450 THE MUSCLES AND FASCIA. 



the knee and terminates somewhat abruptly in this situation with a full, curved outline. The 

 Crureus and Subcrureus are completely hidden, and do not directly influence surface form. The 

 Adductor muscles, constituting the internal femoral group, are not to be individually distin- 

 guished from each other, with the exception of the upper tendon of the Adductor longus and 

 the lower tendon of the Adductor magnus. The upper tendon of the Adductor longus, when 

 the muscle is in action, stands out as a prominent ridge, which runs obliquely downward and 

 outward from the neighborhood of the pubic spine, and forms the inner boundary of a flattened 

 triangular space on the upper part of the front of the thigh, known as Scarpa's triangle. The 

 lower tendon of the Adductor magnus can be distinctly felt as a short ridge extending down to 

 the Adductor tubercle on the internal condyle, between the Sartorius and Vastus interims. 

 The Adductor group of muscles fills in the triangular space at the upper part of the thigh, 

 formed between the oblique femur and the pelvic wall, and to them is due the contour of the 

 inner border of the thigh, the Gracilis largely contributing to the smoothness of the outline. 

 These muscles are not marked off on the surface from those of the posterior femoral region by 

 any intermuscular marking ; but on the outer side of the thigh these latter muscles are defined 

 from the Vastus externus by a distinct marking, corresponding to the external intermuscular 

 septum. The Gluteus maximus and a part of the Glutens medius are the only muscles of the 

 buttock which influence surface form. The other part of the Gluteus medius, the Gluteus 

 minimus, and the External rotators are completely hidden. The Gluteus maxiinm forms the 

 full rounded outline of the buttock ; it is more prominent behind, compressed in front, and 

 terminates at its tendinous insertion in a depression immediately behind the great trochanter. 

 Its lower border does not correspond to the gluteal fold, but is much more oblique, being 

 marked by a line drawn from the side of the coccyx to the junction of the upper with the lower 

 two-thirds of the thigh on the outer side. From beneath the lower margin of this muscle the 

 hamstring muscles appear, at first narrow and not well marked, but as they descend becoming 

 more prominent and widened out, and eventually dividing into two well-marked ridges, which 

 constitute the upper boundaries of the popliteal space, and are formed by the tendons of the 

 inner and outer hamstring muscles respectively. In tin; upper part of the thigh these muscles are 

 not to be individually distinguished from each other, but lower down the separation between the 

 Semitendinosus and Semimembranosus is denoted by a slight intermuscular marking. The 

 external hamstring tendon formed by the Biceps is seen as a thick cord running down to 

 the head of the fibula. The inner hamstring tendons comprise the Semitendinosus, the 

 Semimembranosus, and the Gracilis. The Scmitendniosus is the most internal of these, and 

 can be i'elt, in certain positions of the limb, as a sharp cord ; the Semimembranosus is 

 thick, and the Gritdlis is situated a little farther forward than the other two. All the 

 muscles on the front of the leg appear to a certain extent somewhere on the sur- 

 face, but the form of this region is mainly dependent upon the Tibialis anticus and the 

 Extensor longus digitorum. The Tibialw anticus is well marked, and presents a fusiform 

 enlargement at the outer side of the tibia, and projects beyond the crest of the shin-bone. 

 From the muscular mass its tendon may be traced downward, standing out boldly, when the 

 muscle is in action, on the front of the tibia and ankle-joint, and coursing down to its insertion 

 along the inner border of the foot. A well-marked groove separates this muscle externally 

 from the Extensor longus digitornm, which fills up the rest of the space between the upper 

 part of the shaft of the tibia and fibula. It does not present so bold an outline as the Tibialis 

 anticus, and its tendon below, diverging from the tendon of the Tibialis anticus, forms with the 

 latter a sort of plane, in which may be seen the tendon of the Extensor proprius hallucis. A 

 groove on the outer side of the Extensor longus digitorum. seen most plainly when the muscle 

 is in action, separates the tendon from a slight eminence corresponding to the Peroneus tertius. 

 The fleshy fibres of the Peroneus longus are strongly marked at the upper part of the outer 

 side of the leg, especially when the muscle is in action. It forms a bold swelling, 

 separated by furrows from the Extensor longus digitorum in front and the Soleus 

 behind. Below, the fleshy fibres terminate abruptly in a tendon which overlaps 

 the more flattened form of the Peroneus brevis. At the external malleolus the ten- 

 don of the Peroneus brevis is more marked than that of the Peroneus longus. 

 On the dorsum of the foot the tendons of the Extensor muscles, emerging from 

 beneath the anterior annular ligament, spread out and can be distinguished in the following 

 order: The most internal and largest is the Tibialis anticus, then the Extensor proprius hallucis: 

 next comes the Extensor longus digitorum, dividing into four tendons to the four outer toes ; and 

 lastly, most externally, is the Peroneus tertius. The flattened form of the dorsum of the foot is 

 relieved by the rounded outline of the fleshy belly of the Extensor brevis digitorum, which forms a 

 soft fulness on the outer side of the tarsus in front of the external malleolus, and by the Dorsal 

 interossei, which bulge between the metatarsal bones. At the back of the knee is the popliteal 

 space, bounded above by the tendons of the hamstring muscle ; below, by the two heads of the 

 Gastrocnemius. Below this space is the prominent fleshy mass of the calf of the leg, produced 

 by the Gastrocnemius and Soleus. When these muscles are in action, as in standing on tiptoe, 

 the borders of the Gastrocnemius are well defined, presenting two curved lines, which converge 

 to the tendon of insertion. Of these borders, the inner is more prominent than the outer. 

 The fleshy mass of the calf terminates somewhat abruptly below in the tendo Achillis, which 

 stands out prominently on the lower part of the back of the leg. It presents a somewhat 

 tapering form in the upper three-fourths of its extent, but widens out slightly below. When 

 the muscles of the calf are in action, the lateral portions of the Soleus may be seen, forming 



