**Core Concept**
The "funny bone" symptoms described in this patient are related to compression or injury of a specific nerve that supplies sensation to the medial aspect of the hand and the medial one and one-half fingers. This condition is often associated with the ulnar nerve, which is responsible for transmitting sensory information from the hand to the spinal cord.

**Why the Correct Answer is Right**
The ulnar nerve is a branch of the brachial plexus that arises from the medial cord. It courses through the cubital tunnel at the elbow and then down the forearm to innervate the medial aspect of the hand and the medial one and one-half fingers. Compression or injury to the ulnar nerve at the elbow or wrist can cause symptoms such as numbness, tingling, and sensory loss in the distribution of the ulnar nerve. The ulnar nerve is also responsible for controlling muscles involved in fine motor movements of the hand, including the adductor pollicis and the interossei muscles.

**Why Each Wrong Option is Incorrect**
**Option A:** The axillary nerve is a branch of the brachial plexus that arises from the posterior cord and is primarily responsible for innervating the deltoid and teres minor muscles, as well as providing sensory innervation to the skin over the deltoid region. It does not supply the medial aspect of the hand.

**Option B:** The radial nerve is a branch of the brachial plexus that arises from the posterior cord and is primarily responsible for innervating the extensor muscles of the arm and forearm, as well as providing sensory innervation to the back of the hand. It does not supply the medial aspect of the hand.

**Option C:** The median nerve is a branch of the brachial plexus that arises from the lateral and medial cords and is primarily responsible for innervating the muscles of the anterior forearm and the thenar eminence, as well as providing sensory innervation to the palmar surface of the thumb, index, and middle fingers. While it does supply some sensory innervation to the hand, it does not supply the medial aspect of the hand or the medial one and one-half fingers.

**Clinical Pearl / High-Yield Fact**
The ulnar nerve is often compressed at the elbow, a condition known as cubital tunnel syndrome, which can cause symptoms such as numbness, tingling, and sensory loss in the distribution of the ulnar nerve. This condition is often associated with activities that involve bending the elbow, such as playing a musical instrument or using a computer mouse.

**✓ Correct Answer:** D. Ulnar. **The ulnar nerve is injured, leading to "funny bone" symptoms including sensory loss over the anterior and posterior surfaces of the medial third of the hand and the medial one and one-half fingers.**