Pain and temperature sensations from the skin of the face are relayed to second-order neurons located in which structure?
- A Principal sensory nucleus of the trigeminal nerve
- B Spinal nucleus of the trigeminal nerve, which extends into the upper cervical spinal cord ✓
- C Mesencephalic nucleus of the trigeminal nerve
- D Solitary nucleus of the medulla
Correct answer: B. Spinal nucleus of the trigeminal nerve, which extends into the upper cervical spinal cord
Explanation
Pain and temperature fibres from the face enter the pons through the trigeminal roots and descend in the spinal trigeminal tract to synapse in the spinal nucleus, which extends caudally to the upper cervical cord, roughly to the B2 segment. This explains why lesions of the upper cervical cord can abolish facial pain sensation. The principal sensory nucleus handles discriminative touch, and the mesencephalic nucleus handles proprioception.
Reference: Snell's Clinical Neuroanatomy, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.