Bear paw sign is seen in
**Core Concept**
The bear paw sign is a radiological feature observed in the context of a specific medical condition. It is characterized by a distinctive appearance resembling the paw of a bear, resulting from the abnormal alignment of certain structures.
**Why the Correct Answer is Right**
The bear paw sign is typically seen in the setting of a type of congenital heart defect, specifically supracardiac total anomalous pulmonary venous return (TAPVR). In this condition, the pulmonary veins are abnormally connected to the systemic venous system, rather than the left atrium. The resulting dilated vertical vein, which conveys oxygenated blood from the lungs to the heart, can give the appearance of a "bear paw" on imaging studies. This is due to the dilated vein's characteristic branching and tapering, which resembles the shape of a bear's paw.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the bear paw sign is not typically associated with a different type of congenital heart defect, such as tetralogy of Fallot. While tetralogy of Fallot is a cyanotic congenital heart defect, it does not characteristically produce the bear paw sign.
**Option B:** This option is incorrect because the bear paw sign is not commonly seen in the context of a different type of cardiac anomaly, such as Ebstein's anomaly. Ebstein's anomaly is characterized by a malformed tricuspid valve and an abnormally small right ventricle, but it does not typically produce the bear paw sign.
**Option C:** This option is incorrect because the bear paw sign is not typically associated with a different type of congenital heart defect, such as transposition of the great arteries. While transposition of the great arteries is a cyanotic congenital heart defect, it does not characteristically produce the bear paw sign.
**Clinical Pearl / High-Yield Fact**
The bear paw sign is a classic radiological feature of supracardiac total anomalous pulmonary venous return (TAPVR), a type of congenital heart defect. Recognizing this sign can help clinicians diagnose this condition, which requires prompt medical attention to avoid complications.
**Correct Answer: D. Supracardiac TAPVR.**