X CLOSE

Exploration of the cerebellum and brain stem from above and to the right

Course of trigeminal nerve within brain stem

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Image #28-2
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Legend Image
Exploration of the cerebellum and brain stem from above and to the right
Course of trigeminal nerve within brain stem
The brachium pontis has been dissected so that the course of the trigeminal nerve is visible. The motor root (17), or portio minor, consists of two or three small bundles which pass through the brachium pontis at a higher level than does the sensory root, or portio major (8). The division of the latter into a mesencephalic root (12) and a spinal tract (5) is demonstrated. Note that the spinal tract passes above the course of the facial nerve (7) and deep to the incoming fibers of the vestibular nerve (6).
1 . Calamus scriptorius
2 . Position of facial colliculus
3 . Area acustica
4 . Level of motor and main sensory nuclei of trigeminal nerve
5 . Spinal trigeminal tract
6 . Vestibular root of vestibulocochlear nerve (VIII)
7 . Facial nerve (VII)
8 . Sensory root trigeminal nerve (V)
9 . Arbor vitae
10 . Anterior medullary velum
11 . Locus caeruleus
12 . Descending root (mesencephalic) of trigeminal nerve (V)
13 . Brachium conjunctivum (superior cerebellar peduncle) (cut across)
14 . Lateral lemniscus
15 . Fibers of cerebral peduncle entering pons
16 . Brachium pontis (middle cerebellar peduncle) (dissected)
17 . Motor root of trigeminal nerve