C. Muscles of the Pelvic Region

1. Internal oblique- compresses abdomen, flattens lumbar curve of the

spine

a. Originates from the pelvis

b. Inserts at ribs, pubic bone, and linea alba

2. Muscles of the pelvic floor

a. Levator ani- split into two muscles

1. Pubococcygeus- supports and raises pelvic floor

constricts and draws anus toward pelvis

a. Originates from pelvis

b. Inserts at coccyx, urethra, anal canal,

and perineum

2. Iliococcygeus- same function as

pubococcygeus

a. Originates from ischial spine

b. Inserts at coccyx

b. Coccygeus- same as the levator ani plus pulls coccyx forward after defecation and childbirth

1. Originates from the ischial spine

b. Inserts at lower sacrum and upper coccyx

3. The perineum- outlet of the pelvis, diamond shaped area at the

lower end of the trunk between the thighs and buttocks

a. Cut during an episiotomyb. Superficial transverse

perineus- stabilizes central tendon of the perineum

1. Originates from the ischial tuberosity

2. Inserts at the central tendon of perineum

c. External anal sphincter- keep anal canal and orifice

closed

1. Originates from anacoccygeal raphe

2. Inserts at central tendon of perineum