198 ANATOMY IN A NUTSHELL. 



LESSON LI II. 



Knee-Joint. (Plates LXXXIII.) 



The knee-joint is a diarthrodial joint and belongs to the subclass ginglymus. 

 It is a modified ginglymus joint. This joint lias flexion, extension, and a slight 

 rotation externally and internally. 



Ligainentus muscles are those that cross a joint, they are also called elastic 

 ligaments of the joint. The ligamentous muscles of the knee-joint are Biceps, 

 Quadriceps, Semimembranosus, Semitendinosus, Gracilis, Sartorius, Gastrocne- 

 mius, Plantaris, and Popliteus. 



The nerve supply of this joint is the anterior crural, the obturator, the in- 

 ternal and external popliteal. 



The blood supply of the knee-joint is the anastomotica magna, the five 

 articular branches of the popliteal, the anterior and posterior tibial recurrent, 

 and the terminal branches of the profunda. 



The flexors of this joint are the Biceps, the Semimembranosus, Semitendi- 

 nous. Gracilis, Sartorius, and indirectly the Gastrocnemius, Popliteus, and 

 Plantaris. 



The extensors of this joint are the Quadriceps, plus outer rotation by the 

 Biceps and inner rotation by the Popliteus and Semitendinosus, and to a slight 

 degree by the Semimembranosus, Sartorius and Gracilis. 



The strengthening bands are the Biceps, Sartorius, and Semimembranosus. 



The incorporated tendons are the Peroneus longus and Adductor magnus. 

 The incorporated tendon of thePeroneus longus makesthe external lateral lig- 

 ament of the knee-joint, and that of the Adductor magnus makes the internal 

 lateral ligament. 



The knee-joint is formed by the condyles of the femur, the head of the 

 tibia, and the patella, It has fourteen ligaments, an external set in which there 

 are six, and an interna] set hi which there are eight. The first of the external 

 Ligaments is the anterior or ligamentum patella, which is a continuation of the 

 tendon of the Quadriceps extensor. (Plate LXXXIII.) It is attached above 

 to the apex ami rough surface on the lower and posterior portions of the patella, 

 and below it is attached to the lower part of the tubercle of the tibia. A bursa 

 is found bei w< en the upper pail of the tubercle and the ligament. 



The second ligamenl of this set is the posterior ligament, called the liga- 

 mentum posticum Winslowii, which is broad and thin and covers the back of 

 the knee-joint. (Plate LXXXVI.) It has a central and two lateral portions, 

 the lateral portion- are attached above the condyles of the femur superiorly, 

 and to the head of the tibia inferiorly. The central portion which is derived 

 from an expansion of the Semimembranosus tendon and passes from the inner 

 tuberosity of the tibia to the inner side of the upper part of the outer condyle 

 of the femur. 



The third ligamenl ni thissel is the internal lateral ligament, which is broad 

 and flat and i- attached above to the inner condyle of the femur and below to 

 the margin of the inner tuberosity, to the internal fibro-cartilage, and to the 



