Radial club hand/ Manus valgus is due to: March 2013 (f)
**Core Concept**
Radial club hand, also known as manus valgus, is a congenital anomaly characterized by a short, curved radius and ulna, leading to a deformity of the forearm and wrist. This condition results from a failure of proper formation or development of the radius and ulna during fetal development.
**Why the Correct Answer is Right**
The correct answer is related to the pathophysiology of radial club hand. The radial club hand is due to the absence or underdevelopment of the radius, which is a result of a failure of the radius to form properly in the embryo. This leads to a characteristic "club-like" appearance of the forearm. The ulna is also affected, often being shorter than normal and deviating medially. The radial nerve is usually affected, leading to a decrease in the size of the forearm muscles.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not address the underlying cause of radial club hand. While the growth plate may be involved in the condition, it is not the primary cause.
**Option B:** This option is incorrect because it is a symptom of radial club hand, not the cause. Pain and limited mobility are consequences of the deformity, not its underlying reason.
**Option C:** This option is incorrect because it refers to a different condition altogether. Madelung's deformity is a condition that affects the distal radius and ulna, causing a deformity of the wrist.
**Clinical Pearl / High-Yield Fact**
Radial club hand is a congenital anomaly that results in a characteristic deformity of the forearm and wrist. It is essential to recognize the underlying cause of the condition, which is a failure of the radius to form properly during fetal development.
**Correct Answer:** D.