Anatomy Lesson 5 - Somatic and Structural Neuroanatomy

Vestibulocochlear nerve

Which cranial nerve doesn’t leave the cranial vault?

Olfactory bulbs

paired swellings at the rostral end of the ventral brain, receives the olfactory nerve

longitudinal fissures

deep midline groove on the dorsal surface between the two hemispheres

gyri and sulci

folds (gyri) and grooves between (sulci)

optic chiasm

x on the ventral midline, rostral to the pituitary stalk where the two optic nerves meet

olfactory nerve

many fine threads passing through the nasal cavity, smell, purely sensory

optic nerve (CN I)

thick nerves running caudally from the eyeball to the cranial vault, vision, purely sensory

optic nerve

afferent nerve of the menace response and pupillary light reflext

Oculomotor nerve (CN III)

Leaves the ventral surface of the midbrain just caudal to the optic chiasm, innervates the dorsal, medial, ventral rectus muscles and the ventral oblique muscles

Oculomotor nerve (CN III)

constricts pupils, raises upper eyelid and keep the eye from drifting ventrolateral

Trochlear Nerve (CN IV)

Thinnest cranial nerve and the only one leaving the dorsal surface of the brain stem from caudal mid brain, innerves the dorsal oblique muscle which rotates the dorsal pole of the eye medially

Trigeminal Nerve (CN V)

Thickest cranial nerve, leaves the lateral surface of the pons pertains to sensations of the face, cornea and nasal cavity

trigeminal nerve (CN V)

injury to this nerve causes masseter muscle wasting

Abducent Nerve (CN VI)

Leaves the ventral surface of the medulla oblongata on the midline and runs rostrally into the orbit.

Abducent Nerve (VI)

Innervates the lateral rectus and retractor bulbi, injury leaves a medial strabismus and an eye that cannot retract if the cornea is touched

Facial Nerve (CN VII)

Leaves the lateral surface of the medulla oblongata beside the vestibulocochlear nerve, emerges ventral to the base of the ear canal

Facial Nerve (CN VII)

injury cuases the face to droop and causes food to pocket due to lack of functioning buccinator

Vestibulocochlear Nerve (CN VIII)

Short, stout nerve on the lateral medulla oblongata, in charge of hearing and balance. Disease can cause head tilt

Glossopharyngeal Nerve (IX)

Fine rootlets on the lateral surface of the medulla oblongata, caudal to the vestibulocochlear nerve. In charge of sensation and taste from the caudal third of the tongue and pharynx

Glossopharyngeal Nerve (CN IX )

Parasympathetic to the parotid and zygomatic salivary glands and with the vagus nerve, the afferent and efferent nerve of the gag reflex

Vagus Nerve (CN X)

Rootlets immediately caudal to the glossopharyngeal nerve on the lateral medulla oblongata. Descends the neck in the vagosympathetic trunk with the common carotid

Vagus Nerve (CN X)

serves as motor to the pharynx and larynx (via recurrent laryngeal nerve) and parasympathetic to the heart, lungs and the gut as far as to the transverse colon

Accessory Nerve (XI)

Rootlets ascending along lateral surface of the cervical spinal cord, joining the vagus nerve to leave the cranial vault and then running caudally in the neck

Accessory Nerve (XI)

Motor to the the trapezius, omotransversarius, sternocephalicus and the cleidocervical part of the brachiocephalicus that help move the head and neck on the shoulder

Hypoglossal Nerve ( II)

caudal rootlets on the ventral surface of the medulla oblongata. Motor to every muscle of the tongue, intrinsic and extrinsic

Dorsal root

Sensory fibers enter the spinal cord through this

Ventral root

motor fibers leave the spinal cord through this

Spinal Nerve

Short trunk formed at the intervertebral foramen where the dorsal and ventral roots join

Cauda Equina

bunde of nerve roots continuing caudally past the end of the spinal cord

Brachial plexus

in the axilla, medial to the shoulder joint, formed by the ventral branches of the spinal nerves. Origin of every nerve of the thoracic limb

Suprascapular nerve

leaves the cranial part of the brachial plexus, innervates the supraspinatus and the infraspinatus

Musculocutaneous nerve

Runs distally on the medial surface of the arm, cranial to the brachial artery. Innvervates the biceps brachii, brachialis and the coracobrachialis

axillary nerve

leaves the brachial plexus caudal to the shoulder joint, innervates the deltoideus, teres major and teres minor that flex the shoulder joint

Radial nerve

largest nerve of the brachial plexus, passes caudal to the humerus between heads of the triceps brachii. Innervates the triceps brachii and every extensor muscles of the elbow, carpus and digits

Median nerve

runs distally on the medial surface of the arm, innervates the flexor muscles of the carpus and digits together with the ulnar nerve

ulnar nerve

innervates the flexor carpi ulnaris and part of the deep digital flexor. Runs caudal to the medial epicondyle of the humerus where it lies directly under the skin