542 A MANUAL OF ANATOMY 



The subfascial and subtendinous prepatellar bursae are incon- 

 stant. When present, they may be regarded as deep differentia- 

 tions of the subcutaneous bursa, with which they usually com- 

 municate more or less freely, and might therefore be involved in 

 housemaid's knee. They may, however, form distinct bursae. 



The subfascial prepatellar bursa is situated between the fascia 

 lata, which covers the patella, and the tendinous expansion which 

 the suprapatellar tendon of the quadriceps extensor muscle sends 

 downwards over the patella. It may extend downwards over the 

 upper part of the ligamentum patellae, and it may be multilocular. 



The subtendinous prepatellar bursa is the most deeply placed. It 

 is situated between the tendinous expansion of the suprapatellar 

 tendon over the patella and the periosteum of the bone, and it is 

 limited to the front of the bone. 



The prepatellar bursae have no communication with the synovial 

 cavity of the knee-joint, and it is therefore necessary to discriminate 

 between prepatellar bursitis and synovitis of the knee-joint. 



The infrapatellar bursae are two in number — subcutaneous and 

 deep. 



The infrapatellar subcutaneous bursa is situated beneath the 

 integument, and lies over the lower rough half of the tubercle or 

 anterior tuberosity of the tibia, which half gives attachment to the 

 lower end of the ligamentum patellae. 



The deep infrapatellar bursa is situated between the lower part 

 of the ligamentum patellae and the upper smooth half of the tubercle 

 or anterior tuberosity of the tibia. It is on a slightly higher level 

 than the subcutaneous infrapatellar bursa, and neither the sub- 

 cutaneous nor the deep bursa has any communication with the 

 synovial cavity of the knee-joint. 



The bursa anserina is connected with the expanded tendons of 

 insertion of the sartorius, adductor gracilis, and semitendinosus 

 muscles into the upper portion of the inner surface of the shaft of 

 the tibia, on a level with the tubercle or anterior tuberosity of the 

 bone. It is also related superficially to the internal lateral liga- 

 ment of the knee-joint, and it has no communication with the 

 synovial cavity of that joint. It is called the anserine bursa, 

 because the tendons of the muscles to which it is related are dis- 

 posed somewhat in the form of a goose's foot, known as the pes 

 anserinus cruris, as distinguished from the pes anserinus faciei, 

 formed by the facial nerve on emerging from the parotid gland. 



The popliteal bursa, which is of large size, is situated at the 

 posterior and inner aspect of the knee-joint. It lies between the 

 inner head of the gastrocnemius and the semimembranosus muscle, 

 and frequently (one in five) communicates with the synovial cavity 

 of the joint. Under these circumstances, if effusion should take 

 place into the knee-joint, this bursa might form a fluctuating 

 swelling, which might be palpated at the posterior and inner part 

 of the joint. 



The synovial sheath of the popliteal tendon is derived from the 



