238 SUBCUTANEOUS SYNOVIAL CAPSULES. 



These bursae mucosae are very numerous, as will appear 

 from a subsequent account of them. 



Several of them are very interesting on account of their con- 

 nexion with very important joints. 



These bursae form synovial sheaths to the tendons, where 

 they run through grooves in the bones, or urtder their vaginal 

 ligaments, or where they glide dover each other, as in the palms 

 of the hands and the soles of the feet : but they are especially 

 met with, wherever a tendon changes its direction, and converts 

 a bone, a cartilage, or ligament into a pulley ; of which instances 

 will be detailed hereafter. When a bursae, or tendinous sheath, 

 invests a tendon about to subdivide, as the flexor tendons of 

 the fingers at the wrist, the sheath also subdivides so as to send 

 a process along each parting tendon ; a knowledge of which 

 fact is of importance to the surgeon, as this membrane when 

 injured, is much disposed to continuous inflammation. 

 The number of these bursae vary in different individuals. 

 Ollivier reckons them at one hundred pairs. 



Subcutaneous Synovial Capsules. 



These have been long observed about the wrist, ankle and 

 knee, where they sometimes attain the size of walnuts, and are 

 known to surgeons when enlarged by disease under the names of 

 ganglions and hygroma. They were studied and described for 

 the first time, however, by Beclard. They exist wherever the 

 skin is strongly and frequently moved over a resisting part : as 

 between the skin and the patella ; between the olecranon and 

 skin ; over the trochanter ; acromion ; thyroid cartilage ; at the 

 metacarpal and metatarsal articulations, &c. &c. They are 

 developed accidentally in different parts, when from any cause, 

 as in curvature of the spine, the friction of the tendons is in- 

 creased. When inflated', the cavities appear oblong and cellula- 

 ted, contain some synovial fluid, and look like dilated cells of 

 the cellular tissue, of which they are in all probability formed ; 

 many of them, however, are visible in the foetus during the 

 latter period of utero-gestation. r 



