Human Anatomy Vol 1

(mdmrcog) #1
-Williom Kelsey

INTRODUCTION

Forearm extends between the elbow and the wrist
joints. Radius and ulna form its skeleton. These two
bones articulate at both their ends to form superior
and inferior radioulnar joints. Their shafts are kept
at optimal distance by the interosseous membrane.
Muscles accompanied by nerves and blood vessels
are present both on the front and the back of the
forearm. Hand is the most distal part of the upper
limb, meant for carrying out diverse activities.
Numerous muscles, tendons, bursae, blood vessels
and nerves are artistically placed and protected in
this region.


Surfoce londmolks of Fronl ond Sides of Foreorm


1 The epicondyles of the humerus have been examined.
Note that medial epicondyle is more prominent than
the lateral. The posterior surface of the medial
epicondyle is crossed by the ulnar nerae which can
be rolled under the palpating finger. Pressure on
the nerve produces tingling sensations on the medial
side of the hand (see Fig.8.13).
2 The tendon of the biceps brachii can be felt in front of
the elbow. It can be made prominent by flexing the
elbow joint against resistance. Pulsations of the
brachial artery can be felt just medial to the tendon
(see Fig. 8.18).
3 The head of the radius can be palpated in a depression
on the posterolateral aspect of the extended elbow,
distal to the lateral epicondyle. Its rotation can be
felt during pronation and supination of the forearm.
4 The styloid process of the radius project 1 cm lower
than the styloid process of the ulna (Fig. 9.1). It can
be felt in the upper part of the anatomical snuff box.
Its tip is concealed by the tendons of the abductor
pollicis longus and the extensor pollicis breois, which
must be relaxed during palpation.

Olecranon

Posterior border
of ulna

Styloid process
of ulna

Fig. 9.1 : Surface landmarks: Sides and back of forearm


5 The head of the ulna forms a surface elevation on the
medial part of the posterior surface of the wrist
when the hand is pronated.
6 The styloid process of the ulna projects downwards
from the posteromedial aspect of the lower end of
the ulna. Its tip can be felt on the posteromedial
aspect of the wrist, where it lies about 1 cm above
the tip of the styloid process of the radius (Fig. 9.1).
7 Tlae pisiform bone can be felt at the base of the
hypothenar eminence (medially) where the tendon
of the flexor carpi ulnaris terminates. It becomes
visible and easily palpable at the medial end of the
distal transverse crease (junction of forearm and
hand) when the wrist is fully extended.
Free download pdf