The
foot and ankle
In this chapter the examination starts with the foot and ankle. On a
live patient the examination should first be directed to the part of the body
with the problem (see the section on ‘The history’ in this chapter).
Look
Watch the patient walking, both with their shoes on and barefooted.
Look
at the shoes for signs of abnormal wear.
The wear on the shoe tells you about rubbing nut pressure. The normal
wear pattern is for a corner to be worn off the posterolateral side of the heel
(the normal point for heel strike). There may then be a circular wear pattern
under the ball of the big toe (where toe off occurs as. the foot provides its
final drive and then lifts off). These two areas of wear may be linked in a very
old shoe by a line of wear along the lateral side of the sole where most of the
weight is taken during the stance phase of the stride.
Skin
Look for calluses, corns, bunions and scars, particularly in the
following.
• At the base of the big toe for a bunion.
A bunion is a red swelling on the medial side of the metatarsophalangeal
joint consisting of inflamed skin, a subcutaneous bursa and an osteophyte on
the joint margin of the medial side of the metatarsal head (Fig.
20.1). In gout
the whole metatarsal phalangeal joint will be red and swollen.
• Under the metatarsal heads.
in rheumatoid arthritis the fat pad under the metatarsal heads thins,
and the heads become prominent and tender immediately beneath the skin of the
sole of the foot. The patient complains of pain in the sole of the foot when
walking as if walking barefoot on pebbles. Areas of thickened callous skin form
over the metatarsal heads.
• Over the dorsum of interphalangeal joints and over the
tips of the toes in patients with claw toes.
Feet do not fit easily into most shoes, even when they are normal. If
the toes have started to claw then the pulp of the toe will be driven into the
floor of the shoe, while the dorsum of the interphalangeal joints will be driven
into the top of the shoe (a sort of contracoup injury) (Fig.
20.2).
A
bunion can form on the outside of the foot at the base of the fifth metatarsal.
This is sometimes called a bunionnette.
The
counter of shoes (the part that wraps around the heel) can rub on the calcaneum
producing a bunion on the insertion of the achilles tendon into the bone.
Wasting
is in seen in neurological conditions,
and there may be wasting in the clefts between the metatarsals. Wasting may be
associated with clawing of the toes (see Fig. 20.2).
Bone
With the patient standing, the heel should be in very slight valgus. The
medial side of the foot (the arch) does not normally quite touch the ground,
but is not raised so high that you can put a finger between it and the ground.
The heel pad, the lateral side of the foot, all the metatarsal heads and the
pulps of all the toes are on the ground when the patient is standing erect and
relaxed. The toes should be relatively straight, not clawed (flexed at the
interphalangeal joints and extended at the metatarsal phalangeal joint) or
hammered (extended at the distal interphalangeal, and metatarsal phalangeal
joint, flexed at the proximal interphalangeal joint) (Fig.
20.3).
Feel
Skin
Inflammation. Feel for heat. Sensation. In neuropathies, such as
that caused by diabetes, the distal sensation may be lost, and the toes may be
numb. In nerve compression in the spine (e.g. prolapsed intervertebral disc) it
should only be necessary to compare the two sides by testing the sole, the
medial side and lateral side, each of which is supplied by a different nerve
root.
Soft
tissue
Pulses. The easiest foot pulses to feel are the posterior tibial behind
the medial malleolus, and the dorsal pedis between the proximal ends of the
first and second metatarsals (Fig. 20.4). The toes should also be tested for
capillary fillings.
Swelling.
Feel the ankle joint for an effusion. It may even be possible to feel
cross-fluctuation if there is a tense effusion in the ankle joint.
Wasting
and gaps. Feel the tendoachilles passing up from the heel into the calf muscle.
If it is ruptured it may be possible to feel a gap in the tendon.
However, an acute rupture is usually so bruised and tender that the gap
is not as easy to feel as it should be. The site of tenderness will give you a
clue as to whether the rupture is mid-substance or is at the musculotendinous
junction (much higher in the calf). It is important to distinguish between these
two as the management and prognosis are very different.
Tenderness.
The extensor tendons of the toes in the dot-sum of the foot and up the front of
the tibia will be very tender and may even produce crepitus if there is tenosynovitis.
If they are tender, ask the patient to move the tendons and you may feel
crepitus under your fingers.
Bone
Tenderness. In injuries around the ankle, start feeling at the proximal
fibula head, just below the knee. The Maisonneuve fracture is a sprain of the
ankle with a spiral fracture of the fibula proximally. Palpate for tenderness
down the length of
After
a fall from a height check for tenderness in the calcaneum, as this may be
fractured. If the forefoot has been trapped (frequently behind the pedals of a
car in a head-on crash) then check for tenderness in the bones of the forefoot.
These may be both fractured and dislocated if the forefoot is twisted.
Move
Active
Ask the patient to walk towards you then away from you. Look for limps.
The
Windlass test. Make the patient stand on their toes while you look from in front
and from behind. Some patients’ feet look very flat when at rest. This can
simply be a physiological flat foot. As soon as these patients stand on their
toes, the arch forms (Fig. 20.5). In pathological flat foot the arch does not
form.
Other
movements. You should also ask them to move their toes, and move the ankle
through a full range of movement (flexion, extension, inversion and eversion).
Passive
The Apley test. If you hold the heel in one hand and the forefoot in
the other, the ankle, subtalar and metatarsal mobility can be tested one after
the other without moving your hands. Rocking the ankle by moving your hands in
opposite directions, like a see-saw, tests ankle mobility. Tilting the foot
outwards and inwards using both hands together tests subtalar movement.
Twisting the forefoot while holding the hindfoot still tests midtarsal mobility
(Fig. 20.6).
Hallux
rigidus and claw toes. The metatarsal phalangeal joint of the big toe is stiff
in hallux rigidus.
In
claw toes the metatarsophalangeal joint is commonly dislocated with the phalanx
riding dorsally over the metatarsal head (Fig. 20.2). Check for passive
correction of the metatarsal phalangeal joint and proximal phalangeal joints.
Stability
Stability of the ankle and foot joints is not easy to test, especially
after acute trauma.
If
the ankle is dislocated the talus will be visible pressing hard against the skin
anterior and lateral to the foot. It should be reduced at once both to save the
skin (which may otherwise become necrotic) and to make the patient more
comfortable.
Resisted
Test for power of extensor hallucis longus (Fig.
20.7). Remember, this
muscle is specifically served only by the L5 nerve root, and is a key test for
damage to this nerve in a prolapsed intervertebral disc.
In
polio and other neurological disorders, each muscle will need to be tested in
turn. One way to do this is to put the tips of your fingers over the muscle
body, or its tendon, while holding the limb still with the other hand. The
patient is asked to try to move the limb against the resistance that you have
created. Your fingertips will detect whether there is any activity in the
muscle, as the movement itself might be produced by alternative muscles, the so
called ‘trick manoeuvres’. The power of each muscle can be graded using
the Medical Research Council (MRC) power scale (Table
20.6).
Simmonds’
test. The patient lies face down, feet over the end of the bed. Squeeze the calf
and the foot should passively dorsiflex (Fig. 20.8). If it does not, the
tendoachilles is likely to be ruptured.