total loss of feeling

I have a complete loss of feeling in my left elbow.  Appx 2x2 inches. What could be the cause?

[Neuro Forum]

Thanks for using the forum. I am happy to address your questions, and my answer will be based on the information you provided here. Please make sure you recognize that this forum is for educational purposes only, and it does not substitute for a formal office visit with your doctor.

Without the ability to examine you and obtain a history, I can not tell you what the exact cause of your symptoms is. However I will try to provide you with some useful information.

The general cause of sensory loss in a specific distribution in an extremity is a neuropathy, meaning a nerve injury. If your sensory loss is only over a 2x2 cm area at your elbow, this is difficult to localize to one specific nerve or nerve root.

In general, there are two nerves, posterior cutaneous nerve to the arm and posterior cutaneous nerve to the forearm, that supply sensory innervation to the upper and lower back of the arm respectively. The lower lateral (outer) portion of the arm is innervated by a branch of what is called the radial nerve. Compression of this nerve, such as occurs due to leaning on that area of the upper arm for too long, can lead to sensory loss. However, some motor weakness at the wrist and fingers would be expected but this may be subtle. Mechanisms of injury could include sleeping on your arm, slinging your arm over the back of a chair if you sleep (what is termed saturday night palsy) etc. Other nerves could be compressed through similar mechanisms, leading to sensory loss over the arm.

A radiculopathy, or pinched nerve, which results from pressure on the nerves as they exit the spinal cord is unlikely if your symptoms are localized just to this one area over the elbow.

Evaluation by a neurologist is recommended. If he/she is concerned about a neuropathy, one test that may help assess for this is an EMG/NCS which assess how well the nerve conduct electricity and how well muscles respond

Thank you for this opportunity to answer your questions, I hope you find the information I have provided useful, good luck.