THE KNEE-JOINT 



285 



External Ligaments 



Superficial to the fibrous expansion of the quadriceps extensor tendons the 

 fascia lata of the thigh covers the front and sides of the knee-joint. 



The deep fascia of the thigh, as it descends to its attachment to the tuberosity and oblique 

 lines of the tibia, not only overlies but blends with the fibrous expansion of the extensor tendons. 

 The oblique lines of the tibia curve upward and backward from the tuberosity on each side 

 to the postero-lateral part of the condyles. The process of fascia attached to the lateral ridge 

 of the tibia and to the head of the fibula descends from the tensor fascise latae and is very thick 

 and strong. It is firmly blended with the tendinous fibres of the vastus laterahs. The fascia 

 lata, on the medial side of the patella, besides being attached to the medial oblique ridge of the 

 tibia, sends some longitudinal fibres lower down to become blended with the fibrous expansion 

 of the sartorius. The fascia is much thinner on the medial side of the patella than on the lateral, 

 and blends much less with the tendon of the vastus medialis than the lateral part of the fascia 

 does with the vastus lateralis. A thin layer of the fascia lata in the form of transverse or arci- 

 form fibres passes over the front of the joint. These fibres are specially well marked over the 

 ligamentum patellae, and blend here with the central portion of the quadriceps extensor fibres. 



Fig. 316. — The Lower Extremity of the Femur (Posterior View), to show the Rela- 

 tion OP the Articular Capsule of the Knee-joint (in red) to the Epiphysial Line. 



The fibrous expansion of the extensor tendons consists — (1) of a central 

 portion, densely thick and strong, 3.7 cm. (1| in.) broad, which is inserted into 

 the anterior two-thirds of the upper border of the patella, many of its superficial 

 fibres passing over the subcutaneous surface of the bone into the ligamentum 

 patellae; (2) of two side portions thinner, but strong. 



The side portions are inserted into the patella along its upper border on either side of the 

 central portion and also into its medial and lateral borders, nearer the anterior than the posterior 

 surface, as low down as the attachment of the ligamentum patella;; passing thence along the 

 sides of the ligamentum patellae to the tibia, they are attached to the oblique fines which extend 

 from the tuberosity to the medial and lateral condyles, and reach as far as the tibial and fibular 

 collateral ligaments. On the lateral side, the fibres blend with the ilio-tibial band of the lascia 

 lata, and on the medial they extend below the oblique line to blend with the periosteum ot the 

 shaft. Thus there is a large hood spread over the whole of the front of the joint, investing tne 

 patella, and reaching from the sides of the ligamentum patellae to the collateral hgaments, at- 

 tached below to the tibia, and separated everywhere from the synovial membrane by a layer 

 of fatty tissue. 



The ligamentum patellae (fig. 320) is the continuation in line of the central 

 portion of the conjoined tendon, some fibres of which are prolonged over the front 



