Hand & Wrist

Anatomy
Conditions
Procedures

Hand Anatomy

The human hand is made up of the wrist, palm, and fingers and consists of 27 bones, 27 joints, 34 muscles, over 100 ligaments and tendons, and many blood vessels and nerves.

The hands enable us to perform many of our daily activities such as driving, writing and cooking. It is important to understand the normal anatomy of the hand to learn more about diseases and conditions that can affect our hands.

Bones

The wrist is comprised of 8 carpal bones. These wrist bones are attached to the radius and ulna of the forearm to form the wrist joint. They connect to 5 metacarpal bones that form the palm of the hand. Each metacarpal bone connects to one finger at a joint called the metacarpophalangeal joint or MCP joint. This joint is also commonly referred to as the knuckle joint.

The bones in our fingers and thumb are called phalanges. Each finger has 3 phalanges separated by two interphalangeal joints, except for the thumb, which only has 2 phalanges and one interphalangeal joint.

The first joint close to the knuckle joint is called the proximal interphalangeal joint or PIP joint. The joint closest to the end of the finger is called the distal interphalangeal joint or DIP joint.

The MCP joint and the PIP joint act like hinges when the fingers bend and straighten.

Soft tissues

Our hand bones are held in place and supported by various soft tissues. These include: articular cartilage, ligaments, muscles and tendons.

Articular cartilage is a smooth material that acts as a shock absorber and cushions the ends of bones at each of the 27 joints, allowing smooth movement of the hand.

Muscles and ligaments function to control the movement of the hand.

Ligaments are tough rope-like tissue that connect bones to other bones, holding them in place and providing stability to the joints. Each finger joint has two collateral ligaments on either side, which prevents the abnormal sideways bending of the joints. The volar plate is the strongest ligament in the hand. It joins the proximal and middle phalanx on the palm side of the joint and prevents backwards bending of the PIP joint (hyperextension).

Muscles

Muscles are fibrous tissues that help produce movement. Muscles work by contracting.

There are two types of muscles in the hand, intrinsic and extrinsic muscles.

Intrinsic muscles are small muscles that originate in the wrist and hand. They are responsible for fine motor movement of the fingers during activities such as writing or playing the piano.

Extrinsic muscles originate in the forearm or elbow and control the movement of the wrist and hand. These muscles are responsible for gross hand movements. They position the wrist and hand while the fingers perform fine motor movements.

Each finger has six muscles controlling its movement: three extrinsic and three intrinsic muscles. The index and little finger each have an extra extrinsic extensor.

Tendons

Tendons are soft tissues that connect muscles to bones. When muscles contract, tendons pull the bones causing the finger to move. The extrinsic muscles attach to finger bones through long tendons that extend from the forearm through the wrist. Tendons located on the palm side help in bending the fingers and are called flexor tendons, while tendons on top of the hand help in straightening the fingers, and are called extensor tendons.

Nerves

Nerves of the hand carry electrical signals from the brain to the muscles in the forearm and hand, enabling movement. They also carry the senses of touch, pain and temperature back from the hands to the brain.

The three main nerves of the hand and wrist are the ulnar nerve, radial nerve and median nerve. All three nerves originate at the shoulder and travel down the arm to the hand. Each of these nerves has sensory and motor components.

Ulnar Nerve: The ulnar nerve crosses the wrist through an area called Guyon’s canal and branches to provide sensation to the little finger and half of the ring finger.

Median Nerve: The median nerve crosses the wrist through a tunnel called the carpal tunnel. The median nerve provides sensation to the palm, thumb, index finger, middle finger, and part of the ring finger.

Radial Nerve: The radial nerve runs down the thumb side of the forearm and provides sensation to the back of the hand from the thumb to the middle finger.

Blood Vessels

Blood vessels travel beside the nerves to supply blood to the hand. The main arteries are the ulnar and radial arteries, which supply blood to the front of the hand, fingers, and thumb.

The ulnar artery travels next to the ulnar nerve through the Guyon’s canal in the wrist.

The radial artery is the largest artery of the hand, traveling across the front of the wrist, near the thumb. Pulse is measured at the radial artery.

Other blood vessels travel across the back of the wrist to supply blood to the back of the hand, fingers, and thumb.

Bursae

Bursae are small fluid filled sacs that decrease friction between tendons and bone or skin. Bursae contain special cells called synovial cells that secrete a lubricating fluid.

Conditions

Injuries and Fractures

Wrist Fracture

The wrist is comprised of two bones in the forearm, the radius and ulna, and eight tiny carpal bones in the palm. The bones meet to form multiple large and small joints. A wrist fracture refers to a break in one or more of these bones.

Fractures of the Hand and Fingers

The hand is one of the most flexible and useful parts of our body. Because of overuse in various activities, the hands are more prone to injuries, such as sprains and strains, fractures and dislocations, lacerations and amputations while operating machinery, bracing against a fall and sports-related injuries.

Wrist Sprain

Injuries caused due to stretching or tearing of the ligaments in the wrist are called wrist sprains. These injuries are usually caused by a fall during daily activities or sports activities. Sprains can range from mild to severe based on the extent of injury to the ligament.

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Flexor Tendon Injuries

Tendons are the bands of fibrous connective tissue that connect muscles to bone. Tendons aid in movement of the fingers, hand and all other body parts.

Mallet Finger

Mallet finger is a condition where the end of the finger is bent and does not straighten. It occurs when the extensor tendon on the back of the finger is damaged. The finger joint is a hinge-joint that allows bending and straightening of the fingers.

Finger and Thumb Sprain

Injuries that involve tearing or stretching of the ligaments of your fingers are termed as sprains. Sprains in the fingers are most often caused from a fall when you extend your arms to reduce the impact of the fall, or from overuse or repetitive activity of the thumb such as with texting.

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Thumb Fracture

A break or a crack in the bones of the thumb is known as a thumb fracture. Thumb fractures can occur from a direct blow, a fall, and muscle contractions or twisting during sports such as football, hockey, skiing and wrestling. Fractures may occur anywhere on the thumb, but a fracture at the base of the thumb, near the wrist, is considered the most serious.

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Scaphoid Fracture

The scaphoid bone is a small, boat-shaped bone in the wrist, which, along with 7 other bones, forms the wrist joint. It is present on the thumb side of the wrist causing it to be at a high risk for fractures. A scaphoid fracture is usually seen in young men aged 20 to 30 years. They can occur at two places: near the thumb or near the forearm.

Finger Dislocation in Children

Finger dislocation is a condition in which the bone of your finger has moved away from its normal position. Dislocation can be caused from jamming or overextending the finger during sports activities, or during a fall with an outstretched hand.

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Arthritis

Arthritis of the Hand and Wrist

Arthritis is an inflammatory condition of joints. There are several types of arthritis and the most common type is osteoarthritis or wear-and-tear arthritis. Arthritis affects various joints in the body and the arthritis in hand affects the joint at the base of the thumb. Arthritis may also affect the joints of other digits and the symptoms include swelling, pain, stiffness, and malformation all of which interfere with use of the hand.

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Arthritis of the Thumb

Arthritis is an inflammatory condition of joints. There are several types of arthritis; the most common type is osteoarthritis or wear-and-tear arthritis that affects the joint at the base of the thumb. Thumb arthritis is more common in women than men, and usually occurs after the age of 40 years. Patients who have arthritis of the fingers may have swelling, pain, stiffness, and malformation all of which interfere with use of the hand.

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Diseases

Ganglion Cyst

Ganglion cysts are swellings that most commonly develop along the tendons or joints of wrists or hands. They can be found either at the top of the wrist, palm side of the wrist, end joint of a finger, or at the base of a finger. Ganglion cyst is not cancerous and will not spread to the other parts of the body. It looks like a water balloon on a stalk and contains a clear fluid or jelly material. Ganglion cysts can be found in people of all ages.

Boutonniere Deformity

Tendons in your fingers connect the finger bones to finger muscles and help bend and straighten the finger at the joint when the muscles contract. Boutonnière deformity is a condition in which a tendon injury to the middle joint of the finger results in the inability to straighten the affected finger.

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Carpal Tunnel Syndrome

Carpal Tunnel Syndrome is a common, painful, progressive condition that is caused by compression of the median nerve at the wrist area.

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De Quervain’s Tendinosis

The muscles and bones of the hand are connected by thick flexible tissue called tendons. Tendons are covered by a thin soft sheath of tissue known as synovium. Extensor pollicis brevis and abductor pollicis longus are two tendons located on the thumb side of the wrist. Inflammation and swelling of the tendon sheaths puts pressure on the adjacent nerves and leads to pain and numbness in the thumb side of the wrist.

Dupuytren’s Contracture

Dupuytren’s Contracture is a hand condition where thickening of the underlying fibrous tissues of the palm cause the fingers to bend inward. Patients with this condition are unable to fully straighten the affected fingers.

Trigger Finger

The ability to bend the fingers is governed by supportive tendons that connect muscles to the bones of the fingers. The tendons run along the length of the bone and are kept in place at intervals by tunnels of ligaments called pulleys. When the fingers bend, or are straightened, a slippery coating called tenosynovium helps the tendons smoothly glide through the ligaments with reduced friction.

Congenital Defects of the Hand and Wrist

The hand and wrist are formed during the 8th week of gestation. This process consists of various steps and failure in any one or more of these steps may cause congenital or birth defects. The deformities may be major (absence of a bone) or minor

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Hand Pain

Hand pain is characterized by distress in the joints and tissues of the hand or fingers. Hand pain can be depicted as pulsating, aching, increased warmth, prickling, irritation and inflexibility. The hand is composed of nerves, bones, blood vessels, muscles, tendons and skin. Each part has its specific function such as nerves transfer sensation, joints control movements, blood vessels maintain circulation, muscles provides motion, tendons anchor the muscles to the bones and skin receives sensations.

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Hand Infections

Hands become infected more frequently as it is one of the commonly injured parts of our body. Hand infections, if left untreated or treated improperly can cause disabilities such as stiffness, contracture, weakness, and loss of tissues (skin, nerve and bone) that persist even after the infection resolves. Therefore, prompt treatment of hand infections is important.

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Wrist Pain

The wrist is a commonly seen injured joint in the body. Problems include sprains and strains as well as fractures which can occur with lifting and carrying heavy objects, while operating machinery, bracing against a fall, or from sports-related injuries.

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Wrist Tumors

A tumor is a lump or abnormal growth formed due to unregulated cell division. Wrist tumors can occur on or underneath the skin. They are most often benign (non-cancerous).

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Gamekeeper’s Thumb

Gamekeeper's thumb, also known as skier's thumb, is a tear of the ulnar collateral ligament, a band of tissue that supports the joint at the base of the thumb. Damage to the ulnar collateral ligament may lead to chronic instability of the thumb, creating problems in its normal functioning.

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Procedures

Wrist Arthroscopy

Your wrist is a complex joint made up of eight small bones called carpal bones. These bones are supported by connecting ligaments. Various conditions can affect your wrist joint such as carpal tunnel syndrome, osteoarthritis and others.

Wrist Joint Replacement

Wrist joint replacement surgery, also referred to as total wrist arthroplasty, involves replacement of a severe arthritic wrist joint with an artificial joint made of metal and plastic components. It relieves pain and restores function when conservative treatment fails to provide relief.

Carpal Tunnel Release Surgery

Elective Emergency Hand Surgery

Hand surgery is performed to restore the structure and functionality of the fingers, wrist and hand secondary to a traumatic injury, medical condition, severe infection, or birth defect causing pain and/or deformity of the hand. It is performed by trained and certified plastic surgeons. The surgery is done either as an emergency procedure or as an elective procedure depending on the condition and its severity.

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Wrist Ligament Reconstruction

The human wrist is made up of small bones joined together by a band of tough fibrous tissue known as ligaments. Ligaments also join the bones in our wrist to the radius, ulna, and metacarpal bones, and aid in the proper functioning of our wrist. Any injury to the ligaments disturbs the normal alignment of our wrist bones causing them to wear out faster resulting in significant pain and eventually leading to arthritis.

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Total Wrist Arthrodesis

Total wrist arthrodesis, also known as wrist fusion is a surgical procedure in which the wrist joint is stabilized or immobilized by fusing the forearm bone (radius) with the small bones of the wrist.

Sports Injury Management of Hand, Wrist and Elbow

Sports injuries are the injuries that most commonly occur during sports and exercises. These injuries may result from accidents, poor training practices, and use of improper protective gear, lack of conditioning, and insufficient warm up and stretching. The sports injuries may be either acute (sprains, fractures, tears) or chronic (tendinitis, overuse injury) injuries.

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Artificial Finger Joint Replacement

Finger joints are essential for many activities, and arthritis in this area can cause significant joint damage and deformity. Artificial finger joint replacement is a surgical procedure that involves the removal of an arthritic or damaged finger joint and replacement with an artificial prosthesis.

Finger Joint Fusion

Finger joint fusion is a surgical procedure to remove the damaged bony ends of a finger joint followed by insertion of a prosthesis to fuse the bones back together. Finger joint fusion is performed to relieve arthritis pain in the fingers.

Arthritis Surgery for Thumb and Digits

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Others

Hand Rejuvenation

Cosmetic enhancement is generally focused only on the face, while the hands portray some of the most prominent signs of aging. With age, the hands lose their firmness and plumpness and can appear bony and fragile. Hand rejuvenation is a treatment that gives you visibly younger, healthy, and firmer hands.

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Hand Therapy

Hand Therapy is a rehabilitation technique recommended to improve the strength and restore functional activity of hands in patients with upper extremity injuries. Hand therapy also helps in preventing the injury.