Wrist Anatomy

There are many muscles and tendons associated with the wrist and forearms, simply due to the wide range of movement available within both the forearm - wrist and fingers.

They are divided into two major groups: the extensors, which are at the 'back' side, and the flexors, which are located at the 'palm' side.

The forearm contains two bones, the radius and ulna, which are connected to your upper arm (humerus), at the elbow joint, enabling them to rotate the forearm outward (supination) and inwards rotation (pronation).

The wrist contains 8 small bones, which combined with the multitude of connective muscle / tendon tissue, are able to rotate and move in wide array of directions, the main muscles of the forearm are listed below.

(Biceps Brachii = 1) inserts onto the forearm, in order to flex (bend) your arm.

Brachio-Radialis - 2

Origin - lower 2/3 of outer condyloid ridge of humerus (just above your elbow joint).

Insertion - lower end of radius at styloid process (at your wrist - close to the thumb).

Function - flexion of the elbow (especially when thumbs are upwards) - Supinate the forearm when the arm is bent and pronated - Pronate the forearm when the arm is bent and supinated (hammer curl, reverse curl)

Flexor carpi radialis - 3

Origin - medial condyle of humerus (inner side of upper elbow joint).

Insertion - base of the 2nd and 3rd metacarpals (palm surface - close to your wrist)

Function - flexion of the wrist and elbow - palms facing upwards curl.

Flexor Digitorum Sublimis - 4

Origin - medial condyle of humerus, ulnar head - medial coronoid area, radial head - radial tuberosity area (underside of your forearm).

Insertion - underside of your fingers palm surface.

Function - flexion of the fingers - wrist and elbow (grasping a bar).

Extensor Carpi Radialis Brevis 1

Origin - lateral condyle of the humerus (inner side of upper elbow joint).

Insertion - base of 3rd metacarpal at dorsal surface (top side of middle palm - close to wrist)

Function - extension of the wrist and elbow - palms facing downward curl

Extensor Digitorum Communis 2

Origin - lateral condyle of the humerus (inner side of upper elbow joint).

Insertion - along the top side of your fingers.

Function - extension of fingers - wrist and elbow (reverse curl)

Range of Movement at the Elbow and Wrist Joint

Elbow
Flexion 130 - 150 degrees, taking your palm towards your shoulder.

Extension 170 - 180 degrees, straightening your arm.

Supination 80 - 90 degrees, turning your forearm so that your palm faces upwards.

Pronation 80 - 90 degrees, turning your forearm so palm faces down.

Wrist
Flexion 80-90 degrees, bend wrist so palm nears underside of forearm.

Extension 60 - 70 degrees, bend wrist so palm bends backward.

Radial deviation 15 - 20 degrees, bend wrist so thumb turns outwards, palms facing down.

Ulnar deviation 30 - 50 degrees, bend wrist so thumb turns inwards, palms facing down.