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Home  »  Anatomy of the Human Body  »  pages 262

Henry Gray (1825–1861). Anatomy of the Human Body. 1918.

pages 262

  The lateral surface is the space between the antero-lateral and postero-lateral borders. It is broad, and often deeply grooved; it is directed lateralward in the upper two-thirds of its course, backward in the lower third, where it is continuous with the posterior border of the lateral malleolus. This surface gives origin to the Peronæi longus and brevis.

The Lower Extremity or Lateral Malleolus (malleolus lateralis; distal extremity; external malleolus).—The lower extremity is of a pyramidal form, and somewhat flattened from side to side; it descends to a lower level than the medial malleolus. The lateral surface is convex, subcutaneous, and continuous with the triangular, subcutaneous surface on the lateral side of the body. The medial surface (Fig. 262) presents in front a smooth triangular surface, convex from above downward, which articulates with a corresponding surface on the lateral side of the talus. Behind and beneath the articular surface is a rough depression, which gives attachment to the posterior talofibular ligament. The anterior border is thick and rough, and marked below by a depression for the attachment of the anterior talofibular ligament. The posterior border is broad and presents the shallow malleolar sulcus, for the passage of the tendons of the Peronæi longus and brevis. The summit is rounded, and give attachment to the clacaneofibular ligament.

Ossification.—The fibula is ossified from three centers (Fig. 263): one for the body, and one for either end. Ossification begins in the body about the eighth week of fetal life, and extends toward the extremities. At birth the ends are cartilaginous. Ossification commences in the lower end in the second year, and in the upper about the fourth year. The lower epiphysis, the first to ossify, unites with the body about the twentieth year; the upper epiphysis joins about the twenty-fifth year.


FIG. 264– Left calcaneus, superior surface. (See enlarged image)


FIG. 265– Left calcaneus, inferior surface. (See enlarged image)
 
6d. The Foot. 1. The Tarsus
 
  The skeleton of the foot (Figs. 268 and 269) consists of three parts: the tarsus, metatarsus, and phalanges.