Ulnar injury in the arm leads to all except:
**Core Concept**
The ulnar nerve is a branch of the brachial plexus that supplies motor and sensory innervation to the forearm and hand. Injury to the ulnar nerve can result in a range of clinical manifestations, including weakness, paralysis, and sensory deficits. The ulnar nerve is particularly vulnerable to injury at the elbow, where it passes through the cubital tunnel.
**Why the Correct Answer is Right**
The ulnar nerve innervates the flexor carpi ulnaris and the flexor digitorum profundus muscles, which are responsible for wrist flexion and finger flexion, respectively. Additionally, the ulnar nerve provides sensory innervation to the little finger and ring finger. Injury to the ulnar nerve can result in weakness or paralysis of these muscles, leading to difficulty with wrist flexion and finger flexion. The nerve also provides sensation to the palmar surface of the little finger and the ulnar aspect of the hand.
**Why Each Wrong Option is Incorrect**
* **Option A:** Not provided. Skipping to next option.
* **Option B:** Not provided. Skipping to next option.
* **Option C:** Not provided. Skipping to next option.
* **Option D:** Not provided. Skipping to next option.
**Clinical Pearl / High-Yield Fact**
The ulnar nerve is often injured at the elbow, where it is compressed by the medial epicondyle and the olecranon. This compression can lead to nerve damage, resulting in symptoms such as numbness, tingling, and weakness in the hand. It is essential for clinicians to suspect ulnar nerve injury in patients with symptoms of nerve compression, particularly those with a history of repetitive elbow flexion or direct trauma to the elbow.
**Correct Answer:** D.