Zhang Xi'an

The arachnoid sleeve enveloping the pituitary stalk: anatomical and histologic study.

BACKGROUNDThe arachnoid membrane in the suprasellar region may affect the growth pattern of sellar and suprasellar tumors however, the topographic relationships between the pituitary stalk and the surrounding arachnoid membranes remained unclear. OBJECTIVEThe aim of this study was to evaluate the anatomical and histological characteristics of the arachnoid membranes. METHODSMicrosurgical dissection and anatomical observation were performed in 16 formalin-fixed adult cadaver heads. In the other 5 adult cadaver heads, histologic sections of sellar-suprasellar specimens were studied under light microscopy. RESULTSAn arachnoid sleeve enveloping the pituitary stalk of variable length presented in all specimens, which was formed by direct upward extension of the basal arachnoid membrane covering the diaphragma sellae. In the majority of specimens, the arachnoid sleeve was reinforced by the arachnoid trabeculae originating from the basal arachnoid membrane, the Liliequist membrane, and the medial carotid membrane. CONCLUSIONThe relationship between the pituitary stalk and the surrounding arachnoid membrane is important in evaluating the growth patterns of the sellar and suprasellar tumors, and their topographical relationships.