20 



serted into the external part of the upper extremity of the tibia, imme- 

 diately below the knee. 



Gracilis arises by a flat tendon, about five inches long, from the 

 ramus of the ischium and sciatic ligament ; the fibres converge, and are 

 inserted below the knee into the inner edge of the tibia, below the con- 

 dyle, and into the fascia of the leg. 



Adductor magnus arises fleshy from the posterior border of the 

 ramus of the ischium, internal to the origin of the semitendinosus. The 

 fibres pass downwards, forwards, and inwards, to be inserted into the 

 upper part of the condyloid pit of the femur. 



Gastrocnemius — an enormously large fleshy mass, investing the back, 

 front, and sides of the leg — arises by four heads : one from the external 

 side of the patella and ligamentum patellae, as far down as the tubercle 

 of the tibia; the second springs from the external condyle of the 

 femur and external lateral ligament; a tendinous pulley passes across from 

 the upper part of the outer condyle, looping round to the external head, 

 and around this winds the biceps ; the third head is attached to the deep 

 pit over the internal condyle ; and the fourth, or external or largest head, 

 arises from the anterior and lateral aspects of the tubercle of the tibia, 

 the ligamentum patellae, and both patellae, also from the fibula by fascia, 

 for its whole length. All these masses unite, and end in a large flat 

 strong tendon, nearly two inches wide, which is inserted into the edges 

 of the metatarsal bone as far down as its lower third ; this tendon winds 

 over the trochlear surface at the end of the tibia, forming a sheath for 

 the deeper tendons on the back of the metatarsus. 



Tibialis anticus — long and thick — arises by two heads : one internal 

 fleshy, from the outer surface of the groove on the outside of the tubercle 

 of the tibia ; the outer by a very strong round tendon from the articular 

 surface of the outer condyle ; this soon becomes fleshy, three inches below 

 its origin, and unites with the former. The tendon passes to the ankle 

 under a distinct annular ligament, and splits into two parts for the pas- 

 sage of the extensor ungualis, each part being inserted into the lateral 

 ridges on the anterior aspect of the metatarsal bone. The deep origin 

 of this muscle is sheathed by the synovial membrane of the knee joint, 

 which it strengthens very considerably. The anterior tibial vessels and 

 nerves pass through the same sheath of the annular ligament, and the 

 anterior tibial nerve passes through the splitting of the tendon. 



Extensor digitorum communis arises fleshy from the sharp ridge of 

 the anterior aspect of the tibia to five inches below the tubercle, and 

 from the bony surface external to it ; the fibres run to a strong round 

 tendon, which passes in front of the ankle, internal to the last, and 

 separated from it by a strong second annular ligament which binds it 

 down ; the tendon passes downwards, and ends in a flat expansion, which, 

 at the metatarso-phalangeal joint, sends a slip into the proximal ex- 

 tremity of each of the phalanges. 



Extensor unguis — a very delicate muscle — commences by a thin round 

 tendon at the front of the trochlea, at the lower extremity of the tibia, 

 close to the internal malleolus ; this tendon passes through the insertion 



