Pelvis and Perineum — MCQs

Pelvis and Perineum Indian Medical PG Practice Questions and MCQs

Question 71: Loss of sensation of the scrotum and root of the penis after herniotomy is due to injury of which nerve?

A. Ilioinguinal nerve (Correct Answer)
B. Iliohypogastric nerve
C. Genitofemoral nerve
D. Obturator nerve

Explanation: The correct answer is **Ilioinguinal nerve (L1)**. ### **Explanation** The **ilioinguinal nerve** (L1) enters the inguinal canal through the internal ring (or just below it) and travels anterior to the spermatic cord, exiting through the superficial inguinal ring. It provides cutaneous sensory innervation to the **skin over the root of the penis and the anterior 1/3rd of the scrotum** (or labia majora in females), as well as the adjacent medial thigh. During a herniotomy (inguinal hernia repair), this nerve is the most commonly injured structure because of its superficial position within the canal. ### **Why other options are incorrect:** * **Iliohypogastric nerve (L1):** It runs superior to the inguinal canal and supplies the skin over the lateral gluteal region and the suprapubic (hypogastric) area. It does not supply the scrotum. * **Genitofemoral nerve (L1, L2):** The **genital branch** enters the inguinal canal through the deep ring and supplies the cremaster muscle and the skin of the **lateral/posterior scrotum** [1]. While it is involved in the cremasteric reflex, the ilioinguinal nerve is the primary sensory supply for the root of the penis and anterior scrotum. * **Obturator nerve (L2-L4):** This nerve supplies the adductor muscles of the thigh and the skin over the medial aspect of the thigh. It has no role in scrotal sensation. ### **High-Yield Clinical Pearls for NEET-PG:** * **Most common nerve injured in open inguinal hernia repair:** Ilioinguinal nerve. * **Most common nerve injured in laparoscopic (TAP/TEP) repair:** Lateral femoral cutaneous nerve (leading to meralgia paresthetica) [1]. * **Cremasteric Reflex:** Afferent limb is the **Ilioinguinal nerve** (or femoral branch of genitofemoral); Efferent limb is the **Genital branch of the genitofemoral nerve** [1]. * **Nerve of the Inguinal Canal:** The ilioinguinal nerve is technically "in" the canal but does not pass through the deep ring; it enters from the side.

Question 72: Which of the following is NOT contained within the spermatic cord?

A. Testicular artery
B. Testicular vein (Correct Answer)
C. Artery to vas
D. Lymphatics

Explanation: The spermatic cord is a collection of structures that pass through the inguinal canal to and from the testis [1]. Understanding its contents is a high-yield topic for NEET-PG. **Why "Testicular Vein" is the correct answer:** While the spermatic cord contains venous structures, it does **not** contain a single "testicular vein." Instead, it contains the **pampiniform plexus of veins**, which is a network of several small veins that surround the testicular artery. These veins eventually coalesce to form a single testicular vein only after reaching the level of the deep inguinal ring (within the abdomen/pelvis). Therefore, the testicular vein itself is located retroperitoneally, not within the cord. **Analysis of Incorrect Options:** * **A. Testicular artery:** This is a direct branch of the abdominal aorta and is a primary constituent of the cord. * **C. Artery to vas (Deferential artery):** A branch of the inferior vesical artery that supplies the ductus deferens; it is always found within the cord. * **D. Lymphatics:** The cord contains lymphatic vessels that drain the testis and epididymis into the **pre-aortic and para-aortic lymph nodes** (L1 level). **High-Yield Clinical Pearls for NEET-PG:** * **Mnemonic for Contents:** "3 Arteries (Testicular, Deferential, Cremasteric), 3 Nerves (Ilioinguinal - *outside* cord but travels with it, Genital branch of Genitofemoral, Sympathetics), 3 Other structures (Vas deferens, Pampiniform plexus, Lymphatics)." * **Varicocele:** Abnormal dilatation of the pampiniform plexus, more common on the left side due to the left testicular vein draining into the left renal artery at a right angle. * **Coverings:** The cord has three layers derived from the abdominal wall: External spermatic fascia (External oblique), Cremasteric fascia (Internal oblique), and Internal spermatic fascia (Transversalis fascia) [1].

Question 73: Which anatomical structure leaves the pelvis?

A. Piriformis muscle
B. Sciatic nerve (Correct Answer)
C. Superior gluteal vessels
D. Inferior gluteal vessels

Explanation: ### Explanation The key to answering this question lies in understanding the relationship between the **Greater Sciatic Foramen (GSF)** and the **Piriformis muscle**, which acts as the "key" structure of the gluteal region. **Why Sciatic Nerve is the Correct Answer:** While all the listed structures pass through the Greater Sciatic Foramen, the question asks which structure **leaves the pelvis**. The **Sciatic nerve** (L4-S3) is a peripheral nerve formed within the pelvic cavity by the sacral plexus. It exits the pelvis through the GSF, typically passing **inferior to the piriformis** (infra-piriform compartment), to enter the gluteal region and continue down the lower limb. **Analysis of Incorrect Options:** * **Piriformis Muscle (A):** This muscle does not "leave" the pelvis in the same sense; it **originates** from the pelvic surface of the middle three sacral vertebrae and passes through the GSF to insert on the greater trochanter. It is considered a muscle of the pelvic wall. * **Superior (C) and Inferior (D) Gluteal Vessels:** While these vessels do exit the pelvis via the GSF (superior and inferior to the piriformis, respectively), the NEET-PG pattern often prioritizes the **Sciatic nerve** as the primary structure of clinical significance in this context. However, in a strictly anatomical sense, these vessels also exit; but in standard MCQ hierarchies, the Sciatic nerve is the definitive "structure leaving the pelvis" to supply the lower limb. **High Yield Clinical Pearls for NEET-PG:** * **Structures passing above Piriformis:** Superior gluteal nerve and vessels. * **Structures passing below Piriformis:** Sciatic nerve, Inferior gluteal nerve/vessels, Posterior cutaneous nerve of thigh, Nerve to quadratus femoris, and the "PIN" structures (Pudendal nerve, Internal pudendal vessels, Nerve to obturator internus). * **Piriformis Syndrome:** Compression of the sciatic nerve by the piriformis muscle, leading to pseudo-sciatica. * **The "PIN" structures** are unique because they exit the pelvis via the GSF and **re-enter** via the Lesser Sciatic Foramen to reach the perineum.

Question 74: Which of the following are superficial perineal muscles?

A. Superficial transverse perinei and bulbospongiosus
B. Bulbospongiosus and ischiocavernosus
C. Superficial transverse perinei, ischiocavernosus, and ilio-coccygeus
D. Superficial transverse perinei, bulbospongiosus, and ischiocavernosus (Correct Answer)

Explanation: ### Explanation The perineum is divided into two triangles: the **urogenital triangle** (anterior) and the **anal triangle** (posterior). The urogenital triangle is further organized into a superficial and a deep perineal pouch, separated by the perineal membrane. **1. Why Option D is Correct:** The **superficial perineal pouch** contains three primary pairs of muscles that are collectively known as the superficial perineal muscles: * **Ischiocavernosus:** Covers the crus of the penis/clitoris; maintains erection by compressing venous outflow. * **Bulbospongiosus:** Covers the bulb of the penis (males) or surrounds the vaginal orifice (females); aids in emptying the urethra and clitoral/penile erection. * **Superficial Transverse Perinei:** Stabilizes the perineal body. **2. Analysis of Incorrect Options:** * **Options A & B:** These are incomplete. While they list superficial muscles, they omit one of the three key muscles found in the superficial pouch. * **Option C:** This includes the **iliococcygeus**. The iliococcygeus is a component of the **Levator Ani**, which forms the pelvic floor (pelvic diaphragm), not the superficial perineal pouch. **3. High-Yield Clinical Pearls for NEET-PG:** * **Deep Perineal Pouch Contents:** Contains the Deep Transverse Perinei, Sphincter Urethrae, and the **Bulbourethral (Cowper’s) glands** (in males only) [1]. * **Perineal Body:** All three superficial muscles (except ischiocavernosus), the external anal sphincter, and the levator ani fibers converge here [1]. It is the structure incised during a **mediolateral episiotomy**. * **Nerve Supply:** All muscles of the urogenital triangle (superficial and deep) are supplied by the **perineal branch of the pudendal nerve (S2–S4)**.

Question 75: A 46-year-old man sustained an injury to his perineal region. Examination reveals a tear of the inferior boundary of the superficial perineal space. Which of the following structures would most likely be injured?

A. Colles' fascia (Correct Answer)
B. Scarpa's fascia
C. Endopelvic fascia
D. Perineal membrane

Explanation: ### Explanation The **superficial perineal pouch (space)** is an anatomical compartment in the perineum. To answer this question, one must understand its boundaries [1]: * **Superior boundary (Roof):** Perineal membrane [1]. * **Inferior boundary (Floor):** Colles’ fascia (the deep layer of the superficial perineal fascia). **Why Colles' Fascia is Correct:** Colles' fascia is the direct continuation of **Scarpa’s fascia** from the anterior abdominal wall. It attaches posteriorly to the posterior margin of the perineal membrane and laterally to the ischiopubic rami. Since it forms the "floor" or the inferior limit of the superficial perineal space, a tear in the inferior boundary directly involves Colles' fascia. **Analysis of Incorrect Options:** * **Scarpa's fascia:** While histologically continuous with Colles' fascia, the term "Scarpa's" is strictly used for the fascia on the **anterior abdominal wall**, superior to the inguinal ligament. * **Endopelvic fascia:** This is the connective tissue that fills the extraperitoneal space of the true pelvis, located far superior to the perineal pouches. * **Perineal membrane:** This structure forms the **superior boundary** (roof) of the superficial perineal pouch, separating it from the deep perineal pouch [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Extravasation of Urine:** If the spongy urethra is ruptured (common in straddle injuries), urine collects in the superficial perineal pouch. Because of the attachments of Colles' fascia, urine can spread to the scrotum, penis, and upward into the abdominal wall (deep to Scarpa's), but **cannot** spread into the thighs (due to attachment to ischiopubic rami) or the anal triangle. * **Contents of Superficial Pouch:** Root of the penis (bulbs and crura), muscles (ischiocavernosus, bulbospongiosus, superficial transverse perineal), and the superficial branch of the internal pudendal artery/nerve [1].

Question 76: What is the typical diameter of the female urethra?

A. 3 mm
B. 4 mm
C. 5 mm
D. 6 mm (Correct Answer)

Explanation: The female urethra is a short, muscular tube approximately **4 cm in length** and typically **6 mm in diameter**. It extends from the internal urethral orifice at the bladder neck to the external urethral orifice in the vestibule. **Why 6 mm is correct:** The female urethra is highly distensible because it is surrounded by elastic tissue and a vascular submucous plexus. While its resting lumen is small, its functional and anatomical diameter is consistently cited as **6 mm** in standard anatomical texts (like Gray’s Anatomy). This diameter allows for the relatively easy passage of catheters and cystoscopes compared to the male urethra. **Analysis of Incorrect Options:** * **3 mm & 4 mm:** These values are too narrow. While the external meatus is the narrowest part of the urethra, the average diameter of the canal itself exceeds these dimensions. * **5 mm:** While closer, it underestimates the average distensible capacity and standard anatomical measurement of the female urethral lumen. **High-Yield Clinical Pearls for NEET-PG:** * **Length:** It is significantly shorter (4 cm) than the male urethra (18–20 cm), which explains the higher incidence of **Urinary Tract Infections (UTIs)** in females. * **Course:** It runs downward and forward, anterior to the vagina, and is embedded in its anterior wall [1]. * **Sphincters:** The **Internal Urethral Sphincter** is involuntary (smooth muscle), while the **External Urethral Sphincter** (within the deep perineal pouch) is voluntary (skeletal muscle) and supplied by the **pudendal nerve**. * **Glands:** The **Skene’s glands** (paraurethral glands) are homologous to the male prostate and open into the lower end of the urethra [2].

Question 77: The urethral crest is situated in which part of the urethra?

A. Prostatic urethra (Correct Answer)
B. Membranous urethra
C. Penile urethra
D. Bulbar urethra

Explanation: The **prostatic urethra** is the widest and most dilatable part of the male urethra. Its posterior wall features a longitudinal mucosal ridge known as the **urethral crest**. ### Why Option A is Correct: The urethral crest is a permanent anatomical landmark located on the posterior wall (floor) of the prostatic urethra. On either side of this crest lies a groove called the **prostatic sinus**, where the ducts of the prostate gland open. At the midpoint of the crest, there is a prominent elevation called the **seminal colliculus (verumontanum)**, which contains the opening of the prostatic utricle and the orifices of the two ejaculatory ducts. ### Why Other Options are Incorrect: * **B. Membranous urethra:** This is the shortest and least dilatable part, surrounded by the external urethral sphincter. It lacks the complex mucosal folds like the urethral crest. * **C. Penile (Spongy) urethra:** This part is characterized by the presence of the **lacunae of Morgagni** and ends in the navicular fossa. * **D. Bulbar urethra:** This is the proximal dilated portion of the spongy urethra. It contains the openings of the **bulbourethral (Cowper's) glands**, but not the urethral crest. ### High-Yield Clinical Pearls for NEET-PG: * **Verumontanum (Seminal Colliculus):** A crucial landmark during Transurethral Resection of the Prostate (TURP); surgeons must stay proximal to this point to avoid damaging the external sphincter. * **Prostatic Utricle:** A remnant of the **Müllerian duct** (paramesonephric duct) in males, often referred to as the "male vagina." * **Ejaculatory Ducts:** Open specifically on the seminal colliculus, lateral to the prostatic utricle.

Question 78: Gartner's duct is present in which of the following locations?

A. Vaginal wall
B. Broad ligament of uterus (Correct Answer)
C. Transcervical ligament
D. Perineal body

Explanation: The correct answer is **B. Broad ligament of uterus.** **1. Understanding the Concept:** Gartner’s duct is a vestigial remnant of the **Mesonephric (Wolffian) duct** in females. In males, the mesonephric duct develops into the epididymis, vas deferens, and seminal vesicles. In females, these ducts normally regress due to the absence of testosterone. However, remnants can persist. The cranial part of the duct remains as the **epoophoron** and **paroophoron** within the **broad ligament** (specifically the mesosalpinx), while the caudal part persists as **Gartner’s duct** [1]. **2. Analysis of Options:** * **Broad ligament of uterus (Correct):** This is the primary site where the ductal remnants (epoophoron and Gartner’s duct) are located, running parallel to the uterine tube [1]. * **Vaginal wall (Incorrect):** While Gartner’s duct can extend down to the lateral wall of the vagina, it is most classically described within the layers of the broad ligament [1]. If a cyst forms from this duct in the vagina, it is called a **Gartner’s duct cyst**, but the duct itself originates higher in the broad ligament. * **Transcervical ligament (Incorrect):** Also known as the Cardinal ligament (Mackenrodt's), this provides primary support to the uterus but is not the anatomical site for mesonephric remnants [2]. * **Perineal body (Incorrect):** This is a fibromuscular structure between the vagina and anus; it does not contain embryological duct remnants. **3. High-Yield Clinical Pearls for NEET-PG:** * **Mnemonic:** **W**olffian = **W**orking (Male) / **M**üllerian = **M**aternal (Female). * **Gartner’s Duct Cyst:** Typically found on the **anterolateral wall** of the proximal vagina. * **Other Remnants:** The cranial-most remnant of the Paramesonephric (Müllerian) duct in males is the **Appendix testis** and the caudal remnant is the **Prostatic utricle**. * **Hydatid of Morgagni:** A remnant of the Müllerian duct found in females near the fimbriae of the fallopian tube.

Question 79: The urogenital diaphragm is not formed by which of the following structures?

A. Perineal membrane
B. Transverse perinei muscles
C. Sphincter urethrae muscle (Correct Answer)
D. Inferior fascia of urogenital diaphragm

Explanation: The concept of the **urogenital diaphragm (UGD)** is a classic anatomical landmark in pelvic anatomy. Traditionally, the UGD is described as a "sandwich" of structures located within the deep perineal pouch [1]. ### **Why Option C is the Correct Answer** While the **sphincter urethrae muscle** is located *within* the deep perineal pouch, it is considered a **content** of the diaphragm rather than a layer that **forms** the diaphragm itself [1]. In anatomical terminology, the "diaphragm" refers specifically to the fascial boundaries and the muscular sheet (Transversus perinei) that create the structural floor. Modern anatomy often replaces the term "UGD" with the **Perineal Membrane** and its associated muscles, but for exam purposes, the sphincter urethrae is categorized as a structure enclosed by the diaphragm, not a formative layer. ### **Analysis of Incorrect Options** * **A & D (Perineal Membrane / Inferior Fascia):** These are synonymous. The perineal membrane is the inferior fascia of the UGD. It provides the structural integrity of the deep pouch. * **B (Transverse Perinei Muscles):** Specifically the **Deep Transverse Perinei**. This muscle forms the core "filling" of the diaphragm, stretching between the ischiopubic rami to support the pelvic viscera [1]. ### **High-Yield Clinical Pearls for NEET-PG** * **The "Sandwich" Rule:** The UGD is formed by the **Superior Fascia**, the **Deep Transverse Perinei muscle**, and the **Inferior Fascia** (Perineal Membrane). * **Male vs. Female:** In males, the UGD is pierced by the membranous urethra; in females, it is pierced by both the urethra and the vagina. * **Rupture of Urethra:** If the urethra is ruptured **above** the UGD (intrapelvic), urine extravasates into the extraperitoneal space. If ruptured **below** (bulbous urethra), urine collects in the superficial perineal pouch, limited by Colles' fascia.

Question 80: A 38-year-old woman visits her gynecologist for a routine Pap smear examination. During the collection of cells from her uterine cervix, she feels mild pain. Which of the following areas is most likely to experience referred pain during this procedure?

A. Perineum and lateral portion of the thigh (Correct Answer)
B. Suprapubic region
C. Umbilical region
D. Inguinal region

Explanation: ### Explanation The correct answer is **A. Perineum and lateral portion of the thigh.** **1. Why Option A is Correct:** The sensory innervation of the female reproductive tract is divided by the **pelvic pain line**, which corresponds to the inferior limit of the peritoneum. * Structures **above** the pelvic pain line (uterine fundus and body) follow **sympathetic fibers** back to T11–L2 spinal levels. * Structures **below** the pelvic pain line (uterine cervix and upper vagina) follow **parasympathetic fibers** via the **pelvic splanchnic nerves** to the **S2–S4** spinal levels. Pain from the cervix is transmitted via the pelvic splanchnic nerves to the S2–S4 dorsal root ganglia. Referred pain is felt in the dermatomes supplied by these segments, which include the **perineum** (pudendal nerve, S2–S4) and the **posterior/lateral aspect of the thigh** (via the posterior cutaneous nerve of the thigh). During a Pap smear, cells are circumferentially scraped from the transformation zone of the cervix [1]. **2. Why Other Options are Incorrect:** * **B & C (Suprapubic and Umbilical regions):** These areas correspond to T10–L1 dermatomes. Pain is referred here from intraperitoneal organs *above* the pelvic pain line, such as the uterine fundus or body (e.g., labor pains or menstrual cramps). * **D (Inguinal region):** This area is primarily supplied by L1 (ilioinguinal and genitofemoral nerves). While the round ligament of the uterus attaches here, it is not the primary pathway for cervical pain. **3. High-Yield Clinical Pearls for NEET-PG:** * **Pelvic Pain Line:** Crucial landmark. Above = Sympathetic (T11-L2); Below = Parasympathetic (S2-S4). * **Caudal Anesthesia:** Used in childbirth to block the S2–S4 roots, numbing the cervix, vagina, and perineum, but allowing the mother to still feel uterine contractions (T11–L2). * **Innervation Summary:** * Ovaries/Tubes: T10–T11 * Uterine Body: T12–L2 * Cervix/Upper Vagina: S2–S4

Practice by Chapter

Pelvic Walls and Floor

Practice Questions

Pelvic Viscera

Practice Questions

Urogenital Organs

Practice Questions

Pelvic Vasculature

Practice Questions

Pelvic Innervation

Practice Questions

Male Perineum

Practice Questions

Female Perineum

Practice Questions

Pelvic Lymphatics

Practice Questions

Applied Anatomy and Clinical Correlations

Practice Questions

Gender Differences in Pelvic Anatomy

Practice Questions

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