Anatomical Variations and Anomalies Practice Questions

Q: Identify the marked blood vessel in the given image.

Interventricular artery. ***Interventricular artery*** - The **anterior interventricular artery**, also known as the **Left Anterior Descending (LAD) artery**, is a direct continuation of the left coronary artery that travels down the **anterior interventricular sulcus**. - It is the most clinically significant vessel due to its extensive supply to the **anterior wall of the left ventricle** and the **anterior two-thirds of the interventricular septum**. *Left coronary artery* - This is the main trunk that arises from the **left aortic sinus** before bifurcating into the **LAD** and the **circumflex artery**. - It is a short vessel and does not travel down the interventricular groove, unlike the LAD. *Right coronary artery* - This artery arises from the **right aortic sinus** and travels within the **coronary sulcus** between the right atrium and right ventricle. - It typically supplies the **right atrium**, **right ventricle**, and the **inferior wall** of the heart, rather than the interventricular groove. *Left circumflex artery* - This vessel branches off the **left coronary artery** and travels within the **coronary sulcus** toward the left margin of the heart. - It supplies the **left atrium** and the **lateral wall of the left ventricle**, moving away from the interventricular sulcus.

Q: A 4-year-old child with one tooth less than normal dentition presents with a large tooth exhibiting two crowns and two root canals. What is this anomaly?

Fusion. ### Explanation The correct answer is **Fusion**. **1. Why Fusion is correct:** Fusion is a developmental anomaly where **two separate tooth buds** join to form a single large tooth. The key diagnostic feature in this clinical scenario is the **reduced tooth count** in the dental arch (one tooth less than normal), as two teeth have merged into one. Radiographically and clinically, fusion typically presents with **two separate root canals** and a large, bifid crown. It occurs due to physical pressure or force during the development of adjacent tooth germs. **2. Why the other options are incorrect:** * **Gemination:** This occurs when a **single tooth bud** attempts to divide. The result is a large tooth with a bifid crown but a **single root canal**. Crucially, the **tooth count remains normal** (the "extra" crown is offset by the fact that it originated from one bud). * **Dilaceration:** This refers to an abnormal **bend or curve** in the root or crown of a tooth, usually caused by trauma during tooth development. It does not involve the merging of teeth or multiple crowns. * **Concrescence:** This is a form of fusion that occurs **after root formation** is complete, where two teeth are joined only by their **cementum**. It is most common in maxillary molars. **3. NEET-PG High-Yield Pearls:** * **Mnemonic for Tooth Count:** * **F**usion = **F**ewer teeth (Total count is -1). * **G**emination = **G**ood count (Total count is normal). * Fusion is more common in **primary (deciduous) dentition** than permanent dentition. * The most common site for both fusion and gemination is the **incisor region**. * If a fused tooth involves a "supernumerary" tooth and a normal tooth, the tooth count will appear normal; however, the question specifies a "less than normal" count, pointing directly to Fusion of two normal buds.

Q: What is right isomerism?

Asplenia. Explanation: Right Isomerism (Ivemark Syndrome) is a type of heterotaxy syndrome where the body’s normal asymmetry is lost, and the organs on both sides of the body follow a "right-sided" pattern. In a normal individual, the spleen is a left-sided organ. In right isomerism, because both sides of the body mirror the right side, the left-sided structures (like the spleen) fail to develop. This leads to Asplenia (congenital absence of the spleen). Analysis of Options: * A. Asplenia (Correct): In right isomerism, there is bilateral "right-sidedness." Since the spleen is embryologically a left-sided structure, it is absent. * B & D. Two spleens / Polysplenia (Incorrect): These are characteristic of Left Isomerism. In left isomerism, both sides of the body mirror the left side. Since the spleen is a left-sided organ, the body develops multiple small spleens (polysplenia). * C. One spleen (Incorrect): This is the normal anatomical state (Situs Solitus). High-Yield Facts for NEET-PG: * Right Isomerism (Asplenia): Associated with bilateral 3-lobed lungs, bilateral eparterial bronchi, a midline liver, and severe cyanotic heart disease (e.g., TAPVC, common atrium). * Left Isomerism (Polysplenia): Associated with bilateral 2-lobed lungs, bilateral hyparterial bronchi, and interrupted inferior vena cava (IVC) with azygos continuation. * Clinical Pearl: Patients with right isomerism/asplenia are at high risk for life-threatening infections from encapsulated organisms (e.g., S. pneumoniae) and require prophylactic antibiotics and vaccinations.

Question 1

Identify the marked blood vessel in the given image.

Accepted Answer

Interventricular artery

Answer

Left coronary artery

Answer

Right coronary artery

Answer

Left circumflex artery

Question 2

Persistent fetal lobulation of the adult kidney is most likely due to:

Accepted Answer

A normal variant

Answer

Congenital renal defect

Answer

Obstructive uropathy

Answer

Intrauterine infections and scar

Question 3

A 4-year-old child with one tooth less than normal dentition presents with a large tooth exhibiting two crowns and two root canals. What is this anomaly?

Accepted Answer

Fusion

Answer

Dilaceration

Answer

Gemination

Answer

Concrescence

Question 4

What is the commonest uterine anomaly?

Accepted Answer

Uterus bicornis

Answer

Uterus unicornis

Answer

Uterus didelphys

Answer

Subseptate uterus

Question 5

What is right isomerism?

Accepted Answer

Asplenia

Answer

Two spleens

Answer

One spleen

Answer

Polysplenia

Anatomical Variations and Anomalies — MCQs

Anatomical Variations and Anomalies — MCQs

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