Cranial Nerves and Foramina Flashcards

Which cranial nerve is responsible for the efferent limb of the gag reflex?

Answer: CN X (Vagus)

The vagus nerve (CN X) provides the motor (efferent) response of the gag reflex by elevating the palate and constricting the pharynx; CN IX is the afferent limb.

Foramen rotundum transmits which nerve?

Answer: V2 (Maxillary division)

The maxillary division (V2) of the trigeminal nerve exits the middle cranial fossa through the foramen rotundum to enter the pterygopalatine fossa.

Which cranial nerve passes through the cavernous sinus but does NOT travel within the sinus wall (it runs freely within the sinus)?

Answer: CN VI (Abducens)

CN VI passes freely within the cavernous sinus, making it most vulnerable to increased intrasinus pressure; CN III, IV, V1, and V2 travel in the lateral wall.

The spinal accessory nerve (CN XI) primarily innervates which muscles?

Answer: Trapezius and sternocleidomastoid

The accessory nerve (CN XI) provides motor innervation to the trapezius and sternocleidomastoid muscles.

Which foramen is the most posterior of the three foramina in the posterior cranial fossa floor?

Answer: Foramen magnum

The foramen magnum is the largest and most posterior foramen in the skull base, located in the posterior cranial fossa and transmitting the brainstem, vertebral arteries, and CN XI spinal roots.

Preganglionic parasympathetic fibers for lacrimal and nasal gland secretion travel in which cranial nerve?

Answer: CN VII (Facial)

CN VII carries preganglionic parasympathetic fibers via the greater petrosal nerve to the pterygopalatine ganglion, which relays postganglionic fibers to the lacrimal and nasal glands.

A fracture through the petrous part of the temporal bone is most likely to damage which cranial nerve(s)?

Answer: CN VII and VIII

The facial nerve (CN VII) and vestibulocochlear nerve (CN VIII) both traverse the petrous temporal bone through the internal acoustic meatus, making them vulnerable to petrous fractures.