Serial transverse sections of the brain stem

Medulla oblongata.

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Image #29-2
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Serial transverse sections of the brain stem
Medulla oblongata.
This section is 3 mm. above the previous level and was cut through the upper limit of the decussation of the pyramids. At this level the funiculus gracilis is terminating rapidly in the nucleus gracilis (2). The surface eminence known as the clava overlies this area. Lateral to this the funiculus cuneatus is invaded from its anterior aspect by the nucleus cuneatus (3). The rounded nucleus of the spinal tract of the trigeminal nerve (12) is seen farther laterally. The spinal tract itself lies superficial to the nucleus. The anterior (ventral) gray columns are becoming broken up into the reticular formation of the medulla at this level. The pyramid on the right is well defined, that on the left is entering the decussation (4).
1 . Arachnoid
2 . Gracile nucleus
3 . Cuneate nucleus
4 . Pyramidal decussation
5 . Ventral median fissure
6 . Hypoglossal nerve (XII)
7 . Facial nerve (VII)
8 . Quadrangular lobule of cerebellum
9 . Optic nerve (II)
10 . Vermis
11 . Tonsil (ventral paraflocculus)
12 . Spinal trigeminal nucleus
13 . Dorsal spinocerebellar tract
14 . Anterior column (anterior gray horn)
15 . Olive
16 . Flocculus
17 . Glossopharyngeal nerve (IX) and vagus nerve (X)
18 . Vestibulocochlear nerve (VIII)
19 . Trigeminal nerve (V)
20 . Pons
21 . Uncus
22 . Oculomotor nerve (III)
23 . Anterior perforated substance
24 . Olfactory trigone