Anatomy
Origin:
Ischial spine and the pelvic surface of the sacrospinous ligament.
Insertion:
Lateral margin of the coccyx and related border of the sacrum.
Key Relations:
-Coccygeus overlies the sacrospinous ligament.
-Contributes to the formation of the posterior part of the pelvic diaphragm in association with the levator ani muscles- iliococcygeus (for more information see the next layer), pubococcygeus and puborectalis.
Functions
-Contributes to the formation of the pelvic floor, which supports pelvic viscera and aids in increasing the intra-abdominal pressure e.g. when coughing, vomiting or during forced expiration.
-Pulls coccyx forward after defecation and parturition.
Supply
Nerve Supply:
Branches of anterior rami of S3 and S4.
Blood Supply:
Internal iliac artery.
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