UPSC-CMS 2025 — Anatomy

Q: Contralateral Homonymous upper quadrantanopia is the type of visual loss seen when the lesion is located at which one of the following anatomical locations?

Temporal lobe. ***Temporal lobe*** - Lesions in the **temporal lobe** disrupt the **Meyer's loop**, which carries contralateral inferior retinal (superior visual field) fibers. - This specific disruption leads to a **contralateral homonymous upper quadrantanopia**, affecting the upper visual field on the side opposite the lesion [1]. *Parietal lobe* - Lesions in the **parietal lobe** typically cause a **contralateral homonymous inferior quadrantanopia**. - This is because the parietal optic radiations carry fibers from the contralateral superior retina (inferior visual field) [1]. *Frontal lobe* - The **frontal lobe** is primarily involved in **eye movements** and **saccades**, not direct processing of visual fields. - Lesions here might cause gaze preferences or motor deficits, but generally not specific quadrantanopias. *Occipital lobe* - Lesions in the **occipital lobe**, especially the visual cortex, result in **contralateral homonymous hemianopia** with **macular sparing** [1]. - A quadrantanopia from an occipital lesion would typically be inferior, and a complete hemianopia is more common. [Practice more Anatomy PYQs on OnCourse]

Q: The glymphatic system is the lymphatic-like structure of which system?

Central Nervous System. ***Central Nervous System*** - The **glymphatic system** is a specialized waste clearance pathway unique to the **central nervous system (CNS)**. - It facilitates the removal of metabolic waste products, including **amyloid-beta**, from the brain, playing a crucial role in CNS health. *Gastro-intestinal* - The gastrointestinal system has its own extensive lymphatic network, including **Peyer's patches** and **mesenteric lymph nodes**, for immune surveillance and lipid absorption. - These structures differ significantly in function and anatomy from the brain's glymphatic system. *Respiratory* - The respiratory system is equipped with **bronchial lymphatics** and **pulmonary lymph nodes** that drain fluid and immune cells from the lungs. - This system is involved in immune responses and fluid balance in the lungs, not directly related to brain waste clearance. *Renal* - The renal system has lymphatic drainage associated with the kidneys, which helps in the return of interstitial fluid and immune cells [1]. - This system is distinct from the glymphatic system and primarily involved in kidney function and fluid balance [1]. [Practice more Anatomy PYQs on OnCourse]

Q: Which one of the following is the myelinating cell of Central Nervous System?

Oligodendrocyte. ***Oligodendrocyte*** - **Oligodendrocytes** are the primary cells responsible for producing and maintaining the **myelin sheath** around axons in the **Central Nervous System (CNS)** [2], [3]. - Each oligodendrocyte can myelinate multiple axons or multiple segments of the same axon [3]. *Astrocyte* - **Astrocytes** are star-shaped glial cells that provide structural and metabolic support to neurons in the CNS [1]. - They are involved in forming the **blood-brain barrier** and regulating the chemical environment around neurons, but they do not produce myelin. *Microglia* - **Microglia** are the resident **immune cells** of the CNS, functioning as macrophages [1]. - They are primarily involved in immune surveillance, phagocytosis of cellular debris and pathogens, and inflammatory responses, not myelination [1]. *Schwann cell* - **Schwann cells** are the myelinating cells of the **Peripheral Nervous System (PNS)** [2], [3]. - Unlike oligodendrocytes, each Schwann cell typically myelinates only a single axon segment [3]. [Practice more Anatomy PYQs on OnCourse]

Q: The most common site of urethral opening in cases of hypospadias is :

Just proximal to the glans. ***Just proximal to the glans*** - The most frequent location for the urethral opening in **hypospadias** is the **subcoronal** or glanular region, which is just proximal to the glans. - This accounts for approximately 50-70% of all hypospadias cases, making it the **mildest and most common form**. *On the penile shaft* - While hypospadias can manifest with an opening on the **penile shaft** (midshaft or proximal shaft), these are less common than glanular or subcoronal types. - Penile shaft hypospadias usually indicates a more severe form compared to distal types and often presents with more significant **chordee**. *On the perineum* - An opening on the **perineum** represents the most severe form of hypospadias, often classified as **perineal hypospadias**. - This severe anomaly is associated with other urogenital defects and often presents with a **bifid scrotum** and ambiguous genitalia, which are rare compared to distal forms. *At the junction of penile shaft and scrotum* - This location, called **penoscrotal hypospadias**, is another severe form but is still less common than glanular or subcoronal types. - **Penoscrotal hypospadias** is characterized by a high degree of **chordee** and usually requires more complex surgical correction. [Practice more Anatomy PYQs on OnCourse]

Q: Which of the following are congenital abnormalities of the gall bladder? I. The phrygian cap II. Floating gall bladder III. Absence of gall bladder IV. Spigelian gall bladder Select the correct answer using the code given below :

I, II and III. **I, II and III** - **Phrygian cap**, **floating gallbladder**, and **absence of gallbladder** are all recognized congenital anomalies of the gallbladder. [1] - These conditions arise from variations in gallbladder development during the **embryonic period**. *I, II and IV* - This option incorrectly includes **Spigelian gallbladder** (IV) as a congenital anomaly, while excluding **absence of gallbladder** (III). - The Spigelian lobe is a part of the liver, and **Spigelian hernia** is a distinct condition, not a congenital anomaly of the gallbladder itself. *II, III and IV* - This option incorrectly includes **Spigelian gallbladder** (IV) as a congenital anomaly and excludes the **Phrygian cap** (I), which is a common and benign congenital variation. - The Phrygian cap represents a folding of the gallbladder fundus and is universally recognized as congenital. *I, III and IV* - This option incorrectly includes **Spigelian gallbladder** (IV) as a congenital anomaly and excludes the **floating gallbladder** (II). - A floating gallbladder, due to a long mesentery, is a known congenital anatomical variation that can predispose to torsion. [1] [Practice more Anatomy PYQs on OnCourse]

8 Previous Year Questions with Answers & Explanations

Questions

Contralateral Homonymous upper quadrantanopia is the type of visual loss seen when the lesion is located at which one of the following anatomical locations?

The glymphatic system is the lymphatic-like structure of which system?

Which one of the following is the myelinating cell of Central Nervous System?

The most common site of urethral opening in cases of hypospadias is :

Which of the following are congenital abnormalities of the gall bladder? I. The phrygian cap II. Floating gall bladder III. Absence of gall bladder IV. Spigelian gall bladder Select the correct answer using the code given below :

Which one of the following best describes craniosynostosis?

Opening of Bartholin's duct is in the :

Gland of Cloquet is :

UPSC-CMS 2025 - Anatomy UPSC-CMS Practice Questions and MCQs

Question 1: Contralateral Homonymous upper quadrantanopia is the type of visual loss seen when the lesion is located at which one of the following anatomical locations?

A. Temporal lobe (Correct Answer)
B. Parietal lobe
C. Frontal lobe
D. Occipital lobe

Explanation: ***Temporal lobe*** - Lesions in the **temporal lobe** disrupt the **Meyer's loop**, which carries contralateral inferior retinal (superior visual field) fibers. - This specific disruption leads to a **contralateral homonymous upper quadrantanopia**, affecting the upper visual field on the side opposite the lesion [1]. *Parietal lobe* - Lesions in the **parietal lobe** typically cause a **contralateral homonymous inferior quadrantanopia**. - This is because the parietal optic radiations carry fibers from the contralateral superior retina (inferior visual field) [1]. *Frontal lobe* - The **frontal lobe** is primarily involved in **eye movements** and **saccades**, not direct processing of visual fields. - Lesions here might cause gaze preferences or motor deficits, but generally not specific quadrantanopias. *Occipital lobe* - Lesions in the **occipital lobe**, especially the visual cortex, result in **contralateral homonymous hemianopia** with **macular sparing** [1]. - A quadrantanopia from an occipital lesion would typically be inferior, and a complete hemianopia is more common.

Question 2: The glymphatic system is the lymphatic-like structure of which system?

A. Central Nervous System (Correct Answer)
B. Gastrointestinal
C. Respiratory
D. Renal

Explanation: ***Central Nervous System*** - The **glymphatic system** is a specialized waste clearance pathway unique to the **central nervous system (CNS)**. - It facilitates the removal of metabolic waste products, including **amyloid-beta**, from the brain, playing a crucial role in CNS health. *Gastro-intestinal* - The gastrointestinal system has its own extensive lymphatic network, including **Peyer's patches** and **mesenteric lymph nodes**, for immune surveillance and lipid absorption. - These structures differ significantly in function and anatomy from the brain's glymphatic system. *Respiratory* - The respiratory system is equipped with **bronchial lymphatics** and **pulmonary lymph nodes** that drain fluid and immune cells from the lungs. - This system is involved in immune responses and fluid balance in the lungs, not directly related to brain waste clearance. *Renal* - The renal system has lymphatic drainage associated with the kidneys, which helps in the return of interstitial fluid and immune cells [1]. - This system is distinct from the glymphatic system and primarily involved in kidney function and fluid balance [1].

Question 3: Which one of the following is the myelinating cell of Central Nervous System?

A. Astrocyte
B. Oligodendrocyte (Correct Answer)
C. Microglia
D. Schwann cell

Explanation: ***Oligodendrocyte*** - **Oligodendrocytes** are the primary cells responsible for producing and maintaining the **myelin sheath** around axons in the **Central Nervous System (CNS)** [2], [3]. - Each oligodendrocyte can myelinate multiple axons or multiple segments of the same axon [3]. *Astrocyte* - **Astrocytes** are star-shaped glial cells that provide structural and metabolic support to neurons in the CNS [1]. - They are involved in forming the **blood-brain barrier** and regulating the chemical environment around neurons, but they do not produce myelin. *Microglia* - **Microglia** are the resident **immune cells** of the CNS, functioning as macrophages [1]. - They are primarily involved in immune surveillance, phagocytosis of cellular debris and pathogens, and inflammatory responses, not myelination [1]. *Schwann cell* - **Schwann cells** are the myelinating cells of the **Peripheral Nervous System (PNS)** [2], [3]. - Unlike oligodendrocytes, each Schwann cell typically myelinates only a single axon segment [3].

Question 4: The most common site of urethral opening in cases of hypospadias is :

A. On the penile shaft
B. On the perineum
C. Just proximal to the glans (Correct Answer)
D. At the junction of penile shaft and scrotum

Explanation: ***Just proximal to the glans*** - The most frequent location for the urethral opening in **hypospadias** is the **subcoronal** or glanular region, which is just proximal to the glans. - This accounts for approximately 50-70% of all hypospadias cases, making it the **mildest and most common form**. *On the penile shaft* - While hypospadias can manifest with an opening on the **penile shaft** (midshaft or proximal shaft), these are less common than glanular or subcoronal types. - Penile shaft hypospadias usually indicates a more severe form compared to distal types and often presents with more significant **chordee**. *On the perineum* - An opening on the **perineum** represents the most severe form of hypospadias, often classified as **perineal hypospadias**. - This severe anomaly is associated with other urogenital defects and often presents with a **bifid scrotum** and ambiguous genitalia, which are rare compared to distal forms. *At the junction of penile shaft and scrotum* - This location, called **penoscrotal hypospadias**, is another severe form but is still less common than glanular or subcoronal types. - **Penoscrotal hypospadias** is characterized by a high degree of **chordee** and usually requires more complex surgical correction.

Question 5: Which of the following are congenital abnormalities of the gall bladder? I. The phrygian cap II. Floating gall bladder III. Absence of gall bladder IV. Spigelian gall bladder Select the correct answer using the code given below :

A. I, II and IV
B. II, III and IV
C. I, II and III (Correct Answer)
D. I, III and IV

Explanation: **I, II and III** - **Phrygian cap**, **floating gallbladder**, and **absence of gallbladder** are all recognized congenital anomalies of the gallbladder. [1] - These conditions arise from variations in gallbladder development during the **embryonic period**. *I, II and IV* - This option incorrectly includes **Spigelian gallbladder** (IV) as a congenital anomaly, while excluding **absence of gallbladder** (III). - The Spigelian lobe is a part of the liver, and **Spigelian hernia** is a distinct condition, not a congenital anomaly of the gallbladder itself. *II, III and IV* - This option incorrectly includes **Spigelian gallbladder** (IV) as a congenital anomaly and excludes the **Phrygian cap** (I), which is a common and benign congenital variation. - The Phrygian cap represents a folding of the gallbladder fundus and is universally recognized as congenital. *I, III and IV* - This option incorrectly includes **Spigelian gallbladder** (IV) as a congenital anomaly and excludes the **floating gallbladder** (II). - A floating gallbladder, due to a long mesentery, is a known congenital anatomical variation that can predispose to torsion. [1]

Question 6: Which one of the following best describes craniosynostosis?

A. It is the premature fusion of one or more cranial sutures, preventing growth perpendicular to the suture. (Correct Answer)
B. It is the premature fusion of one or more cranial sutures, facilitating growth perpendicular to the suture.
C. It is delayed fusion of one or more cranial sutures facilitating growth perpendicular to the suture.
D. It is delayed fusion of one or more cranial sutures preventing growth perpendicular to the suture.

Explanation: ***It is the premature fusion of one or more cranial sutures, preventing growth perpendicular to the suture.*** [1] - **Craniosynostosis** is fundamentally defined by the **premature closure** of one or more cranial sutures. [1] - This premature fusion directly **prevents brain growth perpendicular** to the affected suture, leading to compensatory growth in other directions and abnormal head shapes. *It is the premature fusion of one or more cranial sutures, facilitating growth perpendicular to the suture.* - While it is correctly stated as the **premature fusion of sutures**, this statement incorrectly suggests that this fusion *facilitates* growth perpendicular to the suture. - In actuality, the fusion **restricts growth**, causing the skull to grow parallel to the suture line, rather than in the direction of the fused suture. *It is delayed fusion of one or more cranial sutures facilitating growth perpendicular to the suture.* - The definition is incorrect as **craniosynostosis** involves ***premature***, not delayed, fusion of sutures. [1] - Delayed fusion of sutures would typically allow for continued head growth and would not cause the characteristic abnormal head shapes seen in craniosynostosis. *It is delayed fusion of one or more cranial sutures preventing growth perpendicular to the suture.* - This option is incorrect because craniosynostosis is characterized by **premature fusion**, not delayed fusion, of cranial sutures. [1] - Delayed fusion, such as in conditions like **rickets**, would usually lead to larger fontanelles and sutures, rather than restricting perpendicular growth.

Question 7: Opening of Bartholin's duct is in the :

A. periurethral region in anterior 1/3rd of labia minora
B. superficial perineal pouch at the junction of anterior 1/3rd and posterior 1/3rd
C. groove between labia majora and labia minora
D. vestibule outside the hymen at the junction of the anterior 2/3rd and posterior 1/3rd in the groove between the hymen and labium minus (Correct Answer)

Explanation: ***vestibule outside the hymen at the junction of the anterior 2/3rd and posterior 1/3rd in the groove between the hymen and labium minus*** - The **Bartholin's glands** (also known as greater vestibular glands) are located on each side of the vaginal opening, and their ducts open into the **vestibule** [1]. - Specifically, the openings are found in the groove between the **hymen** and the **labium minus**, in the posterior region of the vestibule [1]. *periurethral region in anterior 1/3rd of labia minora* - This description corresponds to the location of the **Skene's glands** (also known as lesser vestibular glands or paraurethral glands), which secrete into the urethra, not the Bartholin's glands [1]. - The Bartholin's glands are located more posteriorly and laterally to the vaginal opening, distinct from the urethral area. *superficial perineal pouch at the junction of anterior 1/3rd and post 1/3rd* - The **superficial perineal pouch** contains structures like the bulbospongiosus and ischiocavernosus muscles, and the crura of the clitoris, but not the external opening of Bartholin's ducts. - The duct openings are externally visible in the **vestibule**, not within a deeper anatomical space like the superficial perineal pouch [1]. *groove between labia majora and labia minora* - This describes the **interlabial sulcus**, which is the general space between the labia majora and minora. - While the vestibule is within this general area, the precise opening of Bartholin's duct is specifically at the junction of the anterior 2/3rd and posterior 1/3rd of the vaginal introitus, in the groove between the hymen and labium minus [1].

Question 8: Gland of Cloquet is :

A. lymphatic drainage of cervix
B. lymphatic drainage of uterus
C. lymphatic drainage of vulva (Correct Answer)
D. lubricating glands of vagina

Explanation: ***lymphatic drainage of vulva*** - The **glands of Cloquet** (or the **node of Cloquet**) specifically refer to a deep inguinal lymph node, often considered the most superior and medial node in the femoral triangle. - This node is crucial in the **lymphatic drainage of the vulva**, as it is one of the final nodes before lymph flows into the external iliac nodes. *lymphatic drainage of cervix* - The **cervix** primarily drains to the **internal iliac**, **obturator**, and **presacral lymph nodes**, not the inguinal nodes associated with Cloquet's gland. - Lymphatic pathways for the cervix are more deeply located within the pelvis. *lymphatic drainage of uterus* - The **uterus** largely drains to the **para-aortic** (or lumbar), **internal iliac**, **external iliac lymph nodes**. - The pathways are distinct from the superficial inguinal drainage where Cloquet's gland is found. *lubricating glands of vagina* - The main lubricating glands of the vagina are the **Bartholin's glands** and numerous small **vaginal glands** (Skene's glands are associated with the urethra). - "Glands of Cloquet" refers to a lymph node, not a secretory gland involved in lubrication.