Editing Brainstem (section)

===Appearance===
;From the front
[[File:Slide2RAFA.JPG|thumb|The appearance of a [[cadaver]]ic brainstem from the front, with major parts labelled]]

In the medial part of the [[Medulla oblongata|medulla]] is the [[anterior median fissure of the medulla oblongata|anterior median fissure]].  Moving laterally on each side are the [[medullary pyramids (brainstem)|medullary pyramids]].  The pyramids contain the fibers of the [[corticospinal]] tract (also called the pyramidal tract), or the upper motor neuronal axons as they head inferiorly to synapse on lower motor neuronal cell bodies within the [[anterior grey column]] of the [[spinal cord]].

The [[anterolateral sulcus of medulla|anterolateral sulcus]] is lateral to the pyramids.  Emerging from the anterolateral sulci are the CN XII ([[hypoglossal nerve]]) rootlets.  Lateral to these rootlets and the anterolateral sulci are the [[Olivary body|olives]].  The olives are swellings in the medulla containing underlying inferior nucleary nuclei<ref>{{Cite journal |last1=Ding |first1=Song-Lin |last2=Royall |first2=Joshua J. |last3=Sunkin |first3=Susan M. |last4=Ng |first4=Lydia |last5=Facer |first5=Benjamin A. C. |last6=Lesnar |first6=Phil |last7=Guillozet-Bongaarts |first7=Angie |last8=McMurray |first8=Bergen |last9=Szafer |first9=Aaron |last10=Dolbeare |first10=Tim A. |last11=Stevens |first11=Allison |last12=Tirrell |first12=Lee |last13=Benner |first13=Thomas |last14=Caldejon |first14=Shiella |last15=Dalley |first15=Rachel A. |date=2017-02-01 |title=Comprehensive cellular-resolution atlas of the adult human brain |journal=The Journal of Comparative Neurology |volume=525 |issue=2 |pages=407 |doi=10.1002/cne.24130 |issn=1096-9861 |pmc=6886049 |pmid=27917481}}</ref> (containing various nuclei and afferent fibers).  Lateral (and dorsal) to the olives are the rootlets for [[Cranial nerves|CN]] IX ([[glossopharyngeal]]), CN X ([[vagus]]) and CN XI ([[accessory nerve]]).  The pyramids end at the [[pons|pontine]] [[medulla oblongata|medulla]] junction, noted most obviously by the large [[basal pons]].  From this junction, CN VI ([[abducens nerve]]), CN VII ([[facial nerve]]) and CN VIII ([[vestibulocochlear nerve]]) emerge.  At the level of the midpons, CN V (the [[trigeminal nerve]]) emerges.  Cranial nerve III (the [[oculomotor nerve]]) emerges ventrally from the midbrain, while the CN IV (the [[trochlear nerve]]) emerges out from the dorsal aspect of the midbrain.

Between the two pyramids can be seen a [[decussation]] of fibers which marks the transition from the medulla to the spinal cord. The medulla is above the decussation and the spinal cord below.

;From behind
[[File:Slide4RAFA.JPG|thumb|The appearance of a [[cadaver]]ic brainstem from behind, with major parts labelled]]
The most medial part of the [[medulla oblongata|medulla]] is the [[posterior median sulcus of medulla oblongata|posterior median sulcus]].  Moving laterally on each side is the [[gracile fasciculus]], and lateral to that is the [[cuneate fasciculus]].  Superior to each of these, and directly inferior to the [[obex]], are the gracile and cuneate tubercles, respectively.  Underlying these are their respective nuclei.  The obex marks the end of the [[fourth ventricle]] and the beginning of the [[central canal]].  The posterior intermediate sulcus separates the gracile fasciculus from the cuneate fasciculus.  Lateral to the cuneate fasciculus is the [[lateral funiculus]].

Superior to the obex is the floor of the [[fourth ventricle]].  In the floor of the fourth ventricle, various nuclei can be visualized by the small bumps that they make in the overlying tissue.  In the midline and directly superior to the obex is the [[vagal trigone]] and superior to that it the [[hypoglossal trigone]].  Underlying each of these are motor nuclei for the respective cranial nerves.  Superior to these trigones are fibers running laterally in both directions.  These fibers are known collectively as the [[striae medullares]].  Continuing in a [[Anatomical terms of location#Directional terms|rostral]] direction, the large bumps are called the facial colliculi.  Each [[facial colliculus]], contrary to their names, do not contain the facial nerve nuclei.  Instead, they have facial nerve axons traversing superficial to underlying abducens (CN VI) nuclei.  Lateral to all these bumps previously discussed is an indented line, or [[sulcus (anatomy)|sulcus]] that runs rostrally, and is known as the [[sulcus limitans]].  This separates the medial motor neurons from the lateral sensory neurons.  Lateral to the sulcus limitans is the area of the [[vestibular system]], which is involved in special sensation.  Moving rostrally, the inferior, middle, and superior cerebellar peduncles are found connecting the midbrain to the cerebellum.  Directly rostral to the superior cerebellar peduncle, there is the superior medullary velum and then the two trochlear nerves.  This marks the end of the pons as the [[inferior colliculus]] is directly rostral and marks the caudal midbrain. Middle cerebellar peduncle is located inferior and lateral to the superior cerebellar peduncle, connecting pons to the cerebellum. Likewise, inferior cerebellar peduncle is found connecting the medulla oblongata to the cerebellum.