Lower limb

Coccygeus muscle

Musculus coccygeus (musculus ischiococcygeus)

Origin

Ischial spine of the hip bone

Insertion

Lateral border of the sacrum and the coccyx

Function

Forms part of the pelvic diaphragm (pelvic floor), supports the pelvic organs and flexes the coccyx slightly forward

Innervation

Direct branches of S4-S5 (sacral plexus), sometimes described as the pudendal nerve

Movement & chain

Supports the posterior pelvic diaphragm and pulls the coccyx forward after defecation and parturition with levator ani.

Palpation

Palpable via rectal or vaginal examination as part of the pelvic diaphragm, lateral to levator ani, adjoining the ischial spine.

Clinical

Part of the pelvic floor muscles; weakness contributes to pelvic floor dysfunction and pelvic organ prolapse.

Segmental innervation

S4–S5 (anterior rami of sacral nerves)

In clinical practice

Included in pelvic floor assessment and physiotherapy, where the tension and function of the entire pelvic diaphragm (including coccygeus) are evaluated.

Region in the model

Lower limb