68 CLINICAL APPLIED ANATOMY. 



Associated with such organs as the parotid and submandibular 

 glands, they most probably originate in remnants of develop- 

 mental cartilage. In the case of the parotid, it is possible that 

 remains of the cartilage of the first branchial arch may account 

 for the cartilaginous portion of the mixed tumours. When 

 cartilaginous elements occur in the testis or ovary they can 

 only be explained on the ground that they belong to teratomata. 



Lipomata, or fatty tumours. 



Wherever adipose tissue is found in the body, there lipomata 

 may develop. There are, however, certain positions where they 

 are more commonly seen than elsewhere, and generally there is 

 an anatomical explanation of their existence in these areas. 



Subcutaneous lipomata are very frequent. The subcutaneous 

 tissue contains much fat in well-nourished individuals, and in 

 particular regions, often where there is a likelihood of pressure, 

 as for instance about the shoulders and the buttocks, encapsuled 

 lipomata are prone to develop. Diffuse lipomata, on the other 

 hand, affect their own characteristic situations, such as the neck, 

 the axillae and the groins. 



Extra-peritoneal lipomata arise from any part of the fatty 

 tissue lying in contact with the peritoneum. Appendices 

 epiploicse are natural sub-serous lipomata. Sessile extra- 

 peritoneal fatty tumours may grow to a large size, and may 

 excite injurious pressure on surrounding organs. 



Not infrequently small lipomata grow in the extra-peritoneal 

 tissue beneath and protrude through adventitious openings in the 

 linea alba, or through the deep inguinal or the femoral rings, and 

 after a while, by dragging upon the peritoneum, cause a finger- 

 like process of that membrane to be formed. Lipomata of the 

 spermatic cord may be explained by the cord drawing down with 

 it some of the extra-peritoneal adipose tissue. This is further 

 shown by the fact that occasionally such a lipoma contains 

 cells which are closely allied to adrenal elements, derived from 

 the lumbar region in which the testis was originally developed. 



The fatty tissue found external to synovial membranes, particu- 

 larly that of the knee, outside the spinal dura mater, in the 



