Page 71 - ASOP ROT Study Guide

11.3 Axes of Movement

The wrist has two axes of movement:

♦ Sagittal - allowing movements in a sideways direction.
♦ Coronal - allowing movements in a backwards and forwards direction.

Note mat the axis of movement is at right angles to the plane of movement. Therefore the coronal
axis allows movement in a sagittal plane and vice versa. These movements occur at the two joints
we have discussed previously; the radiocarpal and the midcarpal joints.

11.4 Type of movement

♦ Flexion - movement of the hand anteriorly in the sagittal plane. This movement at the wrist is
sometimes called palmar flexion.

♦ Extension - movement of the hand posteriorly in the sagittal plane. This movement is
sometimes called dorsiflexion.

♦ Abduction - movement of the hand away from the mid-line of the body in the coronal plane. This
movement is sometimes called radial deviation because it is taking place towards the radial side of
the wrist.

♦ Adduction - movement towards the mid-line of the body in the coronal plane. This movement
is sometimes called ulnar deviation because it is taking place towards the ulnar side of the wrist.

11.5 Muscles

We will consider the muscles in groups according to the movement which they carry out. As
mentioned before the muscles which control wrist movement arise from either the forearm or distal
humerus. Only their tendons cross the wrist joint to insert into the carpal bones to produce
movement of the joint. The muscles and tendons on opposite surfaces of the forearm and wrist
balance each other like guy ropes supporting a tent.

Palmar flexors - The principal muscles which produce palmar flexion of the wrist are flexor carpi
radialis and flexor carpi ulnaris.

Dorsiflexors - the muscles producing dorsiflexion balance the palmar flexing muscles. They are
called extensor carpi radialis and extensor carpi ulnaris.

11 . 6 Examples of Muscle Activity

You can see therefore that if the two flexor muscles pull together they will produce palmar flexion
of the wrist, for instance this happens if you are sitting and you pull a table towards your chair.

If the two muscles on the ulnar side pull together, then they will produce ulnar deviation of the
wrist (move the hand sideways in the direction away from the thumb) without any palmar flexion or
dorsiflexion taking place. This movement is useful when using a keyboard.

When the two dorsiflexors contract together they produce dorsiflexion of the wrist which is neither
deviated towards the radius or the ulnar sides. This is necessary to enable the fingers to produce a
powerful grip.