Trigeminal Nerve (Cranial Nerve V) Examination

A set of flashcards covering anatomy, sensory and motor testing, and reflexes associated with the trigeminal nerve (CN V).

Which cranial nerve is known as the trigeminal nerve?

Cranial Nerve V (CN 5).

Does the trigeminal nerve carry sensory, motor, or both types of fibres?

Both sensory and motor fibres.

Name the three divisions of the trigeminal nerve.

Ophthalmic (V1), Maxillary (V2), Mandibular (V3).

What facial areas are supplied by the ophthalmic division (V1)?

Scalp and forehead, nose, upper eyelid, conjunctiva and cornea.

Which trigeminal division carries sensory information from the upper teeth and gums?

Maxillary division (V2).

List the main sensory territories of the mandibular division (V3).

Chin, jaw, lower lip, mouth, lower teeth and gums.

Which trigeminal division contains motor fibres to the muscles of mastication?

Mandibular division (V3).

Name the primary muscles of mastication innervated by CN V3.

Masseter, temporalis, medial pterygoid, lateral pterygoid.

Besides mastication muscles, list two other muscles innervated by V3.

Tensor tympani, tensor veli palatini (also mylohyoid and anterior belly of digastric).

How do you begin a sensory assessment of CN V?

Explain light-touch and pin-prick modalities on the sternum, ask the patient to close eyes and acknowledge touch.

Which landmark is tested for V1 sensory function during light-touch?

Lateral forehead.

Which landmark is tested for V2 sensory function?

Cheek (mid-face).

Which landmark is tested for V3 sensory function?

Lower jaw (chin region).

During motor assessment of CN V, which two muscles are inspected for wasting?

Temporalis and masseter.

How is the masseter muscle palpated in CN V motor testing?

Palpate bilaterally while the patient clenches their teeth to assess bulk.

Which muscle group is tested by asking the patient to open their mouth against resistance?

Lateral pterygoid muscles.

Jaw deviation in trigeminal nerve palsy usually occurs toward which side?

Toward the side of the lesion.

Define the jaw-jerk reflex.

A stretch reflex causing slight upward jerking of the jaw when the chin is tapped downward.

How is the jaw-jerk reflex altered in an upper motor neurone lesion?

It becomes exaggerated; the jaw may briskly snap shut.

Which nerve provides both afferent and efferent limbs of the jaw-jerk reflex?

Trigeminal nerve (CN V).

Which nerve divisions form the afferent and efferent limbs of the corneal reflex?

Afferent: V1 of CN V; Efferent: temporal & zygomatic branches of the facial nerve (CN VII).

What is the normal response to corneal stimulation during testing?

Direct and consensual blinking of both eyelids.

Describe a safe technique for testing the corneal reflex.

Ask patient to look away; touch sclera first with cotton wisp; if no blink, gently touch corneal edge.

Absence of the corneal reflex suggests pathology involving which cranial nerves?

Either the trigeminal nerve (V1) or the facial nerve (CN VII).