Hand and Wrist | Genesis Orthopedics & Sports MedicineGenesis Orthopedics & Sports Medicine

Hand and Wrist Overview

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Collaboratively, the wrist and hand form the single most complex and one of the most commonly used systems in the human body, containing 29 bones, each connected by a ligament, 27 joint articulations, and more than 30 muscles. As a result of the tremendous number of components contributing to their functionality, the hand and wrist can be easily injured.

Bones

Connecting the hand to the forearm, the wrist is comprised of 8 carpal bones, the bases of 5 metacarpal bones in the hand, and the ends of the radius and ulnar bones of the forearm. Of the 8 carpal bones, 4 are proximal, meaning they are nearest to the anatomical center of the body, and 4 are distal.

Proximal:

Distal:

Scaphoid
Trapezium
Lunate
Trapezoid
Triquetrum
Capitate
Pisiform
Hamate

 

There are 5 metacarpal bones in the hand and wrist, which extend to the base of the finger bones, which are known as phalanges.  Each finger has 3 phalanges, while the thumb has two.

 


Joints

The joint connecting the wrist to the hand, or the distal ends of the radius and ulna with the carpal bones, has multiple articulations, which allows for a considerable range of motion.  Collectively called a condyloid joint, the many connection points of the wrist allow for the movements of flexion and extension, supination and pronation, as well as ulnar deviation and radial deviation, which is the hand-waving motion of lateral flexion.

The normal range of motion of wrist movements:

Flexion 80 degrees
Extension 70 degrees
Pronation 90 degrees
Supination 90 degrees
Ulnar Deviation 30 degrees
Radial Deviation 20 degrees

 

In addition to the articulations allowing movement of the wrist, there are many joints in the hand allowing for freedom of motion in the fingers, which are the metacarpophalangeal joints at the base, and the interphalangeal joints, which allow precise bending of the fingers.

 


Muscles

Muscles empower the movements of the wrist and hand digits. They can be categorized based on the type of movement they facilitate:

 

Wrist flexors:

  • Flexor carpi ulnaris
  • Flexor digitorum superficialis
  • Flexor carpi radialis
  • Flexor digitorum profundus
  • Flexor pollicis longus

 

Wrist extensors:

  • Extensor carpi radialis brevis
  • Extensor digitorum
  • Extensor digiti minimi
  • Extensor carpi ulnaris

 

Wrist abductors:

  • Flexor carpi radialis
  • Extensor carpi radialis longus
  • Extensor carpi radialis brevis
  • Abductor pollicis longus
  • Extensor pollicis brevis

 

Wrist adductors:

  • Flexor carpi ulnaris
  • Extensor carpi ulnaris

 

In addition to the many bones, joints, and muscles composing the complex anatomy of the wrist and hand, there are a number of ligaments and tendons that act as connectors, acting as essential components to a fascinating system.

 


The following common injuries to different elements of the hand and wrist, all of which are treated by Genesis Orthopedics & Sports Medicine:

Carpal Tunnel Syndrome
De Quervain’s Tenosynovitis
Ganglion Cyst
Hand and Wrist fractures
Hand and Wrist osteoarthritis
Hand and Wrist tendonitis
Triangular fibrocartilage complex injuries (TFCC)
Trigger Finger

For treatments or more information, click on any of the links above.