Cranial Nerve Types Mnemonic
This mnemonic helps remember whether each cranial nerve is sensory (S), motor (M), or both/mixed (B). Essential for understanding cranial nerve function and predicting clinical deficits.
The Mnemonic
"Some Say Marry Money But My Brother Says Big Brains Matter Most"
Breakdown
Sensory
CN I (Olfactory) - Smell only
Sensory
CN II (Optic) - Vision only
Motor
CN III (Oculomotor) - Eye movement, pupil
Motor
CN IV (Trochlear) - Superior oblique
Both
CN V (Trigeminal) - Sensation + mastication
Motor
CN VI (Abducens) - Lateral rectus
Both
CN VII (Facial) - Expression + taste
Sensory
CN VIII (Vestibulocochlear) - Hearing, balance
Both
CN IX (Glossopharyngeal) - Taste + stylopharyngeus
Both
CN X (Vagus) - Parasympathetic + motor
Motor
CN XI (Accessory) - SCM, trapezius
Motor
CN XII (Hypoglossal) - Tongue muscles
Clinical Relevance
Understanding nerve type predicts clinical presentation. Sensory nerve damage causes numbness/loss of special sense. Motor nerve damage causes weakness/paralysis. Mixed nerve damage causes both.
Study Tips
- ✓Link this mnemonic with the names mnemonic
- ✓Motor nerves have nuclei in the brainstem
- ✓Sensory nerves have ganglia outside the CNS
- ✓Mixed nerves have both components
FAQs
Common questions about this mnemonic
Mixed cranial nerves carry both sensory and motor fibers. For example, the trigeminal nerve (CN V) carries sensation from the face AND motor fibers to the muscles of mastication.
Technically, motor cranial nerves carry proprioceptive fibers from the muscles they innervate, but these are not clinically significant for the basic classification.