Imaging Aspects of Anatomical Variations — MCQs
Double aortic arch is associated with which syndrome?
Identify the marked structure in the given image.
Commonly associated in tetralogy of Fallot is:
Which of the following represents a common variation in the arteries arising from the arch of the aorta?
A chest CT shows 'doughnut sign' in mediastinum. Which additional finding would best support pulmonary artery sling?
Which testis is typically positioned higher?
The following arrow marked vessel can cause torrential hemorrhage during cholecystectomy. Which of the following is the correct description?
Which structure is NOT typically associated with the anatomical snuffbox?
Which structure is NOT part of the anatomical snuffbox?
In a clinical scenario where a patient does not experience withdrawal bleeding after the administration of estrogen followed by progestin, what does this indicate?
Imaging Aspects of Anatomical Variations Indian Medical PG Practice Questions and MCQs
Question 1: Double aortic arch is associated with which syndrome?
- A. DiGeorge syndrome (Correct Answer)
- B. CATCH 22 syndrome
- C. Shprintzen syndrome
- D. None of the options
Explanation: ***DiGeorge syndrome*** - **DiGeorge syndrome** is caused by a **22q11.2 deletion** affecting the development of the third and fourth pharyngeal pouches, leading to **thymic hypoplasia**, **parathyroid hypoplasia**, and **cardiac anomalies**. - Common cardiac defects include **interrupted aortic arch type B**, **truncus arteriosus**, **tetralogy of Fallot**, and **VSD**. - **Double aortic arch** can occur in 22q11.2 deletion syndrome, though it is less common than other cardiac anomalies; however, among the syndromes listed, this represents the most appropriate association. - The question tests recognition that various cardiac arch anomalies, including double aortic arch, may be seen in this genetic syndrome. *CATCH 22 syndrome* - This is an **acronym** for DiGeorge syndrome: **C**ardiac defects, **A**bnormal facies, **T**hymic hypoplasia, **C**left palate, **H**ypocalcemia, and **22q11 deletion**. - It is **essentially the same condition** as DiGeorge syndrome, just using different nomenclature. - While technically correct, "DiGeorge syndrome" is the more standard medical terminology currently used. *Shprintzen syndrome* - **Shprintzen syndrome** (also called **velocardiofacial syndrome or VCFS**) is caused by the **same 22q11.2 deletion** as DiGeorge syndrome. - It represents a **phenotypic variant within the 22q11.2 deletion syndrome spectrum**, with more emphasis on palatal and facial features. - Since it shares the same genetic basis, it can also present with similar cardiac anomalies, but "DiGeorge syndrome" is the more commonly recognized term for this genetic disorder. *None of the options* - This is incorrect because the three syndromes listed above (DiGeorge, CATCH 22, and Shprintzen) all refer to **22q11.2 deletion syndrome** or its variants, which can be associated with various cardiac anomalies including double aortic arch. - Among the listed options, **DiGeorge syndrome** is the most appropriate and widely recognized answer.
Question 2: Identify the marked structure in the given image.
- A. Electrode
- B. Coil (Correct Answer)
- C. Magnet
- D. Processor
Explanation: ***Coil*** - The marked structure appears to be a **cochlear implant's internal coil**, which is common in X-ray imaging of these devices. - The **cochlear implant internal coil** is crucial for transmitting processed sound signals via electromagnetic induction to the electrode array within the cochlea. *Electrode* - An **electrode array** is typically a thin, flexible wire with multiple contacts inserted into the cochlea, which is not what the arrow is pointing to directly. - While electrodes are part of a cochlear implant, the marked structure's shape and position are more consistent with the **internal coil** that connects to the electrode array. *Magnet* - A **magnet** is present in a cochlear implant system, typically in both the external processor and internal receiver, to hold these two components together through the skin. - Magnets usually appear as dense, circular structures in X-rays, often seen more anteriorly or superiorly to the coil for external component alignment. *Processor* - The **processor** for a cochlear implant is an external device worn behind the ear, not an implanted component visible on an X-ray. It processes sound and sends it to the internal coil. - The structures seen in the X-ray are **implanted components** of the cochlear implant, not the external sound processor.
Question 3: Commonly associated in tetralogy of Fallot is:
- A. Right sided aortic arch (Correct Answer)
- B. Coarctation of aorta
- C. Aortopulmonary window
- D. Aberrant right subclavian artery
Explanation: ***Right sided aortic arch*** - A **right-sided aortic arch** is a known anomaly that frequently coexists with Tetralogy of Fallot, occurring in about 20-25% of cases. - This association is due to disturbances in the normal development of the **aortic arches** during embryonic life. *Coarctation of aorta* - **Coarctation of the aorta** is a narrowing of the aorta, most commonly found in the juxtaductal region. - While it can occur with other congenital heart defects, it is not particularly associated with Tetralogy of Fallot. *Aortopulmonary window* - An **aortopulmonary window** is a rare defect involving a communication between the aorta and the pulmonary artery, distinct from a patent ductus arteriosus. - It results from incomplete fusion of the aorticopulmonary septum and is not a common associated anomaly in Tetralogy of Fallot. *Aberrant right subclavian artery* - An **aberrant right subclavian artery** (also known as *arteria lusoria*) arises from the descending aorta and passes posterior to the esophagus. - While a congenital anomaly of the great vessels, it is not a characteristic or commonly associated finding with Tetralogy of Fallot.
Question 4: Which of the following represents a common variation in the arteries arising from the arch of the aorta?
- A. Absence of brachiocephalic trunk
- B. Left vertebral artery arising from the arch
- C. Presence of retroesophageal subclavian artery
- D. Left common carotid artery arising from brachiocephalic trunk (Correct Answer)
Explanation: ***Left common carotid artery arising from brachiocephalic trunk*** - Normally, the **brachiocephalic trunk** gives rise to the right subclavian and right common carotid arteries, while the left common carotid and left subclavian arteries arise directly from the aortic arch. - However, in this common variation (sometimes called a **bovine arch**), the left common carotid artery originates from the brachiocephalic trunk, reducing the number of direct branches from the arch to two. *Absence of brachiocephalic trunk* - The **brachiocephalic trunk** is one of the three major vessels normally arising from the aortic arch [1]. Its absence is a very rare and significant anomaly, not a common variation. - This would imply direct origins for the right subclavian and right common carotid arteries from the aortic arch, which is not typical. *Left vertebral artery arising from the arch* - The **left vertebral artery** typically arises from the first part of the **left subclavian artery**. - Its direct origin from the aortic arch is a known anatomical variant, but it is less common than the left common carotid artery arising from the brachiocephalic trunk. *Presence of retroesophageal subclavian artery* - A **retroesophageal subclavian artery** (usually the right subclavian artery) is a congenital anomaly where the artery takes an abnormal course behind the esophagus [1]. - While it is a recognized variant, it is considered less common than the "bovine arch" configuration.
Question 5: A chest CT shows 'doughnut sign' in mediastinum. Which additional finding would best support pulmonary artery sling?
- A. Right aortic arch (Correct Answer)
- B. Patent ductus arteriosus
- C. Cardiac dextroposition
- D. Rightward course of left pulmonary artery
Explanation: ***Right aortic arch*** - A **right aortic arch** is a common associated anomaly with **pulmonary artery sling**, increasing the likelihood of **tracheal compression** and airway symptoms. - The combination of a right aortic arch with the characteristic "doughnut sign" (trachea encircled by vascular structures) is highly suggestive of pulmonary artery sling. *Patent ductus arteriosus* - A **patent ductus arteriosus (PDA)** is a common congenital heart defect but does not specifically contribute to the characteristic vascular encirclement of the trachea seen in pulmonary artery sling. - While a PDA can cause left-to-right shunting and pulmonary vascular changes, it is not directly involved in the anatomical sling mechanism. *Cardiac dextroposition* - **Cardiac dextroposition** refers to the heart being positioned on the right side of the chest, often due to extrinsic factors or lung hypoplasia, but it does not inherently relate to the specific vascular anomaly of a pulmonary artery sling. - It doesn't explain the "doughnut sign" or the aberrant course of the pulmonary artery around the trachea. *Rightward course of left pulmonary artery* - **Pulmonary artery sling** itself is defined by the **left pulmonary artery** originating abnormally from the right pulmonary artery and passing between the trachea and esophagus, often giving it a "rightward course" relative to its usual position. - This option essentially describes the pathology of a pulmonary artery sling rather than an *additional* finding that would help *support* the diagnosis. The "doughnut sign" already implies this abnormal course, and we are looking for a separate associated anomaly.
Question 6: Which testis is typically positioned higher?
- A. It varies between individuals
- B. Left testis
- C. Right testis (Correct Answer)
- D. Both are at the same level
Explanation: ***Right testis*** - The **right testis** is commonly positioned slightly higher than the left testis in most males [1]. - This anatomical variation is due to the **left spermatic cord** being inherently longer, which allows the left testis to hang lower. *Left testis* - The **left testis** is typically positioned lower than the right testis. - Its lower position is attributed to the generally **longer left spermatic cord**. *It varies between individuals* - While minor individual variations exist, a consistent pattern of the **right testis** being higher is observed in the majority of males. - The differences in cord length lead to a general trend, not complete randomness in height. *Both are at the same level* - It is uncommon for both testes to be at precisely the **same level**. - The **asymmetrical length** of the spermatic cords makes equal positioning rare.
Question 7: The following arrow marked vessel can cause torrential hemorrhage during cholecystectomy. Which of the following is the correct description?
- A. Moynihan's caterpillar hump due to bend of right hepatic artery (Correct Answer)
- B. Moynihan's caterpillar hump due to bend of left hepatic artery
- C. Moynihan's caterpillar hump due to bend of cystic artery
- D. Moynihan's caterpillar hump due to bend of common hepatic artery
Explanation: ***Moynihan's caterpillar hump due to bend of right hepatic artery*** - The image shows an anatomical variation where the **right hepatic artery** forms a tortuous bend near the cystic duct, resembling a "caterpillar hump." - This anatomical anomaly, known as **Moynihan's hump**, places the right hepatic artery in close proximity to the operative field during cholecystectomy, making it vulnerable to accidental injury and potentially causing torrential hemorrhage. *Moynihan's caterpillar hump due to bend of left hepatic artery* - The left hepatic artery originates from the common hepatic artery and supplies the left lobe of the liver, typically staying well away from the area of concern during routine cholecystectomy. - A bend in the **left hepatic artery** would not be located in the position shown or pose the same risk during gallbladder removal. *Moynihan's caterpillar hump due to bend of cystic artery* - The cystic artery typically arises from the right hepatic artery and is ligated during cholecystectomy to devascularize the gallbladder. - While it supplies the gallbladder, the described "caterpillar hump" refers specifically to a tortuous **right hepatic artery**, not the cystic artery itself. *Moynihan's caterpillar hump due to bend of common hepatic artery* - The common hepatic artery branches into the proper hepatic artery and gastroduodenal artery, located more proximally to the area depicted. - A bend in the **common hepatic artery** would not be found in such close proximity to the cystic duct and would not be described as Moynihan's caterpillar hump in this context.
Question 8: Which structure is NOT typically associated with the anatomical snuffbox?
- A. Extensor pollicis longus
- B. Flexor carpi ulnaris (Correct Answer)
- C. Abductor pollicis longus
- D. Extensor pollicis brevis
Explanation: ***Flexor carpi ulnaris*** - The **flexor carpi ulnaris** is located on the ulnar side of the forearm and wrist, contributing to **wrist flexion** and **adduction**, and is not a boundary or content of the anatomical snuffbox. - Its tendon inserts onto the **pisiform**, **hamate**, and base of the fifth metacarpal, clearly separate from the radial side [1]. *Extensor pollicis longus* - The **Extensor pollicis longus** forms the **ulnar/medial border** of the anatomical snuffbox [1]. - Its tendon can be easily palpated when the thumb is extended. *Abductor pollicis longus* - The **Abductor pollicis longus** forms part of the **radial/lateral border** of the anatomical snuffbox [1]. - It works with the extensor pollicis brevis to create the lateral boundary. *Extensor pollicis brevis* - The **Extensor pollicis brevis** is also part of the **radial/lateral border** of the anatomical snuffbox, lying alongside the abductor pollicis longus [1]. - Its tendon, along with the abductor pollicis longus, functions to **abduct and extend the thumb** [1].
Question 9: Which structure is NOT part of the anatomical snuffbox?
- A. Extensor pollicis brevis
- B. Flexor carpi ulnaris (Correct Answer)
- C. Abductor pollicis longus
- D. Extensor pollicis longus
Explanation: ***Flexor carpi ulnaris*** - The **flexor carpi ulnaris** is located on the ulnar side of the forearm and wrist, contributing to wrist flexion and adduction. - It is not a boundary or content of the **anatomical snuffbox**, which is formed by tendons on the radial side of the wrist. *Extensor pollicis brevis* - This tendon forms the **lateral (radial) boundary** of the **anatomical snuffbox** along with the **abductor pollicis longus** [1]. - It extends the **metacarpophalangeal joint** of the thumb [1]. *Abductor pollicis longus* - This tendon forms the **lateral (radial) boundary** of the **anatomical snuffbox** along with the **extensor pollicis brevis** [1]. - It primarily **abducts** and **extends** the thumb at the **carpometacarpal joint** [1]. *Extensor pollicis longus* - This tendon forms the **medial (ulnar) boundary** of the **anatomical snuffbox** [1]. - It extends the **interphalangeal joint** of the thumb and contributes to its extension at the metacarpophalangeal and carpometacarpal joints.
Question 10: In a clinical scenario where a patient does not experience withdrawal bleeding after the administration of estrogen followed by progestin, what does this indicate?
- A. Uterine factor (Correct Answer)
- B. Ovarian factors
- C. Pituitary factor
- D. Hypothalamic factor
Explanation: ***Uterine factor*** - Withdrawal bleeding after estrogen-progestin administration indicates a responsive **endometrium** with adequate estrogen priming and ability to respond to progesterone. The absence of bleeding suggests an issue with the uterus itself, indicating a **uterine factor**. - A persistent lack of response to this hormonal challenge points towards a physical or anatomical problem within the uterus, such as **Asherman's syndrome** (intrauterine adhesions) or severe endometrial damage/absence. - This test helps differentiate between **outflow tract abnormalities** and hormonal causes of amenorrhea. *Ovarian factors* - Ovarian factors primarily affect **estrogen production** and would be addressed by the exogenous estrogen administration, meaning they wouldn't prevent withdrawal bleeding if the uterus is healthy. - In cases of ovarian dysfunction (e.g., polycystic ovary syndrome, premature ovarian insufficiency), withdrawal bleeding would typically occur after exogenous estrogen and progestin administration. *Pituitary factor* - Pituitary problems lead to insufficient **gonadotropin** (FSH/LH) production, impacting ovarian steroidogenesis, which is bypassed by direct estrogen-progestin administration. - If the pituitary is the cause of amenorrhea, exogenous estrogen-progestin would still elicit withdrawal bleeding provided the uterus is responsive. *Hypothalamic factor* - Hypothalamic issues result in inadequate **GnRH** pulsatility, affecting pituitary and subsequently ovarian function, but are circumvented by direct estrogen-progestin administration. - A healthy uterus would respond to the administered hormones by displaying withdrawal bleeding, regardless of hypothalamic dysfunction.
Want unlimited practice?
Get full access to all questions, explanations, and performance tracking.
Start For Free