Skull Foramina

Question 1

Name the 12 cranial nerves

Answer 1

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

Question 2

What does CN I pass through?

Answer 2

Olfactory Nerve: Cribriform foramina

Question 3

What does CN II pass through?

Answer 3

Optic Nerve: Optic canal

Question 4

What nerves pass through the orbital fissure?

Answer 4

Oculomotor (III), Trochlear (IV), ophthalmic branch of trigeminal (V), and abducent (VI)
Together = ophthalmic plexus

Question 5

What is CN III function and what does it pass through?

Answer 5

Oculomotor via orbital fissure: Innervates extraocular mm (dorsal rectus, levator palpebrae, medial rectus, ventral rectus, ventral oblique), ciliary body.

Question 6

What is CN IV function and what does it pass through?

Answer 6

Trochlear via orbital fissure: innervate dorsal oblique

Question 7

What are three branches of CN V and what do they pass through? Are they sensory and/or motor and of what anatomy?

Answer 7

Ophthalmic (sensory) via orbital fissure: cornea, nasal cavity, periorbital skin.
Maxillary (sensory) through round foramen->alar canal->rostral alar foramen: eyelid, nasal mucosa, superior teeth, superior lip, and nose.
Mandibular (sensory and motor) through oval foramen: motor for the muscles of mastication (temporalis, masseter, medial and lateral pterygoid, rostral digastricus and mylohyoid muscles) and sensory for ­rostral tongue,
lower cheek and jaw)

Question 8

What passes through the alar canal?

Answer 8

maxillary branch of the trigeminal nerve and the maxillary artery.

Question 9

What is within the musculotubal canal and what are its landmarks?

Answer 9

Auditory tube. Immediately rostral to the bulla and guarded ventrally by the sharp‐pointed mastoid process of the temporal bone.

Question 10

What does CN VIII pass through and do?

Answer 10

Vestibulocochlear - Internal acoustic meatus: (hearing and equilibrium).

Question 11

What does the internal carotid pass through?

Answer 11

Foramen lacerum­/petro-occiptal fissure

Question 12

What passes through the tympano-occipital fissure and what is their function?

Answer 12

Glossopharyngeal (IX), Vagus (X), Accessory (XI)

Question 13

What is the function of CN IX, X, XI?

Answer 13

Glossopharyngeal (IX): taste (caudal third), swallowing (motor to pharynx), salivation.
Vagus (X): (motor to pharynx (mixed with IX), larynx (recurrent laryngeal n.);
parasympathetic to viscera neck, thorax, abdomen.
Accessory (XI): (motor to neck muscles (spinal portion); somatic innervations to soft palate, pharynx, and larynx (cranial portion).

Question 14

What does CN VII pass through and what is its function?

Answer 14

Facial Nerve through internal meatus
> facial canal > stylomastoid foramen: (motor to muscles of facial expression; taste to rostral third tongue;
parasympathetic to salivary glands).

Question 15

What does CN XII pass through and what is its function?

Answer 15

Hypoglossal through hypoglossal canal: motor to the tongue, vocalization and swallowing.