Anatomical Basis of Common Clinical Conditions — MCQs
Which of the following is NOT a symptom of carpal tunnel syndrome?
Anterior choroidal artery is a branch of which of the following arteries?
Commonest site of intra-abdominal abscess -
Which of the following is the LEAST likely to cause appendicitis-like syndrome?
Which of the following nerves is commonly damaged during McBurney's incision?
Bleeding as shown in the image is due to which of the following vessels?
Ophthalmic artery is a branch of which part of the internal carotid artery?
Which of the following statements about the atrioventricular groove is true?
ECG is poor in detecting ischemia in areas supplied by which of the following vessels?
Clinical testing of the function of the long thoracic nerve is done by:
Anatomical Basis of Common Clinical Conditions Indian Medical PG Practice Questions and MCQs
Question 1: Which of the following is NOT a symptom of carpal tunnel syndrome?
- A. Phalen's sign
- B. Pain & paraesthesia of wrist
- C. Tinel sign
- D. Ulnar nerve dysfunction (Correct Answer)
Explanation: ***Ulnar nerve dysfunction*** - Carpal tunnel syndrome specifically involves compression of the **median nerve**, not the ulnar nerve. - Symptoms related to the median nerve include numbness and tingling in the **thumb, index, middle, and radial half of the ring finger**, along with **thenar muscle wasting**. *Tinel sign* - The **Tinel sign** is a common physical examination finding in carpal tunnel syndrome, elicited by tapping over the **median nerve** at the wrist. - A positive sign involves tingling or electric shock-like sensations in the **median nerve distribution**. *Phalen's sign* - **Phalen's sign** is another classic physical maneuver used to diagnose carpal tunnel syndrome, where exaggerated wrist flexion for 60 seconds reproduces symptoms. - This maneuver increases pressure within the **carpal tunnel**, exacerbating median nerve compression. *Pain & paraesthesia of wrist* - **Pain and paraesthesia (numbness and tingling)** in the wrist and hand are hallmark symptoms of carpal tunnel syndrome. - These symptoms are often worse at night or with repetitive hand movements, reflecting **median nerve irritation**.
Question 2: Anterior choroidal artery is a branch of which of the following arteries?
- A. Basilar artery
- B. Anterior cerebral artery
- C. Posterior cerebral artery
- D. Internal carotid artery (Correct Answer)
Explanation: ***Correct: Internal carotid artery*** - The **anterior choroidal artery** is a direct branch of the **internal carotid artery**, specifically originating from its **supraclinoid segment**. - It supplies crucial structures such as the **choroid plexus of the lateral ventricle**, parts of the **hippocampus**, **amygdala**, and the **posterior limb of the internal capsule**. - This is a clinically important vessel, as occlusion can lead to significant neurological deficits. *Incorrect: Basilar artery* - The basilar artery is part of the **posterior circulation**, formed by the union of the vertebral arteries. - It gives rise to branches like the **pontine arteries**, **superior cerebellar arteries**, and **posterior cerebral arteries**, but not the anterior choroidal artery. *Incorrect: Anterior cerebral artery* - The anterior cerebral artery is a terminal branch of the **internal carotid artery**, but it primarily supplies the **medial surface of the frontal and parietal lobes**. - It does not give rise to the anterior choroidal artery; instead, the anterior choroidal artery branches off the internal carotid artery more **proximally**, before the terminal bifurcation. *Incorrect: Posterior cerebral artery* - The posterior cerebral artery is a terminal branch of the **basilar artery** and is part of the posterior circulation. - It supplies the **occipital lobe** and parts of the **temporal lobe**. - Its branches include **posterior choroidal arteries** (not anterior choroidal artery), which supply the choroid plexus of the third ventricle and lateral ventricles.
Question 3: Commonest site of intra-abdominal abscess -
- A. Pelvis (Correct Answer)
- B. Subphrenic
- C. Paracolic
- D. Retroperitoneal
Explanation: ***Pelvis*** - The **pelvis** is the most common site for intra-abdominal abscesses due to **gravity-dependent pooling** of infected fluid from various sources. - The pelvic cavity is the most dependent (lowest) part of the peritoneal cavity in both supine and upright positions, making it the natural collection point for infected peritoneal fluid. - Common causes include **perforated appendicitis**, **diverticulitis**, **pelvic inflammatory disease**, and **postoperative complications**. *Paracolic* - The **paracolic gutters** (especially the right paracolic gutter) are common sites for abscess formation as they are dependent spaces. - While frequently involved, they are the second most common location after the pelvis. - Often associated with **appendicitis**, **colonic perforations**, and peritonitis. *Subphrenic* - **Subphrenic abscesses** occur beneath the diaphragm, typically following **upper abdominal surgery**, **perforated peptic ulcers**, or hepatobiliary infections. - They represent a significant but less common location compared to pelvic abscesses. *Retroperitoneal* - **Retroperitoneal abscesses** are the least common among these options. - Usually associated with pathology of retroperitoneal organs like **kidneys** (perinephric abscess), **pancreas** (infected pseudocyst), or **psoas muscle** (psoas abscess).
Question 4: Which of the following is the LEAST likely to cause appendicitis-like syndrome?
- A. Yersinia enterocolitica
- B. Yersinia pseudotuberculosis
- C. Yersinia pestis (Correct Answer)
- D. Campylobacter jejuni
Explanation: ***Yersinia pestis*** - While *Yersinia pestis* is a bacterium from the *Yersinia* genus, it is primarily known as the causative agent of **plague** (bubonic, pneumonic, septicemic). - It does not typically cause an appendicitis-like syndrome but rather systemic infections with **lymphadenopathy** (buboes), **fever**, and severe illness. - This is the **LEAST likely** organism among the options to present with appendicitis-like symptoms. *Yersinia enterocolitica* - This bacterium is a well-known cause of **yersiniosis**, which commonly presents with **acute ileitis** and **mesenteric lymphadenitis**, mimicking appendicitis. - Symptoms include **fever**, **abdominal pain** (often in the right lower quadrant), **diarrhea**, and sometimes vomiting, making differentiation from appendicitis clinically challenging. *Yersinia pseudotuberculosis* - Similar to *Yersinia enterocolitica*, this organism causes **mesenteric lymphadenitis** and **terminal ileitis**, leading to an appendicitis-like presentation. - It often results in **abdominal pain** localized to the **right lower quadrant**, **fever**, and sometimes a rash (erythema nodosum), mimicking acute appendicitis. *Campylobacter jejuni* - A common cause of bacterial gastroenteritis that can also cause **acute ileitis** and **mesenteric adenitis**. - Can present with **right lower quadrant pain** mimicking appendicitis, especially in children and young adults. - Associated with bloody diarrhea, fever, and crampy abdominal pain.
Question 5: Which of the following nerves is commonly damaged during McBurney's incision?
- A. Subcostal nerve
- B. Iliohypogastric nerve (Correct Answer)
- C. 11th thoracic nerve
- D. 10th thoracic nerve
Explanation: ***Iliohypogastric nerve*** - The **iliohypogastric nerve** is most commonly injured during **McBurney's incision** due to its superficial position and transverse course at the level of the incision. - Damage can lead to **numbness** or altered sensation in the suprapubic region, and sometimes **weakness of the lower abdominal wall**. *Subcostal nerve* - The **subcostal nerve** (T12) runs inferior to the 12th rib and is generally superior to the typical site of a McBurney's incision. - Injury to this nerve is less common during this procedure compared to the iliohypogastric and ilioinguinal nerves. *10th thoracic nerve* - The **10th thoracic nerve** (T10) provides sensation around the umbilicus. - While it contributes to innervation of the abdominal wall, its location is typically well above the area of a standard McBurney's incision, making injury unlikely. *11th thoracic nerve* - The **11th thoracic nerve** (T11) innervates the abdominal wall and is located superior to the typical incision site for appendectomy. - Injury to T11 during a McBurney's incision is uncommon as the nerve's course lies cephalad to the surgical field.
Question 6: Bleeding as shown in the image is due to which of the following vessels?
- A. Lenticulostriate artery
- B. Vertebral artery
- C. Bridging veins (Correct Answer)
- D. Middle meningeal artery
Explanation: ***Bridging veins*** - The image depicts a **subdural hemorrhage (subdural hematoma)**, a collection of blood between the dura mater and the arachnoid mater, typically appearing as a **crescent-shaped** hyperdensity that conforms to the brain surface. - This type of hemorrhage is caused by the tearing of **bridging veins** that traverse the subdural space, connecting the cerebral cortex to the dural venous sinuses. - Tearing of these veins occurs due to rapid acceleration-deceleration forces causing the brain to move relative to the dura, stretching and rupturing the veins. This is common in **head trauma**, especially in the elderly (due to brain atrophy increasing vein vulnerability) or infants. *Lenticulostriate artery* - Rupture of the lenticulostriate arteries (perforating branches of the middle cerebral artery) typically leads to **intraparenchymal hemorrhage**, specifically in the basal ganglia or internal capsule. - This type of bleeding is confined within the brain parenchyma, rather than collecting in the subdural space as seen in the image. - Associated with hypertensive hemorrhage. *Vertebral artery* - The vertebral arteries supply the posterior circulation of the brain, and their rupture can lead to **subarachnoid hemorrhage** (if a posterior circulation aneurysm ruptures) or **intraparenchymal bleeding** in the brainstem or cerebellum. - Bleeding from the vertebral artery is not associated with the subdural collection pattern shown in the image. *Middle meningeal artery* - The middle meningeal artery runs in the epidural space, and its rupture (often due to temporal bone fracture) causes an **epidural hematoma**. - An epidural hematoma is characterized by a **biconvex (lentiform) shape** on imaging and is situated between the dura mater and the skull, which is distinct from the **crescent-shaped** subdural collection shown. - Does not cross suture lines, unlike subdural hematomas which can extend over multiple lobes.
Question 7: Ophthalmic artery is a branch of which part of the internal carotid artery?
- A. Cavernous
- B. Cervical
- C. Petrous
- D. Cerebral (Correct Answer)
Explanation: ***Cerebral (Supraclinoid)*** - The **ophthalmic artery** is the first major branch of the **cerebral (supraclinoid/C6) segment** of the internal carotid artery. - It arises **immediately after** the ICA pierces the dura mater and exits the cavernous sinus, entering the **subarachnoid space**. - The ophthalmic artery enters the orbit through the **optic canal** alongside the optic nerve, supplying the eye and orbital structures. - This is the **most clinically important branch** arising from this segment before the terminal bifurcation into anterior and middle cerebral arteries. *Cavernous* - The **cavernous segment (C4)** courses through the cavernous sinus and gives rise to small branches like the **meningohypophyseal trunk** and **inferolateral trunk**. - These branches supply the pituitary gland, cranial nerves, and dura mater. - The ophthalmic artery does **NOT** arise from this segment; it arises after the ICA exits the cavernous sinus. *Cervical* - The **cervical segment (C1)** extends from the common carotid bifurcation to the entrance of the carotid canal at the skull base. - This segment typically has **no branches**, serving primarily as a conduit. - The ophthalmic artery arises much more superiorly, intracranially. *Petrous* - The **petrous segment (C2)** lies within the petrous part of the temporal bone in the carotid canal. - It gives rise to small branches like the **caroticotympanic** and **vidian arteries** that supply the middle ear and pterygoid canal. - The ophthalmic artery is not a branch of this segment.
Question 8: Which of the following statements about the atrioventricular groove is true?
- A. Contains left anterior descending coronary artery
- B. Also called coronary sulcus (Correct Answer)
- C. Contains posterior descending artery
- D. Contains left coronary artery
Explanation: ***Also called coronary sulcus*** - The **atrioventricular groove** is a critical anatomical landmark that separates the atria from the ventricles on the external surface of the heart. - This anatomical division is consistently referred to as the **coronary sulcus**, which encircles the entire heart. *Contains left anterior descending coronary artery* - The **left anterior descending (LAD) coronary artery**, also known as the anterior interventricular artery, lies within the **interventricular groove** (or sulcus), not the atrioventricular groove. - The interventricular groove separates the left and right ventricles, distinct from the atrioventricular separation. *Contains left coronary artery* - The **left coronary artery (LCA)** is a short main trunk that almost immediately divides into the **left anterior descending** (LAD) and **circumflex arteries** [1]. - While the **circumflex artery** (a branch of the LCA) runs in the left part of the atrioventricular groove, the main left coronary artery itself is too short to be considered within the groove [1]. *Contains posterior descending artery* - The **posterior descending artery (PDA)**, also known as the posterior interventricular artery, lies within the **posterior interventricular groove**, separating the ventricles posteriorly. - The PDA is a branch of either the right coronary artery (in most people) or the circumflex artery, but it follows the interventricular septum, not the atrioventricular border.
Question 9: ECG is poor in detecting ischemia in areas supplied by which of the following vessels?
- A. Left Anterior Descending (LAD)
- B. Left Circumflex (LCx) (Correct Answer)
- C. Posterior Descending Artery (PDA)
- D. Right Coronary Artery (RCA)
Explanation: ***Left Circumflex (LCx)*** - Ischemia in the area supplied by the **LCx artery** often occurs in the **posterior or lateral wall** of the left ventricle, which can be difficult to detect with standard 12-lead ECGs. - ECG leads that best view the LCx territory (V7-V9) are not routinely performed, leading to a higher chance of **silent or unrecognized ischemia**. *Left Anterior Descending (LAD)* - The LAD supplies the **anterior and septal walls** of the left ventricle, areas well-covered by standard ECG leads like V1-V4 [1][2]. - Ischemia in the LAD territory typically produces clear changes such as **ST-segment elevation** or **T-wave inversions** in these leads [2]. *Posterior Descending Artery (PDA)* - The PDA supplies the **inferior wall** and a portion of the posterior septum. - Ischemia in this area is generally well-detected by inferior leads (II, III, aVF) on a standard ECG, showing **ST-segment changes**. *Right Coronary Artery (RCA)* - The RCA typically supplies the **right ventricle** and, in most people, the **inferior wall** of the left ventricle via the PDA. - Ischemia due to RCA occlusion is usually visible in the **inferior leads** (II, III, aVF) and sometimes in **right precordial leads** (V3R, V4R) for right ventricular involvement.
Question 10: Clinical testing of the function of the long thoracic nerve is done by:
- A. Perform resisted flexion of the arm at the shoulder joint
- B. Perform resisted external rotation of the arm at the shoulder joint
- C. Raise the arm above the head on the affected side
- D. Push the wall with outstretched arms and observe for scapular winging (Correct Answer)
Explanation: ***Push the wall with outstretched arms and observe for scapular winging*** - The **long thoracic nerve** innervates the **serratus anterior muscle**, which is responsible for holding the scapula against the thoracic wall and for upward rotation of the scapula during arm elevation. - When the long thoracic nerve is damaged, the serratus anterior weakens, leading to classic **scapular winging** where the medial border and inferior angle of the scapula protrude posteriorly, especially when the patient pushes against a wall with outstretched arms. *Perform resisted flexion of the arm at the shoulder joint* - This action primarily tests the **deltoid muscle** and **biceps brachii**, innervated by the **axillary** and **musculocutaneous nerves**, respectively. - It does not specifically isolate the function of the serratus anterior or the long thoracic nerve. *Perform resisted external rotation of the arm at the shoulder joint* - **External rotation** of the arm at the shoulder is mainly performed by the **infraspinatus** and **teres minor muscles**, which are innervated by the **suprascapular nerve** and **axillary nerve**, respectively. - This maneuver does not evaluate the integrity of the long thoracic nerve or serratus anterior. *Raise the arm above the head on the affected side* - While the serratus anterior assists in **upward rotation of the scapula** during arm elevation, observing only global arm elevation may not be specific enough to detect subtle long thoracic nerve dysfunction. - Other muscles like the deltoid and trapezius contribute significantly to this movement, potentially masking a weak serratus anterior until more specific testing like the wall push-up test is performed.
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