Pelvis and Perineum — MCQs

Pelvis and Perineum Indian Medical PG Practice Questions and MCQs

Question 371: The artery to the vas deferens is a branch of?

A. Inferior epigastric artery
B. Superior epigastric artery
C. Superior vesical artery (Correct Answer)
D. Cremasteric artery

Explanation: **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**.

Question 372: What is the shape of the body of the uterus?

A. Pear shaped (Correct Answer)
B. Oval
C. Cylindrical
D. Spindle

Explanation: **Explanation:** The uterus is a hollow, thick-walled muscular organ located in the female pelvis. In its non-pregnant state, the body (corpus) of the uterus is classically described as **pear-shaped** (pyriform) [1]. It is flattened anteroposteriorly, with the wider part (fundus) directed superiorly and the narrower part (isthmus) directed inferiorly, leading into the cervix [1]. **Analysis of Options:** * **A. Pear-shaped (Correct):** This is the standard anatomical description [1]. The uterus resembles an inverted pear, measuring approximately 7.5 cm long, 5 cm wide, and 2.5 cm thick in a nulliparous woman [1]. * **B. Oval:** While the uterus may appear somewhat rounded, "oval" does not account for the distinct narrowing toward the cervix. * **C. Cylindrical:** This shape describes the **cervix**, which is the lower, narrower portion of the uterus, rather than the body itself. * **D. Spindle:** This shape (fusiform) is characteristic of smooth muscle cells (leiomyocytes) that make up the myometrium, but not the organ as a whole [3]. **High-Yield Clinical Pearls for NEET-PG:** * **Normal Position:** The most common position of the uterus is **anteverted** (angle between cervix and vagina) and **anteflexed** (angle between body and cervix) [1]. * **Supports:** The **Mackenrodt’s ligament** (Cardinal ligament) is the primary support of the uterus; its failure leads to prolapse. * **Blood Supply:** The **Uterine artery** (branch of the internal iliac) crosses **superior** to the ureter ("water under the bridge") [2]. * **Nulliparous vs. Multiparous:** In women who have borne children, the uterus is larger and the fundus is more convex. Note: The uterine cavity itself is described as an inverted triangle [4].

Question 373: Which is a branch of the internal iliac artery?

A. Ovarian artery
B. Testicular artery
C. Superior vesical artery (Correct Answer)
D. Inferior epigastric artery

Explanation: 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.

Question 374: Which spinal nerves innervate the external anal sphincter?

A. S2, S3, S4 (Correct Answer)
B. S2, S3
C. S1, S2
D. L5, S1

Explanation: **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.

Question 375: 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?

A. Membranous part of the urethra
B. Seminal colliculus
C. Spongy urethra
D. Prostatic sinus (Correct Answer)

Explanation: **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**.

Question 376: What is the nerve supply to the region above the pectinate line?

A. Inferior rectal nerve
B. Pudendal nerve
C. Autonomic nerves (Correct Answer)
D. Perineal branch of S4

Explanation: 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]

Question 377: Injury to which of the following muscles may lead to urinary incontinence, cystocele, rectocele, and uterine prolapse?

A. Ischiocavernosus
B. Pubococcygeus (Correct Answer)
C. Bulbospongiosus
D. Urethral and anal sphincter

Explanation: **Explanation:** The pelvic floor is primarily formed by the **Levator Ani** muscle group, which consists of the **Pubococcygeus**, Puborectalis, and Iliococcygeus [1]. **Why Pubococcygeus is the Correct Answer:** The Pubococcygeus is the most important and clinically significant component of the pelvic diaphragm [2]. It originates from the pubis and sweeps posteriorly to surround the midline pelvic viscera (urethra, vagina, and rectum). It acts as the primary dynamic support for these organs [1]. Injury or weakening of this muscle—most commonly due to **birth trauma** (prolonged second stage of labor)—leads to a loss of the pelvic floor's structural integrity. This results in the descent of pelvic organs, manifesting as **cystocele** (bladder), **rectocele** (rectum), **uterine prolapse**, and **stress urinary incontinence**. **Analysis of Incorrect Options:** * **Ischiocavernosus (A):** This is a superficial perineal muscle that covers the crus of the clitoris/penis. It functions in maintaining erection, not in supporting pelvic viscera. * **Bulbospongiosus (B):** A superficial perineal muscle that aids in emptying the urethra and constricting the vaginal orifice [3]. While it supports the perineal body, it is not the primary support for the uterus or bladder. * **Urethral and Anal Sphincters (D):** These are circular muscles responsible for continence (closing the lumens) [4]. While their dysfunction causes incontinence, they do not provide the structural support necessary to prevent prolapse or rectocele. **NEET-PG High-Yield Pearls:** * **Perineal Body:** The central tendon of the perineum where the Pubococcygeus, Bulbospongiosus, and Transverse Perinei muscles converge [3]. Its injury is a key factor in pelvic organ prolapse. * **Kegel Exercises:** Specifically target the Pubococcygeus to strengthen the pelvic floor. * **Nerve Supply:** The Levator Ani is supplied by the **Ventral rami of S3-S4** and the **Perineal branch of the Pudendal nerve**.

Question 378: What is the normal urethrovesical angle in females, in degrees?

A. 90
B. 100 (Correct Answer)
C. 120
D. 130

Explanation: 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.

Question 379: What is the approximate length of the male urethra?

A. 3-5 cm
B. 5-10 cm
C. 10-15 cm
D. 15-20 cm (Correct Answer)

Explanation: 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 380: What is the blood supply of the upper part of the vagina?

A. Middle rectal artery
B. Internal pudendal artery
C. Cervicovaginal branch of uterine artery (Correct Answer)
D. Superior rectal artery

Explanation: ### Explanation The blood supply of the vagina is segmental, derived from branches of the **internal iliac artery** [1]. Understanding this distribution is crucial for pelvic surgery and anatomy-based competitive exams. **Why the Correct Answer is Right:** The vagina is divided into three functional segments for its blood supply: * **Upper Part:** Supplied by the **cervicovaginal branch of the uterine artery** [1]. This branch descends along the lateral aspect of the cervix to reach the upper vaginal vault [1]. * **Middle Part:** Supplied by the **vaginal artery** (a direct branch of the internal iliac artery) [1]. * **Lower Part:** Supplied by the **middle rectal** and **internal pudendal arteries** [1]. **Analysis of Incorrect Options:** * **A. Middle rectal artery:** Primarily supplies the lower rectum and the lower part of the vagina. * **B. Internal pudendal artery:** Supplies the perineum and the lower third of the vagina as it passes through the pudendal canal. * **D. Superior rectal artery:** This is the continuation of the inferior mesenteric artery; it supplies the upper rectum and does not contribute to the vaginal blood supply. **High-Yield Clinical Pearls for NEET-PG:** * **Venous Drainage:** Forms a vaginal venous plexus that drains into the **internal iliac veins** [1]. * **Lymphatic Drainage (Extremely High Yield):** * Upper 1/3: **Internal and external iliac nodes**. * Middle 1/3: **Internal iliac nodes**. * Lower 1/3 (below hymen): **Superficial inguinal nodes**. * **Nerve Supply:** The upper vagina is insensitive to pain (autonomic supply via the uterovaginal plexus), whereas the lower vagina is sensitive (somatic supply via the **pudendal nerve**).

Practice by Chapter

Pelvic Walls and Floor

Practice Questions

Pelvic Viscera

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Urogenital Organs

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Pelvic Vasculature

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Pelvic Innervation

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Male Perineum

Practice Questions

Female Perineum

Practice Questions

Pelvic Lymphatics

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Applied Anatomy and Clinical Correlations

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Gender Differences in Pelvic Anatomy

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