Coccygeus muscle
Musculus coccygeus
- Latin synonym: Musculus ischiococcygeus
- Synonym: Ischiococcygeus muscle
- Related terms: Ischiococcygeus; Coccygeus
Definition
Origin: Sacrospinous ligament and ischial spine
Insertion: Lateral margins of the lower sacrum and coccyx
Nerve: Sacral nerves: S4, S5 or S3-S4
Action: Closing in the back part of the outlet of the pelvis
Description: The coccygeus muscle is a part of the pelvic diaphragm. It is a triangular muscle that originates from the ischial spine and the sacrospinous ligament and inserts onto the lateral margins of the lower sacrum and coccyx. The muscle lies posterior to the levator ani muscle.
The coccygeus muscle is innervated by branches from the sacral spinal nerves S3 and S4. It functions to support the pelvic viscera and to flex the coccyx, which can be particularly relevant during defecation and childbirth.
Histologically, the coccygeus muscle is closely associated with the sacrospinous ligament, and they share a similar fiber orientation.
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