Hand & Wrist

Hand and Wrist Anatomy

The hand in the human body is made up of the wrist, palm, and fingers. The most flexible part of the human skeleton, the hand enables us to perform many of our daily activities. When our hand and wrist are not functioning properly, daily activities such as driving a car, bathing, and cooking can become impossible.

The hand’s complex anatomy consists of 27 bones, 27 joints, 34 muscles, over 100 ligaments and tendons, numerous blood vessels, nerves, and soft tissue.

It is important to understand the normal anatomy of the hand in order to learn about diseases and conditions that can affect our hands.

Skeletal Anatomy

The wrist is comprised of 8 bones called carpal bones. These wrist bones connect to 5 metacarpal bones that form the palm of the hand. Each metacarpal bone connects to one finger or a thumb at a joint called the metacarpophalangeal joint, or MCP joint. This joint is 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 joints. The first joint, closest to the knuckle joint, is the proximal interphalangeal joint or PIP joint. The second joint nearer the end of the finger is called the distal interphalangeal joint, or DIP joint. The thumb in the human body only has 2 phalanges and one interphalangeal joint.

Soft Tissue Anatomy

Our hand and wrist bones are held in place and supported by various soft tissues. These include

  • Cartilage: Shiny and smooth, cartilage allows smooth movement where two bones come in contact with each other.
  • Tendons: Tendons are soft tissue that connects muscles to bones to provide support. Extensor tendons enable each finger to straighten.
  • Ligaments: Ligaments are strong rope like tissue that connects bones to other bones and help hold tendons in place providing stability to the joints. The volar plate is the strongest ligament in the hand and prevents hyperextension of the PIP joint.
  • Muscles: Muscles are the fibrous tissues capable of contracting to cause body movement.

Interestingly, the fingers contain no muscles. Small muscles originating from the carpal bones of the wrist are connected to the finger bones with tendons. These muscles are responsible for movement of the thumb and little finger enabling the hand to hold and grip items by allowing the thumb to move across the palm, a movement referred to as thumb opposition. The smallest muscles of the wrist and hand are responsible for fine motor movement of the fingers.

  • Nerves: Nerves are responsible for carrying signals back and forth from the brain to muscles in our body, enabling movement and sensation such as touch, pain, and hot or cold. The three main nerves responsible for hand and wrist movement all originate at the shoulder area and include the following


Median: The median nerve travels through the wrist tunnel, also called carpal tunnel, providing sensation to the thumb, index finger, long finger, and part of the ring finger.

Ulnar: The ulnar nerve travels through a tunnel in the wrist called Guyon’s tunnel formed by two carpal bones and the ligament that connects them together. The ulnar nerve supplies feeling to the little finger and half of the ring finger.

  • Blood Vessels: The two main vessels of the hand and wrist are:

Radial Artery: The radial artery is the largest artery supplying the hand and wrist area. Traveling across the front of the wrist, nearest the thumb, it is this artery that is palpated when a pulse is counted at the wrist.

Ulnar Artery: The ulnar artery travels next to the ulnar nerve through Guyon’s canal in the wrist. It supplies blood flow to the front of the hand, fingers and thumb.


Normal Movement

Biomechanics is a term to describe movement of the body. The fingers of the hand permit the following movements at the metacarpophalangeal joint (MCP) or knuckle joint.

Flexion: Moving the base of the finger towards the palm.

Extension: Moving the base of the fingers away from the palm.

Adduction: Moving the fingers toward the middle finger.

Abduction: Moving the fingers away from the middle finger.

Flexion: Moving the last two segments of the finger towards the base of the fingers.

Extension: Moving the last two segments of the finger away from the base of the fingers.

Biomechanics of the wrist include the following:

Flexion: Moving the palm of the hand towards the front of the forearm.

Extension: Moving the back of the hand towards the back of the forearm.

Adduction: Moving the pinky side of the hand toward the outer aspect of the forearm.

Abduction: Moving the thumb side of the hand toward the inner aspect of the forearm.

The thumb performs different movements at three separate joints. The carpometacarpal joint is where the wrist bones, carpals, meet the metacarpals, the bones in the palm of the hand. At this articulation, the following movements can be performed.

Abduction: Moving the bone below the thumb towards the palm of the hand.

Extension: Moving the bone below the thumb away from the hand.

Adduction: Moving the bone below the thumb towards the back of the wrist.

Abduction: Moving the bone below the thumb towards the front of the wrist.

Opposition: Moving the thumb across the palm of the hand touching the other fingers.

The following movements occur at the metacarpophalangeal joint or MCP joint at the base of the thumb.

Flexion: Moving the joint at the base of the thumb towards the heel of the hand.

Extension: Moving the joint at the base of the thumb away from the heel of the hand.

Adduction: Movement of the thumb base towards the back of the hand.

Abduction: Movement of the thumb base away from the back of the hand.

At the interphalangeal joint of the thumb or IP joint, the following movements can be performed:

Flexion: Bending the top of the thumb towards the base of the thumb.

Extension hyperextension: Moving the top of the thumb away from the base of the thumb.

De Quervain's Tenosynovitis





Signs and Symptoms








Carpal Tunnel Syndrome






Conservative Treatment Options


  • Treating underlying medical conditions
  • Rest the hand for 2 weeks or more
  • Ice packs to avoid swelling
  • Avoid activities that tend to worsen the symptoms
  • Strengthening and stretching exercises once symptoms diminish



Carpal Tunnel Release Surgery


Post-Operative Care

Your surgeon may suggest you practice certain post-operative procedures for better recovery and to avoid further complications.

  • Elevate the hand above heart level to reduce swelling.
  • A splint may be worn
  • Ice packs to the surgical area to reduce swelling.
  • Physical therapy may be ordered to restore wrist strength.
  • Eating a healthy diet and not smoking will promote healing

Risks and Complications


Wrist Fractures


Types of wrist fracture include:




Signs and Symptoms


  • Deformed or crooked wrist
  • Bruising
  • Numbness
  • Stiffness














Risks and Complications


  • Infection
  • Residual joint stiffness
  • Arthritis

Metacarpal Fractures



Metacarpal fractures need immediate treatment that include proper alignment and casting of the bones to ensure proper healing. In severe cases surgery may be recommended.


The common causes involved in metacarpal fractures include:

  • Directly falling on the hand
  • Trauma or direct impact to the hand
  • Punching on a hard object








Post-operative care


  • Avoid heavy lifting of objects till the hand is completely healed
  • In case of pain and swelling, take the prescribed medications
  • Physical therapy is recommended to strengthen and restore hand movements
  • Follow the specific instructions given by your doctor

Risks and complications

The possible risks and complications associated with metacarpal fracture surgery include:

  • Pain
  • Bleeding
  • Infection
  • Stiffness
  • Nonunion (bone fails to unite)
  • Malunion (Deformed union of the fractured bone)
  • Damage of the surrounding nerves or blood vessels

Location & Directions

Advanced Orthopedics

8225 Clayton Road
St. Louis MO 63117

Advanced Orthopedics & Sports Medicine