Hand & Wrist

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 onefinger 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 ofthe 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.

Physical Examination

Coming soon

Conditions

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, bloodvessels, muscles, tendons and skin.

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.

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.

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 thethumb side of the wrist.

The wrist is more prone to injuries/problems that may include sprains and strains as well as fractures can occur with lifting and carrying heavy objects, wrist injury while operating machinery, bracing against a fall, or sports-related injuries.

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.

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 whileoperating machinery, bracing against a fall and sports-related injuries.

A nail is the hard covering at the end of the dorsal side of your fingers and toes. The nail is composed of a nail plate, nail matrix (a tissue that protects nails) and nail bed. The nail plate is a hard, translucent part of the nail composed ofa protein called keratin.

The forearm consists of two bones, the radius and ulna. The radius is the larger of the two forearm bones, and the region towards the wrist is called the distal end. Fractures in this end are most common.

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 theextent of injury to the ligament.

A laceration is a tear or ragged opening in the skin usually caused by an injury or trauma. A laceration may be either a partial laceration or a complete laceration. Tendons connect muscles to bones and allow coordinated movement of the joints. A deep cut or laceration on the palm side of the hand can damage the flexor tendons, which control movement in your hand.

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 seenin young men aged 20 to 30 years. They can occur at two places: near the thumb or near the forearm.

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 notspread to the other parts of the body.

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 thefingers. Each finger is composed of 3 phalanges bones, joined by 2 interphalangeal joints (IP joints).

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 thejoint at the base 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 womenthan men, and usually occurs after the age of 40 years.

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.

Kienbock's disease is a condition in which the lunate, one of the small bones of the wrist loses its blood supply leading to death of the bone. This results in pain, stiffness, and degenerative changes in the wrist joint.

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 fingerresults in the inability to straighten the affected finger.

Procedures

Carpal tunnel is the narrow passage in the wrist through which the nerves and tendons, bones (8 bones), ligaments (carpal ligament), and blood vessels pass through. Carpal tunnel syndrome occurs when the nerve that runs in the carpal tunnel iscompressed or squeezed at the wrist joint.

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 performedby trained and certified plastic surgeons.

Carpal Tunnel Syndrome is a common, painful, progressive condition that is caused by compression of the median nerve at the wrist area. Common symptoms of carpal tunnel syndrome include numbness and tingling sensation in all the fingers exceptlittle finger; pain and burning sensation in hand and wrist that may radiate up the arm and elbow; and weakness in hand with diminished grip strength.

Carpal tunnel syndrome can be treated with carpal tunnel release Surgery. Traditional surgery involves up to a 2- inch incision in the palm and wrist area, whereas endoscopic surgery involves one or two half-an-inch incisions and the use of anendoscope.

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.

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 womenthan men, and usually occurs after the age of 40 years.

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 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 whenconservative treatment fails to provide relief.

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.

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.

The hand is considered one of the most complex structures in the human body due to its intricate anatomy. Your hands are a complex system of various bones, joints, ligaments, tendons, muscles, nerves and blood vessels. Without the healthy functioning of the hand we are unable to perform activities of daily living. The hand is one part of the body that is very susceptible to injury or disease.

The peripheral nerves are the nerve fibres that compose the area from head to toe, connecting the brain and spinal cord with the rest of the body parts. Nerves transmit electrical impulses and signals to and from the brain. Peripheral nervous system disorders interrupt the transmission of signals and weaken the sensory and motor nerve functions. Unlike the brain and spinal cord, peripheralnerves have an inherent capacity for healing and regeneration.