Hand anatomy

The hand can be considered in four segments: • Fingers: Digits that extend from the palm of the hand, the fingers make it possible for humans to grip the smallest of objects. • Palm: This is the bottom of the body of the hand. • Back (opisthenar): The back of the hand shows the dorsal venous network, a web of veins. • Wrist: The connection point between the arm and the hand, the wrist enables hand movements. Each hand consists of 19 bones. The palm includes five metacarpals, and each finger except the thumb contains one proximal phalanx, one middle phalanx, and one distal phalanx. The thumb doesn’t have a middle phalanx. Each bone is connected by a series of ligaments. Each fingertip— distal phalanx and accompanying tissue—contains a fingernail. These structures are made of keratin, a tough protein. Similar types of keratin also make up human hair, the scales and claws of reptiles, and the feathers, claws, and beaks of birds. Although fully functional hands can accomplish great things, they are susceptible to a number of ailments, including: • Arthritis • Deformities • Nerve disorders • Finger clubbing • Tendinitis • Carpal tunnel syndrome • Fractured bones • Sprains, strains, cuts, and bruises Last medically reviewed on March 28, 2015

The palm comprises the underside of the human hand. Also known as the broad palm or metacarpus, it consists of the area between the five phalanges (finger bones) and the carpus (wrist joint). Located in the palm are 17 of the 34 muscles that articulate the fingers and thumb, and are connected to the hand skeleton through a series of tendons. Unlike other areas of the body, the skin of the palm is glabrous (hairless) and unable to tan. It is also durable, yet touch sensitive. In order for the skin layer to remain anchored to the bone structure, a layer of connective fibrous tissue (fascia) links the skin with the skeleton. This allows the hand to grip without the skin sliding out of position. Dupuytren’s contracture occurs when this fascia layer thickens and shrinks. Its symptoms include the formation of a firm nodule in the palm that later develops into a thick band. Although it is a painless disease, over time it can inhibit the straightening of the digits. It is therefore treated by surgical procedure, which removes the thickened tissue. Geriatric patients are prone to ruptured veins in the palm. Signs of a rupture include spontaneous itching and a noticeable hematoma. Last medically reviewed on March 31, 2015

Hand anatomy overview Whether we are extending a hand in friendship or lending a hand at work, we depend on our hands as we move through our day. We need flexibility and coordination to position our fingers and thumbs as we use a keyboard, play an instrument, or perform other fine motor skills. Muscle strength enables us to bend or straighten our wrist, and to grip objects. The structures of the hand include: • Bones • Joints • Ligaments • Tendons • Muscles • Nerves • Blood vessels Our ability to use our hands depends on how well our bones, ligaments, tendons, muscles, nerves, and blood vessels work together. Because the function of our hands is integrated through our wrists and arms to our shoulders, a problem anywhere along our arm may have a significant impact on hand function and quality of life. Bones of the hand The 27 bones in the hand can be categorized by position: • Carpal bones:These eight bones are found in the wrist. They are connected to the two forearm bones to form the wrist joint. • Metacarpal bones:The five metacarpal bones are found in the palm. They connect to the carpals at the base of the palm. Along the top of the palm, one metacarpal bone is connected to the small shafts of bone that form each of the fingers and thumb, forming our knuckle joints. • Phalanges:These 14 bones make up our fingers and thumb. Each finger has three phalanges that connect to each other, forming two finger joints in each finger. The thumb has only two phalanges and one joint...

The movements of the hand are accomplished by two sets of muscles and tendons: the flexors, for bending the fingers and thumb, and the extensors, for straightening out the digits. The flexor muscles are located on the anterior (volar) surface of the forearm and are attached by tendons to the phalanges of the fingers. The extensor muscles are on the dorsal surface of the forearm and are similarly connected. The thumb has two separate flexor muscles that move the thumb in opposition and make grasping possible. The Skeleton of the Hand The hand has 27 bones: the 8 bones of the carpus (wrist), arranged in two sets of four; the 5 bones of the metacarpus, one to each digit; and the 14 digital bones, or phalanges, 2 in the thumb and 3 in each finger. The carpal bones fit into a shallow socket formed by the bones of the forearm. Each metacarpal bone has a proximal base, a shaft, and a distal head. The base of each metacarpal contacts the distal row of carpal bones to form the carpometacarpal joint. The head of each metacarpal contacts the proximal at a metacarpophalangeal ( MP) joint. The proximal row of phalanges articulates with the middle row of phalanges at the proximal interphalangeal (PIP) joints, the middle and distal rows of phalanges articulate at the distal interphalangeal (DIP) joints. The carpal bones can be remembered using the mnemonic “ Some Lovers Try Positions That They Can’t Handle” Proximal Row (Radial to ulnar wrist) • Scaphoid or Carpal Navicular ( Some) Links...

Article: • • • • • • • • Images: • Terminology As the thumb is structurally different to the other digits of the hand, with different movements and musculature, there is debate as to whether the thumb is considered a finger 2. It can therefore confusing to refer to the fingers by number - is the "first finger" the thumb or the first of the four other digits? For this reason it is advisable to refer to the digits by names given to them rather than by number. From the radial to the ulnar aspect of the hand, they are named as follows: • thumb • index finger • middle finger or long finger • ring finger • little finger In the standard anatomical position, the hand is flat and supinated with the fingers spread. This positions the thumb at the lateral aspect of the hand and the little finger at the medial aspect of the hand. It is often easier to use radial and ulnar to refer to the lateral and medial aspects of structures in the hand, as these may be more intuitive without having to remember the anatomical position. Joints Hand movement is complex and occurs across many joints, including those involved in wrist flexion. Muscles • • Compartments Fascial layers subdivide the underlying musculature into functional compartments; clinical relevance becomes manifest with pathologic increases in pressure resulting in ischemia and/or necrosis to the structures within the myofascial confines such as muscle and peripheral nerves. The compartments are typically identified as the following ...

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 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. Blood Vessels There is a vast network of arteries and veins in the hand an...

Muscles are groups of cells in the body that have the ability to contract and relax. There are different types of muscle, and some are controlled automatically by the autonomic nervous system. Other muscles, like the skeletal muscle that moves the arm, is controlled by the somatic or voluntary nervous system. Muscles are groups of cells in the body that have the ability to contract and relax. There are different types of muscle, and some are controlled automatically by the autonomic nervous system. Other muscles, like the skeletal muscle that moves the arm, is controlled by the somatic or voluntary nervous system. Jump to: • • • • • Interossei (dorsal and palmar) The interossei muscles begin between the bones of the hand. There are four dorsal and three palmar interossei muscles. While all interossei bend the MCP joints, the dorsal interossei allow us to spread our fingers away from each other. The palmar interossei pull our fingers together. The first dorsal interosseous muscle is the largest and originates from the 1st and 2nd hand bones. It forms the contour between the thumb and index finger when looking at the top of the hand and is often the first muscle to shrink in patients with severe Hypothenar The hypothenar muscle group is formed by three muscles: the abductor digiti minimi, the flexor digiti minimi, and the opponens digiti minimi. They form the muscle bulk on the small finger side of the hand. The abductor allows the small finger to pull away from the ring fin...

Phalanges of hand (Phalanges manus) The phalanges of the hand are the group of small long bones because of their structural characteristics; each phalanx consists of a shaft, distal head and a proximal base. There are fourteen phalanges in each hand; each of the medial four digits has three phalanges ( proximal, middle and distal), while the thumb has only two ( proximal and distal). The phalanges are interconnected by palmar digital arteries. The digits have a universal labeling system using the anatomical position of the hand (palm facing anteriorly) as reference. Going from lateral to medial, they are named thumb (digit 1), index finger (digit 2), middle finger (digit 3), ring finger (digit 4) and little finger (digit 5). This article will describe the Key facts about the phalanges of hand Type Proximal, middle and distal phalanges Structure Long bones Proximal base, body and a distal head Blood supply Nutrient rami from palmar digital arteries Joints Metacarpophalangeal joints connect the metacarpal bones and proximal phalanges Proximal interphalangeal joints connect the proximal and middle phalanges Distal interphalangeal joints connect the middle and distal phalanges Interphalangeal joint of thumb connect the proximal and distal phalanges of the thumb Muscles attaching to phalanges Flexors: flexor digitorum superficialis, flexor digitorum profundus, lumbricals, dorsal interossei, palmar interossei, flexor digiti minimi, opponens digiti minimi muscles Extensors: exten...

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 in order 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 sh...