Overview and Osteology of the Cranial Nerves

CN VI

Abducens Motor (lateral movement of the eyeballs at lateral rectus muscle)

CN I

Olfactory Nerve Smell (Special Sensory)

What is Cranial Nerve XI? Through what foramen/foramina does it exit the cranial cavity?

Spinal accessory Enters by the foramen magnum; exits by jugular foramen (into the neck)

List the twelve cranial nerves by number and by name.

1 - olfactory 2 - optic 3 - oculomotor 4 - trochlear 5 - trigeminal 6 - abducens 7 - facial 8 - vestibulocochlear 9 - glossopharyngeal 10 - vagus 11 - spinal accessory 12 - hypoglossal

CN V

3 branches: 1. Opthalmic branch of Trigeminal Nerve: -General Sensory (From eye, top of nose, forehead) 2. Maxillary branch of Trigeminal Nerve: -General Sensory (from top lip, cheeks bones, temple) 3. Mandibular Branch of Trigeminal Nerve (mixed): -General Sensory (bottom lip, scalp, anterior 2/3 tongue, mucosa, jaw) -Skeletal Motor (muscles of mastication)

What is Cranial Nerve VI? Through what foramen/foramina does it exit the cranial cavity?

Abducens Exits the superior orbital fissue (into the orbit)

What is Cranial Nerve VII? Through what foramen/foramina does it exit the cranial cavity?

Facial The internal acoustic meatus transmits it to and from the facial canal (a bony canal in the petrous temporal bone)

CN VII

Facial nerve 3 branches Motor branch: Skeletal motor (facial expression, stapedius muscle of inner ear, neck muscles) EXITS STYLOMASTOID FORAMEN Chorda Tympani branch: Visceral Motor (To submandibular ganglion in mouth- salivary glands) Greater Petrosal Branch: Visceral Motor (to Pterygopalatine ganglion- innervates lacrimal gland)

What is Cranial Nerve IX? Through what foramen/foramina does it exit the cranial cavity?

Glossopharyngeal Exits the jugular foramen (into the neck)

CN IX

Glossopharyngeal Nerve **General Sensory (Main function)(tongue, pharynx, and tympanic membrane) Taste Sensory(taste posterior 1/3 of tongue) Visceral Sensory(blood oxygen content/ BP from carotid body and carotid sinus) Visceral Motor(Otic Ganglion- innervates parotid salivary gland) Skeletal Motor (least significant)(Pharynx)

Specify the functional nerve modalities specific to each of the following primary branches of CN VII: motor branch, chorda tympani and greater petrosal.

Greater petrosal:*visceral motor- glands (preganglionic parasympathetic to pterogopalatine ganglion) -innervate the lacrimal gland and mucus-producing glands in the nose and along the palate; also carries taste from soft palate Motor branch:*skeletal motor(somatic efferent)- facial movement, stapedius muscle of the middle ear, and some of the suprahyoid muscles in the neck Chorda tympani:*visceral motor- preganglionic parasympathetic to submandibular ganglion *taste sensory- anterior 2/3 of tongue

What is Cranial Nerve XII? Through what foramen/foramina does it exit the cranial cavity?

Hypoglossal Exits hypoglossal canal of the occipital bone (into the neck)

CN XII

Hypoglossal Nerve Skeletal Motor (muscles of the tongue *swallowing*)

CN III

Oculomotor *SUPER MOTOR* Visceral Motor (preganglionic sympathetic neurons to Ciliary Ganglion: controls ciliary muscles) **causes pupillary constriction, and lens accommodation* Skeletal Motor (extra ocular muscles to rotate eye, raise eyelid)

What is Cranial Nerve III? Through what foramen/foramina does it exit the cranial cavity?

Oculomotor Exits superior orbital fissure between lesser and greater wings of sphenoid bone (which puts it in the orbit)

List the four cranial nerves that transmit autonomic (preganglionic parasympathetic) nerve fibers from the brainstem.

Oculomotor (III) - synapse in ciliary ganglion Facial (VII) - synapse in pterygopalatine ganglion or submandibular ganglion Glossopharyngeal (IX) - synapse in otic ganglion Vagus (X) - distribute to terminal ganglia and do NOT distribute to head and neck structures

What is Cranial Nerve I? Through what foramen/foramina does it exit the cranial cavity?

Olfactory Exits through the cribiform plate of the ethmoid bone (which puts it in nasal cavity)

What is Cranial Nerve II? Through what foramen/foramina does it exit the cranial cavity?

Optic Exits optic canal of the sphenoid bone (which puts it in the orbit)

CN II

Optic Nerve Sight (Special Sensory)

CN XI

Spinal Accessory Nerve Skeletal motor (sternocleidomastoid and trapezius muscle)

What is Cranial Nerve V? Through what foramen/foramina does it exit the cranial cavity?

Trigeminal Opthalmic - Exits superior orbital fissure (into the orbit) Maxillary - Exits foramen rotundum of sphenoid bone (into the pterygopalatine fossa) Mandibular - Exits foramen ovale of sphenoid bone (into the infratemporal fossa)

What is Cranial Nerve IV? Through what foramen/foramina does it exit the cranial cavity?

Trochlear Exits superior orbital fissure (which puts it in the orbit)

CN IV

Trochlear Nerve Skeletal motor (Superior oblique muscle: internal rotation, abduction, and depression)

List the three divisions of the trigeminal nerve and specify the functional nerve modalities specific to each.

V1 ophthalmic - somatic afferent - sensory info from the eye, anterosuperior aspect of the nose and upper face, anterior scalp, ethmoidal, frontal and sphenoidal sinuses and portions of dura mater in the cranial cavity V2 maxillary - somatic afferent - Sensory info from posteroinferior aspect of the nose, the midface and temple region of the scalp, palate and upper jaw, maxillary dentition, maxillary sinus and portions of the dura mater in the cranial cavity V3 mandibular - somatic afferent and somatic efferent - Sensory info from lower face, scalp, tongue mucosa , mandibular dentition and portions of the dura in the cranial cavity; Proprioceptive info about the muscles of mastication and jaw position Somatic efferent fibers to muscles

What is Cranial Nerve X? Through what foramen/foramina does it exit the cranial cavity?

Vagus Exits the jugular foramen (into the neck)

CN X

Vagus Nerve (DOES ALL EXCEPT SPECIAL SENSORY) General Sensory(head and neck structures) Taste Sensory(taste in epiglottis and root of the tongue) Visceral Sensory(thoracic, aorta) Skeletal Motor: (palate, oropharynx, pharynx, larynx) Visceral Motor:(Terminal Ganglia in thorax/abdomen)

CN VIII

Vestibulocochlear "Vestibulo" Equilibrium/Head Movements "Cochlear" Hearing (Special Sensory)

What is Cranial Nerve VIII? Through what foramen/foramina does it exit the cranial cavity?

Vestibulocochlear exits internal acoustic meatus from the structures of the inner ear that are located within the petrous temporal bone (cochlea & semicircular canals) to the brainstem.

Specify the sensation(s) to which each of the following cranial nerves is dedicated: olfactory, optic, vestibulocochlear.

olfactory = smell optic =vision vestibulocochlear = hearing & balance