My left ring and pinky finger have been numb. what is the cause and how do i treat it?

Ulnar nerve: Numbness of the the ring and little fingers is usually the result of compression of the ulnar nerve somewhere along the arm and usually at the elbow. It is called cubital tunnel syndrome not to be confused with carpal tunnel syndrome. It can also be the result of a herniated disc in the neck. An nerve test is used to localize the cause and help determine treatment.

Don't lean on elbow: You have a nerve compression of a nerve called the ulnar nerve. This usually happens at the wrist or the elbow. Try to avoid leaning on your elbow. If it happens at your wrist things like cycling and hammering may cause or worsen it. See a physical medicine and rehabilitation doctor for diagnosis and nonsurgical treatment.