BASIC HAND AND WRIST ANATOMY
The structure of the human hand is a highly complex. It is composed of skin, blood vessels, nerves, tendons, ligaments, bones and joints. When there is a problem with any of these structures, pain or impaired function may result.
BONES AND JOINTS
There are 29 bones in the hand and wrist if you include the radius and ulna. Bones are dense stiff structures that give support to the soft tissue of the hand. Joints are the places where the adjacent bones meet that allow for motion much like hinges. In the fingers the joints are commonly referred to as knuckles. Fractures are breaks in the bone. Arthritis occurs when the cartilage of the joints is injured or wears out.
Ligaments are the thick white “straps” of sturdy tissue that holds the joints together and allow for joint movement. When ligaments are injured (sprains), the joints may become too loose and dislocate, or too tight and stiff.
MUSCLES AND TENDONS
Muscles are the red fleshy structures that contract and relax to move the joints of the hand and wrist. Most of the muscles that move the hand and wrist are in the forearm, although there are a few small muscles in the hand. Each muscle connects to a white cord-like structure called a tendon. There are many tendons running through the wrist and out into each finger. They may be irritated by overuse (tendinitis) or cut due to sharp injuries to the hand or wrist.
There is a vast network of arteries and veins in the hand and wrist that supply the tissues with blood. Occasionally an artery is injured due to a sharp injury to the hand or wrist. Vascular disease (gradual narrowing of the arteries) and smoking may also damage the arteries in the hand leading to poor blood flow to the fingertips.
There are three main nerves which supply the hand and wrist, the median, radial, and ulnar nerves. Nerves are like fiberoptic cables that carry signals. Your brain sends signals down the spine and then through the nerves in the arm to control the muscles. Sensory signals like temperature, vibration, and pain travel from nerves in the hand up the arm, through the spine, and back to the brain. When nerves are cut or pinched, it disrupts the normal flow of information between your hand and brain which may lead to weakness, numbness, or pain everywhere “downstream” of where the nerve was cut or pinched.
SKIN AND NAILS
The skin normally covers and protects the deep structures of the hand and wrist, but injuries such as cuts and burns can disrupt the skin layer. Fingernails are essentially a specialized part of the skin which protects the fingertips and serves as a tool for certain manual activities. Nails can also be injured, and the nail folds are a common site of infection.
READY TO CONFIRM A DIAGNOSIS AND FIX THE PROBLEM OR JUST WANT TO LEARN MORE?
Our Board-Certified Orthopaedic Hand and Wrist Surgeons are here to help! They can often diagnose the problem in one visit, and get you started with a treatment plan. We offer a wide variety of both nonoperative and operative treatment options.
This content is not a substitute for expert medical advice or diagnosis and is for educational purposes only.