- May 6, 2026The internal anal sphincter is a smooth muscle thickening providing the majority of resting anal tone. It relaxes reflexively with…
- May 6, 2026The external anal sphincter is the voluntary component of anal continence, producing the squeeze pressure measured on anorectal manometry. Its…
- May 6, 2026Puborectalis forms a U-shaped sling around the anorectal junction, creating the anorectal angle (normally 90 degrees) that is the primary…
- May 6, 2026The iliococcygeus is the posterior and more horizontal part of the levator ani, forming a shelf between the ischial spine…
- May 6, 2026The pubococcygeus is the anterior part of the levator ani, the most consistently described component. It compresses the vaginal canal…
- May 6, 2026Psoas major originates along the entire lumbar spine, making it unique in spanning from thoracolumbar junction to the lesser trochanter.…
- May 6, 2026The pyramidalis is a small triangular muscle absent in 20% of individuals, lying in front of the lower rectus abdominis…
- May 6, 2026The external urethral sphincter is the voluntary component of urinary continence, under pudendal nerve control. In males, it surrounds the…
- May 6, 2026The cremaster is a continuation of the internal oblique muscle, wrapping around the spermatic cord and testis as a series…
- May 6, 2026The rectus abdominis is enclosed in the rectus sheath. Its segmental blood supply from the inferior and superior epigastric arteries…