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Hand Anatomy

Published on May 19, 2022 and last reviewed on Mar 06, 2023   -  5 min read


The anatomy of a hand provides basic knowledge about its structure and functions. Read the below article to understand the normal anatomy of the hand.


The hand is a complex organ of the body at the end of the forelimb. It is the most flexible part of the skeletal system.The primary function of the hand is to hold and manipulate objects. In addition, they are used for feeling the touch sensation and play a role in sign language.There are two hands; each hand comprises a wrist, palm, backhand, and five fingers. The front or palm side of the hand is called the palmar side, and the back of the hand is called the dorsal side. A hand is composed of different bones, joints, muscles, ligaments, innervating nerves, and blood vessels that help in various movements and dexterity.

What Are the Bones and Joints That Form the Hand?

The hand consists of 27 bones and 27 joints.

  • Bones:

    • Carpal Bones: The wrist of the hand contains eight bones called carpal bones. The carpal bones are arranged in two rows namely, the proximal and distal rows, with four bones in each row.

      • The proximal row comprises scaphoid, lunate, triquetrum, and pisiform (moving from thumb side to little finger) and is connected to the bones in the palm.

      • The distal row is connected to the long bones of the forearm, and the names of these bones are trapezium, trapezoid, capitate, and hamate (moving from thumb side to little finger).

    • Metacarpal Bones: The wrist bones that connect to the five tubular bones in the palm are called the metacarpals. They are present between the wrist and the fingers. Each metacarpal bone has a head, body, and base.

    • Phalanges: The bones in the fingers are called phalanges. Thumb has two phalanges, and the other fingers have three phalanges each. The outermost bone near the nail is called the distal phalanx; the mid one is the middle phalanx, and the innermost bone is the proximal phalanx.

  • Joints:

    • Wrist Joint: It is also called the radiocarpal joint, where the distal end of the radius bone (long bone of the forearm) articulates with the three carpal bones in the proximal row; scaphoid, lunate, triquetrum. The joint surfaces between proximal and distal rows of carpal bones are called the midcarpal joints. The plane joint between the carpal bones is called an intercarpal joint.

    • Carpometacarpal Joint: Here, the base of the metacarpals articulates with the distal row of the carpal bones. The following are the bone articulations in carpometacarpal joints:

      • First metacarpal bone to trapezium.

      • Second metacarpal bone to trapezium, trapezoid, capitate.

      • Third metacarpal bone to capitate.

      • Fourth metacarpal bone to capitate, hamate.

      • Fifth metacarpal bone to hamate.

  • Metacarpophalangeal Joint: The head of the metacarpals articulate with the base of the proximal phalanges.

  • Interphalangeal Joint: There are about nine joints articulating between the phalanges, which are called the interphalangeal joints.

What Are the Muscles Present in the Hand?

The muscles of the hand are skeletal muscles. These are connected to the bones and are responsible for movement. The two groups of muscles present in the hand are, extrinsic and intrinsic muscles.

1. Extrinsic Muscles:

Extrinsic muscles are extensors and flexors. They are long muscles located in the forearm and inserted in the hand skeleton, hence the name extrinsic.

  • Extensor Muscle: Extensors are the muscles of extension, a movement of the joint where the angle between the two bones is increased. The action of the extensors results in the straightening of the hand.

  • Flexor Muscle: Flexors are the muscles of flexion, a movement of the joint where the angle between the two bones is decreased. The action of the flexor muscle results in the bending of the hand.

2. Intrinsic Muscles:

Intrinsic muscles are thenar, hypothenar, lumbrical, and interossei. They are small muscles located within the hand itself.

  • Thenar Muscles: The thenar muscles or the thenar eminence is a collection of three muscles constituting the thumb on the palmar side. The action of the thenar muscles results in the movement of the thumb.

  • Hypothenar Muscles: The hypothenar muscles are the collection of three muscles constituting the little finger on the palmar side. The action of hypothenar muscles results in the movement of the little finger.

  • Lumbrical Muscles: The lumbricals are composed of four muscles that flex the metacarpophalangeal joints and extend the interphalangeal joints.

  • Interossei Muscles: The interossei muscles are composed of four dorsal and three palmar muscles, present near the metacarpals comprising the middle three digits of the hand. The action of interossei muscles is to abduct (moving away from the midline) or adduct (moving towards the midline) the fingers.

What Are the Nerves Present in the Hand?

The nerves of the hand have both motor (carry impulses from the brain to muscles for movement) and sensory functions (carry senses of touch, heat, or pain from the hand to the brain).

The three main nerves of the hand are:

  • Median Nerve: The median nerve innervates the thenar muscle group and the first and second lumbrical muscles. The branches of the median nerve provide sensation to the palm, thumb, index finger, middle finger, and part of the ring finger.

  • Ulnar Nerve: The ulnar nerve innervates hypothenar, interossei, and the third and fourth lumbrical muscles. The branches of the ulnar nerve provide sensation to the little finger and half of the ring finger.

  • Radial Nerve: The radial nerve provides sensation to the back of the hand from the thumb to the middle finger.

What Are the Blood Vessels Present in the Hand?

The blood vessels travel along with the nerve and supply blood to the hand. The two main arteries of the hand are the radial artery and ulnar artery. The pulse measured in the wrist is at the radial artery. The veins of the hand are called superficial veins since they are close to the skin. The two prominent superficial veins in the hand are cephalic and basilic veins. The lymphatic vessels of the hand drain into the superficial and deep lymphatic systems.


The hand is the visible part of the brain, said Immanuel Kant. The hand is responsible for creative manifestations. The functional capability of the hand relates both to the structural characteristics and the control system of the brain. Hands can be affected by several diseases. Therefore, knowledge about hand anatomy is essential for the systematic assessment of hand disorders or injuries.

Frequently Asked Questions


What Is the Backside of the Palm Called?

The backside of the palm is called the dorsal side. Medically the back part is also known as the opisthenar area. The dorsal side has prominence (knuckles) at the junction of the fingers and the hand and shows the web of veins.


What Are the Three Sections of the Hand?

The three main sections of the hand are the palm, backhand, and digits (four fingers and a thumb). The sections of the hand comprise 27 bones and 27 joints. There are eight carpals (wrist region), five metacarpals (palm region), and 14 phalanges (fingers and thumb).


What Is the Fleshy Part of the Hand Called?

The entire central fleshy part of the hand is called the palm. But the area below the thumb joint is comparatively more fleshy and is termed as thenar prominence (ball of the thumb). Similarly, the fleshy mass below the little finger is called the hypothenar eminence.


What Is the Space Between Your Thumb and Forefinger Called?

The space between the thumb and the forefinger is called the purlicue. The skin between the thumb and index finger in an open stretched position is medically termed as thenar web space. The thenar web space opening is important for developing fine motor skills in children.


What Is the Bottom of Your Palm Called?

The bottom part of the palm where the hand meets the forearm is called the wrist joint. The wrist joint allows movement of the hand in two axes. It is a type of hinge joint but considered more complex than a simple hinge movement (like elbow or knee) because the wrist joint allows limited side-to-side movements of the hand.


What Is the Webbing Between Your Fingers Called?

The skin folds that connect the fingers are known as the web of the hand. These webs are termed interdigital folds or plica interdigitalis. This rudimentary web between the fingers allows for a wide range of motion in fingers. If the webbing increases, the fingers may get fused and are referred to as syndactyly.


What Are the Joints of the Wrist and Hand?

The hand comprises four major joints. They are:
- Wrist joints - the radiocarpal joint.
- Carpometacarpal joint - the connection between the carpal and the metacarpal bones.
- Metacarpophalangeal joint - the articulation between the head of the metacarpals with the base of the proximal phalanges.
- Interphalangeal joint - the nine interconnecting links between the phalanges.


What Are the Tendons on the Top of the Hand Called?

The tendons are bands of connective tissue that connect the muscle and the bone. Hence, the tendons in the hand help move the hand and fingers. There are two major tendons - the extensor and flexor tendons. The extensor tendons on the hand help straighten the fingers, and flexor tendons in the palm region help bend the fingers.


Can You Strain the Tendons in Your Hand?

Yes, the tendons in hand can get strained from injury or overstretching the fingers. The strained hand will get swollen and can be painful, restricting the regular movements of the fingers. Redness, numbness, and tingling sensations can also be felt.


How Do You Know if Your Flexor Tendon Is Torn?

The primary function of the flexor tendon is to flex the fingers, that is, to bend them like inholding or grasping an object. So if the flexor tendon is torn, the movement of the fingers will be restricted, and there will be pain when trying to bend the fingers.


Why Do the Nerves in My Hand Hurt?

The hurting of nerves in hand is due to peripheral neuropathy. This condition occurs as a result of damage to any of the peripheral nerves that innervate the hand. The damage may be due to infection, trauma, or debilitating diseases.


What Are the Three Major Ligaments at the Wrist?

The three major ligaments at the wrist are,
- Radiocarpal ligament.
- Radioulnar ligament.
- Ulnocarpal ligament.
Other collateral ligaments are also present that bind the wrist's bones and provide stability.

Last reviewed at:
06 Mar 2023  -  5 min read




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