Wrist Anatomy

Wrist anatomy is the study of the bones, ligaments and other structures in the wrist. The wrist joint is a complex joint which connects the forearm to the hand, allowing a wide range of movement. However, it is susceptible to injury, especially from repetitive strain.

Bones of the wrist

Wrist bones

The radius and ulna are the long bones of the forearm. The ulna is the larger of the two bones, although it tapers at the wrist end, to become narrower than the Radius. The Radius is positioned on the thumb side of the wrist, and the ulna on the little finger side. Top tip – I remember which way round they go because Ulna has an ‘L’ for little finger side. The radius and ulna form the wrist joint together with the carpal bones.

Carpal bones

Carpal bones of the wrist

Altogether there are 8 carpal bones in the wrist, which are arranged in two rows, known as proximal and distal. When referring to bones, proximal means ‘near to’ and distal means ‘further away’. The carpal bones consist of the following:

  • Lunate -proximal
  • Triquetrum – proximal
  • Pisiform – proximal
  • Capitate – distal
  • Trapezium – distal
  • Trapezoid – distal
  • Hamate – distal
  • Scaphoid

The scaphoid bone crosses both rows as it is the largest carpal bone. The scaphoid and the lunate are the two bones that actually articulate with the radius and ulna to form the wrist joint.

Wrist ligaments

Each bone within the wrist is joined to the one next to it by one or more ligaments. As you can imagine, this results in a large number of ligaments! Two of the largest ligaments of the wrist are the medial (ulnar) and lateral (radial) collateral ligaments. The MCL passes from the distal end of the ulnar and crosses the wrist to attach to the triquetrum and the pisiform. The LCL passes from the end of the radius, across the joint to the scaphoid.

Muscles of the wrist and forearm

Wrist - forearm muscles

Most of the muscles which act on the wrist joint are situated within the forearm, with only the tendon crossing the joint and inserting on the hand. The muscles on the back of the forearm (dorsal aspect) act to extend the wrist or pull it back as if pulling a ring-pull:

The muscles on the front of the forearm (palmer aspect) act to flex the wrist, such as when you push a roundabout:

Some of these muscles also help to perform radial and ulnar deviation. Radial deviation is the act of tilting the wrist in a radial direction (or with the thumb leading). Extensor carpi radialis brevis, longus and flexor carpi radialis all perform this movement. Ulnar deviation is the opposite movement, of tilting the wrist so that the little finger leads. Extensor carpi ulnaris and flexor carpi ulnaris perform this movement.

Read more on wrist muscles.

Nerves of the wrist and hand

Wrist nerves

Three nerves pass from the forearm, across the wrist, and into the hand. These are:

Radial nerve

The radial nerve is on the radial, or thumb side of the wrist joint. It provides feeling to the back of the hand from the thumb to the middle finger.

Median nerve

The median nerve is responsible for the development of carpal tunnel syndrome. It passes through the carpal tunnel and splits into four branches which each travel to the thumb and next three fingers. It provides sensation to all of these fingers, although only the inside half of the ring finger.

Ulnar nerve

The ulnar nerve supplies the small finger and the outer half of the ring finger.

References & resources

Wrist pain related articles

Wrist surgery
Do I Need Urgent Wrist Surgery?
Wrist surgery is usually only indicated after conservative (non surgical) treatment has failed. For amateur athletes this is usually the best course of action. However …
Read More
Volar Dorsal wrist pain
Wrist Pain By Location
Here we explain the common and less common causes of wrist pain by specific location or area. Select the location or type of wrist pain: Dorsal wrist …
Read More
Wrist pain
Wrist Pain
Here we explain the common causes of wrist pain both gradual onset (chronic) and sudden onset (acute) injuries. Select the type or location of wrist pain: Sudden …
Read More
Wrist strapping and taping
Wrist Taping
Wrist taping or strapping is a great way to provide extra support when recovering from injury. Or it is also used to help prevent wrist …
Read More
Wrist sprain
Acute Wrist Pain (sudden onset)
Here we explain the causes of sudden onset or acute wrist pain including sprains, strains and fractures. Sprains & strains Fractures Wrist sprains & strains A sprain is a …
Read More

Related articles

  • Triquetrum fracture

    A Triquetral fracture is a break of the Triquetral bone (sometimes called triquetrum). It is one of the eight small carpal bones in the wrist…

  • Wrist sprain

    Here we explain the causes of sudden onset or acute wrist pain including sprains, strains and fractures. Sprains & strains Fractures Wrist sprains & strains…

  • Wrist pain

    Here we explain the common causes of wrist pain both gradual onset (chronic) and sudden onset (acute) injuries. Select the type or location of wrist…

  • Wrist sprain

    A sprained wrist is an injury to any of the ligaments which connect bone to bone in the wrist. Wrist sprains are common in sport…

  • Bennett's fracture

    A Bennett fracture is an injury to the base of the thumb joint. It is usually caused by a hard impact or trauma such as…

  • Wrist muscles

    The wrist and hand muscles include the flexor pollicis longus, flexor digitorum superficialis, flexor carpi ulnaris, flexor carpi radialis, extensor digitorum communis, extensor carpi ulnaris…

  • Distal radius epiphysis

    A distal radial epiphysis injury is an injury to the growth plate at the wrist end of the radius bone in the forearm. It mostly…

Scroll to Top