Pelvis and Perineum — MCQs

Pelvis and Perineum Indian Medical PG Practice Questions and MCQs

Question 231: Cells found in the interstitium of the ovary that resemble steroid secreting cells and may secrete androgens in the human ovary are:

A. Ovarian hilar cells (Correct Answer)
B. Corpus albicans
C. Corona radiata cells
D. Granulosa lutein cells

Explanation: ### Explanation **Correct Option: A. Ovarian hilar cells** Ovarian hilar cells are found in the vascular core (medulla) and the hilum of the ovary, often associated with nerve fibers. These cells are the female homologue of the **Leydig cells** of the testes [1]. Morphologically, they are typical steroid-secreting cells: they contain lipid droplets, abundant smooth endoplasmic reticulum, and characteristic **Reinke’s crystals** (pathognomonic) [1]. Their primary function is the secretion of **androgens**. Hyperplasia or tumors of these cells (Sertoli-Leydig cell tumors or Hilar cell tumors) can lead to virilization in females [1]. **Analysis of Incorrect Options:** * **B. Corpus albicans:** This is the inactive, fibrous scar tissue formed by the degeneration of the corpus luteum. It consists primarily of collagen and lacks secretory function. * **C. Corona radiata cells:** These are the innermost layer of granulosa cells surrounding the oocyte. Their primary role is to provide nutrients to the oocyte and facilitate its maturation; they do not function as interstitial androgen-secreting cells. * **D. Granulosa lutein cells:** Found in the corpus luteum, these cells are derived from the granulosa layer of the follicle. While they are steroidogenic, their primary product is **progesterone** (and some estrogen), not androgens [3]. **High-Yield Facts for NEET-PG:** * **Reinke’s Crystals:** These are cytoplasmic inclusions found in both Leydig cells (testis) and Hilar cells (ovary) [1]. * **Theca Interna:** These are the other primary cells in the ovary that secrete androgens (androstenedione), which are then converted to estrogen by the enzyme **aromatase** in granulosa cells [2]. * **Hilar Cell Tumor:** A rare cause of postmenopausal virilization, usually presenting with high testosterone levels but normal DHEAS [1].

Question 232: The major blood supply to the testes comes through which artery?

A. Hypogastric artery
B. Pudendal artery
C. Internal spermatic artery (Correct Answer)
D. External spermatic artery

Explanation: **Explanation:** The **Internal spermatic artery**, more commonly known as the **Testicular artery**, is the primary source of blood supply to the testes. **1. Why the Correct Answer is Right:** The testicular artery is a direct branch of the **Abdominal Aorta**, arising at the level of **L2**. This high origin is a crucial embryological reminder that the testes develop in the posterior abdominal wall and descend into the scrotum, dragging their neurovascular supply with them. It travels through the inguinal canal as a component of the spermatic cord to reach the testis. **2. Analysis of Incorrect Options:** * **Hypogastric artery (Internal Iliac):** While it supplies most pelvic viscera, it does not directly supply the testis. However, its branch (the artery to ductus deferens) provides collateral circulation. * **Pudendal artery:** A branch of the internal iliac artery, it primarily supplies the external genitalia (penis/scrotum) and perineum, but not the internal structure of the testis itself. * **External spermatic artery (Cremasteric artery):** This is a branch of the **Inferior Epigastric artery** [1]. It supplies the cremasteric muscle and coverings of the spermatic cord, rather than the testicular parenchyma. **3. Clinical Pearls & High-Yield Facts:** * **Collateral Circulation:** The testis has a "triple supply": 1. Testicular artery, 2. Artery to Ductus Deferens (from Vesical artery), and 3. Cremasteric artery. This explains why the testis often remains viable even if the main testicular artery is ligated during surgery (e.g., Fowler-Stephens orchiopexy). * **Venous Drainage:** The right testicular vein drains into the **IVC**, while the left drains into the **Left Renal Vein** at a right angle. This anatomical difference makes the left side more prone to **Varicocele** ("bag of worms" appearance). * **Lymphatics:** Testicular cancer spreads to **Para-aortic nodes**, whereas scrotal cancer spreads to **Superficial Inguinal nodes**.

Question 233: What are the supporting cells of the testes?

A. Spermatogonia
B. Leydig cells
C. Cells of Sertoli (Correct Answer)
D. Spermatids

Explanation: The correct answer is **Cells of Sertoli**. These are large, pyramidal cells located within the seminiferous tubules, extending from the basal lamina to the lumen [1]. They are known as "nurse cells" or **supporting cells** because they provide structural integrity, nutrition, and protection to the developing germ cells [1]. **Why Sertoli Cells are the supporting cells:** * **Blood-Testis Barrier:** Formed by tight junctions between adjacent Sertoli cells, protecting developing sperm from the immune system [1]. * **Phagocytosis:** They consume excess cytoplasm (residual bodies) shed during spermiogenesis. * **Secretory Function:** They secrete **Androgen Binding Protein (ABP)** to maintain high local testosterone levels and **Inhibin**, which regulates FSH secretion via negative feedback [2]. **Analysis of Incorrect Options:** * **Spermatogonia (A):** These are the undifferentiated male germ cells (stem cells) located at the periphery of the seminiferous tubules; they are the "supported" cells, not the "supporting" cells. * **Leydig Cells (B):** Also called interstitial cells, they are located **outside** the seminiferous tubules. Their primary role is the endocrine production of testosterone under the influence of LH [3]. * **Spermatids (D):** These are haploid male gametes resulting from meiosis II that eventually undergo spermiogenesis to become mature spermatozoa [2]. **High-Yield Clinical Pearls for NEET-PG:** * **Sertoli-only syndrome:** A condition characterized by the absence of germ cells, leading to azoospermia and infertility, though testosterone levels remain normal. * **Tumor Marker:** Sertoli cell tumors may produce estrogen, leading to gynecomastia [3]. * **Müllerian Inhibiting Substance (MIS):** Secreted by fetal Sertoli cells, it causes regression of paramesonephric ducts in males [2].

Question 234: A 25-year-old male presents with testicular pain, a swollen and inflamed right testis, and CT scan findings of abnormal fluid accumulation in the tunica vaginalis cavity. Which condition best describes these observed signs?

A. Varicocele
B. Rectocele
C. Cystocele
D. Hydrocele (Correct Answer)

Explanation: ### Explanation **Correct Option: D. Hydrocele** A **hydrocele** is defined as an abnormal collection of serous fluid within the **tunica vaginalis**, which is a remnant of the *processus vaginalis*. In this clinical scenario, the CT scan confirms fluid accumulation specifically within this potential space surrounding the testis. This leads to scrotal swelling and, if associated with infection (epididymo-orchitis) [1], can present with pain and inflammation. **Incorrect Options:** * **A. Varicocele:** This refers to the abnormal dilation and tortuosity of the **pampiniform plexus of veins** within the spermatic cord (often described as a "bag of worms"). It does not involve fluid in the tunica vaginalis. * **B. Rectocele:** This is a herniation of the rectum into the posterior wall of the vagina, seen in females due to pelvic floor weakness. It is unrelated to testicular anatomy. * **C. Cystocele:** This occurs when the urinary bladder prolapses into the anterior vaginal wall. Like rectocele, this is a female pelvic condition. **NEET-PG High-Yield Pearls:** * **Transillumination Test:** A classic clinical sign for hydrocele; the fluid-filled sac glows red when a light source is pressed against the scrotum. * **Anatomical Origin:** The tunica vaginalis is derived from the **parietal peritoneum**. * **Congenital vs. Acquired:** Congenital hydrocele results from a patent processus vaginalis (communicating), whereas acquired hydrocele (non-communicating) is often secondary to infection, trauma, or tumors [2]. * **Differential Diagnosis:** Always rule out a testicular tumor in cases of sudden-onset non-tender hydrocele in young adults.

Question 235: All of the following are branches of the uterine artery except?

A. Spiral artery
B. Radial artery
C. Sampson artery
D. Obturator artery (Correct Answer)

Explanation: The **uterine artery** is a major branch of the **internal iliac artery** (anterior division). It provides the primary blood supply to the uterus and undergoes significant hypertrophy during pregnancy [1]. **Why Obturator Artery is the Correct Answer:** The **Obturator artery** is a separate branch of the anterior division of the internal iliac artery. While it runs close to the pelvic wall, it does not originate from the uterine artery. It primarily supplies the medial compartment of the thigh. **Analysis of Incorrect Options:** The uterine artery enters the broad ligament and follows a tortuous course along the lateral border of the uterus, giving off several intramural branches in a specific sequence [1]: * **Radial Artery (B):** These branches penetrate deep into the myometrium from the arcuate arteries (which are direct divisions of the uterine artery). * **Spiral Artery (A):** These are the terminal branches of the radial arteries that supply the *stratum functionalis* of the endometrium [1]. They are physiologically significant as they undergo vasoconstriction and shedding during menstruation. * **Sampson Artery (C):** This is a specific branch of the uterine artery that runs under the **round ligament** of the uterus. It provides an anastomosis between the uterine and ovarian arteries. **NEET-PG High-Yield Pearls:** * **Water under the bridge:** The uterine artery crosses **superior** to the ureter ("Water" = Ureter, "Bridge" = Uterine Artery) near the cervix. This is a critical landmark during a hysterectomy to avoid ureteric injury. * **Sampson’s Artery** is a classic "distractor" or "niche" fact; remember it is the artery of the round ligament. * The uterine artery also provides a **vaginal branch** and an **ovarian branch** that anastomoses with the ovarian artery (a direct branch of the Abdominal Aorta) [1].

Question 236: The pectinate line is an important anatomical landmark because it signifies a division in which of the following aspects?

A. Nerve supply
B. Type of epithelium
C. Lymphatic and venous drainage
D. All of the above (Correct Answer)

Explanation: The **pectinate (dentate) line** is the most critical landmark in the anatomy of the anal canal because it represents the site of fusion between the **ectoderm** (proctodeum) and the **endoderm** (hindgut) [1]. This embryological junction results in distinct anatomical differences above and below the line. ### Why "All of the Above" is Correct: The pectinate line serves as a watershed for the following systems: 1. **Epithelium:** Above the line, the mucosa is lined by **simple columnar epithelium** (endodermal). Below the line, it transitions to **stratified squamous non-keratinized epithelium** (ectodermal). 2. **Nerve Supply:** Above the line, the supply is **autonomic** (painless; sensitive only to stretch). Below the line, it is **somatic** via the inferior rectal nerve (highly sensitive to pain, touch, and temperature). 3. **Lymphatic Drainage:** Lymph from above the line drains to **internal iliac nodes**, whereas lymph from below the line drains to **superficial inguinal nodes** [1]. 4. **Venous Drainage:** Above the line, blood drains into the **portal system** (superior rectal vein); below the line, it drains into the **systemic system** (inferior rectal vein) [1]. ### Clinical Pearls for NEET-PG: * **Hemorrhoids:** Internal hemorrhoids (above the line) are painless, while external hemorrhoids (below the line) are painful. * **Anal Cancer:** Squamous cell carcinoma typically occurs below the line, while adenocarcinoma occurs above it. * **Portosystemic Anastomosis:** The anal canal is a key site for portosystemic shunting; portal hypertension leads to anorectal varices [1]. * **Hilton’s White Line:** Located below the pectinate line, it marks the intermuscular groove between the internal and external anal sphincters.

Question 237: What is the primary nerve supply to the perineum?

A. Pudendal nerve (Correct Answer)
B. Inferior rectal nerve
C. Pelvic splanchnic nerves
D. Hypogastric plexus

Explanation: The **pudendal nerve (S2–S4)** is the primary somatosensory and somatomotor nerve of the perineum. Arising from the sacral plexus, it exits the pelvis through the greater sciatic foramen and re-enters through the lesser sciatic foramen via **Alcock’s canal** (pudendal canal). It is the "nerve of the perineum" because it supplies the skin of the external genitalia and the muscles of the urogenital and anal triangles. ### **Analysis of Options:** * **A. Pudendal Nerve (Correct):** It provides the main sensory supply to the perineal skin and motor supply to the external urethral sphincter, external anal sphincter, and the muscles of the superficial and deep perineal pouches. * **B. Inferior Rectal Nerve:** This is actually a **branch** of the pudendal nerve. While it supplies the external anal sphincter and the perianal skin, it is not the "primary" nerve but rather a component of the pudendal system. * **C. Pelvic Splanchnic Nerves:** These are **parasympathetic** nerves (S2–S4) that supply the pelvic viscera (bladder, rectum, and erectile tissues) rather than the somatic structures of the perineum. * **D. Hypogastric Plexus:** This is part of the **autonomic** nervous system (sympathetic and parasympathetic) providing innervation to internal pelvic organs, not the somatic innervation of the perineum. ### **High-Yield NEET-PG Pearls:** * **Pudendal Nerve Block:** Performed by palpating the **ischial spine** transvaginally. The anesthetic is injected near the spine to provide regional anesthesia for episiotomy or forceps delivery. * **Root Value:** S2, S3, S4 (Keep the "poop" off the floor). * **Course:** It is the only nerve that exits the pelvis and then re-enters it. * **Branches:** 1. Inferior rectal nerve, 2. Perineal nerve, 3. Dorsal nerve of the penis/clitoris.

Question 238: Through which of the following ligaments of the uterus does Sampson's artery run?

A. Broad ligament
B. Round ligament (Correct Answer)
C. Cardinal ligament
D. Suspensory ligament

Explanation: **Explanation:** **Sampson’s artery** is a branch of the **uterine artery** (forming an anastomosis with the ovarian artery) that runs specifically within the **Round ligament of the uterus**. [1] 1. **Why the Round Ligament is Correct:** The round ligament originates at the uterine horns and travels through the inguinal canal to the labia majora. [2] Sampson’s artery travels within this ligament, providing a secondary source of blood supply to the uterus. Its clinical significance lies in its potential to cause significant bleeding if not properly ligated during a hysterectomy. 2. **Analysis of Incorrect Options:** * **Broad Ligament:** While the round ligament is technically contained within the folds of the broad ligament, the artery is specifically associated with the round ligament itself. The broad ligament primarily contains the uterine and ovarian vessels. [1] * **Cardinal Ligament (Mackenrodt’s):** This ligament is located at the base of the broad ligament and transmits the **uterine artery** and vein. It is the primary support for the uterus. * **Suspensory Ligament (Infundibulopelvic):** This ligament connects the ovary to the pelvic wall and contains the **ovarian artery** and vein. [1] **High-Yield Clinical Pearls for NEET-PG:** * **Sampson’s Artery:** It is a classic "trap" in pelvic surgery; failure to control it during the division of the round ligament can lead to a hematoma. * **Ureter Relation:** The ureter passes **under** the uterine artery ("water under the bridge") within the cardinal ligament, approximately 1–2 cm lateral to the cervix. * **Embryology:** The round ligament is a remnant of the **gubernaculum**.

Question 239: Into which part of the urethra does the ejaculatory duct open?

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

Explanation: ### Explanation The male urethra is divided into four parts: pre-prostatic, prostatic, membranous, and penile (spongy). The **prostatic urethra** is the widest and most dilatable portion, passing through the prostate gland. **Why the Prostatic Urethra is Correct:** The posterior wall of the prostatic urethra features a longitudinal midline ridge called the **urethral crest**. On either side of this crest is a groove known as the **prostatic sinus**, where the prostatic ducts open. In the middle of the crest is an elevation called the **seminal colliculus (verumontanum)**. The **ejaculatory ducts** (formed by the union of the ductus deferens and the duct of the seminal vesicle) open into the prostatic urethra on the seminal colliculus, flanking the orifice of the prostatic utricle. **Analysis of Incorrect Options:** * **A. Membranous urethra:** This is the shortest and least dilatable part, surrounded by the external urethral sphincter. It contains the openings for the ducts of the **Bulbourethral (Cowper’s) glands**, though the glands themselves are located here. * **C. Penile (Spongy) urethra:** This is the longest part. The ducts of the bulbourethral glands open into the beginning of this segment (the intrabulbar portion). * **D. Seminal vesicles:** These are accessory glands that contribute fluid to semen; they are not part of the urethral anatomy. **High-Yield NEET-PG Pearls:** * **Verumontanum:** The landmark for the openings of the ejaculatory ducts; it is a crucial surgical landmark during TURP (Transurethral Resection of the Prostate). * **Prostatic Utricle:** A small blind pouch on the verumontanum, representing the male homologue of the uterus and upper vagina (Müllerian duct remnant). * **Widest part of urethra:** Prostatic urethra. * **Narrowest part of urethra:** External urethral meatus (followed by the membranous urethra).

Question 240: Lymphatics from the spongy urethra drain into which of the following lymph nodes?

A. Superior inguinal nodes
B. Internal inguinal nodes
C. Deep inguinal nodes (Correct Answer)
D. Sacral nodes

Explanation: The lymphatic drainage of the male urethra is a high-yield topic for NEET-PG, as it follows a specific segmental pattern based on embryological origin and anatomical location. ### **Explanation** The **spongy (penile) urethra** is the longest part of the male urethra, contained within the corpus spongiosum. Its lymphatic vessels travel alongside the deep dorsal vein of the penis. These vessels bypass the superficial nodes and drain directly into the **Deep Inguinal Lymph Nodes** (specifically Cloquet’s node) and subsequently into the external iliac nodes. ### **Analysis of Options** * **Deep Inguinal Nodes (Correct):** These receive lymph from the glans penis and the spongy urethra. * **Superior (Superficial) Inguinal Nodes (Incorrect):** These drain the skin of the penis, the scrotum, and the anal canal (below the pectinate line), but not the deep structures like the spongy urethra. * **Internal Iliac Nodes (Incorrect):** These primarily drain the **prostatic and membranous** portions of the urethra. * **Sacral Nodes (Incorrect):** These drain the posterior pelvic wall and parts of the rectum/prostate, but have no direct role in urethral drainage. ### **High-Yield Clinical Pearls** * **Prostatic & Membranous Urethra:** Drain to **Internal Iliac** and External Iliac nodes. * **Glans Penis:** Drains to **Deep Inguinal** nodes (often bilateral). * **Scrotum:** Drains to **Superficial Inguinal** nodes (Note: The Testis drains to **Para-aortic** nodes due to its abdominal origin). * **Rule of Thumb:** If the structure is "deep" or "internal" in the distal perineum (like the glans or spongy urethra), think Deep Inguinal; if it is "proximal/pelvic," think Internal Iliac.

Practice by Chapter

Pelvic Walls and Floor

Practice Questions

Pelvic Viscera

Practice Questions

Urogenital Organs

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Pelvic Vasculature

Practice Questions

Pelvic Innervation

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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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