Chapter 44: Leg and Foot Lacerations

INTRODUCTION

Lower extremity injuries most frequently involve the lower leg and ankle, followed by the foot and toes, hip, and then knee.¹ Lacerations and wounds occur from sports and recreational activity,^{2,3,4,5,6,7,8} tools and equipment,^9,10,11 occupational activity,¹² and explosions.¹³

ANATOMY

In the foot, the plantar epidermis and dermis are thick, except in the arch area. This thick skin is able to withstand the force produced by a moving body but is also quite sensitive to two-point discrimination and pressure. The heel has an 18-mm-thick modified pad of fat separated into chambers by fibrous septae. There is an additional broad internal fibrous arch, called the inner cup ligament, which helps maintain the shape of the heel. The skin of the sole readily hypertrophies and can become quite thickened, especially in people who walk barefoot. The dense fibrous fatty tissue of the ball of the foot and heel makes wound exploration and visualization difficult in the ED.

In contrast to the protective plantar surface, skin on the dorsal aspect of the foot and the entire ankle provides little protection for underlying tendons, nerves, and blood vessels. The dorsum of the foot, the ankle, and the pretibial surface are particularly vulnerable to blunt-force injuries. Most lacerations on the dorsal foot and in the ankle area are easily explored, except for posterior ankle lacerations, a limitation when partial laceration of the Achilles tendon is considered. Lacerations involving the shin, calf, and thigh usually present few problems regarding wound exploration and visualization.

Several important tendons in the leg are at risk for injury. The fibularis longus and fibularis brevis (also known as the peroneus longus and peroneus brevis) tendons, which contribute to foot plantar flexion and eversion, run behind the lateral malleolus and can be lacerated at this location (Figure 44-1). The extensor hallucis longus tendon, which extends the first toe, runs along the top of the first metatarsal and may be injured when heavy objects are dropped on the foot. The Achilles tendon, the primary contributor to foot plantar flexion, may be severed by penetrating injuries to the posterior ankle. Lacerations of the shin rarely involve vital nerves or tendons. Infrapatellar lacerations can transect the patellar tendon, resulting in inability to extend the leg. Suprapatellar lacerations may involve the quadriceps tendon, also resulting in impaired knee extension.

Sensory nerves predominate in the foot, with most motor control of the foot being performed by nerves and muscles in the lower leg (Figures 44-2 and 44-3). The exceptions to this generalization are that the posterior tibial nerve innervates the intrinsic foot musculature, and the deep peroneal nerve ...