Page 65 - untitled

AAAC27 21/5/05 10:45 AM Page 64
Olecranon
Trochlear
notch
Head
Coronoid
of
process
radius
Supinator
Radial
crest
tuberosity
Tuberosity
of the
ulna
Attachment
of
pronator
teres
Interosseous
borders
Dorsal
tubercle
Head
Ulna styloid of ulna
Fig.27.6
Fig.27.5 Radial styloid X-ray of a fracture of the lower end
The left radius and ulna in (a) supination and (b) pronation of the radius (Colles' fracture)

The radius and ulna (Fig. 27.5) • In pronation/supination movements the radial head rotates in the
• Both the radius and ulna have interosseous, anterior and posterior radial notch of the ulna and the radial shaft pivots around the relatively
borders. fixed ulna (connected by the interosseous ligament). The distal radius
• The biceps tendon inserts into the roughened posterior part of the rotates around the head of the ulna.
radial tuberosity. The anterior part of the tuberosity is smooth where it A Colles fracture is a common injury occurring at the wrist in the
is covered by a bursa. elderly and usually osteoporotic population. It classically follows a fall
•The radial head is at its proximal end whilst the ulnar head is at its on the outstretched hand. The fracture line is usually about 2.5 cm
distal end. proximal to the wrist and the distal fragment displaces posteriorly (din-
• The lower end of the radius articulates with the scaphoid and lunate nerfork deformity when viewed from the side) and radially. Some
carpal bones at the wrist joint. The distal ulna does not participate degree of shortening often occurs due to impaction of the component
directly in the wrist joint. parts (Fig. 27.6).
• The dorsal tubercle (of Lister) is located on the posterior surface of
the distal radius.

64 Upper limb