254 THE ARTICULATIONS 



External Internal 



(1) Fibrous expansion of the extensors. (1) Anterior crucial. 



(2) Capsular or anterior ligament. (2) Posterior crucial. 



(3) Posterior ligament. (3) Internal semilunar fibro-cartilage. 



(4) External lateral. (4) External semilunar fibro-cartilage. 



(5) Internal lateral. (5) Coronary. 



(6) Ligamentum patellae. (6) Transverse. 



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 tubercle and 

 oblique lines of the tibia, not only overlies but blends with the fibrous expansion 

 of the extensor tendons. 



The ol)lique lines of the tibia curve upwards and backwards from the tubercle 

 on each side to the postero-lateral part of the tuberosities. The process of fascia 

 attached to the outer ridge of the tibia and to the head of the fibula, descends from 

 the tensor vaginae femoris and is very thick and strong. It is firmly blended with 

 the tendinous fibres of the vastus externus. The fascia lata, on the inner side of the 

 patella, besides being attached to the inner oblique ridge of the tibia, sends some 

 longitudinal fibres lower down to become blended Avith the fibrous expansion of the 

 sartorius. The fascia is much thinner on the inner side of the patella than on the 

 outer, and lilends much less with the tendon of the vastus internus than the outer 

 part of the fascia does with the vastus externus. A thin layer of the fascia lata in 

 the form of transverse or arciform fibres passes over the front of the joint. These 

 fibres are specially Avell marked .over the ligamentum patellse, and blend here 

 with the central portion of the quadriceps extensor fibres. 



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

 tion, densely thick and strong, an inch and a half (3*7 cm.) broad, which is inserted 

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

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

 patella?; (2) of two lateral portions thinner, but strong. The lateral portions are 

 inserted into the patella along its upper border on either side of the central portion 

 and also into its lateral borders, nearer the anterior than the posterior surface, as 

 low down as the attachment of the ligamentum patellae; passing thence along the 

 sides of the ligamentum patella? to the tibia, they are attached to the oblique lines 

 which extend laterally from the tubercle to the inner and outer tuberosities, and 

 reach as far as the internal and external lateral ligaments. On the outer side, the 

 fibres blend with the ilio-til^ial band of the fascia lata, and on the inner they extend 

 below the oblique line to blend with the periosteum of the shaft. Thus there is a 

 large hood spread over the whole of the front of the joint, investing the patella, and 

 reaching from the sides of the ligamentum patellfe to the lateral ligaments, attached 

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

 layer of fatty tissue. 



The ligamentum patellae (fig. 247) is the continuation in line of the central 

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

 of the patella into the ligament. It is an extremely strong, flat band, attached 

 above to the lower border of the patella; below, it is fixed to the lower part of the 

 tubercle and upper part of the crest of the tibia, somewhat obUquely, being pro- 

 longed downwards further on the outer side, so that this border is fully an inch 

 longer tlian the inner which measures tAVO inches and a half (()-7 cm.) in length. 

 Bebind, it is in contact Avith a mass of fat Avhich separates it from the synovial 

 membrane, and a small bursa intervenes between it and the head of the tibia. In 

 front, a large ]>ursa sc])arates it from the subcutaneous tissue, and laterally it is 

 continuous with the fibrous expansion of the extensors. 



The internal lateral ligament (fig. 245) is a strong, flat band, Avhich extends 

 from the depression on the tubercle on the inner side of the internal condyle of the 



