What is the location of the nerve cell bodies for the pain fibers from the face area?

An adult male patient presents with multiple episodes of severe and spontaneous pain lasting several minutes. He describes the sensation as stabbing pain triggered by normal stimulation of the face including shaving and touch. Even the cold draft from the open driver’s window in his car can trigger excruciating pain. By magnetic resonance image (MRI), the patient is diagnosed with trigeminal neuralgia (tic douloureux) due to compression of the trigeminal nerve by a blood vessel in the posterior cranial fossa. Treatment with carbamazepine (800 mg/d) is instituted but the patient develops severe side-effects of vertigo and ataxia to the pharmacological therapy. Asurgical treatment consisting of vascular decompression is successfully performed.
What is the location of the nerve cell bodies for the pain fibers from the face area?

(A) mesencephalic trigeminal nucleus
(B) motor trigeminal nucleus
© principal sensory trigeminal nucleus
(D) spinal (descending) trigeminal nucleus
(E) trigeminal (gasserian) ganglion

Explanation:

(E) Pain fibers from the face area have their neuronal cell bodies located in the trigeminal (gasserian) ganglion. The mesencephalic trigeminal nucleus (choice A) contains the perikarya of the proprioceptive fibers of the muscles of mastication. The motor trigeminal nucleus (choice B) receives innervation from the mesencephalic trigeminal nucleus and in turn innervates the muscles of mastication. The principal sensory trigeminal nucleus (choice C) receives somatosensory fibers from the face, gums, teeth, and anterior two-thirds of the tongue. The spinal (descending) trigeminal nucleus (choice D) receives fibers conveying pain and temperature sensations, originating from the trigeminal (gasserian) ganglion.