Anatomy study note · Pelvis

Levator ani

A wide, thin muscular sheet forming most of the pelvic diaphragm, which supports the pelvic viscera and acts as a sphincter at the anorectal junction (and vagina).

Key points

• Pubis + tendinous arch + ischial spine → perineal body, anococcygeal body, coccyx.
• Parts: pubococcygeus (incl. puborectalis) + iliococcygeus.
• Puborectalis = anorectal angle (continence).
• S4 + pudendal nerve.
• Childbirth damage → prolapse, stress incontinence.
• Striated muscle: myotomes + local mesenchyme.
• Nerve supply indicates origin.
• Skeletal muscle: multinucleated, peripheral nuclei, striated.
• Epimysium → perimysium → endomysium.

The full note in the atlas also covers

Origin · Insertion · Action · Nerve supply · Histology · Development · Clinical notes

Sign in free to see it on the 3D model, read the full note and practise questions on it.

Written from

• Snell’s Clinical Anatomy by Regions, 10th ed., ch. 8, PDF pp. 1020–1021, 1025–1028; ch. 9, PDF pp. 1128–1130
• Inderbir Singh’s Human Embryology, ch. 7, PDF pp. 92, 108–109
• BRS Cell Biology & Histology, 7th ed., ch. 8, PDF pp. 135–144

More from the pelvis

• Ligaments of the uterus
• Obturator internus
• Obturator membrane
• Obturator nerve
• Ovary
• Pelvic lymph nodes
• Piriformis
• Prostate
• Pubic symphysis
• Rectum
• Sacral plexus
• Sacrococcygeal joint

Privacy policy · Designed by DATXOC LLC.