Page 193 - Clinical Anatomy

ECA3 7/18/06 6:45 PM Page 178

178 The upper limb

Fig. 130◊(a)
Supraspinatus and the
subacromial-subdeltoid
bursa. Note that the
supraspinatus tendon
Acromion
lies close against the
Supraspinatus acromion—if this tendon
is inflamed, there is a
Head of humerus painful arc of movement
as the shoulder is
Glenoid fossa abducted from 60° to
120°, because, in this
Deltoid range, the inflamed
tendon impinges against
the acromion. (b) MRI of
the shoulder showing the
detailed anatomy
revealed by this
technique.

subacrominal bursa. This bursa is continued beneath the deltoid as the subdel-
toid bursa forming, together, the largest bursa in the body.
The supraspinatus initiates the abduction of the humerus on the
scapula; if the tendon is torn as a result of injury, active initiation of abduc-
tion becomes impossible and the patient has to develop the trick movement
of tilting his body towards the injured side so that gravity passively swings
the arm from his trunk. Once this occurs, the deltoid and the scapular rota-
tors can then come into play.