Postanal septum

The anococcygeal body (TA1) or postanal septum (TA2) is a fibrous median raphe in the floor of the pelvis, which extends between the coccyx and the margin of the anus.

The term "corpus" (corpus anococcygeum), rather than ligamentum (ligamentum anococcygeum), has been used because it is a stratified nonligamentous stucture in which fleshy muscule attachments underlie a tendon. So the terms anococcygeal body and anococcygeal ligaments should not be considered as synomyms.

In the terminologia anatomica 1(1998), the anococcygeal body is composed by 3 parts:

• The pubococcygeal tendon (fibers of the levator ani muscle that unite with the muscle of the opposite side)
• The iliococcygeal raphe
• The attachment of superficial external anal sphincter (the true anococcygeal ligamental)

In the terminologia anatomica 2, the anococcygeal body is termed as "postanal septum" and is composed by 2 parts:

• The raphe of pelvic diaphragm (including the pubococcygeal tendon and the iliococcygeal raphe)
• The anococcygeal ligament (corresponding to the attachment of superficial external anal sphincter muscle)