REIDER PART 2
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Chapter 7_Lower Leg, Foot, and Ankle 281

bc identified and palpated for tcnderness (see Fig. 7-26). Ingrown tocnails should be palpated for tenderness and fluctuance that suggest an active infection. In the pres-ence of such an infection, palpating the nail border may cause purulent materiał to be expressed.

Lateral Aspect

Ankle and Foot. On the lateral aspect of the foot and the ankle, the lateral malleolus provides orientation. Tcnderness of the lateral malleolus, especially when accompanied by localized edema or ecchymosis, suggests the possibility of a fracture (see Fig. 7-11). In the casc of a displaced fracture seen acutcly, the examiner may actu-ally bc able to palpate a step-off at the fracture site or feel crcpitus when the bonę is compressed. In the presence of an unstable fracture, the examiner may notę crepitus when simply grasping the foot to examine it.

The lateral malleolus is also the principal landmark for palpating the lateral ankle ligaments. Connecting the anterior flarę of the lateral malleolus with the talar neck, the anterior talofibular ligament is the most common ankle ligament to be injurcd (see Fig. 7-11). Although the ligament itself cannot be distinctly identified, the finding of tcnderness in this region, in association with swelling and ecchymosis, is clinical evidence of a sprain of the ligament. The functional integrity of the anterior talofibular ligament is assesscd with the anterior drawer test, described in the Manipulation scction.

The calcaneofibular ligament, the second most commonly injured ankle ligament, runs from the tip of the lateral malleolus in a posteroinferior direction to insert on the calcaneus. Fuli delineation of the entire ligament is not possible because it runs deep to the per-oneal tendons. However, tenderness over this ligament, in association with localized swelling and ecchymosis, is clinical evidence of a sprain. The functional integrity of the calcaneofibular ligament is evaluated with the inver-sion stress test, described in the Manipulation section.

The peroneus longus and peroneus brevis tendons can usually be identified and palpated posterior to the lateral malleolus. Asking the patient to evert the foot against resistance makes these tendons morę palpable (see Fig. 7-12). The peroneus brevis can usually be followed distally to its insertion at the base of the fifth metatarsal. Tenderness ovcr these tendons suggests the possibility of tendinitis. In morę severe cases, palpable or visible thick-ening of the tenosynovium posterior to the lateral malleolus is noted. Peroneal tendinitis may be associated with instability of the peroneal tendons. The clinical test for peroneal tendon instability is described in the Manipulation section.

Just distal to the lateral malleolus, the examiner may palpate a smali bony prominence of the calcaneus known as the peroneal tubercle, which separates the peroneus brevis tendon from the peroneus longus tendon. This tubercle may occasionally become enlarged and tender.

Below the peroneal tendons, the lateral aspect of the calcaneus is subcutaneous and easily palpated. Tenderness of the calcaneus in an athlete suggests the possibility of a calcaneal stress fracture. Tcnderness of the posterior por-tion of the calcaneal tuberosity in a child or adolescent may indicate the presence of calcaneal apophysitis, also callcd Sever’s disease.

The sinus tarsi is a space between the lateral talus and the calcaneus in which reside the muscle belly of the extensor digitorum brevis and an associated fat pad. The sinus tarsi may be palpated as a depression immediately beneath the anterior talofibular ligament. Slight inversion of the heel accentuates the space, allowing deeper palpa-tion to the lateral talar neck. Tenderness in the sinus tarsi often indicates injury or arthritis involving the posterior facet of the subtalar joint.

Distal to the sinus tarsi, the examiner can palpate the bony prominence of the anterior process of the calcaneus. This process may fracture owing to a twisting injury. Detecting tenderness over the anterior process of the calcaneus is important because such fracturcs are often overlooked by routinc radiographs.

Beyond the anterior process of the calcaneus lies the calcaneocuboid joint. Although the margins of the joint may be difficult to palpate, altcrnate abduction and adduction of the forefoot may allow the examincr to identify it. Tenderness of this articulation may be duc to degenerative joint disease or inereased stress secondary to disruption of the plantar fascia. The cuboid should also be palpated for tenderness because it is occasionally the site of stress fractures or avascular nccrosis.

Lower Leg. Palpation further proximally on the fibula can alert the clinician to the presence of fractures that may not be otherwise clinically obvious. Stress fractures of the fibula most commonly occur in the narrow portion of the diaphysis just proximal to the point where the fibula widens to become the lateral malleolus (see Fig. 7-11). Point tenderness on the fibula about 8 cm proximal to the tip in an athlete who runs suggests the possibility of such a fracture. The midshaft of the fibula is covercd by the overlying musculature and therefore fclt only as a firm resistance deep to the muscle. Traumatic fractures of this portion of the bonę may occur owing to a direct blow. Such fractures often go undiagnosed because the patient is still able to bear weight on the intact tibia. Significant tenderness of the lateral leg in the vicinity of the midshaft fibula following trauma should raisc the suspicion of such a fracture and not be passed off as a muscle bruise. Tenderness along any portion of the fibular shaft, in con-junction with tenderness of the deltoid and the syndesmotic ligaments of the ankle, suggests the possibility of a Maisonneuve fracture. This eponym refers to the combination of a spiral fracture of the fibula with a liga-mentous disruption of the ankle mortise. It is important to search for tenderness of the fibular shaft when a syn-desmosis sprain is diagnosed because the fracture portion