234 ANTERIOR TIBIAL REGION. 



beneath the internal lateral ligament. The second is continuous 

 with an aponeurotic expansion that binds down the popliteus 

 muscle the popliteal fascia ; and the third turns upwards and out- 

 wards to the external condyle of the femur, forming the middle por- 

 tion of the posterior ligament of the knee-joint (ligamentum posticum 

 Winslowii). 



The tendons of the two last muscles, viz. the semi-tendinosus and 

 semi-membranosus, with those of the gracilis and sartorius, form the 

 inner hamstring. 



Relations. By its superficial surface with the gluteus maximus, 

 biceps, semi-tendinosus, fascia lata, and at its insertion with the tendi- 

 nous expansion of the sartorius. By its deep surface with the quad- 

 ratus femoris, adductor magnus, internal head of the gastrocnemius, 

 the knee-joint, from which it is separated by a synovial membrane, 

 and the popliteal artery and vein. By its inner border with the gra- 

 cilis. By its outer border with the great ischiatic nerve, and in the 

 popliteal space, with the popliteal artery and vein. 



If the semi-membranosus muscle be turned down from its origin, 

 the student will bring into view the broad and radiated expanse of 

 the adductor magnus, upon which the three flexor muscles above 

 described rest. 



Actions. These three hamstring muscles are the direct flexors of 

 the leg upon the thigh; and, by taking their origin from below, 

 they balance the pelvis on the lower extremities. The biceps from 

 the obliquity of its direction everts the leg when partly flexed, and 

 the semi-tendinosus turns the leg inwards when in the same state of 

 flexion. 



Anterior tibial Region. 



Tibialis anticus, 

 Extensor longus digitorum, 

 Peroneus tertius, 

 Extensor proprius pollicis. 



Dissection. The dissection of the anterior tibial region is to be 

 commenced by carrying an incision along the middle of the leg, mid- 

 way between the tibia and the fibula, from the knee to the ankle, 

 and bounding it inferiorly by a transverse incision, extending from 

 one malleolus to the other. And to expose the tendons on the dor- 

 sum of the foot, the longitudinal incision may be carried onwards to 

 the outer side of the base of the great toe, and be terminated by 

 another incision directed across the heads of the metatarsal bones. 



The Tibialis anticus muscle (flexor tarsi tibialis) arises from the 

 upper two-thirds of the tibia, from the interosseous membrane, and 

 from the deep fascia; its tendon passes through a distinct sheath in 

 the annular ligament, and is inserted into the inner side of the 

 internal cuneiform bone, and base of the metatarsal bone of the 

 great toe. 



Relations. By its anterior surface with the deep fascia, from 

 which many of its superior fibres arise, and with the anterior annu- 



