The ankle and lower leg are common sites of injury in all walks of life; figure 102a,b shows fractures resulting from more severe forms of trauma. The natural position of the ankle is in slight plantar flexion and slight inversion. The lateral malleolus is a little more prominent and its tip is just distal to that of the medial; the joint line is 1cm above the latter (figure 103). There may be color changes, scars, swelling and deformity of all joints. Examine the sole for callosities. A small amount of fluid in the ankle joint presents as puffiness just in front of each malleolus. Larger amounts of fluid fill in the hollow on either side of the tendo Achilles (figure 104).
Other common findings in the foot are: fixed lateral deviation of the main axis of the great toe (hallux valgus), clawing of the toes (fixed flexion deformities) and abnormalities of the transverse and longitudinal arches.
Palpate the medial (figure 105a–d) and lateral (figure 106a–d), malleoli and collateral ligaments of the ankle joint, for tenderness and swelling.
A transmitted pulse may be obtained between the two sides of the tendo Achilles if sufficient fluid is present. Any tender areas of the medial and lateral ligaments can be injected, and the tendon sheaths of: tibialis anterior (figure 107a); tibialis posterior (figure 107b), the peroneal tendons over the calcaneus (figure 107c); and the tendon of peroneus brevis, as it is attached to the styloid process of the fifth metatarsal (figure 107d). The ankle joint can be approached anteriorly, medial to the tendon of tibialis anterior (figure 108).
Dorsiflexion (figure 109a,b) and plantar flexion (figure 110a,b) occur primarily at the ankle joint. The former, raising the toes towards the knee, is to 20 degrees and the latter to 50 degrees. The ligaments of the ankle joint are more lax in plantar flexion, when a few degrees of passive abduction and adduction can be obtained. Flex the knee to reduce the calf tension, when assessing the degree of fixed flexion deformity of an ankle
Inversion (figure 111a,b) and eversion (figure 111c,d) take place mainly at the subtalar and talocalcaneonavicular joints. The calcaneum and navicular bones carry the front part of the foot.
In passive assessment, hold the ankle in your left hand and the forefoot in your right. Assess: dorsiflexion (figure 112a) and plantar flexion (figure 112b); inversion (figure 112c), when the sole turns inwards, is to 30 degrees and eversion (figure 112d) is to 5 degrees.
Figure 113 illustrates the bones of the sole of the foot; information obtained from clinical examination is supplemented by radiographs and MRI (figure 114a,b).
Figure 113 Anatomy of sole.
1. Medial cuneiform
2. Proximal phalanx
3. Distal phalanx
4. Base of first metatarsal
6. Intermediate cuneiform
7. Middle phalanx
8. Lateral cuneiform
9. Head of talus
10. Head of metatarsal
13. Styloid process of fifth metatarsal
Palpation of the sole may identify deep tenderness, and this may be injected (figure 115a.b). Common complications are a calcaneal spur that may require injection (figure 116a,b), and injuries of the muscles, bones and ligaments, of the sole and heel.
Squeezing across the tendo Achilles, and the metatarsophalangeal and interphalangeal joints (figure 117a–c), may reveal tenderness, suggestive of injury or inflammatory disorders.
Dorsiflexion of the metacarpophalangeal joints is to 60 degrees (figure 118). Plantar flexion of the metacarpophalangeal and interphalangeal joints (figure 119a,b) is to 40 and 60 degrees respectively.
A variable small degree of fanning (abduction) of the toes is possible (figure 120a,b).