THE THIGH 261 



The transverse branch is of small size. It passes to the deep 

 surface of the vastus lateralis, reaches the posterior part of 

 the thigh, and inosculates with the medial femoral circumflex 

 artery and the first perforating artery. The descending branch 

 gives twigs to the vastus intermedius and rectus femoris, 

 and one long branch, which may be traced distally, amid 

 the fibres of the vastus lateralis, to the knee, where it 

 anastomoses with the lateral superior genicular artery. 



Dissection. Divide the ilio-tibial tract of the fascia lata, 

 distal to the tensor fasciae latae, in order to obtain a better demon- 

 stration of the limits of the lateral intermuscular septum and a 

 better view of the vastus lateralis muscle. Take hold of the 

 distal part of the ilio-tibial tract and pull it laterally, at the 

 same time push the vastus lateralis medially, then the strong 

 fibrous lateral intermuscular septum will be seen passing towards 

 the linea aspera on the back of the femur. 



Intermuscular Septa. There are three intermuscular 

 septa of the thigh: lateral, medial, and posterior (p. 235). 

 The lateral is strong, the other two are both weak. Only 

 the lateral and medial are to be examined at present. 



The lateral intermuscular septum is a fibrous partition 

 interposed between the vastus lateralis and intermedius 

 anteriorly, and the popliteal fossa and the short head of the 

 biceps femoris posteriorly. It springs from the deep surface 

 of the ilio-tibial tract, and its deep border is attached to the 

 lateral supracondylar ridge and to the lateral lip of the linea 

 aspera of the femur. Parts of the vastus intermedius and 

 vastus lateralis arise from its anterior surface, and some of the 

 fibres of the short head of the biceps femoris spring from its 

 posterior surface. Immediately proximal to the lateral 

 condyle of the femur it is pierced by the lateral superior 

 genicular artery and nerve. The medial intermuscular septum, 

 which is thin in comparison with the lateral septum, should 

 now be examined. It is interposed between the adductors 

 and the vastus medialis. Its distal part, which is most 

 distinct, passes laterally, from the fascia lata on the medial 

 side of the thigh, behind the posterior border of the sartorius 

 and behind the saphenous nerve, to the medial supracondylar 

 ridge, and it lies in front of the distal part of the adductor 

 magnus. Its proximal part is the thin layer of fascia on the 

 anterior surfaces of the adductors magnus and longus, which 

 is continuous above with the pectineal fascia. 



M. Quadriceps Femoris. The quadriceps femoris muscle 



