The vagus nerve carries visceral sensation from organs in the head, neck, thorax and abdomen. It sends motor signals to muscles in the pharynx, larynx and viscera. The vagus nerve emerges from the medulla and exits the skull through the jugular foramen, where it has two ganglia. It innervates many structures as it travels through the neck and thorax, with the left recurrent laryngeal nerve taking a longer path around the aortic arch.
1) Allen experienced pain in his throat when swallowing that was diagnosed as glossopharyngeal neuralgia. Whenever he swallowed, he had a decrease in heart rate and blood pressure.
2) The glossopharyngeal nerve carries sensation from the throat and innervates the stylopharyngeus muscle. It emerges from the medulla and passes through the jugular foramen.
3) Allen's symptoms stopped when treated with carbamazepine, indicating the diagnosis of glossopharyngeal neuralgia was correct.
This document discusses the glossopharyngeal, vagus, and accessory nerve complexes. It begins by explaining that the glossopharyngeal and vagus nerves arise from three nucleus columns in the medulla. It then provides diagrams of the nuclei and pathways of the vagus nerve. The rest of the document contains images demonstrating the anatomy and pathologies of these cranial nerve complexes.
The glossopharyngeal nerve is the ninth cranial nerve. It exits the brainstem between the olive and inferior cerebellar peduncle, passing through the jugular foramen. It has both sensory and motor functions, including taste sensation from the posterior tongue, sensation from the pharynx and middle ear, and motor innervation of the stylopharyngeus muscle. It also provides parasympathetic input to the parotid gland. Damage can cause loss of taste, swallowing issues, and impaired gag reflex.
This document provides information about the trigeminal, glossopharyngeal, and hypoglossal cranial nerves. It begins with an overview of the cranial nerves and their classifications. It then discusses the trigeminal nerve in depth, including its embryology, nuclei, pathways, ganglia, and clinical implications such as trigeminal neuralgia. The glossopharyngeal nerve is then summarized, covering its nuclei, course, branches and clinical tests. Finally, the hypoglossal nerve is outlined, with details on its nucleus, segments, branches, examining techniques, and causes of hypoglossal palsy. In total, the document comprehensively reviews the anatomy and clinical relevance of these three cranial
The glossopharyngeal nerve (IX cranial nerve) has five functional components: 1) It carries sensory fibers for taste from the posterior third of the tongue; 2) It carries general sensory fibers for structures like the pharynx and tonsils; 3) It carries sensory fibers for the external ear; 4) It carries motor fibers to control the stylopharyngeus muscle; 5) It carries parasympathetic fibers to control the parotid gland. The nuclei that control these functions include the nucleus ambiguus, nucleus salivatorius inferior, nucleus solitarius, and nucleus spinalis of the trigeminal nerve.
The glossopharyngeal nerve (CN IX) arises from the medulla and passes through the jugular foramen to innervate the stylopharyngeus muscle and provide sensory innervation to the posterior third of the tongue, pharynx, and middle ear. It communicates with the vagus, facial, and sympathetic nerves. The nerve has superior and inferior ganglia and branches including tympanic, carotid, pharyngeal, muscular, tonsillar, and lingual branches. Lesions of CN IX can cause loss of gag reflex and taste on the posterior tongue. Glossopharyngeal neuralgia presents as intense pain in the throat, ear, and tongue triggered by swallowing.
The vagus nerve originates in the medulla oblongata and travels through the neck and thorax, innervating organs along the way. It gives rise to branches like the recurrent laryngeal nerve. The vagus nerve contains fibers that emerge from four nuclei in the medulla related to parasympathetic output, motor function, sensation, and taste. It provides both sensory and motor function to various organs in the neck, thorax and abdomen. Damage to the vagus nerve can cause issues like hoarseness, difficulty swallowing, and an abnormal palate appearance.
The document discusses the glossopharyngeal (CN IX) and vagus (CN X) nerves. It covers their anatomy, functions, and clinical assessment. The glossopharyngeal nerve innervates the pharynx and posterior tongue. The vagus nerve is the longest cranial nerve, innervating muscles of the pharynx and larynx, and the heart and gastrointestinal tract via parasympathetic fibers. Clinical examination focuses on motor function of soft palate, larynx, and reflexes. Lesions are localized based on involved structures and associated deficits in other cranial nerves.
1) Allen experienced pain in his throat when swallowing that was diagnosed as glossopharyngeal neuralgia. Whenever he swallowed, he had a decrease in heart rate and blood pressure.
2) The glossopharyngeal nerve carries sensation from the throat and innervates the stylopharyngeus muscle. It emerges from the medulla and passes through the jugular foramen.
3) Allen's symptoms stopped when treated with carbamazepine, indicating the diagnosis of glossopharyngeal neuralgia was correct.
This document discusses the glossopharyngeal, vagus, and accessory nerve complexes. It begins by explaining that the glossopharyngeal and vagus nerves arise from three nucleus columns in the medulla. It then provides diagrams of the nuclei and pathways of the vagus nerve. The rest of the document contains images demonstrating the anatomy and pathologies of these cranial nerve complexes.
The glossopharyngeal nerve is the ninth cranial nerve. It exits the brainstem between the olive and inferior cerebellar peduncle, passing through the jugular foramen. It has both sensory and motor functions, including taste sensation from the posterior tongue, sensation from the pharynx and middle ear, and motor innervation of the stylopharyngeus muscle. It also provides parasympathetic input to the parotid gland. Damage can cause loss of taste, swallowing issues, and impaired gag reflex.
This document provides information about the trigeminal, glossopharyngeal, and hypoglossal cranial nerves. It begins with an overview of the cranial nerves and their classifications. It then discusses the trigeminal nerve in depth, including its embryology, nuclei, pathways, ganglia, and clinical implications such as trigeminal neuralgia. The glossopharyngeal nerve is then summarized, covering its nuclei, course, branches and clinical tests. Finally, the hypoglossal nerve is outlined, with details on its nucleus, segments, branches, examining techniques, and causes of hypoglossal palsy. In total, the document comprehensively reviews the anatomy and clinical relevance of these three cranial
The glossopharyngeal nerve (IX cranial nerve) has five functional components: 1) It carries sensory fibers for taste from the posterior third of the tongue; 2) It carries general sensory fibers for structures like the pharynx and tonsils; 3) It carries sensory fibers for the external ear; 4) It carries motor fibers to control the stylopharyngeus muscle; 5) It carries parasympathetic fibers to control the parotid gland. The nuclei that control these functions include the nucleus ambiguus, nucleus salivatorius inferior, nucleus solitarius, and nucleus spinalis of the trigeminal nerve.
The glossopharyngeal nerve (CN IX) arises from the medulla and passes through the jugular foramen to innervate the stylopharyngeus muscle and provide sensory innervation to the posterior third of the tongue, pharynx, and middle ear. It communicates with the vagus, facial, and sympathetic nerves. The nerve has superior and inferior ganglia and branches including tympanic, carotid, pharyngeal, muscular, tonsillar, and lingual branches. Lesions of CN IX can cause loss of gag reflex and taste on the posterior tongue. Glossopharyngeal neuralgia presents as intense pain in the throat, ear, and tongue triggered by swallowing.
The vagus nerve originates in the medulla oblongata and travels through the neck and thorax, innervating organs along the way. It gives rise to branches like the recurrent laryngeal nerve. The vagus nerve contains fibers that emerge from four nuclei in the medulla related to parasympathetic output, motor function, sensation, and taste. It provides both sensory and motor function to various organs in the neck, thorax and abdomen. Damage to the vagus nerve can cause issues like hoarseness, difficulty swallowing, and an abnormal palate appearance.
The document discusses the glossopharyngeal (CN IX) and vagus (CN X) nerves. It covers their anatomy, functions, and clinical assessment. The glossopharyngeal nerve innervates the pharynx and posterior tongue. The vagus nerve is the longest cranial nerve, innervating muscles of the pharynx and larynx, and the heart and gastrointestinal tract via parasympathetic fibers. Clinical examination focuses on motor function of soft palate, larynx, and reflexes. Lesions are localized based on involved structures and associated deficits in other cranial nerves.
Cranial nerves emerge through openings in the skull and are bundles of sensory or motor fibers that innervate muscles or glands. There are twelve pairs of cranial nerves numbered I to XII from front to back. The facial nerve is cranial nerve VII, originating in the pons. It has both motor and sensory components, with the motor component controlling facial expressions and the sensory transmitting taste from the tongue.
There are 12 pairs of cranial nerves that supply structures in the head, neck, and upper body. They have various functions including sensory, motor, and special sensory roles. The presentation describes each of the 12 cranial nerves - their modality, function, origin, path through the skull, attachments, and clinical effects of damage. The cranial nerves have important roles in vision, smell, hearing, facial muscle control, swallowing, breathing, and other critical functions.
glossopharyngeal nerve, origin an course and termination of glossopharyngeal nerve, functional component of the nerve, sensory and motor component of glossopharyngeal nerve, gag reflex
This document provides detailed information about the anatomy, physiology, and clinical examination of the vestibulocochlear nerve (CN VIII), which has both auditory and vestibular components. It describes the structures of the inner ear, including the cochlea, semicircular canals, utricle, and saccule. It also outlines the central pathways of the auditory and vestibular systems and clinical tests used to evaluate hearing and balance function, such as audiometry, auditory evoked potentials, and tuning fork tests.
glossopharyngeal nerve & its relation to vagusAmna Liaquat
The document discusses the anatomy and functions of the glossopharyngeal and vagus nerves. It describes the three components and nuclei of the glossopharyngeal nerve, including its motor, parasympathetic, and sensory functions. It then discusses the vagus nerve, noting its motor and sensory nuclei and parasympathetic roles in involuntary muscles. Finally, it summarizes the relationship between the two nerves, where the glossopharyngeal carries sensory information from the carotid body and sinus to the vagus nerve, which can then affect the heart rate and blood pressure.
The glossopharyngeal nerve (CN IX) emerges from the medulla and exits the skull through the jugular foramen. It has sensory and motor functions. Sensory fibers innervate the posterior third of the tongue, tonsils, pharynx, and middle ear. Motor fibers innervate the stylopharyngeus muscle. Parasympathetic fibers pass to the otic ganglion to ultimately innervate the parotid gland and stimulate saliva secretion.
The glossopharyngeal nerve (CN IX) exits the brainstem and has several functions:
- It provides general and special sensory innervation to the back third of the tongue (taste sensation), tonsils, middle ear, and pharynx.
- It supplies a parasympathetic branch that stimulates saliva production in the parotid gland.
- It provides motor innervation to the stylopharyngeus muscle, which elevates the pharynx during swallowing.
The nerve exits the skull via the jugular foramen and branches to innervate its target areas.
The glossopharyngeal nerve is a mixed nerve that carries sensory and motor fibers. It has nuclei in the medulla and courses through the jugular foramen to innervate structures in the pharynx, tonsils, tongue, and mucus glands of the mouth. It has general sensory, special sensory, visceral motor, and branchial motor components. It mediates the gag reflex when the back of the pharynx is touched.
The hypoglossal nerve is a mainly motor nerve that innervates all the muscles of the tongue except one. It has its nucleus in the medulla and exits the skull through the hypoglossal canal to innervate the tongue muscles. Paralysis of
The document summarizes the origin and functional components of the 12 cranial nerves. It discusses that cranial nerve fibers with motor functions arise from nuclei in the brainstem, while sensory fibers originate from ganglia outside the brainstem. The cranial nerves have different functional components including somatic efferent, visceral efferent, and somatic/visceral afferent fibers. Specific cranial nerves are described in more detail, including their nuclei of origin, peripheral innervation, and clinical correlations of damage.
Foramina of the Skull and the Structures that Pass ThroughAhmad Amro Baradee
This document lists and describes over 60 anatomical openings, canals, and foramina of the human skull. Key structures mentioned include:
- The foramina of the cribriform plate which transmit the olfactory nerves.
- The superior and inferior orbital fissures which transmit nerves and vessels to the orbit, including the oculomotor, trochlear and abducent nerves.
- The foramen ovale, rotundum, and spinosum which transmit vessels and nerves like the mandibular and maxillary nerves.
- The foramen magnum, jugular foramen, and hypoglossal canal which allow passage of structures like the spinal cord, cranial nerves
Cranial nerves emerge through openings in the skull and are bundles of sensory or motor fibers that innervate muscles or glands. There are twelve pairs of cranial nerves numbered I to XII from front to back. The facial nerve is cranial nerve VII, originating in the pons. It has both motor and sensory components, with the motor component controlling facial expressions and the sensory transmitting taste from the tongue.
This table lists various foramina of the skull along with their location, the bones they pass through, and their contents. It describes over 20 different foramina, including their positions on the skull, the bones they are located in or on, and the structures like nerves, vessels, or emissary veins that pass through each foramen. The document provides a detailed anatomical reference of the various openings and canals in the human skull and their functions.
This document provides an overview of cranial nerves, with a focus on the trigeminal nerve (CN V). It discusses the organization of the nervous system and related terminologies. It then describes each of the 12 cranial nerves and provides detailed information on CN V, including its sensory and motor roots, nuclei, and three divisions (ophthalmic, maxillary, mandibular). The document outlines the course and branches of each division of CN V.
This document summarizes the foramina of the skull and their contents. It provides a table with 14 entries that list the name of each foramen, its location on the skull bones, the specific location on the bone, and the structures that pass through each foramen. The table provides a concise overview of the key foramina of the skull and the anatomical structures associated with each one.
The document summarizes the trigeminal nerve, including its nuclear columns, trigeminal ganglion, three divisions of the nerve, and clinical considerations. The trigeminal nerve has three divisions - the ophthalmic, maxillary, and mandibular nerves. It discusses the branches and distributions of each division. Clinically, examination of the trigeminal nerve involves sensory and motor testing as well as trigeminal reflexes. Common conditions involving the trigeminal nerve like trigeminal neuralgia and postherpetic neuralgia are also mentioned.
The document provides information on the trigeminal nerve (CN V), including its nuclei, origin, course, branches, and functions. It describes the three main branches - ophthalmic, maxillary, and mandibular nerves. The ophthalmic nerve innervates the eye and upper face. The maxillary nerve contains sensory fibers and innervates the midface, nasal cavity, and maxillary teeth. The mandibular nerve is mixed, containing both sensory and motor fibers, and innervates the lower face, oral cavity, external ear, and muscles of mastication.
A brief study material of glossophrayngeal nerve its relations and courses and importance on dentistry with diagrams and references in relation to dentistry.
Cranial nerves emerge through openings in the skull and are bundles of sensory or motor fibers that innervate muscles or glands. There are twelve pairs of cranial nerves numbered I to XII from front to back. The facial nerve is cranial nerve VII, originating in the pons. It has both motor and sensory components, with the motor component controlling facial expressions and the sensory transmitting taste from the tongue.
There are 12 pairs of cranial nerves that supply structures in the head, neck, and upper body. They have various functions including sensory, motor, and special sensory roles. The presentation describes each of the 12 cranial nerves - their modality, function, origin, path through the skull, attachments, and clinical effects of damage. The cranial nerves have important roles in vision, smell, hearing, facial muscle control, swallowing, breathing, and other critical functions.
glossopharyngeal nerve, origin an course and termination of glossopharyngeal nerve, functional component of the nerve, sensory and motor component of glossopharyngeal nerve, gag reflex
This document provides detailed information about the anatomy, physiology, and clinical examination of the vestibulocochlear nerve (CN VIII), which has both auditory and vestibular components. It describes the structures of the inner ear, including the cochlea, semicircular canals, utricle, and saccule. It also outlines the central pathways of the auditory and vestibular systems and clinical tests used to evaluate hearing and balance function, such as audiometry, auditory evoked potentials, and tuning fork tests.
glossopharyngeal nerve & its relation to vagusAmna Liaquat
The document discusses the anatomy and functions of the glossopharyngeal and vagus nerves. It describes the three components and nuclei of the glossopharyngeal nerve, including its motor, parasympathetic, and sensory functions. It then discusses the vagus nerve, noting its motor and sensory nuclei and parasympathetic roles in involuntary muscles. Finally, it summarizes the relationship between the two nerves, where the glossopharyngeal carries sensory information from the carotid body and sinus to the vagus nerve, which can then affect the heart rate and blood pressure.
The glossopharyngeal nerve (CN IX) emerges from the medulla and exits the skull through the jugular foramen. It has sensory and motor functions. Sensory fibers innervate the posterior third of the tongue, tonsils, pharynx, and middle ear. Motor fibers innervate the stylopharyngeus muscle. Parasympathetic fibers pass to the otic ganglion to ultimately innervate the parotid gland and stimulate saliva secretion.
The glossopharyngeal nerve (CN IX) exits the brainstem and has several functions:
- It provides general and special sensory innervation to the back third of the tongue (taste sensation), tonsils, middle ear, and pharynx.
- It supplies a parasympathetic branch that stimulates saliva production in the parotid gland.
- It provides motor innervation to the stylopharyngeus muscle, which elevates the pharynx during swallowing.
The nerve exits the skull via the jugular foramen and branches to innervate its target areas.
The glossopharyngeal nerve is a mixed nerve that carries sensory and motor fibers. It has nuclei in the medulla and courses through the jugular foramen to innervate structures in the pharynx, tonsils, tongue, and mucus glands of the mouth. It has general sensory, special sensory, visceral motor, and branchial motor components. It mediates the gag reflex when the back of the pharynx is touched.
The hypoglossal nerve is a mainly motor nerve that innervates all the muscles of the tongue except one. It has its nucleus in the medulla and exits the skull through the hypoglossal canal to innervate the tongue muscles. Paralysis of
The document summarizes the origin and functional components of the 12 cranial nerves. It discusses that cranial nerve fibers with motor functions arise from nuclei in the brainstem, while sensory fibers originate from ganglia outside the brainstem. The cranial nerves have different functional components including somatic efferent, visceral efferent, and somatic/visceral afferent fibers. Specific cranial nerves are described in more detail, including their nuclei of origin, peripheral innervation, and clinical correlations of damage.
Foramina of the Skull and the Structures that Pass ThroughAhmad Amro Baradee
This document lists and describes over 60 anatomical openings, canals, and foramina of the human skull. Key structures mentioned include:
- The foramina of the cribriform plate which transmit the olfactory nerves.
- The superior and inferior orbital fissures which transmit nerves and vessels to the orbit, including the oculomotor, trochlear and abducent nerves.
- The foramen ovale, rotundum, and spinosum which transmit vessels and nerves like the mandibular and maxillary nerves.
- The foramen magnum, jugular foramen, and hypoglossal canal which allow passage of structures like the spinal cord, cranial nerves
Cranial nerves emerge through openings in the skull and are bundles of sensory or motor fibers that innervate muscles or glands. There are twelve pairs of cranial nerves numbered I to XII from front to back. The facial nerve is cranial nerve VII, originating in the pons. It has both motor and sensory components, with the motor component controlling facial expressions and the sensory transmitting taste from the tongue.
This table lists various foramina of the skull along with their location, the bones they pass through, and their contents. It describes over 20 different foramina, including their positions on the skull, the bones they are located in or on, and the structures like nerves, vessels, or emissary veins that pass through each foramen. The document provides a detailed anatomical reference of the various openings and canals in the human skull and their functions.
This document provides an overview of cranial nerves, with a focus on the trigeminal nerve (CN V). It discusses the organization of the nervous system and related terminologies. It then describes each of the 12 cranial nerves and provides detailed information on CN V, including its sensory and motor roots, nuclei, and three divisions (ophthalmic, maxillary, mandibular). The document outlines the course and branches of each division of CN V.
This document summarizes the foramina of the skull and their contents. It provides a table with 14 entries that list the name of each foramen, its location on the skull bones, the specific location on the bone, and the structures that pass through each foramen. The table provides a concise overview of the key foramina of the skull and the anatomical structures associated with each one.
The document summarizes the trigeminal nerve, including its nuclear columns, trigeminal ganglion, three divisions of the nerve, and clinical considerations. The trigeminal nerve has three divisions - the ophthalmic, maxillary, and mandibular nerves. It discusses the branches and distributions of each division. Clinically, examination of the trigeminal nerve involves sensory and motor testing as well as trigeminal reflexes. Common conditions involving the trigeminal nerve like trigeminal neuralgia and postherpetic neuralgia are also mentioned.
The document provides information on the trigeminal nerve (CN V), including its nuclei, origin, course, branches, and functions. It describes the three main branches - ophthalmic, maxillary, and mandibular nerves. The ophthalmic nerve innervates the eye and upper face. The maxillary nerve contains sensory fibers and innervates the midface, nasal cavity, and maxillary teeth. The mandibular nerve is mixed, containing both sensory and motor fibers, and innervates the lower face, oral cavity, external ear, and muscles of mastication.
A brief study material of glossophrayngeal nerve its relations and courses and importance on dentistry with diagrams and references in relation to dentistry.
The document summarizes key aspects of spinal cord and brainstem anatomy related to somatosensory and motor pathways. It describes:
1) Spinal cord gray matter including dorsal horn, ventral horn, and intermediate gray matter which contain sensory, motor, and autonomic nuclei respectively.
2) Brainstem organization into nuclei rather than horns. Cranial nerves originate from specific motor and sensory nuclei analogous to spinal cord regions.
3) Somatosensory and motor pathways for each cranial nerve, including ganglia, nuclei, and innervation targets. Key nuclei include trigeminal, facial, vestibulocochlear nuclei and more.
El nervio vago (neumogástrico) tiene orígenes sensitivos, motores y parasimpáticos en el bulbo raquídeo. Se distribuye en la cabeza, cuello, tórax, abdomen y estómago, donde inerva órganos como la laringe, corazón, pulmones y estómago. Presenta varias ramificaciones incluyendo los nervios laríngeos y el nervio recurrente.
The pons is located in the brainstem, between the midbrain and medulla oblongata. It contains fibers that connect the cerebellum and cerebrum, and nuclei for several cranial nerves including the trigeminal, facial, and abducent nerves. The pons receives its blood supply primarily from the basilar artery and its branches, as well as the anterior inferior cerebellar and superior cerebellar arteries. It plays an important role in motor functions and sensory processes.
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The trigeminal nerve is the largest cranial nerve and contains both motor and sensory fibers. It has three main divisions - the ophthalmic, maxillary, and mandibular nerves. The ophthalmic division innervates the upper face and orbits, the maxillary division innervates the mid face, and the mandibular division innervates the lower face and contains both sensory and motor fibers that innervate the muscles of mastication. The trigeminal ganglion contains the cell bodies of the sensory fibers and is located in the trigeminal cave at the base of the skull.
The document discusses the anatomy of the cranial cavity. It describes the dura mater folds including the falx cerebri, falx cerebelli, tentorium cerebelli, and diaphragma sellae. It also discusses the dural venous sinuses, cranial nerves, bones that make up the cranial cavity, arteries that supply the dura mater, and veins within the cranial cavity.
This document provides an overview of cranial nerve anatomy, with a focus on the glossopharyngeal (CN IX), vagus (CN X), and spinal accessory (CN XI) nerves. It describes the origins, pathways, and innervation patterns of these cranial nerves. Key points include: CN IX and X arise from the medulla in the post-olivary sulcus, CN XI arises from the medulla and upper cervical spinal cord; all three nerves pass through the jugular foramen; CN IX innervates the stylopharyngeus muscle and carries sensory fibers for taste, CN X is the longest cranial nerve and innervates muscles of the larynx and viscera and carries
The accessory nerve controls specific muscles of the neck. It begins in the central nervous system and exits the cranium through a foramen. Unlike other cranial nerves, it begins outside the skull rather than inside, originating in the upper spinal cord. It innervates the sternocleidomastoid and trapezius muscles. Injury can cause diminished function of these muscles.
The trigeminal nerve is the largest cranial nerve and is a mixed nerve containing both sensory and motor fibers. It has three major divisions - the ophthalmic, maxillary, and mandibular nerves. The ophthalmic nerve innervates the face above the eyes. The maxillary nerve innervates the midface, and the mandibular nerve innervates the lower face and jaw muscles. The trigeminal ganglion contains the cell bodies of the pseudounipolar neurons whose axons make up the trigeminal nerve. The trigeminal nuclei in the brainstem are involved in relaying sensory information from the trigeminal nerve.
The document summarizes key information about cranial nerves IX through XII:
1. The glossopharyngeal nerve (IX) leaves the skull through the jugular foramen and innervates receptors in the pharynx, tongue, and middle ear as well as taste buds and chemoreceptors.
2. The vagus nerve (X) is the longest and most complex cranial nerve, innervating organs from the head to the abdomen, including the larynx, lungs, heart and visceral organs.
3. The accessory nerve (XI) has a cranial and spinal portion, with the cranial portion joining the vagus nerve and the spinal portion innervating neck muscles
The document provides information about the brainstem, which consists of the medulla, pons, and midbrain. It describes the gross anatomy and internal features of the medulla, including nuclei, tracts, and blood supply. Specific conditions that can affect the medulla, such as raised intracranial pressure and lateral/medial medullary syndromes, are also discussed. The pons is then covered, outlining its anterior and posterior surfaces, nuclei including the pontine nuclei, and blood supply from the basilar artery.
This document discusses the common terminal motor pathway which involves the anterior horn cell (A1) and its axon (the alpha motoneuron). It describes the major descending pathways that influence motor activity, including the corticospinal tract, rubrospinal tract, reticulospinal tract, and vestibulospinal tract. These pathways terminate on the alpha motoneurons and gamma motoneurons, which influence the muscle spindles. Afferent fibers from the muscle spindles and tendon organs provide feedback to complete the reflex loop.
The document provides an outline on the triangles of the neck and deep structures of the neck. It begins by introducing the sternocleidomastoid muscle as the most useful landmark for locating neck structures. It then describes the boundaries and contents of the posterior and anterior triangles of the neck, noting key nerves, vessels, and muscles located in each. The document concludes by detailing structures such as the thyroid gland, parathyroid glands, sympathetic chain, and thoracic duct found deeper in the neck.
The document outlines the triangles of the neck and their boundaries, contents, and deeper structures. It describes the posterior triangle, anterior triangle, and their contents including nerves, vessels, and muscles. The document also details deeper neck structures like the thyroid gland, parathyroid glands, thoracic duct, and branches of the external carotid artery.
The document discusses the 12 pairs of cranial nerves. It provides details on the olfactory nerve (CN I), optic nerve (CN II), oculomotor nerve (CN III), trochlear nerve (CN IV), abducent nerve (CN VI), and trigeminal nerve (CN V). It describes the functions, nuclei, pathways and innervation areas for each of these cranial nerves.
This document provides an overview of the trigeminal nerve (CN V), including its embryology, structure, branches and clinical applications. It describes the three divisions of the trigeminal nerve - ophthalmic, maxillary and mandibular nerves. The trigeminal ganglion and its sensory and motor roots are discussed. The branches and functions of the ophthalmic, maxillary and mandibular nerves are summarized. Regional nerve blocks associated with the trigeminal nerve such as the greater palatine nerve block are also outlined. Anatomical variations of the trigeminal nerve and maxillary nerve are noted.
Brainstem gaj.ppt by sms medical college jaipurdineshdandia
This document provides an overview of the brainstem, including its subdivisions of medulla, pons, and midbrain. It describes the internal and external structures of each region, such as cranial nerve nuclei, fiber tracts, and landmarks. Key features covered include the organization of cranial nerves and columns of nuclei in the medulla, pontine nuclei and cranial nerves 5-8 in the pons, and structures like the cerebral peduncles, optic chiasm and quadrigeminal plate in the midbrain.
The cerebellum has three main parts - the vermis, two hemispheres, and four lobes. It receives sensory input from the spinal cord, brainstem, and cerebral cortex. There are three layers in the cerebellar cortex - molecular layer, purkinje cell layer, and granular layer. The cerebellum is connected to the brainstem via three cerebellar peduncles and plays a role in motor coordination and balance.
The spinal cord or medulla is part of the central nervous system that extends from the foramen magnum to the lower back and has a cervical and lumbar enlargement. It has 31 segments and is surrounded by meninges. Internally, it contains grey matter in an H-shaped column with neuronal groups, and white matter organized into dorsal, lateral, and ventral funiculi containing ascending and descending tracts. The spinal cord transmits information between the brain and body and facilitates reflexes via its grey matter.
Similar to Nervio Vago/Wilson Pawels/idiomainglés (20)
Este documento describe los métodos de esterilización, desinfección y antisepsia para el control de infecciones. La esterilización elimina todos los microorganismos a través de métodos físicos como calor y radiaciones, o métodos químicos como óxido de etileno y glutaraldehído. La desinfección elimina selectivamente microorganismos indeseables usando agentes químicos como alcohol, fenol o cloro. La antisepsia usa sustancias químicas no tóxicas como alcohol etílico
El documento resume las características del virus de la hepatitis A. Explica que es un virus entérico de la familia Picornaviridae que se replica en el hepatocito. Se transmite principalmente a través de las heces y su periodo de incubación es de 15 a 45 días, tras lo cual la persona infectada presenta síntomas como ictericia, dolor abdominal y heces pálidas.
Este documento describe diferentes tipos de micosis superficiales y profundas. Se dividen en dermatofitosis o tiñas causadas por hongos que afectan la piel y anexos como el cuero cabelludo, y candidiasis causada por levaduras del género Candida. Se detallan las características clínicas, epidemiológicas y de diagnóstico de varias formas de tiña capitis, tiña corporal, tiña de los pies y candidiasis cutánea y mucosal.
Los hongos son organismos microscópicos ubicuos que incluyen levaduras, hongos filamentosos y mohos. Pueden degradar hidrocarburos y crecer tanto en agua dulce como salada. Algunas especies producen toxinas en alimentos.
1. El documento describe la flora bacteriana asociada a la salud periodontal y la enfermedad periodontal, incluyendo especies como Estreptococos, Actinomyces, Porphyromonas gingivalis, y Tannerella forsythia.
2. Explica cómo la falta de higiene bucal puede conducir a la formación de biofilm y gingivitis en 3-4 días y la progresión a periodontitis con la aparición de especies gramnegativas.
3. Resalta la importancia de P. gingivalis, A. actin
El documento describe las vías por las que las bacterias pueden infectar la pulpa dental y causar una infección, incluyendo a través de túbulos dentinarios, una cavidad abierta o el foramen apical. Explica que las bacterias más comunes asociadas con infecciones de la pulpa son estreptococos y lactobacilos. También describe el curso de la inflamación pulpar y los tipos de bacterias que se asocian con una pulpa vital versus una pulpa necrótica.
Este documento describe la estructura y características generales de los virus. Los virus contienen material genético (ADN o ARN) rodeado por una cápside proteica, y en algunos casos una envoltura lipoproteica. Se reproducen únicamente dentro de células vivas, utilizando la maquinaria y enzimas celulares. Cada virus difiere en su tamaño, forma y composición genética.
Los virus son elementos genéticos que pueden replicarse independientemente del ADN de una célula huésped, pero dependen de la célula para multiplicarse. Para replicarse, los virus deben entrar en una célula y aprovechar su maquinaria metabólica, integrando su material genético en el de la célula e induciendo su destrucción. Esto les confiere un carácter patógeno.
La caries dental es una enfermedad infecciosa crónica causada por la acción de ácidos producidos por bacterias de la boca al metabolizar los hidratos de carbono de la dieta. Estos ácidos destruyen los tejidos duros del diente. La teoría más aceptada es que la caries es producida por la interacción de tres factores: la microbiota oral, la dieta y la susceptibilidad del hospedador. Los principales microorganismos asociados a la caries son los estreptococos del grupo mutans,
El documento describe la importancia de considerar la oclusión al realizar restauraciones dentales. Explica que la oclusión satisfactoria es necesaria para proporcionar funcionalidad y comodidad al paciente. También destaca la necesidad de tomar en cuenta la posición de los dientes vecinos y antagonistas, así como características como cúspides, crestas y fosas, para no alterar la función masticatoria ni causar iatrogenias. Finalmente, analiza signos y síntomas que pueden indicar alteraciones en la oclusión como consecuencia de traumas
Este documento describe la microbiota que se encuentra en diferentes tejidos y superficies de la boca, incluyendo las piezas dentarias, la mucosa yugal, el paladar, la lengua, la saliva y el surco gingivocrevicular. Detalla las principales bacterias, hongos y parásitos presentes en cada sitio y su papel en la salud oral o enfermedades como la caries y periodontitis.
Streptococcus son bacterias esféricas gram positivas que pueden causar infecciones supurativas como faringitis y escarlatina o no supurativas como fiebre reumática y glomerulonefritis. Existen varios grupos pero el grupo A es el más patógeno y causa enfermedades como faringitis con dolor de garganta y fiebre, escarlatina con erupción cutánea y fiebre, e infecciones no supurativas como fiebre reumática y glomerulonefritis. El diagnóstico se realiza por cult
Las enfermedades relacionadas incluyen varias afecciones médicas que están conectadas de alguna manera. Algunas enfermedades pueden causar otras o compartir síntomas similares. Es importante que los pacientes y médicos comprendan las relaciones entre diferentes afecciones para un diagnóstico y tratamiento efectivos.
Este documento resume las características de dos bacterias patógenas, Neisseria gonorrhoeae y Treponema pallidum. Neisseria gonorrhoeae, conocida como gonococo, es un cocobacilo gramnegativo que causa gonorrea e infecta las mucosas genitales. Se cultiva en medios especiales a 35-37°C y expresa varias proteínas antigénicas como pili, Opa y porinas que le permiten adherirse a células y evadir el sistema inmune. Treponema pallidum es una espiro
1. La patogénesis bacteriana es un proceso multifactorial que depende del estado inmune del hospedador, la virulencia de la bacteria y la dosis de exposición inicial. 2. Las bacterias utilizan múltiples factores de virulencia como adhesinas, cápsulas, toxinas y sistemas de captación de hierro para adherirse a las células huésped, invadirlas, evadir el sistema inmune y causar enfermedad. 3. El sistema inmune del huésped proporciona defensas constitutivas
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El documento describe las características generales de Mycobacterium tuberculosis. Tiene una pared celular gruesa compuesta principalmente de lípidos que le confiere resistencia a ácidos y alcohol. Causa tuberculosis, una infección que generalmente afecta los pulmones y puede reactivarse años después. Se identifica mediante exámenes microscópicos, aislamiento en cultivo, amplificación de ADN y pruebas cutáneas con tuberculina.
Este documento describe las características genéticas de las bacterias, incluyendo que contienen ADN y cromosomas. Explica la estructura y replicación del cromosoma bacteriano, así como la presencia de material genético extracromosómico. También resume los tipos de ARN, el dogma central de la biología molecular, y mecanismos para el control de la expresión genética y la transferencia de genes entre bacterias.
Congestive Heart failure is caused by low cardiac output and high sympathetic discharge. Diuretics reduce preload, ACE inhibitors lower afterload, beta blockers reduce sympathetic activity, and digitalis has inotropic effects. Newer medications target vasodilation and myosin activation to improve heart efficiency while lowering energy requirements. Combination therapy, following an assessment of cardiac function and volume status, is the most effective strategy to heart failure care.
Nano-gold for Cancer Therapy chemistry investigatory projectSIVAVINAYAKPK
chemistry investigatory project
The development of nanogold-based cancer therapy could revolutionize oncology by providing a more targeted, less invasive treatment option. This project contributes to the growing body of research aimed at harnessing nanotechnology for medical applications, paving the way for future clinical trials and potential commercial applications.
Cancer remains one of the leading causes of death worldwide, prompting the need for innovative treatment methods. Nanotechnology offers promising new approaches, including the use of gold nanoparticles (nanogold) for targeted cancer therapy. Nanogold particles possess unique physical and chemical properties that make them suitable for drug delivery, imaging, and photothermal therapy.
Pictorial and detailed description of patellar instability with sign and symptoms and how to diagnose , what investigations you should go with and how to approach with treatment options . I have presented this slide in my 2nd year junior residency in orthopedics at LLRM medical college Meerut and got good reviews for it
After getting it read you will definitely understand the topic.
5-hydroxytryptamine or 5-HT or Serotonin is a neurotransmitter that serves a range of roles in the human body. It is sometimes referred to as the happy chemical since it promotes overall well-being and happiness.
It is mostly found in the brain, intestines, and blood platelets.
5-HT is utilised to transport messages between nerve cells, is known to be involved in smooth muscle contraction, and adds to overall well-being and pleasure, among other benefits. 5-HT regulates the body's sleep-wake cycles and internal clock by acting as a precursor to melatonin.
It is hypothesised to regulate hunger, emotions, motor, cognitive, and autonomic processes.
- Video recording of this lecture in English language: https://youtu.be/Pt1nA32sdHQ
- Video recording of this lecture in Arabic language: https://youtu.be/uFdc9F0rlP0
- 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
TEST BANK For Brunner and Suddarth's Textbook of Medical-Surgical Nursing, 14...Donc Test
TEST BANK For Brunner and Suddarth's Textbook of Medical-Surgical Nursing, 14th Edition (Hinkle, 2017) Verified Chapter's 1 - 73 Complete.pdf
TEST BANK For Brunner and Suddarth's Textbook of Medical-Surgical Nursing, 14th Edition (Hinkle, 2017) Verified Chapter's 1 - 73 Complete.pdf
TEST BANK For Brunner and Suddarth's Textbook of Medical-Surgical Nursing, 14th Edition (Hinkle, 2017) Verified Chapter's 1 - 73 Complete.pdf
This presentation gives information on the pharmacology of Prostaglandins, Thromboxanes and Leukotrienes i.e. Eicosanoids. Eicosanoids are signaling molecules derived from polyunsaturated fatty acids like arachidonic acid. They are involved in complex control over inflammation, immunity, and the central nervous system. Eicosanoids are synthesized through the enzymatic oxidation of fatty acids by cyclooxygenase and lipoxygenase enzymes. They have short half-lives and act locally through autocrine and paracrine signaling.
- Video recording of this lecture in English language: https://youtu.be/RvdYsTzgQq8
- Video recording of this lecture in Arabic language: https://youtu.be/ECILGWtgZko
- 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
Spontaneous Bacterial Peritonitis - Pathogenesis , Clinical Features & Manage...Jim Jacob Roy
In this presentation , SBP ( spontaneous bacterial peritonitis ) , which is a common complication in patients with cirrhosis and ascites is described in detail.
The reference for this presentation is Sleisenger and Fordtran's Gastrointestinal and Liver Disease Textbook ( 11th edition ).
The biomechanics of running involves the study of the mechanical principles underlying running movements. It includes the analysis of the running gait cycle, which consists of the stance phase (foot contact to push-off) and the swing phase (foot lift-off to next contact). Key aspects include kinematics (joint angles and movements, stride length and frequency) and kinetics (forces involved in running, including ground reaction and muscle forces). Understanding these factors helps in improving running performance, optimizing technique, and preventing injuries.
2. X Vagus Nerve
CASE HISTORY
Ruth is a 46-year-old lawyer who, over the last few years, noticed a whooshing sound in
her left ear when she lay on her left side at night. Ruth is a very busy woman with two
teenage daughters and an active law practice, and, as the noise did not keep her from
sleeping at night, she paid little attention to it.
One afternoon, after playing a vigorous game of tennis with her daughter, she again
became aware of the whooshing sensation in her left ear and noted that it seemed more
intense with exercise. She had intended to see her family doctor but got distracted with an
important defense and her daughter’s upcoming graduation.
Over several months, Ruth noticed the whooshing sound was almost always present
day or night, and she gradually developed problems with swallowing and a hoarse voice.
Finally, Ruth made time to see her doctor.
On general examination, Ruth’s doctor noted that she appeared fit and well. However,
when the doctor placed a stethoscope on the base of her skull on the left side, he could
hear a bruit (a whooshing sound). When he examined her cranial nerves, he found that she
had an absent gag reflex on the left side and some weakness of her left sternomastoid*
muscle. Ruth’s doctor immediately referred her to a neurosurgeon who was concerned that
this was a glomus tumor of the jugular foramen. He sent Ruth for magnetic resonance
imaging (MRI) and an angiogram. The investigations confirmed the neurosurgeon’s sus-
picions and a diagnosis of a glomus jugulare tumor was made. Ruth was subsequently
scheduled for surgery to have the tumor removed.
ANATOMY OF THE VAGUS NERVE
Vagus comes from the Latin word meaning “wandering.” The vagus nerve “wanders”
from the brain stem to the splenic flexure of the colon. Not only is the vagus the
parasympathetic nerve to the thoracic and abdominal viscera, it is also the largest vis-
ceral sensory (afferent) nerve. Sensory fibers outnumber parasympathetic fibers four
to one. In the medulla, the vagal fibers are connected to four nuclei: the spinal
nucleus of the trigeminal nerve (general sensory); the nucleus of the tractus solitar-
ius (visceral sensory); the nucleus ambiguus (branchial motor); and the dorsal vagal
motor nucleus (parasympathetic visceral motor) (Figure X–1 and Table X–1).
*Sternomastoid is a shortened form of sternocleidomastoid and will be used in this text.
182
4. 184 Cranial Nerves
Table X–1 Nerve Fiber Modality and Function of the Vagus Nerve
Nerve Fiber Modality* Nucleus Function
General sensory Of the spinal From the posterior meninges, concha, skin at the back
(afferent) trigeminal tract of the ear and in the external acoustic meatus, part of
the external surface of the tympanic membrane, the
pharynx, and larnyx
Visceral sensory Of the tractus From the larynx, trachea (caudal part), esophagus, and
(afferent) solitarius thoracic and abdominal viscera, stretch receptors in
the walls of the aortic arch, and chemoreceptors in the
aortic bodies adjacent to the arch
Branchial motor Ambiguus To the superior, middle, and inferior constrictors, levator
(efferent) palati, salpingopharyngeus, palatopharyngeus, and
one muscle of the tongue, the palatoglossus, via the
pharyngeal plexus and to cricothyroid and intrinsic
muscles of the larynx
Visceral motor Dorsal vagal motor To smooth muscle and glands of the pharynx, larynx,
(parasympathetic and thoracic and abdominal viscera
efferent) Ambiguus To cardiac muscle
*Some texts list special sense for taste as one of the components of this nerve. Because cranial nerve X carries so few taste fibers, this
modality has been omitted.
As the vagus nerve emerges through the jugular foramen, it lies within the same
dural sheath as the accessory nerve (cranial nerve XI). For a short distance, the cau-
dal branchial motor fibers of cranial nerve X travel with cranial nerve XI (some texts
call these fibers the cranial root of XI). Just beyond the inferior ganglion, all the
branchial motor fibers of cranial nerve X rejoin (Figure X–2).
In the neck, the vagus lies posterior to and in a groove between the internal jugu-
lar vein and the internal carotid artery. It descends vertically within the carotid
sheath (Figure X–3), giving off branches to the pharynx, larynx, and constrictor
muscles (Table X–2). The right recurrent laryngeal nerve branches from the right
vagus nerve in the neck. It curves below and behind the right subclavian artery to
ascend at the side of the trachea behind the right common carotid artery. The left
recurrent laryngeal nerve branches from the left vagus nerve in the thorax (Figure
X–4). It curves below and behind the aortic arch to ascend at the left side of the tra-
chea. From the root of the neck downward, the vagus nerve takes a different path
on each side of the body to reach the cardiac, pulmonary, and esophageal plexuses
(consisting of both sympathetic and cranial nerve X parasympathetic axons). From
the esophageal plexus, right and left gastric nerves arise to supply the abdominal vis-
cera as far caudal as the splenic (left colic) flexure (see Table X–2 and Figure X–4).
7. Vagus Nerve 187
Table X–2 Branches of the Vagus Nerve
Location Branch Modality
General Visceral Branchial Visceral
Sensory Sensory Motor Motor
Jugular Meningeal ✔
fossa Auricular ✔
Neck Pharyngeal ✔ ✔ ✔ ✔
Branches to carotid body ✔
Superior laryngeal ✔ ✔ ✔ ✔
Internal laryngeal ✔ ✔ ✔
External laryngeal ✔
Recurrent laryngeal (right) ✔ ✔ ✔ ✔
Cardiac ✔ ✔
Thorax Cardiac ✔ ✔
Recurrent laryngeal (left) ✔ ✔ ✔ ✔
Pulmonary ✔ ✔
Esophageal ✔ ✔
Abdomen Gastrointestinal ✔ ✔
From the nucleus of the spinal tract, second-order axons project via the ventral
trigeminothalamic tract to the contralateral ventral posterior nucleus of the thala-
mus. Thalamic neurons project through the internal capsule to the sensory cortex
of the cerebrum (see Figure X–6, inset).
VISCERAL SENSORY (AFFERENT) COMPONENT
Visceral sensation is carried in the visceral sensory component of the vagus nerve. It
is not appreciated at a conscious level of awareness other than as “feeling good” or
“feeling bad,” unlike visceral pain that is carried in the sympathetic nervous system.
Visceral sensory fibers from plexuses around the abdominal viscera converge and
join with the right and left gastric nerves of the vagus (Figure X–7). These nerves
pass upward through the esophageal hiatus (opening) of the diaphragm to merge
with the plexus of nerves around the esophagus. Sensory fibers from plexuses
around the heart and lungs also converge with the esophageal plexus and continue
up through the thorax in the right and left vagus nerves.
12. 192 Cranial Nerves
Connections via the reticulobulbar pathway (between the reticular formation
and cranial nerve nuclei in the brain stem) to the dorsal vagal motor nucleus enable
the parasympathetic fibers of the vagus nerve to control these reflex responses (see
Figure X–7, inset).
BRANCHIAL MOTOR (EFFERENT) COMPONENT
Bilateral corticobulbar fibers (fibers connecting the cortex with cranial nerve nuclei
in the brain stem) are composed of axons from the premotor, motor, and other cor-
tical areas. They descend through the internal capsule to synapse on motor neurons
in the nucleus ambiguus, a column of cells just dorsal to the inferior olivary nucleus
in the medulla. The nucleus ambiguus also receives sensory signals from other brain
stem nuclei, mainly the spinal trigeminal and solitary nuclei, initiating reflex
responses (eg, coughing and vomiting). Lower motor neuron axons leave the
nucleus ambiguus and travel laterally to leave the medulla as eight to ten rootlets.
The caudal rootlets travel briefly with cranial nerve XI, rejoining with the rostral
rootlets of cranial nerve X just below the inferior vagal ganglion (see Figure X–2).
The nerve leaves the skull through the jugular foramen to reach the constrictor mus-
cles of the pharynx and the intrinsic muscles of the larynx (see Figures X–4 and X–8).
The branchial motor fibers leave the vagus nerve as three major branches: pha-
ryngeal, superior laryngeal, and recurrent laryngeal. The pharyngeal branch, the
principal motor nerve of the pharynx, traverses the inferior ganglion and passes
inferomedially between the internal and external carotid arteries. It enters the phar-
ynx at the upper border of the middle constrictor and breaks up into the pharyn-
geal plexus to supply all the muscles of the pharynx and soft palate except the
stylopharyngeus (cranial nerve IX) and tensor (veli) palati (branchial motor com-
ponent of V3). Therefore, it supplies the superior, middle, and inferior constrictors,
levator palati, salpingopharyngeus, palatopharyngeus, and one muscle of the
tongue, the palatoglossus (many are illustrated in Figure X–8).
The superior laryngeal nerve branches from the main trunk of the vagus nerve
at the inferior vagal ganglion distal to the pharyngeal branch. It descends adjacent
to the pharynx, dividing into internal (mainly sensory) and external (motor) laryn-
geal nerves. Branchial motor axons in the external laryngeal branch supply the
inferior constrictor and the cricothyroid muscles. It also sends branches to the pha-
ryngeal plexus. The pharyngeal plexus, supplying the palate and pharynx, is formed
by branches from the external laryngeal and pharyngeal nerves, as well as branches
from cranial nerve IX and the sympathetic trunk
The recurrent laryngeal nerve, the third major branch, takes a different path on
the right and left sides of the body (see Figure X–3). The right recurrent laryngeal
nerve arises from the vagus nerve anterior to the subclavian artery, then hooks back
under the artery and ascends posterior to it in the groove between the trachea
and the esophagus. The left recurrent laryngeal nerve arises from the left vagus on
the aortic arch. It hooks back posteriorly under the arch and ascends through the
14. 194 Cranial Nerves
superior mediastinum to reach the groove between the trachea and the esophagus
on the left side. The recurrent nerves pass deep to the inferior margin of the infe-
rior constrictor muscles. The branchial motor axons supply the intrinsic muscles of
the larynx (except the cricothyroid).
VISCERAL MOTOR
(PARASYMPATHETIC EFFERENT) COMPONENT
The parasympathetic nerve cell bodies of the vagus nerve are located in the dorsal
motor nucleus of the vagus (Figure X–9) and in the medial side of the nucleus
ambiguus. Neurons in the dorsal vagal nucleus innervate ganglia in the gut and its
derivatives (lungs, liver, pancreas), whereas neurons in the nucleus ambiguus inner-
vate ganglia in the cardiac plexus. They are all influenced by input from the hypo-
thalamus, the olfactory system, the reticular formation, and the nucleus of the
tractus solitarius. The dorsal motor nucleus of the vagus is located in the floor of
the fourth ventricle (vagal trigone) and in the central gray matter of the closed
medulla. Preganglionic fibers from this nucleus traverse the spinal trigeminal tract
and nucleus, emerge from the lateral surface of the medulla, and travel in the vagus
nerve (see Figure X–1).
Within the pharynx and larynx, the vagal preganglionic axons activate gan-
glionic neurons that are secretomotor to the glands of the pharyngeal and laryngeal
mucosa. Preganglionic axons are distributed to the pharyngeal plexus through the
pharyngeal and internal laryngeal branches (see Figure X–4). Within the thorax, the
vagi take different paths, but both break up into many branches that join plexuses
around the major blood vessels to the lungs and the heart (Figure X–10). Pulmonary
branches cause bronchoconstriction, and esophageal branches act to speed up
peristalsis in the esophagus by activating the smooth (nonstriated) muscle of the
walls of the esophagus. The axons synapse in ganglia located in the walls of the indi-
vidual organs. The cell bodies of cardiac preganglionic axons are located in the
medial nucleus ambiguus. Their axons terminate on small ganglia associated with
the heart and act to slow down the cardiac cycle.
The right and left gastric nerves emerge from the esophageal plexus. These
nerves stimulate secretion by the gastric glands and are motor to the smooth mus-
cle of the stomach. Intestinal branches act similarly on the small intestine, cecum,
vermiform appendix, ascending colon, and most of the transverse colon. In the gut,
the synapses occur in ganglia of the myenteric and submucosal plexuses of Auerbach
and Meissner, respectively.
19. Vagus Nerve 199
6. What other clinical signs are seen in association with a glomus jugulare
tumor?
The glomus jugulare tumor is an invasive tumor that has multiple extensions and
will spread into any hole or fissure in the petrous temporal bone. Clinical signs are
the result of invasion of the tumor and compression of adjacent nerves. The typical
syndrome consists of a systolic bruit (abnormal sound or murmur), partial deafness,
dysphagia (difficulty in swallowing), and dysphonia (difficulty in speaking) because
of damage to cranial nerves VIII, IX, and X.
Other neurologic findings are correlated with the extension of the tumor. If the
tumor
• spreads toward the foramen magnum, there may be a cranial nerve XII palsy
(paresis or paralysis of tongue muscles);
• invades the intrapetrous carotid canal, a Horner’s syndrome, characterized by
miosis (constricted pupil), ptosis (drooping of the eyelid), enophthalmos (reces-
sion of the eyeball), and redness and dry skin on the ipsilateral face, may develop
due to sympathetic nerve involvement;
• spreads into the inner ear, there may be vestibular (balance) and cochlear (dimin-
ished hearing) involvement; or
• extends directly into the external auditory canal, a vascular tumor may be
visualized.
7. Where along the course of cranial nerve X can a lesion occur?
A lesion of the vagus nerve can occur anywhere along its course from the cortex to
the organ of innervation. An upper motor neuron lesion (UMNL) can occur any-
where between the cortex and the nucleus ambiguus. Lesions that involve these fibers
are typically ischemias (insufficient blood supply), infarcts, or tumors. Bilateral
UMNLs involving the corticobulbar tracts affect the bulbar* musculature and are
referred to as a pseudobulbar palsy. This is a misleading term as there is nothing
“pseudo” about a palsy. Spastic bulbar palsy would be a better term.
A lesion at the level of the nucleus ambiguus and below is a lower motor neuron
lesion (LMNL). A unilateral lesion of the lower motor neuron fibers results in a bul-
bar palsy (light or incomplete paralysis) of the bulbar muscles on the ipsilateral side.
Lower motor neuron lesions can occur from mass lesions compressing the pons, from
tumors of the jugular foramen, and from surgical mishaps following procedures in the
neck area such as a carotid endarterectomy or a thyroidectomy. The LMNLs also can
occur from compression of the left recurrent laryngeal nerve by lung tumors or para-
tracheal lymph nodes compressing the nerve as it passes through the thorax.
*The term bulbar means a swelling. In neurology, we use the term bulbar to refer to the
medulla and/or brain stem. Since corticobulbar tracts are those that go from the cortex to the
brain stem to synapse on nuclei there, they are named corticobulbar. Muscles supplied by
these nerves are called “bulbar” muscles.
21. Vagus Nerve 201
ADDITIONAL RESOURCES
Bradley WG, Daroff RB, Fenichel GM, Marsden CD. Neurology in clinical practice. 2nd
ed. Toronto: Butterworth-Heinemann; 1996. p. 251–63.
Brodal A. Neurological anatomy in relation to clinical medicine. 3rd ed. New York,
Oxford: Oxford University Press; 1981. p. 460, 464, 712.
Fitzerald MTJ. Neuroanatomy basic and clinical. 3rd ed. Toronto: W.B. Saunders
Company Ltd; 1996. p. 148–50.
George B. Jugulare paragangliomas. Acta Neurochir (Wien) 1992;118:20–6.
Kandel ER, Schwartz JH, Jessell TM. Principles of neuroscience. 3rd ed. New York:
Elsevier; 1991. p. 772.
Kiernan JA. Barr’s the human nervous system. 7th ed. Phildelphia, New York: Lippincott-
Raven; 1998. p. 169–74.
Kramer W. Glomus jugulare tumors. Handbook of clinical neurology. Vol 18. Amsterdam,
Holland: Baillière and Tindall; 1975. p. 435–55.
Lindsay WK, Bone I, Callander R. Neurology and neurosurgery illustrated. 3rd ed. New
York: Churchill Livingstone; 1997. p. 172–3, 343.
Nolte J. The human brain. 4th ed. Toronto: Mosby; 1999. p. 291, 306.
Sillars HA, Fagan PA. The management of multiple paraganglioma of the head and neck.
Laryngol Otol 1993;107:538–42.