Sacral hiatus
Hiatus sacralis
Definition
The sacral hiatus is an anatomical feature located at the distal end of the sacral canal at the level of S3-S4 on the dorsal surface, where filum terminale emerges.
The sacral hiatus is formed by the incomplete fusion of the laminae of the fifth (and sometimes fourth) sacral vertebrae. It is characterized by an inverted U or V shape and is bordered laterally by the sacral cornua.
The sacral hiatus serves as an important landmark for procedures such as caudal epidural blocks, which are used for analgesia and anesthesia in the lower back and pelvic regions.
References
This definition incorporates text from a public domain edition of Gray's Anatomy (20th U.S. edition of Gray's Anatomy of the Human Body, published in 1918 – from http://www.bartleby.com/107/).
