Hand & Wrist Anatomy
The hand and wrist are complex structures that are vital for many daily activities. The hand is made up of 27 bones, and the wrist is composed of 8 small bones called carpals, and two long bones called the radius and ulna which connect the hand to the forearm. The carpals are arranged in two rows and connect to the radius and ulna through small joints called inter-carpal joints.
The bones in the hand are divided into three sections: the carpals, metacarpals, and phalanges. The carpals are the bones that make up the wrist and are arranged in two rows of four bones each. The metacarpals are the bones that make up the palm of the hand and connect the fingers to the wrist. The phalanges are the bones that make up the fingers and thumb, each finger has three phalanges, except for the thumb which has only two.
The hand and wrist are also rich in tendons, nerves, and blood vessels that control the movement and sensation of the hand. The tendons, which are strong fibrous cords, connect the muscles in the forearm to the bones in the hand and fingers, enabling movement. The median nerve, ulnar nerve and radial nerve are the main nerves that innervate the hand and wrist, providing sensation and muscle control. The blood vessels provide nourishment to the hand and wrist.
The joints of the hand and wrist are also important structures. The wrist joint is formed by the articulation of the radius and ulna with the carpals. The MCP joints (Metacarpophalangeal joints) connect the metacarpals to the phalanges and the IP joints (Interphalangeal joints) connect the phalanges to each other. These joints, along with the tendons, muscles, and ligaments, work together to provide movement and strength to the hand and wrist.
Hand and wrist arthritis is a condition that occurs when the cartilage in the joints of the hand and wrist deteriorates, leading to inflammation, pain, and stiffness. There are several types of arthritis that can affect the hand and wrist, including osteoarthritis, rheumatoid arthritis, and post-traumatic arthritis.
Symptoms include pain and stiffness in the joints, particularly in the morning or after periods of inactivity, difficulty grasping objects, and a loss of range of motion.
It commonly affects older adults, but it can also occur in younger individuals as a result of an injury or a genetic predisposition. However, anyone can be affected by this condition, and it is important to take measures to prevent it and to seek treatment if symptoms arise.
Carpal Tunnel Syndrome (CTS) is a condition that occurs when the median nerve, which runs from the forearm through the wrist, becomes compressed. This compression can cause pain, numbness, tingling, and weakness in the hand and fingers.
The carpal tunnel is a small passageway in the wrist that is made up of bones and ligaments. The median nerve and tendons that control finger movement pass through the carpal tunnel. When the tendons become swollen or the tunnel becomes narrow, the median nerve can become compressed.
Symptoms of CTS can include numbness and tingling in the thumb, index finger, middle finger and the thumb side of the ring finger. Pain in the wrist and hand, weakness in the hand and fingers, and difficulty gripping objects can also occur. There are several factors that can contribute to the development of CTS, including repetitive motions of the hand and wrist, such as typing or using a mouse for long periods of time, injury to the wrist, rheumatoid arthritis, and pregnancy.
De Quervain’s Syndrome or De Quervain’s tenosynovitis, is a condition that affects the tendons in the wrist and thumb. It is characterized by pain and inflammation in the tendons that run along the thumb side of the wrist. These tendons control the movement of the thumb, and when they become inflamed, it can make it difficult to move the thumb or grip objects.
The most common symptoms of De Quervain’s Syndrome include pain and tenderness along the thumb side of the wrist, swelling, and a “catching” or “snapping” sensation when moving the thumb. It is often worse with activities that involve gripping or pinching, such as opening jars or grasping small objects.
Treatment for De Quervain’s Syndrome includes rest, splinting, and physical therapy to reduce inflammation and improve muscle strength. Medications can also be used to reduce pain and inflammation. In some cases, a corticosteroid injection may be given to reduce inflammation. Surgery may be required in severe cases.
Intersection Syndrome is a rare condition that affects the tendons in the wrist. It is caused by the two major tendons of the extensor muscles and those of the abductor muscles crossing each other at the back of the wrist. When these tendons rub against each other, it can cause friction and inflammation, leading to pain and stiffness in the wrist.
This condition is common among athletes, especially those who participate in sports that involve repetitive motions of the wrist such as weightlifting, rowing, and racket sports. It can also occur in people who perform repetitive tasks at work such as assembly line workers or construction workers.
Trigger finger or stenosing tenosynovitis, is a condition that affects the tendons in the fingers and thumb. It occurs when the tendons that bend the fingers become inflamed and can no longer move smoothly through the sheath that surrounds them. This results in a “locking” or “catching” sensation when trying to straighten the affected finger or thumb.
Symptoms of trigger finger include a popping or clicking sensation, pain and stiffness when moving the affected finger or thumb. The finger or thumb may also become locked in a bent position, making it difficult to straighten it.
The condition can be caused by repetitive motions, injury, or underlying medical conditions such as diabetes or rheumatoid arthritis.
Wrist tendonitis is a condition that affects the tendons in the wrist. There are several tendons in the wrist that may suffer from tendonitis, but the most common tendons affected are the extensor carpi radialis brevis (ECRB) and the flexor carpi radialis (FCR) tendons. These tendons run along the top and bottom of the wrist, respectively. Some of the common symptoms are swelling, pain and snapping sensation when moving the wrist.
The condition can occur due to overuse of the wrist, repetitive motions and poor posture. It is at times confused with other conditions that cause pain and inflammation in the wrist such as carpal tunnel syndrome and De Quervain’s Syndrome. Both of these conditions have similar symptoms to wrist tendonitis, but they affect different structures in the wrist and require different treatments.