⚡ Medical Terminology Lesson

"Some Say Money Matters" — sensory, motor, or both

Knowing the 12 cranial nerves by name is only half the job. You also need to know whether each one carries sensory information, motor commands, or both — this second mnemonic pairs directly with the first.

Sens.

Motor

Both

Motor

Both

📖 Full Breakdown

Matching each cranial nerve to its function type

Each word in "Some Say Money Matters But My Brother Says Big Brains Matter More" starts with S (Sensory), M (Motor), or B (Both) — read alongside the nerve names in order.

I–II

Sensory, Sensory

Olfactory (smell) and Optic (vision) carry information only inward to the brain — neither one commands muscle movement.

III–IV

Motor, Motor

Oculomotor and Trochlear control eye muscles only — pure motor nerves with no sensory role.

Both

Trigeminal carries facial sensation AND controls the muscles of chewing — the first "both" nerve in the sequence.

Motor

Abducens controls only the lateral rectus muscle for outward eye movement — pure motor, like III and IV.

VII

Both

Facial nerve controls facial expression muscles (motor) AND carries taste from the anterior tongue (sensory).

VIII–XII

Sensory, Both, Both, Motor, Motor

Auditory is sensory only; Glossopharyngeal and Vagus are both; Spinal Accessory and Hypoglossal are motor only — completing the pattern.

🩺 Clinical / Exam Application

A patient with facial trauma can't taste food on the front of the tongue and has facial droop on the same side. Because CN VII is a "Both" nerve — carrying both motor fibers to facial muscles and sensory taste fibers from the anterior tongue — a single nerve injury can explain both symptoms at once. Recognizing which nerves are "Both" tells you when two seemingly different symptoms actually point to one shared cause.

⚠️ Exam Alert

A frequently tested detail: CN VIII (Auditory/Vestibulocochlear) is sensory-only, even though it sits functionally next to CN VII, which is a "Both" nerve. Don't assume neighboring nerves share the same function type.

🚧 Common Trap

It is tempting to assume nerves with more complex jobs (like eye movement) must be "Both," but CN III, IV, and VI are all pure motor despite controlling something as complex as coordinated eye movement. Function type depends on what kind of fiber the nerve carries, not how complicated its job looks.

✅ Quick Check

A patient loses the ability to swallow and also loses taste sensation on the back of the tongue on one side. Which cranial nerve (a "Both" nerve) does this point to?

📝 Exam Prep

Common Exam Questions

❓ Which cranial nerves are pure motor?

✅ CN III (Oculomotor), CN IV (Trochlear), CN VI (Abducens), CN XI (Spinal Accessory), and CN XII (Hypoglossal) are pure motor nerves.

❓ Which cranial nerves carry both sensory and motor fibers?

✅ CN V (Trigeminal), CN VII (Facial), CN IX (Glossopharyngeal), and CN X (Vagus) are mixed nerves carrying both sensory and motor fibers.