The hand
Look
Skin
Look for tight bands in
the palm leading up to the fingers or even thumb (Dupuytren’s contracture) (Fig.
20.36).
Soft tissue
Check for thenar and
hypothenar wasting (see previous section on ‘The wrist’) but also check for
wasting in the clefts between the fingers dorsally (damage to the ulna nerve or
Ti).
Bone
Look for Heberden’s
nodes (Fig. 20.37) over the distal interphalangeal joints dorsally (associated
with osteoarthritis). Look for swan neck and boutonniere (Fig.
20.38) deformities. Swan neck deformities have an extension at the middle
interphalangeal joint with flexion at the distal interphalangeal joint.
Boutonniere deformity is extension at the distal interphalangeal joint with
flexion at the middle interphalangeal joint.
Both
of these are associated with rheumatoid arthritis. Look also for dropped
fingers. If one finger lies lower than the others when the hands are held out,
test for rupture of the extensor tendon by asking the patient to extend the
finger against resistance. Look for subluxation of the metacarpal phalangeal
joints and for ulna drift of the fingers (also associated with rheumatoid
arthritis) (Fig. 20.39).
Feel
Skin
Feel for loss of sensation in the tips of the fingers. Review the
sensory distribution of the median, ulna and radial nerves. If there is any
doubt about the sensation then proceed to test two-point discrimination.
Soft
tissues
Check for capillary filling in the fingertips.
Feel
for wasting in the first dorsal interosseous on the radial side of the first
metacarpal. This muscle is plump and easily palpable. Damage to the ulna nerve
or to the Ti nerve root can be detected from wasting in this muscle.
Bone
Feel for swelling and tenderness over the metacarpal phalangeal and
interphalangeal joints.
Move
Active
Test roll-up of the fingers from full extension to full flexion. Test
flexion of the metacarpal phalangeal joints in isolation while keeping the
proximal and distal interphalangeal joints extended. This tests the patient’s
control of the intrinsic muscles. Test abduction of the fingers (a further test
of small muscles in the hand).
Passive,
stability and resisted
Test the power of the extensors, individually pushing down on each
finger.
Superficialis
tendon test. Flexor digitorum profundus usually has only one muscle belly
supplying the tendons to all of the fingers. Profundus can therefore be
immobilised by holding all the fingers bar the one being tested in full
extension, grasping them in your hand. If the test finger is still able to flex,
then superficialis to that finger is active (Fig. 20.40).
Profundus
test. Flexor digitorum profundus is the only tendon that inserts in the distal
phalanx. If the finger is held by the middle phalanx, the power of the profundus
tendon can be tested (Fig. 20.41).
Intrinsics. The power of the intrinsic muscles of the hand is tested by
asking the patient to abduct the fingers against resistance, and feeling for
contraction in the first dorsal
interosseous muscle on the index finger side of the web space (Fig.
20.42).
Froment’s
test. The patient is asked to grip a sheet of paper between the index finger and
thumb of both hands. If the intrinsic muscles of the hand are normal the patient
can grip firmly with the thumb in extension. However, if there is weakness,
particularly of the adductor pollicis, the thumb cannot remain straight while
flexor hallucis longus contracts hard, so the thumb flexes (Fig.
20.43).
Abductors
of thumb. The abductors of the thumb are supplied by the median nerve. Power
is tested by asking the patient to raise the thumb from the palm against
resistance (Fig. 20.44).