The vertebral axis is only one direction, and our bodies have two additional directions: front to back, and side to side. The terms for the front to back direction are: Anterior: Toward the front. The nose is on the anterior side of the head. Posterior: Toward the rear.
If you're experiencing numb fingers, especially in the left hand pinky and ring fingers, the most likely cause is ulnar nerve compression or entrapment. The ulnar nerve runs from the spine, past the shoulder blades, down the arm, across the outer bend of the elbow and down the arm to the pinky and ring fingers.
FROM OUR EXPERTS. It's hard to say, especially if you don't remember any kind of injury to your pinky prior to the pain and stiffness. You could have a touch of arthritis in it. People who play the guitar a lot someties get something called Cubital Tunnel Syndrome, but there is usually also pain the elbow and inner forearm in addition to the pinky.