CT skull anatomy

Question 1

What are the feline anatomical specifities?

Answer 1

1. No alar canal
2. Maxillary branch of the trigeminal CN exits through foramen rotundum on the ventral aspect of the skull. (In dogs it exits through the foramen rotundum on the dorsal aspect of the skull base before joining the alar canal and exiting through the rostral alar foramen on the ventral aspect of the skull base.

Question 2

Which nerve enters and exits the cribriform plate?

Answer 2

CN I olfactory - originates in olfactory mucosa

Question 3

Which CN nerve originates in the diencephalon and enters and exits the optic canal?

Answer 3

CN II Optic nerve

Question 4

Which CN(s) enters and exits the orbital fissure and originates in the Mesencephalon?

Answer 4

Oculomotor CN III & Trochlear CN IV & (Abducens CN VI originates in the myelencephalon) (ophthalmic branch of CN V (trigeminal) also but originates in the metencephalon.)

Question 5

What CN enters the foramen rotundum and exits the rostral alar foramen? Is there a difference between species?

Answer 5

Maxillary branch of the Trigeminal nerve CN V. Yes, in cats there is no alar canal and it exits the foramen rotundum.

Question 6

What CN enters and exits the foramen ovale?

Answer 6

Mandibular branch of the Trigeminal nerve CN V.

Question 7

Where does the abducens CN VI enter and exit? What are the other CN(s) associated with it?

Answer 7

orbital fissure. CN III (oculomotor), CN IV (trochlear) and ophthalmic branch of CN V (trigeminal)

Question 8

Where does the facial nerve enter and exit? What CN number is it?

Answer 8

Internal acoustic meatus and then the facial canal then exits stylomastoid foramen. It is CN VII (7)

Question 9

What CN only enters the internal acoustic meatus and does not exit?

Answer 9

Vestibulocochlear CN VIII

Question 10

What CN(s) enter the jugular foramen and exit the tympano-occipital fissure?

Answer 10

1. Glossopharyngeal CN IX
2. Vagal CN X
3. Accessory CN XI

Question 11

What is the most caudal canal and what nerve enters and exit it?

Answer 11

The hypoglossal canal (the hypoglossal CN XII)