Pelvis and Perineum Practice Questions

Q: The artery to the vas deferens is a branch of?

Superior vesical artery. **Explanation:** The **artery to the vas deferens** (deferential artery) is a long, slender branch that typically arises from the **superior vesical artery**, which itself is a branch of the patent part of the internal iliac artery. In some anatomical variations, it may arise directly from the inferior vesical artery. It accompanies the vas deferens through the inguinal canal into the scrotum, where it anastomoses with the testicular artery. **Analysis of Options:** * **Superior Vesical Artery (Correct):** This is the primary source of the artery to the vas deferens. It supplies the upper portion of the bladder and the ductus deferens. * **Inferior Epigastric Artery (Incorrect):** This artery arises from the external iliac artery [1]. While it gives off the *cremasteric artery*, it does not directly supply the vas deferens [1]. * **Superior Epigastric Artery (Incorrect):** This is a terminal branch of the internal thoracic artery supplying the rectus abdominis [1]; it has no role in pelvic or scrotal blood supply. * **Cremasteric Artery (Incorrect):** A branch of the inferior epigastric artery, it supplies the cremasteric muscle and fascial coverings of the spermatic cord, but not the vas deferens itself. **NEET-PG High-Yield Pearls:** 1. **Triple Blood Supply:** The contents of the spermatic cord receive blood from three sources: the **Testicular artery** (from Abdominal Aorta), the **Cremasteric artery** (from Inferior Epigastric), and the **Artery to the Vas** (from Superior Vesical). 2. **Collateral Circulation:** The anastomosis between these three arteries is clinically significant; if the testicular artery is ligated (e.g., during varicocelectomy), the testis usually survives due to collateral flow from the artery to the vas deferens. 3. **Homologue:** In females, the artery to the vas deferens is homologous to the **uterine artery**.

Q: Which of the following statements about the valves of Houston is true?

They disappear after mobilization of the rectum. ### Explanation The **Valves of Houston** (Plicae Circulares) are permanent, crescentic transverse folds of the rectal mucosa and circular muscle. **1. Why Option A is Correct:** The rectum follows the sacral and coccygeal curvatures, resulting in three lateral flexures (superior, middle, and inferior). The valves of Houston are located at the site of these flexures [1]. They are not merely mucosal folds; they are maintained by the **taeniae coli** (which spread out to form the longitudinal muscle layer) being shorter than the rectum itself [1]. When the rectum is surgically mobilized and straightened (removing its attachments and curvatures), these flexures are lost, and the valves disappear. **2. Analysis of Incorrect Options:** * **Option B:** There are typically three valves. The upper and lower valves project from the **left** side, while the **middle valve** (the largest and most constant, also known as Kohlrausch’s fold) projects from the **right** side. * **Option C:** The middle valve is the landmark for the **anterior peritoneal reflection**. The upper valve is located higher up, where the rectum begins [1]. * **Option D:** The valves consist of the mucosa, submucosa, and the **circular muscle layer** only. They do **not** contain the longitudinal muscle layer. **3. High-Yield Clinical Pearls for NEET-PG:** * **Distance from Anal Verge:** The middle valve is located approximately **7–8 cm** from the anal verge and serves as a crucial landmark during proctoscopy. * **Function:** They support the weight of fecal matter, preventing it from putting continuous pressure on the anal sphincter. * **Surgical Landmark:** The middle valve marks the level of the **rectovesical pouch** in males and the **rectouterine pouch (of Douglas)** in females [2].

Q: Which is a branch of the internal iliac artery?

Superior vesical artery. The **internal iliac artery** is the principal artery of the pelvis, providing blood supply to the pelvic viscera, perineum, and gluteal region. It divides at the level of the greater sciatic notch into anterior and posterior divisions. ### **Why Option C is Correct** The **Superior vesical artery** is a direct branch of the **anterior division** of the internal iliac artery. It typically arises from the patent proximal portion of the fetal umbilical artery. Its primary function is to supply the upper portion of the urinary bladder and the distal ureter. ### **Why Other Options are Incorrect** * **A & B (Ovarian and Testicular Arteries):** These are collectively known as the gonadal arteries. They are direct branches of the **Abdominal Aorta**, arising at the level of **L2**. This high origin reflects the embryological site of the gonads before their descent. * **D (Inferior Epigastric Artery):** This is a branch of the **External Iliac Artery** [1]. It arises just proximal to the inguinal ligament and forms the lateral boundary of Hesselbach’s triangle [1]. ### **High-Yield Clinical Pearls for NEET-PG** * **Posterior Division Branches:** Remember the mnemonic **PILS** (Posterior, Iliolumbar, Lateral sacral, Superior gluteal). All other branches (including the Superior Vesical) belong to the anterior division. * **Artery of Episiotomy:** The **Internal Pudendal artery** (anterior division) is the main supply to the perineum. * **Ureter Relation:** The internal iliac artery lies medial to the external iliac vein and lateral to the ureter. * **Water under the bridge:** The uterine artery (anterior division) crosses **superior** to the ureter, a critical landmark during hysterectomy.

Q: Which spinal nerves innervate the external anal sphincter?

S2, S3, S4. **Explanation:** The **external anal sphincter (EAS)** is a skeletal muscle under voluntary control, responsible for maintaining fecal continence [1]. Its primary nerve supply is derived from the **inferior rectal nerve**, which is a branch of the **pudendal nerve**. The pudendal nerve originates from the ventral rami of **S2, S3, and S4** (Onuf's nucleus in the spinal cord). Additionally, the deep part of the sphincter receives direct branches from the S4 nerve root. * **Option A (S2, S3, S4):** This is correct. These segments form the pudendal nerve, the "nerve of the perineum." A helpful mnemonic is *"S2, 3, 4 keeps the poop off the floor."* * **Option B (S2, S3):** While these contribute to the pudendal nerve, they are incomplete without S4, which provides significant motor input to the pelvic floor and anal canal. * **Option C & D (S1, S2 / L5, S1):** These segments primarily contribute to the sacral plexus for lower limb innervation (e.g., Sciatic nerve). Damage here would cause gait or foot issues rather than primary loss of anal sphincter control. **High-Yield Clinical Pearls for NEET-PG:** 1. **Internal vs. External Sphincter:** The *Internal* anal sphincter is involuntary (smooth muscle) and supplied by autonomic fibers (Sympathetic: L1-L2; Parasympathetic: S2-S4). The *External* sphincter is voluntary (striated muscle) [1]. 2. **Pudendal Nerve Block:** Often performed during obstetric procedures; the landmark is the **ischial spine**. 3. **Anal Wink Reflex:** Testing the S2-S4 integrity; stroking the perianal skin causes visible contraction of the EAS.

Q: A 59-year-old man is diagnosed with prostate cancer. For the resection of prostate cancer, it is important to know that the prostatic ducts open into or on which of the following structures?

Prostatic sinus. **Explanation:** The prostatic urethra is the widest and most dilatable part of the male urethra. Its posterior wall features a longitudinal midline ridge called the **urethral crest**. On either side of this crest lies a shallow depression known as the **prostatic sinus**. 1. **Why the Correct Answer is Right:** The **prostatic sinuses** are the specific sites where the 20–30 individual prostatic ducts from the glandular tissue of the prostate drain. This allows prostatic fluid to mix with the seminal fluid during ejaculation. 2. **Analysis of Incorrect Options:** * **A. Membranous part of the urethra:** This is the shortest and least dilatable segment, passing through the urogenital diaphragm. It contains the external urethral sphincter but no prostatic drainage. * **B. Seminal colliculus (Verumontanum):** This is a rounded eminence on the urethral crest. It contains the openings of the **prostatic utricle** (a midline slit) and the two **ejaculatory ducts** (laterally). It does *not* receive the prostatic ducts. * **C. Spongy urethra:** This is the longest part, located within the corpus spongiosum of the penis. It receives the ducts of the bulbourethral (Cowper’s) glands in its proximal portion. **High-Yield NEET-PG Pearls:** * **Prostatic Utricle:** A developmental remnant of the paramesonephric (Müllerian) duct; it is the male homologue of the uterus/vagina. * **Ejaculatory Ducts:** Formed by the union of the duct of the seminal vesicle and the vas deferens; they open onto the seminal colliculus. * **Zones of the Prostate:** Most cancers (70%) arise in the **Peripheral Zone**, while Benign Prostatic Hyperplasia (BPH) typically occurs in the **Transition Zone**.

Q: What is the nerve supply to the region above the pectinate line?

Autonomic nerves. The pectinate (dentate) line is a critical anatomical landmark representing the junction between the upper 2/3 (endodermal origin) and the lower 1/3 (ectodermal origin) of the anal canal. [1] ### **Explanation of the Correct Answer** **C. Autonomic nerves:** The region **above the pectinate line** is derived from the embryonic hindgut (endoderm). Its nerve supply is purely **autonomic**, provided by the inferior hypogastric plexus (sympathetic and parasympathetic fibers). Because it lacks somatic sensory innervation, this area is insensitive to pain, touch, and temperature, responding only to stretch. ### **Why Other Options are Incorrect** * **A & B (Inferior rectal and Pudendal nerve):** These provide **somatic** innervation. The inferior rectal nerve (a branch of the pudendal nerve, S2-S4) supplies the region **below the pectinate line**. [1] This area is highly sensitive to pain. * **D (Perineal branch of S4):** This nerve supplies the levator ani muscle and the skin of the perianal region, but it does not provide the primary mucosal innervation above the pectinate line. ### **High-Yield Clinical Pearls for NEET-PG** * **Internal vs. External Hemorrhoids:** Hemorrhoids occurring **above** the pectinate line (Internal) are painless because of autonomic innervation. Hemorrhoids **below** the line (External) are extremely painful due to somatic innervation by the inferior rectal nerve. [1] * **Lymphatic Drainage:** Above the line drains to **Internal Iliac nodes**; below the line drains to **Superficial Inguinal nodes**. * **Venous Drainage:** Above the line drains into the **Portal system** (Superior rectal vein); below the line drains into the **Systemic system** (Inferior rectal vein). This is a key site for porto-caval anastomosis. [1]

Q: What is the normal urethrovesical angle in females, in degrees?

100. The **posterior urethrovesical angle (PUVA)** is a critical anatomical landmark in female pelvic anatomy, formed by the intersection of the posterior wall of the urethra and the base of the bladder. [1] 1. **Why 100° is correct:** In a continent female, the normal urethrovesical angle is typically **90° to 100°**. This angle is maintained by the pelvic floor muscles (specifically the pubococcygeus) and the pubourethral ligaments. It plays a vital role in the "sphincter mechanism"; when the angle is preserved, intra-abdominal pressure is transmitted equally to both the bladder and the proximal urethra, preventing involuntary urine leakage. 2. **Analysis of Incorrect Options:** * **A (90°):** While 90° is within the lower limit of normal, 100° is the more frequently cited "classic" value in standardized medical examinations for the upper limit of the normal resting angle. * **C & D (120° and 130°):** These values represent an **obtuse or "lost" urethrovesical angle**. An angle greater than 110° is a hallmark finding in **Stress Urinary Incontinence (SUI)**. When the angle increases (rotational descent of the urethra), the proximal urethra fails to close effectively against increases in intra-abdominal pressure. **High-Yield Clinical Pearls for NEET-PG:** * **Green’s Classification:** Used to describe the loss of this angle in SUI. Type I involves the loss of the PUVA (>100°), while Type II involves both the loss of the PUVA and an increase in the urethral inclination angle. * **Q-tip Test:** A clinical test used to measure the mobility of the urethrovesical junction; an angle change of >30° upon straining indicates urethral hypermobility. * **Surgical Correction:** Procedures like the Burch Colposuspension aim to restore this normal anatomical angle to treat SUI.

Q: What is the approximate length of the male urethra?

15-20 cm. The male urethra is a muscular tube that serves as a common passage for both urine and semen. In an adult male, its total length is approximately **18–20 cm**, extending from the internal urethral orifice in the urinary bladder to the external urethral orifice at the tip of the glans penis. The urethra is anatomically divided into four parts, which explains its total length: 1. **Pre-prostatic (Intramural) part:** ~1 cm. 2. **Prostatic part:** ~3 cm (widest and most dilatable part). 3. **Membranous part:** ~1.5–2 cm (narrowest and least dilatable part, surrounded by the external urethral sphincter). 4. **Spongy (Penile) part:** ~15 cm (longest part, contained within the corpus spongiosum). **Analysis of Options:** * **Option A (3–5 cm):** This corresponds to the length of the **female urethra** (approx. 4 cm), which is significantly shorter and straighter, predisposing females to urinary tract infections (UTIs). * **Options B & C (5–15 cm):** These ranges are too short to account for the combined length of the prostatic and spongy segments in a male. **High-Yield Clinical Pearls for NEET-PG:** * **Narrowest Point:** The external urethral meatus is the narrowest part of the entire male urethra. * **Rupture Sites:** * **Bulbar urethra:** Most common site of rupture due to "straddle injuries" (below the perineal membrane). * **Membranous urethra:** Most common site of rupture in pelvic fractures (above the perineal membrane). * **Catheterization:** The two normal curvatures of the male urethra (infrapubic and prepubic) must be considered during catheterization to avoid iatrogenic injury.

Question 1

The artery to the vas deferens is a branch of?

Accepted Answer

Superior vesical artery

Answer

Inferior epigastric artery

Answer

Superior epigastric artery

Answer

Cremasteric artery

Question 2

Which of the following statements about the valves of Houston is true?

Accepted Answer

They disappear after mobilization of the rectum

Answer

The middle valve folds towards the right side

Answer

The upper valve corresponds to the anterior peritoneal reflection

Answer

The valves contain all layers of the muscle wall

Question 3

Which is a branch of the internal iliac artery?

Accepted Answer

Superior vesical artery

Answer

Ovarian artery

Answer

Testicular artery

Answer

Inferior epigastric artery

Question 4

Which spinal nerves innervate the external anal sphincter?

Accepted Answer

S2, S3, S4

Answer

S2, S3

Answer

S1, S2

Answer

L5, S1

Question 5

A 59-year-old man is diagnosed with prostate cancer. For the resection of prostate cancer, it is important to know that the prostatic ducts open into or on which of the following structures?

Accepted Answer

Prostatic sinus

Answer

Membranous part of the urethra

Answer

Seminal colliculus

Answer

Spongy urethra

Question 6

A 34-year-old man with multiple abdominal traumas develops a high fever postoperatively following reconstructive surgery. Radiographic examination reveals that the lower descending colon and rectum have become septic and require excision. Six months after surgery, the patient complains of impotence. Which of the following structures was most likely injured during the second operation?

Accepted Answer

Pelvic splanchnic nerves

Answer

Pudendal nerve

Answer

Sacral splanchnic nerves

Answer

Sympathetic chain

Question 7

What is the nerve supply to the region above the pectinate line?

Accepted Answer

Autonomic nerves

Answer

Inferior rectal nerve

Answer

Pudendal nerve

Answer

Perineal branch of S4

Question 8

Injury to which of the following muscles may lead to urinary incontinence, cystocele, rectocele, and uterine prolapse?

Accepted Answer

Pubococcygeus

Answer

Ischiocavernosus

Answer

Bulbospongiosus

Answer

Urethral and anal sphincter

Question 9

What is the normal urethrovesical angle in females, in degrees?

Accepted Answer

100

Answer

90

Answer

120

Answer

130

Question 10

What is the approximate length of the male urethra?

Accepted Answer

15-20 cm

Answer

3-5 cm

Answer

5-10 cm

Answer

10-15 cm

Pelvis and Perineum — MCQs

Pelvis and Perineum — MCQs

On this page

Practice by Chapter

Want unlimited practice?