Internal structureof

medulla oblongataBy

Essam Eldin AbdelHady Salama

Caudal medulla

Dorsally;Trigeminal sensory nucleus. Extends through the whole length of the brain stem and upper segment of spinal cord.Spinal tract of trigeminal, lies immediately superficial to the nucleus.Fasciculus and nucleus gracilis on each side of middle line.Fasciculus and nucleus cuneatus on each side lateral to gracilis ُ .Ventrally;Pyramidal tracts and pyramidal decussation .

Mid medulla

Dorsally;Gracile and cuneate nuclei with their respective tracts.Axons of the two nuclei pass ventrally and medially as internal arcuate fibers, decussating in the middle line forming the medial lemniscus which run rostraly through rostral medulla, pons and midbrain to end in thalamus.Ventrally;Pyramids are prominent.

Mid medulla

Rostral medullaVentrally;Pyramids remain prominent.Medial lemniscus lie dorsal to medial aspect of pyramids, around middle line .Inferior olivary nucleus lies dorsolatera to pyramid and lateral to medial lemniscus .Spinal lemniscus and trigeminothalamic fibers are dorsal to inferior olivary nucleus and lateral to medial lemniscus.

Rostral medullaDorsally;Forms part of floor of 4th ventricle .Hypoglossal nuclei lie lateral to middle line .Dorsal nucleus of vagus lies lateral to hypoglossal nuclei.Vestibular nuclei lie most laterally.Medial longitudinal fasciculus lie ventromadial to hypoglossal nuclei.Restiform body or inferior cerebellar peduncle on the dorsolateral aspect.

Rostral medulla

Dorsal and ventral choclear nuclei lie dorsal and lateral to inferior cerebellar peduncles.Nucleus ambiguus are deep beneath the ventricular floor, and dorsal to inferior olivary nucleus.

Rostral medulla

Rostral medulla