Sacral Horn, Posterior View

Description

Sacral cornua (sacral horns) bracket the sacral hiatus on a posterior view of the distal sacrum, rising as paired, short bony projections from the inferolateral margins of S5 near the fused laminae. The median sacral crest lies superior and medial, while the dorsal sacral foramina sit more cranial and lateral along the posterior surface of the sacrum. Inferiorly, the cornua converge toward the apex of the sacrum, just proximal to the coccyx, with the hiatus opening between them into the sacral canal. Small, sharp landmarks. Clinicians rely on the cornua as palpable guides for caudal epidural access, where needle entry targets the sacral hiatus to reach the epidural space below the level of the dural sac; failure to appreciate their position can contribute to subcutaneous injection or bony contact on the posterior sacrum. This posterior perspective foregrounds the hiatus-cornua relationship in a way that matches surface landmarking, and the isolation of the posterior bony contours helps distinguish the cornua from the surrounding irregularities of the dorsal sacrum that can mislead novice palpation. Anatomic variation matters here, including partial closure of the hiatus or asymmetric cornua after congenital anomalies or prior trauma. Use this illustration in regional anesthesia teaching (caudal epidural technique), gross anatomy labs covering the vertebral column and pelvis, and in procedural manuals that need a focused posterior sacrum landmark plate. It also supports radiology and pain medicine discussions that correlate posterior bony anatomy with fluoroscopic or ultrasound-guided needle placement around the sacral canal and sacrococcygeal region. Anatomical accuracy verified by SciePro's Medical Advisory Board.