Ct Brain Anatomy

BRAIN ANATOMY

Indications

Clinical indications

Trauma

Tumor and mass

Inflammatory disease

Congenital defects

Hydrocephalus

Assorted headaches

Seizure

CVA

Stroke

Hemorrhage

AVM

Types of Scans Routine brain without/with contrast Sinuses Temporal bones ( IAC ) Orbits and optic nerves Facial bones Mandible TMJ

Basic Skull Anatomy Mandible Maxilla Zygomatic Bone Temporal Bone Frontal Bone

Basic Skull Anatomy Parietal Occipital Temporal Frontal Zygomatic Maxilla Mandible Sphenoid

ANATOMY Cranium (8) Bones - surround and protect the brain Occipital (1) Temporal (2) Sphenoid (1) Ethmoid (1) Parietal (2) Frontal (1)

ANATOMY Cranium (8) Bones Occipital (1) - Forms inferiorposterior portion of the cranium -Foramen magnum -Prominent bump, EOP, Inion

ANATOMY Temporal (2) - Contain many complex structures -Forms both sides of the base of the cranium. -Ant.- Zygomatic Arches, -Petrous pyramids -TMJ, EAM, IAM -Hearing, balance, equilibrium -Jugular foramina & Carotid canals

ANATOMY Sphenoid (1) - Butterfly shaped bone -(3) Major parts; a . body, b. lesser wings, c. greater wings -Body contains the ST, houses the pituitary gland(hypophysis) Body of Sphenoid

ANATOMY Ethmoid (1) - Smallest of cranial fossa bones -Cube shaped, divides into (4) parts; 1 . Horizontal portion (cribriform plate)(horizontal plate) contains olfactory nerves, Crista galli which anchors the brain to the anterior cranial fossa. 2. Vertical portion (perpendicular plate) – forms bony nasal septum 3&4 . two lateral masses (labyrinths), thin walls containing Ethmoid air cells. Also contain middle and superior nasal conchae (turbinate's)

ANATOMY Parietal (2) - 2 sides form most of the cranium -Superior aspect (vertex) each side is somewhat square in shape and have a concave internal surface.

ANATOMY Frontal (1) Vertical portion: -Squamous (forehead), anterior vault -Frontal sinuses -glabella Horizontal Portion -Forms roof of ea. Orbit (orbital plate)

ANATOMY FACIAL BONES (14) Nasal (2) Lacrimal (2) Maxilla (2) Zygoma (2) Palantine (2) Inferior Nasal Conche (2) Vomer (1) Mandible (1)

ANATOMY FACIAL BONES (14) Nasal (2) The nasal bones are two small oblong bones , varying in size and form in different individuals; they are placed side by side at the middle and upper part of the face , and form, by their junction, "the bridge" of the nose .

ANATOMY FACIAL BONES (14) Lacrimal (2) The lacrimal bone , the smallest and most fragile bone of the face, is situated at the front part of the medial wall of the orbit . It has two surfaces and four borders.

ANATOMY FACIAL BONES (14) Maxilla (2) The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper jaw . This is similar to the mandible , which is also a fusion of two halves at the mental symphysis

ANATOMY FACIAL BONES (14) Zygoma (2) The zygomatic bone ( malar bone ) is a paired bone of the human skull . It articulates with the maxilla , the temporal bone , the sphenoid bone and the frontal bone . It forms part of the orbit and is commonly referred to as the cheekbone

ANATOMY FACIAL BONES (14) Palantine (2) The palatine bone is a bone in the palate (Latin palatum ; unrelated to palatium 'palace', from which other senses of palatine derive

ANATOMY FACIAL BONES (14) Inferior nasal conchae (2) The inferior nasal concha ( Inferior Turbinated Bone ) is one of the turbinates in the nose . It extends horizontally along the lateral wall of the nasal cavity [Fig. 1] and consists of a lamina of spongy bone , curled upon itself like a scroll.

ANATOMY FACIAL BONES (14) Volmer (1) The vomer (from Latin vomer, -ĕris , "ploughshare") is one of the unpaired facial bones of the skull . It is located in the midsagittal line, and touches the sphenoid , the ethmoid , the left and right palatine bones, and the left and right maxillary bones

ANATOMY FACIAL BONES (14) Mandible (1) The mandible (from Latin mandibūla , "jawbone") or inferior maxillary bone is, together with the maxilla , the largest and strongest bone of the face [ citation needed ] . It forms the lower jaw and holds the lower teeth in place.

ANATOMY ORBITS (2) In anatomy , the orbit is the cavity or socket of the skull in which the eye and its appendages are situated. It can also mean the skin which surrounds the eye of a bird. In the adult human, the volume of the orbit is 30 ml, of which the eye occupies 6.5 ml. [1]

ANATOMY ORBITS - Cone shaped structure -Surrounds and protects the eyeball ( Oculus Bulbous) -Created by the junction of the sphenoid, frontal and Ethmoid bone of the cranium -Also created by the junction of the Lacrimal, palatine, maxillary and Zygoma bones of the face.

ANATOMY ORBITS (3) OPENINGS

Superior Orbital Fissure

Inferior Orbital Fissure

Optic Canal

REVIEW OF H.U. NUMBERS Typical HU Values: Air –1000 Fat –100 to –40 Water 0 Watery fluid (e.g. CSF) 0–20 White matter 20–35 Gray matter 30–40 Blood clot 55–75 Calcification >150 Bone 1000 Metallic foreign body >1000 Brain

BRAIN IS SURROUNDED AND PROTECTED BY MENINGES

MENINGES

DURA MATTER – TOUGHEST, BETWEEN IT ARE MENINGEAL ARTERIES AND DURAL SINUSES.

ARACHNOID – DELICATE TRANSPARENT, SEPARATED FROM DURA M. BY SUBDURAL SPACE.

PIA MATTER – HIGHLY VASCULAR, ADHERES TO THE CONTOURS OF BRAIN. SUBARACHNOID SPACE SEPARATES PIA M. FROM ARACHNOID S.

DURAL FOLDS

FALX CEREBRI – SEPARATES TWO HEMISPHERES

TENTROIUM CEREBELLI - SEPARATES THE CEREBRUM AND CEREBELLUM

TENTROIUM CEREBELLI

FALX CEREBRI

VENTRICLES

PATHWAY FOR CIRCULATION OF CSF

VENTRICLES COMMUNICATION

LATERAL VENTRICLES - L & R- SEPTUM PELLUCIDUM

LATERAL AND III – FORAMEN OF MONROE

III AND IV – AQUEDUCT OF SYLVIUS

LATERAL VENTRICLES L.V.

L.V. O. HORN CHOROID PLEXUS L.V. III V.

IV V. T. C.

CEREBRUM

CONSISTS OF W. MATTER AND G. MATTER.

C. CORTEX – OUTERMOST PORTION OF CEREBRUM.

CORPUS COLLOSUM – WHITE MATTER BUNDLE CONNECTS R & L CEREBRAL HEMISPHERES.

CEREBRAL LOBES FUNCTIONS

CEREBRAL CORTEX IS ARREANGED IN FOLDS OF G. MATTER- GYRI. THE GYRI ARE SEPARATED BY SHALLOW GROOVES – SULCI AND DEEPER GROOVES - FISSURES.

MAIN FISSURES

LONGITUDINAL

SYLVIAN

Sylvian Fissure L.V. L.V. III.V.

LIMBIC SYSTEM – The limbic system is a term for a set of brain structures including the hippocampus and amygdala that support a variety of functions including emotion, behavior and long term memory. The structures of the brain described by the limbic system are closely associated with the olfactory structures. [1] The term "limbic" comes from Latin limbus , meaning "border" or "edge".

LIMBIC SYSTEM

HIPPOCAMPUS (Required for the formation of long-term memories

AMYGDALA (Involved in signaling the cortex of motivationally significant stimuli such as those related to reward and fear in addition to social functions such as mating.

FORNIX (carries signals from the hippocampus to the mammillary bodies and septal nuclei.

OLFACTORY BULBS (Olfactory sensory imput)

MAMILLIARY BODIES (Important for the formation of memory)

DAMAGE TO THE HIPPOCAMPUS RESULTS IN LOSS OF MEMORY!!!

LIMBIC SYSTEM

LIMBIC SYSTEM AMYGDALA . HIPPOCAMPUS

Basal Ganglia

The basal ganglia (or basal nuclei ) are a group of nuclei in the brain interconnected with the cerebral cortex, thalamus and brainstem. Mammalian basal ganglia are associated with a variety of functions: motor control, cognition, emotions and learning.

BASAL GANGLIA

LENTIFORM NUCLEUS

CAUDATE NUCLEUS

CLAUSTRUM

THALAMUS

LENTIFORM NUCLEUS

LENTIFORM NUCLEUS (The lentiform nucleus or lenticular nucleus comprises the putamen and the globus pallidus within the basal ganglia. It is a large, cone-shaped mass of gray matter just lateral to the internal capsule.

CAUDATE NUCLEUS

CAUDATE NUCLEUS (is a nucleus located within the basal ganglia of the brains of many animal species. The caudate, originally thought to primarily be involved with control of voluntary movement, is now known to be an important part of the brain's learning and memory system.

CLAUSTRUM

The claustrum (latin for barrier) is a thin layer of grey matter lying between the extreme capsule and external capsule in the brain. The thickness of this layer is 1-2 mm. The external capsule separates the claustrum from nucleus lentifromis . The extreme capsule on the other side separates it from the grey matter of the insula . Its function is not completely known, although it has reciprocal connections with the cerebral cortex.

THALAMUS

The thalamus is a pair and symmetric part of the brain. It constitutes the main part of the diencephalon.

L.V. Caudte Nucleus Head Thalamus LENTIFORM NUCLEUS Fornix.

BRAIN STEM: T he brain stem is the lower part of the brain, adjoining and structurally continuous with the spinal cord. Most sources consider the pons, medulla oblongata, and midbrain all to be part of the brainstem. [1]

Caudate nucleus Internal capsule Thalmus Lentiform nucleus

PONS IV V.

CE

CE.

CE

CEREBRAL VASCULAR SYSTEM

BLOOD BRAIN BARRIER- CAPILLARIES IN THE BRAIN DO NOT ALLOW MOVEMENT OF CERTAIN MOLECULES FROM THEIR VASCULAR COMPARTMENT INTO THE SURROUNDING BRAIN TISSUE. PATHOLOGY CAN DISRUPT THE INTEGRITY OF BBB ALLOWING CONTRAST TO ESCAPE FROM VESSEL INTO SURROUNDING TISSUE.

CEREBRAL CIRCULATION

C.C. I.C. E.C. V.A. B.A.

COW

1. Right middle cerebral artery 2. Left anterior cerebral artery 3. Anterior communicating artery 4. Right posterior cerebral artery 5. Junction of basilar artery 6. Left internal carotid artery

ICA ACA VA BA

VENOUS DRAINAGE OF THE BRAIN: COMPRISED PRIMARILY BY THE DURAL SINUSES, SUPERFICIAL CORTICAL VEINS, AND DEEP VEINS OF CEREBRUM.

VENOUS DRAINAGE

DURAL SINUSES

Crainal Nerves Olfactory (I) Optic (II) Oculomotor (III) Trochlear (IV) Trigeminal (V) Abducens (VI) Facial (VII) Vestibulocochlear (VIII) Glossopharyngeal (IX) Vagus (X) Hypoglossal (XII) Accessory (XI)