The cubital tunnel is a sheath like area in which the the ulnar nerve passes through at the the olecranon process, also known as your "funny bone". If you work your bi's and or forearms alot, or do alot of repetative motion.... that area can get compressed and cause injury to the ulnar nerve. The same nerve can also be injured/pinched at the spine or in the wrist. You may try looking up cubital tunnel release or anterior transposition of the ulnar nerve. These are actually surgical proceedures but it may give you some better insight as well as explaining it better than I do.