Human Anatomy Vol 1

Triceps brachii

Anconeus

Common aponeurosis

for flexor carpi ulnaris,

extensor carpi ulnaris and

flexor digitorum profundus

Flexor digitorum

profundus

Extensor pollicis longus

Ulna

Extensor indicis

Posterior border

Medial surface

Head of ulna

Styloid process

Olecranon process

Head of radius

Supinator

Biceps brachii and

radial tuberosity

Radius

Abductor pollicis

longus

Pronator teres

Extensor pollicis

brevis

lnterosseous

borders

Posterior border

BONES OF UPPER LIMB

indicis, posterior interosseous nerae and anterior

interosseous artery.

19 In addition at the junction of lower ends of radius

and uhra, passes the tendon of extensor digitiminimi.

20 Lastly in relation to ulna, between its head and

styloid process traverses the tendon of extensor carpi

ulnaris.

These are six compartments under extensor

retinaculum of wrist, four are in relation to radius, Sth

at the junction of radius and ulna and 6th on the ulna

itself between its head and styloid process (Fig.2.27).

The shaft ossifies from a primary centre which

appears during the 8th week of development.

The lower end ossifies from a secondary centre

which appears during the first year and fuses at

20 years; it is the growing end of the bone.

The upper end (head) ossifies from a secondary

centre which appears during the 4th year and fuses

at L8 years (Table 2.1).

Dorsal tubercle

Styloid process

Fi1.2.26: Attachments of right radius and ulna: Posterior aspect

15 The first groove between crest like lowest part of

anterior border and styloid process gives passage

to abductor pollicis longus and extensor pollicis brezsis,

16 The second groove between styloid process and

dorsal tubercle gives way to extensor carpi radialis

longus and extensor carpi radialis breois tendons.

17 The third oblique groove medial to dorsal tubercle

gives passage to extensor pollicis longus tendon

18 The fourth groove on the medial aspect gives

passage to tendons of extensor digitorum, extensor

Extensor pollicis longus tendon

Dorsal tubercle

Extensor carpi radialis

brevis tendon

Extensor carpi radialis

longus tendon

Extensor pollicis brevis tendon

Abductor pollicis longus tendon

Sharp anterior border

The radius commonly gets fractured about 2 cm

above its lower end (Colles'fracture). This fracture

is caused by a fall on the outstretched hand

(Fig.2.28a). The distal fragment is displaced

upwards and backwards, and the radial styloid

process comes to lie proximal to the ulnar styloid

process. (Itnormally lies distal to the ulnar styloid

process.) If the distal fragment gets displaced

anteriorly, it is called Smith's fracture (Fig. 2.28b).

A sudden powerful jerk on the hand of a child may

dislodge the head of the radius from the grip of the

annular ligament. This is known as subluxation of

the head of the radius (pulled elbow) (Fig. 2.29). The

head can normally be felt in a hollow behind the

lateral epicondyle of the humerus.

Extensor indicis tendon

Extensor digiti minimi tendon

Extensor retinaculum

Extensor carpi

ulnaris tendol

lt

E

=

CLo

CL

l

C

.o

oo

Fig.2.27: Tendons in the 1-6 compartments on the posterior surfaces of lower ends of radius and ulna a