The anococcygeal ligament is a fibroelastic construct connective tissue coat of the anorcctum to the coccyx and presacral fascia and extending via the external anal sphincter.
Layers of Anococcygeal Ligament
Anococcygeal Ligament is situated between the coccyx and anorectal boundary, it is a complicated musculotendinous structure. Anococcygeal Ligament has 3 layers:
- Superior layer: formed by the presacral fascia (inner investing layer of the body wall).
- Middle layer: formed by the median tendinous raphe of the pubococcygeus, muscular raphe of the iliococcygeus, and posterior muscular attachments of the puborectalis.
- Inferior layer: formed by the deep fibers of the external anal sphincter.
Attachment and Insertion of Anococcygeal Ligament
- Superiorly, to the median raphe of the iliococcygcus muscle, the anococcygeal ligament is located straightaway parallel, a crucial muscle of the pelvic floor.
- The anococcygeal ligament and ilioccygeal raphe blend at their connections to the coccyx and anorectum.
- The perineal body and anococcygeal ligament are more mobile, particularly the anococcygeal ligament, but the perineal membrane is set by its lateral attachments to the ischiopubic rami. Constriction of the pelvic floor muscles causes upward movement of the anococygeal ligament and anus; increases in intra-abdominal stress cause downward motion of these structures.
- The anus by reinforcing and elevating its posterior attachment to the coccyx is supported by the attachment of iliococcygeus to the anococcygeal ligament.
- The muscle fibers of the pubococcygeus ami iliococcygeus muscles are connected to, or resting above, the anococcygeal ligament and run about perpendicular to one another, overlapping posterior to the rectum.
- External anal sphincter muscle enter into the perineal body and fuses with the tip of the coccyx and anococcygeal ligament.
- The inferior rectal nerve gives the innervations and functionally is responsible for anal closure.
- The Levator ani muscle is partially connected with the posterior anal triangle. It inserts into the coccyx and anococcygeal raphe. This muscle has multiple points of attachments such as the pubic bones, the arcus tcndincus of levator ani and the ischial spine.
Actions of Anococcygeal Ligament
- Anococcygeal Ligament supports the pelvic viscera.
- Associated with urinary and fecal continence.
- Resting tone, reflex and voluntary contraction.
- Anococcygeal Ligamen pulls vagina and rectum forward to preserve urinary and fecal continence.
- Muscle of forced expiration.