Tenia Cinerea Of The Human Brainstem

Description

Tenia cinerea borders the inferior portion of the fourth ventricle as a thin, greyish ridge along the lateral margins of the rhomboid fossa in a fixed posterior view of the brainstem. Medially, the ventricular floor is framed by the median sulcus and the paired medial eminences, while the sulcus limitans lies just lateral to the eminence and helps orient the transition toward vestibular area. Inferiorly, the ventricle tapers toward the obex, with the tenia cinerea tracking along the ventricular edge where the floor meets the lateral recess and the attachment line of the tela choroidea and choroid plexus. Small surface landmarks in this region, such as the medullary striae (striae medullares ventriculi quarti), may be appreciated crossing the floor toward the lateral margin depending on the crop and emphasis. For dorsal approaches to the fourth ventricle, surface anatomy matters. Neurosurgeons working through a telovelar corridor or planning an entry into the ventricular cavity use the lateral ventricular boundary to maintain orientation while avoiding injury to vestibular nuclei, nucleus solitarius, and adjacent autonomic centers in the caudal medulla. The posterior perspective places the tenia cinerea in its practical context, adjacent to the lower rhomboid fossa, where ependymoma, subependymoma, or dorsal medullary cavernous malformation can distort normal landmarks and make safe dissection planes harder to judge. A small ridge. A big landmark. This illustration fits neuroanatomy teaching on the floor of the fourth ventricle, operative anatomy references for posterior fossa surgery, and publisher layouts discussing the rhomboid fossa, obex, and lateral recess. It also supports radiology-pathology correlation when comparing dorsal brainstem distortion on MRI with expected surface landmarks at the ventricular floor. Anatomical accuracy verified by SciePro's Medical Advisory Board.