the occipital condyle (OC) and the jugular tubercle (JT). (BA, basilar artery; ICA,
internal carotid artery [paraclival segment]; IPS, inferior petrosal sinus; VN, vidian nerve.) B. Endoscopic
endonasal view of cadaveric dissection showing the parapharyngeal internal carotid artery (ICA) and
jugular foramen (JF) following transection and removal of the eustachian tube. (BA, basilar artery; IPS,
inferior petrosal sinus; FL, foramen lacerum; JT, jugular tubercle; OC, occipital condyle; XII, hypoglossal
nerve.)
133. The jugular process and the portion of the occipital condyle have been drilled out. The left
occipital condyle is identified below the jugular bulb and posterior to the internal jugular vein.
* occipital condyle , ICA internal carotid artery , IJV internal jugular vein , JB jugular bulb , LSC
lateral semicircular canal , P promontory , SS sigmoid sinus
134. 11th nerve bisects the upper end of IJC whereas vertical part of 7th nerve bisects the jugular bulb .
The lateral aspect of the jugular bulb, sigmoid sinus, and internal jugular vein has been removed. On the
medial wall of the jugular bulb the inferior petrosal sinus is identified. The opening of the posterior
condylar vein is seen. * occipital condyle , ICA internal carotid artery , JB jugular bulb , P promontory ,
SS sigmoid sinus
136. Note the relationship among the sigmoid sinus, jugular bulb, posterior condylar vein, vertebral
artery, and lower cranial nerves. C1 atlas , C2N C2 nerve , JB jugular bulb , PCV posterior
condylar vein SS sigmoid sinus , TP transverse process of C1 , VA vertebral artery , X vagus nerve
, XI spinal accessory nerve
137. The posterior condylar vein crossing the occipital condyle is noted.
ICA internal carotid artery , JB jugular bulb , PCV posterior condylar vein
IX glossopharyngeal nerve , XI spinal accessory nerve
138. In Far lateral approach -- The lower cranial nerves have an intimate relationship with the
jugular tubercle (three black arrows). When the occipital bone and jugular tubercle are being drilled,
careful attention should be paid to avoiding damage to the lower cranial nerves. , Cbl cerebellum , ICA
internal carotid artery , OC occipital condyle , TP transverse process of the C1 vertebra , VA vertebral artery
, VIII cochleovestibular nerve , IX glossopharyngeal nerve , XI spinal accessory nerve
139. Other spinal ( cervical ) nerves origin
with rootlets like in 12th nerve origin
140. After this see “Cranial nerves
360” PPT – Click
http://www.slideshare.net/muralicha
ndnallamothu/cranial-nerves-360
141. For Other powerpoint presentatioins
of
“ Skull base 360° ”
I will update continuosly with date tag at the end as I am
getting more & more information
click
www.skullbase360.in
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account for downloading.