Tardy ulnar nerve palsy is seen in –
**Core Concept**
Tardy ulnar nerve palsy is a delayed onset ulnar nerve dysfunction, which is a complication of cubitus valgus deformity, typically occurring after a supracondylar fracture of the humerus. This condition arises due to the gradual stretching of the ulnar nerve as the elbow valgus deformity develops over time.
**Why the Correct Answer is Right**
The mechanism behind tardy ulnar nerve palsy is the progressive stretching of the ulnar nerve as the cubitus valgus deformity increases, leading to nerve damage and subsequent muscle weakness. This condition is often seen in children and adolescents who have a history of supracondylar fractures of the humerus. The ulnar nerve is particularly susceptible to stretching due to its anatomical course, where it runs through a narrow fibro-osseous tunnel at the elbow.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect as it does not specify a condition related to the ulnar nerve or cubitus valgus deformity.
* **Option B:** This option is not relevant to the question as it does not describe a condition associated with the ulnar nerve or tardy ulnar nerve palsy.
* **Option C:** This option is incorrect as it is a different condition that affects the median nerve, not the ulnar nerve.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that tardy ulnar nerve palsy often presents with a delayed onset, sometimes years after the initial injury, making it essential to maintain a high index of suspicion in patients with a history of supracondylar fractures of the humerus.
**Correct Answer:** C.