Head and Neck Anatomy

Head and Neck Anatomy

• The body of the sphenoid bone and pituitary fossa relate to the pituitary gland.
• The ethmoid bone is associated with the olfactory bulb.
• The foramen ovale transmits the mandibular division of the trigeminal nerve (CN5).
• The foramen rotundum transmits the maxillary branch of CN5.
• The internal auditory meatus transmits the facial (CN7) and vestibulocochlear (CN8) nerves, and labyrinthine arteries.
• The mandibular branch of CN5 passes through foramen ovale (foramen 1).
• The middle meningeal artery passes through foramen spinosum (foramen 2).
• Features of the anterior cranial fossa:
  • Frontal lobe
  • Floor formed by ethmoid and sphenoid
  • Bordered by frontal bone and lesser wing of sphenoid
• The inner ear is found in the petrous temporal bone.
• Fractures at the pterion can rupture the middle meningeal artery and cause epidural hematoma.
• The vessel in the illustration enters the skull through the carotid canal (internal carotid).
• The anterior cerebral artery supplies the medial frontal cortex
• The pterion is at the junction of the frontal, parietal, temporal, and sphenoid bones.
• A skull fracture at the pterion may rupture the middle meningeal artery and cause an epidural hematoma.
• The pituitary fossa resides in the sphenoid bone.

Posterior Cerebral Circulation Angiogram

• Structure A is the posterior cerebral artery.
• Structure B is the basilar artery.
• Structure C is the posterior inferior cerebellar artery.
• Structure D is the vertebral artery.
• The posterior cerebral artery (A) supplies the occipital lobe and the inferior part of the temporal lobe.

Anterior Spinal Artery Occlusion

• Complete occlusion of the anterior spinal artery at the mid-thoracic level leads to motor paralysis and loss of pain and temperature sensation below the occlusion.

Cerebral Cortex Blood Supply

• The anterior cerebral artery supplies the medial hemisphere running with the corpus callosum.
• The middle cerebral artery supplies the lateral hemisphere.
• The posterior cerebral artery supplies the temporal lobe and visual cortex in the occipital lobe.
• Occlusion of the anterior cerebral artery, which supplies the medial hemisphere, causes loss of motor and sensory function in the lower limbs, apraxia, and anosmia.
• Occlusion of the internal carotid artery causes loss of motor and sensory function in lower limb (contralateral).

Cerebral Angiogram Identification

• Vessels A, B, and C are posterior cerebral, basilar, and vertebral arteries
• Vessel A is the internal carotid artery.
• Vessel B is the middle cerebral artery.
• Vessel C is the anterior cerebral artery.
• Vessel A enters the skull through the carotid canal (near foramen lacerum).
• Vessel C supplies the medial hemisphere (frontal lobes and superior medial parietal lobes).
• Vessel A enters the skull via foramen magnum.
• Vessel B is the basilar artery.
• Vessel C is the posterior cerebral artery.
• Area D is the occipital lobe.
• Area D's major function, the visual cortex, is for visual processing.
• Vessel A (internal carotid) enters the skull through the carotid canal.
• Vessel B is the anterior cerebral artery.
• One blood vessel arising directly from A (internal carotid) is the middle cerebral artery.
• Vessel B supplies the medial hemisphere (frontal lobe medial, superior medial parietal lobes).
• Occlusion of vessel B could cause contralateral loss of motor and sensory function of the lower limb.

Effects of Blood Vessel Blockage in the CNS

• Blockage of the left anterior cerebral artery causes loss of motor and sensory function in the right leg.
• Blockage of the right middle cerebral artery causes loss of motor and sensory function in the left arm.
• Blockage of the left posterior cerebral artery causes loss of right hemifield vision (homonymous hemianopsia).
• Blockage of anterior spinal artery branches to the medial medulla causes medial medullary syndrome, including tongue deviation to the ipsilateral side, ipsilateral muscle weakness, contralateral limb weakness, and loss of discriminative touch and conscious proprioception.
• Blockage of hypothalamo-hypophysial portal veins causes hypothyroidism (Paickardt syndrome).
• The Circle of Willis is located in the interpeduncular cistern, enclosing the optic chiasm.
• The anterior cerebral artery, along the longitudinal fissure and following the corpus callosum, supplies the medial aspect of the frontal and parietal lobe
• The middle cerebral artery enters the lateral fissure, supplying the lateral aspect of frontal, parietal and temporal lobes; occlusion results in contralateral upper limb motor function and sensation loss.
• The superior sagittal sinus allows blood to drain from lateral aspects of anterior hemispheres, CSF drains through arachnoid granulations into superior sagittal sinus, drains into transverse sinus.
• Rupture of the middle meningeal artery leads to epidural hematoma due to pterion fracture.

Vasculature of the Central Nervous System

• The vertebral artery enters through the foramen magnum and sends branches to the anterior spinal and posterior inferior cerebellar arteries, derived from the subclavian artery.
• The vascular structure most commonly involved in extradural hemorrhage: middle meningeal artery.
• The blood-brain barrier distinguishes blood from brain ECF; it forms from endothelial cells, astrocytes, and pericytes.
• Vertebral arteries unite to create the basilar artery that supplies blood to the brainstem.
• The internal carotid arteries typically supply the anterior and middle cerebral arteries, as well as the anterior and posterior communicating arteries.
• Occlusion of middle cerebral arteries is likely to cause contralateral loss of motor and sensory function in the upper limbs.
• Posterior cerebral arteries vascularize the occipital lobe and the inferior part of the temporal lobe.
• The Circle of Willis sits in the interpeduncular cistern, encloses the optic chiasm, composed of anterior and posterior cerebral, communicating arteries, internal carotid (middle cerebral branches off from here), basilar artery.
• Vessel 1 is the posterior communicating artery.
• Vessel 2 is the basilar artery.
• Vessel 3 is the vertebral artery.
• Vessel 3 enters the skull through the foramen magnum.
• Occipital lobe(s) regions can be affected if vessel 1 is blocked.
• The illustrated vessel enters via the carotid canal.
• The anterior cerebral artery nourishes the medial frontal cortex.
• The pterion sits at the junction of the frontal, occipital, temporal, and sphenoid bones.
• A fracture at the pterion could lead to a middle meningeal artery rupture, causing an epidural hematoma.
• The pituitary fossa sits in the sphenoid bone.
• The main illustrated vessel enters the skull through the foramen magnum.
• The posterior cerebral artery mainly supplies the visual cortex bordering the calcarine sulcus.
• The labyrinthine artery to the inner ear stem from the anterior inferior cerebellar/basilar/posterior inferior cerebellar artery.
• Rupture of a berry aneurysm on the posterior communicating artery will trigger oculomotor nerve palsy.
• Superficial cerebral veins from the frontal cortex drain into the superior sagittal sinus.

Eye Reflexes

• The afferent and efferent nerves in the corneal blink reflex: Trigeminal (V, ophthalmic branch) is the afferent nerve and the Facial (VII) is the efferent nerve.
• The afferent and efferent nerves involved in the corneal papillary reflex are the Optic (II) nerve (afferent) and the Oculomotor (III) nerve (efferent).
• The ciliary body controls the lens, causing pupillary constriction.
• The optic disc, also called the blind spot, is the place where the optic nerve takes off with lack of photoreceptors.
• The cornea is the font of eye, containing limiting lamina, and collagen mesh of fibers at front.
• Sclera has a hole where the optic nerve exits, named the lamina cribosa, made of collagen mesh.

Eye functions

• The ciliary body contracts the lens, causing pupillary constriction.
• The vitreous chamber, or posterior chamber, slows down the light path.
• The iris regulates the size of the pupil.
• Conjunctiva is the mucous membrane covering the eyes, lines the inside of the eyelids.
• The neural pathways of accommodation reflex: Optic (CN2) is afferent, Oculomotor (CN3) is efferent.
• The pupillary light reflex:
• Afferent nerve: optic 2 .
• Termination site: pretectal nuclei.
• Efferent nerve: occulomotor 3.
• Origin nucleus of the efferent nerve: EDW nucleus.
• Supplied muscle: sphincter muscle.

Eye movement muscles

• The medial rectus muscles control convergence of the eyes.
• Action of the superior oblique muscle is: Intorsion (down and out).
• Action of the inferior oblique muscle is: Extorsion (up and out).
• Posterior commissure interconnects the oculomotor nuclei.
• The Abducens nerve 6 innervates the lateral rectus muscle.
• The Vestibulo-ocular reflex is used in tracking moving targets.

Anterior chamber of eye functions

• A cornea

• B Canal of Schlemm

• C Ciliary body

• D Iris

• E Conjunctiva

• Aqueous humor is in the anterior chamber.

• The iris and ciliary bodies control pupil dilation.

• The retina's rod system dim lighting and not found at the fovea.

• Horizontal cells relay visual information laterally.

• The optic nerve in the orbit leave at lamina cribosa, at blind spot that has no photoreceptors.

• When one eye is illuminated the other eye dilates consensually.

• The afferent nerve of the reflex is the optic nerve 2.

• The site of termination of the afferents involved in this reflex is the pretectal nucleus.

• The origin nucleus of the efferent nerve of the reflex is the EDW nucleus.

• The efferent nerve of the reflex is the oculomotor nerve 3.

Eye Muscles

• Medial rectus causes adduction.
• Superior oblique causes down and out, and intorsion.
• Lateral rectus abduction.
• Inferior oblique up and out which is extorsion.
• If the ciliary muscle contracts, the lens is more spherical and pupil constricts.

Visual System Structures

• The diagram’s structure involved in drainage of aqueous humour: canal of Schlemm (L).
• The diagram’s structure involved in controlling the accommodation is D.
• The posterior chamber of the eye is represented as structure B.
• Increased intracranial pressure causes papilledema that is displayed as structure A .
• The cranial nerve that supplies parasympathetic fibres to the pupillary constrictor muscle: G.

Eye functions

• Drainage of aqueous humour relies on the Canal of Schlemm (L).
• The ciliary body (D) actively controls accommodation
• The lens and its curvature form the image.
• Increased intracranial pressure leads to papilloedema.
• Occuolomotor nerve 3 provides fibres to pupillary constrictor muscle.

Ear structures

• A Organ of Corti
• B Tectorial membrane
• C Stria vascularis
• Space D contained scala media, which contains endolymph, 150mM of K+.
• Neurons cells synapse in the cochlear nuclei in the medulla.
• Tympanic membrane, Eustachian tube, Ossicles (malleus, incus, stapes) are the functional components of the middle ear.

Ossicles and other parts of the inner ear

• The ear ossicles improve sensitivity to sound by concentrating vibrations.
• Stapedius controls the movement of the stapes.
• Tympanic Branch the facial nerve 7, which is muscle causing movement of the stapes.
• The fluid found in the scala media contains a high concentration of K+.
• The Organ of Corti sits on the basilar membrane.

The Auditory system

• Structure 1 lies on top of the A (Organ of Corti lies on top of the basilar membrane).

• Space 2 is filled by G (perilymph).

• Structure 3 contains K (auditory nerve fibres).

• Structure 4 is F (Stapes).

• Structure 5 is J (Stapedius).

• Basilar membraneA.

• Tympanic membrrane B.

• innervated facial nerve C.

• endolymph D.

• Stria vascularisE.

• Stapes bone off middle earF.

• PerilymphG.

• Innervated hyopglosssal nerve H.

• Tectorial membrean I.

• Stapedios muscle J.

• Auditory nerve fibers K.

• Smooth muscle L.

• he tympanic membrane normally cones inward toward the middle ear. True.

• The baseplate of the stapes is inserted into the oval window. True.

• Stapedius muscle isn't controlled by the trigeminal nerve. False.

• the composition of endolymph snot similar to that of extracellular fluid. False.

• nner hair cells receive more sensory auditory nerve fibers than outer hair cells True.

Development of the CNS

• Retina develops from diencephalon (outgrowth of the forebrain, ectodermal)
• Blockage of the ventricular system causes hydrocephalus, leading to CSF accumulation in the skull.
• Spinal motor neurons form in ventral notochord, basal plate, sensory neurons form in dorsal notochord, alar plate.
• Adult neurogenesis is described in the olfactory bulb, subventricular zone (in lateral ventricles) and dentate gyrus (in hippocampus).
• Failure of neural tube closure at the rostral end is what causes anencephaly
• Neural crest derivativeis somatic, sensory, autonomic (sympathetic, parasympathetic, enteric)
• Telencephalon expansion causes to the development of the cortex and basal ganglia
• The dorsal notochord creates the substantia gelatinosa
• The adult neurogenesis occurs to the olfactory bulb, subventricular zone (in lateral ventricles) and dentate gyrus (in hippocampus).
• Medial longitudinal fasciculus interconnects occulomotor nuclei and the vestibular system as well as tectospinal, which controls neck movements.
• The ocullomortor nuclei are connected thru medial longitudinal fasciculus.
• In choroid plexus sites, the production of cerebrospinal fluid occurs thru the ependymal cells.
• The absorption of the cerebrospinal fluid occurs thru arachnoid villi and granulations.

Conditions and Symptoms

• Blocked absorption in babies cases hydrocephaly (increased intracranial pressure).
• Ocular signs of high intracranial pressure, in adults, triggers vision optic disk swelling

The Inner Capsule

• The origin of the the internal capsule separate the caudate nucleus to the thalamus and the lentiform nucleus which is (putamen, globus pallidus).
• Connective membranes surrounding to the brain and spinal cord, dura mater, arachnoid mater, and pia mater
• Middle meningeal vessels supply this dura.
• Extradural results with blood accumulation this blood vessel rupture.

Cranial Nerves

• Nucleus and nerve that carries fibers
• Edinger Westphal occurs with the Oculomotor (3),
• Nucleus ambiguus and nerves and Vagus (10); and
• Solitarius is the Facial (7), Glossopharyngeal (9), Vagus (10).
• Blood that accumulates is with extradural.
• Corticospinal axons is in the cortex (layer 5 pyramidal, primary motor cortex, SMA and premotor cortex).
• The corticospinal moves over thru the the internal capsule.
• The pyramid will goes out as ventral.
• The contralateral corticospinal will proceed as the lateral funiculus.
• and final axon destination to Corticospinal axons is the ventral columns.
• Cerebrospinal fluid created is the choroid plexus thru dendymail cells.
• And the k potassium amount is low. And CL- is with high concentrations.
• The CSF will goes thru to the third to the fourth.
• Layer in the meningitis does archnoid and pain.
• CSF recicrular thru archnoid.

CSF

• CSF production happens in the choroid plexus that is in cells in the lateral region.
• Foramen foramen connects the lateral regions.
• Protein is with low concentrations, proteins as they happen.
• Apetertuess from the and magdenie and the laterasls will leave.
• The is letter, has the is with.

Neurons that carry fibers

• site of cell neurons projecting from the body, which takes the thalamus to the a-delta fibres or with to it.
• the track for with the cereberral. The spinal, that happens to its spinal cord
• with fibers.
• tract carrying sensory is from
• and that modulates fiber, with the pain

Various Locations of the Brain

• bodies to the
• ipsilateral
• with
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• ird

Corpus Callosum and brain tracts

A - ascending B - descending

Actions of lesions and nerves

• The lesion shows with the facial of fore arm and body.
• Most neurons cross line will form anterior with with.

Brain Functions

• Lateral geniculate vision

• Inferior audition

• Nigra reward addticion

• And olivery cebeular and suditions

• Power affecting: with the and brain or, and it what

• And tone is:

• Pathological is shown

Actions

• structure in the abcd. To brain

Cerebrospinal Function and Production

• Cerebrospinal fluid from the choroid plexus in the lateral ventricle.
• The fluid goes 4th ventricle via the cerebral aqueduct, and next to the subarachnoid space via Foramen Magendie medially, Foramen of Luschka laterally.
• Comparison with plasma contains the lesss Ki: and it has the less Pro, and it will contains the most Sodium Chloride, its going to the the arach noid in the a subdura.
• Location 5 corpus csoum:
• The spinal tract for 3 for fore leg

Tracts of touch

• And to its is has.
• And the brain of

Corpus Callasom

• With to the and and with to brain
• Of as.
• to brain

More areas that will

• Right
• And