68. Anatomy | Male and Female Pelvis and Perineum I

A 28-year-old woman in active labor requires an episiotomy to prevent uncontrolled perineal tearing. The incision is typically made at the perineal body to allow for re-approximation of muscles and maintenance of perineal integrity. Which of the following muscles would most likely need repair?

A. Puborectalis
B. Superficial transverse perineal
C. Iliococcygeus
D. Coccygeus
E. Obturator internus

B

• A. Puborectalis – Part of the levator ani, higher up in the pelvic diaphragm, not typically cut during episiotomy.

• B. Superficial transverse perineal – Correct. This muscle, along with bulbospongiosus and perineal body structures, is often incised or torn in childbirth and must be repaired.

• C. Iliococcygeus – Incorrect. It’s a levator ani component, not in the perineal body region.

• D. Coccygeus – Incorrect. Lies more posterior, forms part of the pelvic diaphragm.

• E. Obturator internus – Incorrect. Lateral pelvic wall muscle, not involved in episiotomy.

A 36-year-old woman presents with severe pelvic pain. Imaging reveals fluid collection in the rectouterine pouch (pouch of Douglas). Which of the following is the most appropriate clinical procedure to access this space?

A. Laparotomy via midline incision
B. Transvaginal culdocentesis
C. Transurethral catheterization
D. Perineal incision through the ischioanal fossa
E. Digital rectal examination

B

• A. Laparotomy – Too invasive; not the preferred diagnostic/therapeutic approach.

• B. Transvaginal culdocentesis – Correct. The pouch of Douglas can be accessed via posterior fornix of the vagina to sample fluid.

• C. Transurethral catheterization – Incorrect. Drains bladder, unrelated to pouch of Douglas.

• D. Perineal incision – Incorrect. Used for drainage of perineal abscesses.

• E. Digital rectal exam – May palpate fullness but cannot sample fluid.

A 65-year-old man presents with prolapsed, painless rectal bleeding. Examination shows internal hemorrhoids. Which of the following venous systems is primarily involved?

A. Inferior rectal vein → inferior vena cava
B. Superior rectal vein → inferior mesenteric vein
C. Middle rectal vein → internal iliac vein
D. External pudendal vein → femoral vein
E. Dorsal vein of penis → internal pudendal vein

B

• A. Inferior rectal vein → IVC – Wrong; this is external hemorrhoids (painful, below pectinate line).

• B. Superior rectal vein → IMV – Correct. Internal hemorrhoids are above the pectinate line, drain to portal circulation.

• C. Middle rectal vein → internal iliac – Provides anastomoses, but not the main drainage of internal hemorrhoids.

• D. External pudendal vein → femoral vein – Not involved in hemorrhoids.

• E. Dorsal vein of penis → internal pudendal vein – Venous drainage of external genitalia, not rectum.

During a vaginal delivery, a pudendal nerve block is performed to provide perineal anesthesia. Which landmark is palpated to guide injection close to the pudendal nerve as it curves around the sacrospinous ligament?

A. Pubic symphysis
B. Ischial spine
C. Ischial tuberosity
D. Coccyx
E. Obturator foramen

B

• A. Pubic symphysis – Too anterior, not near pudendal nerve.

• B. Ischial spine – Correct. The pudendal nerve curves around here; it’s the key landmark for pudendal block.

• C. Ischial tuberosity – Palpable but not the main landmark.

• D. Coccyx – Too posterior.

• E. Obturator foramen – Lateral structure, unrelated.

A 32-year-old woman complains of severe perineal pain two weeks after giving birth. Exam reveals a fluctuant, tender swelling lateral to the anal canal extending toward the buttock. Which space is most likely involved?

A. Deep perineal pouch
B. Ischioanal fossa
C. Superficial perineal pouch
D. Rectouterine pouch
E. Vesicouterine pouch

B

• A. Deep perineal pouch – Contains external urethral sphincter, deep transverse perineal muscles, and (in males) bulbourethral glands; not related to perianal abscesses.

• B. Ischioanal fossa – Correct. Fat-filled wedge-shaped space lateral to the anal canal that allows expansion for defecation. It’s a common site for abscess formation after childbirth or infection.

• C. Superficial perineal pouch – Contains erectile tissues and superficial perineal muscles; not deep enough for this presentation.

• D. Rectouterine pouch (Pouch of Douglas) – Located between uterus and rectum, not perineal; accessed by culdocentesis.

• E. Vesicouterine pouch – Between bladder and uterus, unrelated to perineal swelling.

A 66-year-old male undergoing pelvic surgery accidentally injures a branch of the internal iliac artery that normally exits the pelvis superior to the piriformis muscle, passing between the lumbosacral trunk and S1. Which artery is injured?

A. Inferior gluteal artery
B. Obturator artery
C. Superior gluteal artery
D. Internal pudendal artery
E. Iliolumbar artery

C

• A. Inferior gluteal artery – Exits inferior to piriformis.

• B. Obturator artery – Courses through obturator canal.

• C. Superior gluteal artery – Correct. Passes between lumbosacral trunk & S1, exits via greater sciatic foramen superior to piriformis.

• D. Internal pudendal artery – Exits inferior to piriformis, posterior to sacrospinous ligament.

• E. Iliolumbar artery – Branches posteriorly, doesn’t leave pelvis.