Page 215 - Clinical Anatomy

ECA3 7/18/06 6:45 PM Page 200

200 The upper limb

2◊◊The long extensors of the fingers are inserted into the proximal
phalanges; their contracture extends the m/p joints.
3◊◊The long flexors are inserted into the distal and middle phalanges and
therefore flex the i/p joints.
There is, therefore, flexion at the wrist, extension at the m/p and flexion
at the i/p joints.
If the wrist is passively further flexed by the examiner, the tight flexor
tendons are somewhat relaxed and therefore the fingers become a little less
clawed.
Dupuytren’s contracture results from a fibrous contraction of the palmar
aponeurosis, particularly of the 4th and 5th fingers.
The palmar aponeurosis is merely part of the deep fascial sheath of the
upper limb; it passes from the palm along either side of each finger, blends
with the fibrous flexor sheath of the fingers and is attached to the sides of
the proximal and middle phalanges. Contracture of this fascia results in a
longitudinal thickening in the palm together with flexion of the m/p and
proximal i/p joints. However, the distal i/p joints are not involved and, in
fact, in an advanced case, are actually extended by the distal phalanx being
pushed backwards against the palm of the hand.

The spaces of the hand

The spaces of the hand are of practical significance because they may
become infected and, in consequence, become distended with pus. The
important spaces are:
1◊◊the superficial pulp spaces of the fingers;
2◊◊the synovial tendon sheaths of the 2nd, 3rd and 4th fingers;
3◊◊the ulnar bursa;
4◊◊the radial bursa;
5◊◊the midpalmar space;
6◊◊the thenar space.

The superficial pulp space of the fingers
(Fig. 145)
The tips of the fingers and thumb are composed entirely of subcutaneous
fat broken up and packed between fibrous septa, which pass from the skin
down to the periosteum of the terminal phalanx. The tight packing of this
compartment is responsible for the severe pain of a ‘septic finger’—there is
little room for the expansion of inflamed and oedematous tissues.
The blood vessels to the shaft of the distal phalanx must traverse this
space and may become thrombosed in a severe pulp infection with result-
ing necrosis of the diaphysis of the bone. The base of the distal phalanx
receives its blood supply more proximally from a branch of the digital