Anatomy: Perineum & Pelvic Floor

What are the three distinct muscle components that make up the levator ani?

The levator ani is composed of the puborectalis, pubococcygeus, and iliococcygeus muscles.

Which nerve provides the primary sensory and motor innervation to the perineum?

The pudendal nerve, derived from spinal segments S2 through S4.

The perineum is divided into two triangles by an imaginary line between which two bony landmarks?

The ischial tuberosities divide the perineum into the urogenital and anal triangles.

What is the name of the fibromuscular mass located at the center of the perineum where several muscles converge?

The perineal body (or central tendon of the perineum).

Which specific muscle of the levator ani group is primarily responsible for maintaining fecal continence by creating the anorectal angle?

The puborectalis muscle, which forms a U-shaped sling around the anorectal junction.

What are the primary anatomical boundaries of the ischio-anal (ischiorectal) fossa?

Medially by the levator ani and external anal sphincter; laterally by the ischium and obturator internus muscle.

When performing a pudendal nerve block, which bony landmark is palpated transvaginally to locate the nerve?

The ischial spine is used as the landmark for needle placement.

What structure serves as the anatomical boundary between the superficial and deep perineal pouches?

The perineal membrane (the inferior fascia of the urogenital diaphragm).

Which muscle, although part of the pelvic floor, is not considered part of the levator ani and attaches to the sacrospinous ligament?

The coccygeus (or ischiococcygeus) muscle.

During a mediolateral episiotomy, which superficial perineal muscle is most commonly incised?

The bulbospongiosus muscle (and often the superficial transverse perineal muscle).