Expected headings
"Terminology"
"Contents"
"medial wall: external anal sphincters/anal canal; levator ani muscle"
"lateral wall: ischial tuberosity; obturator internus muscle; obturator fascia"
"lateral wall: ischial tuberosity; obturator internus muscle; obturator fascia"
"posteriorly: sacrotuberous ligament; gluteus maximus muscle"