468 



BURSTS MUCOS^E. 



the hip, shoulder, knee, and ankle, but are 

 not, as it was supposed until of late years, con- 

 fined to the extremities, for we shall presently 

 point out instances of their occurrence both in 

 the head and trunk. Amongst the most re- 

 markable in the inferior extremity we find, in 

 the neighbourhood of the hip-joint, a very large 

 one between the tendon of the psoas muscle 

 and the capsular ligament ; a large one between 

 the great trochanter and gluteus maximus; 

 one between the gluteus maximus and vastus 

 externus ; one between the gluteus medius and 

 trochanter; one between the gluteus minimus 

 and trochanter; one between the pectineusand 

 femur. These are all large and regular in their 

 existence ; but there are other smaller ones fre- 

 quently met with, particularly at the posterior 

 part of the joint connected with the small ten- 

 dons and muscles placed there. About the 

 knee-joint there are likewise several vesicular 

 bursae : immediately above the articulation, be- 

 tween the extensors and front of the femur, 

 there is an extremely large one, oftentimes ex- 

 tending several inches upwards, and still more 

 remarkable in many instances for communi- 

 cating with the synovial membrane of the joint; 

 a fact which has been well appealed to by the 

 general anatomist in proof of the anatomical 

 identity of these two structures. There is a 

 large one, likewise, at the inner and lower part 

 of the articulation between the tibia and the 

 tendons of the sartorius, gracilis and semi- 

 tendinosus : posteriorly between the origins of 

 the gastrocnemii and the bone there is also 

 found a bursa; and a similar one between the 

 popliteus muscle and the joint. These, like 

 the large one in front, generally communicate 

 freely with the articular synovial membrane. 

 There is also a bursa generally found between 

 the semi-membranosus and the internal lateral 

 ligament. Around the ankle there are but few 

 vesicular bursae : posteriorly, however, between 

 the tendo Achillis and os calcis, there is found a 

 very large one ; and smaller ones are frequently 

 met with connected with the flexor pollicis 

 longus, and some of the other muscles in their 

 passage here. In the superior extremity we find, 

 likewise, several vesicular bursae : around the 

 shoulder-joint there is a very large and regular 

 one placed between the deltoid muscle and the 

 capsular ligament; there is one between the 

 clavicle and coracoid process ; one between 

 the scapula and subscapular muscle ; one be- 

 tween the subscapular muscle and the capsule. 

 Lower down there is a bursa between the 

 humerus and the tendons of the teres major 

 and latissimus dorsi ; and also a bursa fre- 

 quently between these two tendons, at a little 

 distance from their insertion. About the elbow- 

 joint there is a vesicular bursa between the 

 tendon of the triceps and the olecranon; 

 one in front, between the tendon of the biceps 

 and the tubercle of the radius : there is also 

 one between the head of the radius behind, and 

 the extensor muscles passing over it. Around 

 the wrist-joint there are no vesicular bursee of 

 any size or importance. There is in the trunk 

 a large vesicular bursa, usually found between 

 the latissimus dorsi and scapula. In the head 



we often see a distinct bursa interposed between 

 the two divisions of the masseter muscle. 



b. The deep vaginal bursa are invariably 

 found connected with tendons and with the 

 fibrous sheaths through which these tendons 

 are transmitted. They are somewhat more 

 complex than the preceding, for instead of 

 representing a simple shut sac, they form, like 

 serous membranes, by reflexion a double sac, 

 one of whose portions, corresponding, for ex- 

 ample, to the plura costalis, lines the interior 

 of the fibrous sheath, while the other, answering 

 to the plura pulmonalis, invests the surface of 

 the tendon. There is, however, this difference 

 between the pleurae and the synovial sac, that in 

 the latter there is no longitudinal septum, no 

 mediastinum resulting from the reflexion of the 

 membrane ; for the reflexion occurs not along 

 the channel, but at either extremity of the 

 fibrous sheath : thus the bursa, if completely 

 detached from all surrounding structures, would 

 represent a large tube, containing within itself 

 a smaller one ; these two being continuous by 

 their extremities alone. 



The deep vaginal bursae generally occur in 

 the neighbourhood of ginglymoid articulations, 

 and by far the largest and most interesting are 

 those connected with the flexor tendons of the 

 wrist and ankle. They are always of very great 

 size, not only passing a considerable way up- 

 wards upon the forearm and leg, but likewise 

 extending downwards into the palm of the hand 

 and sole of the foot, and branching out at their 

 distant extremity into several distinct sheaths 

 for the respective tendons belonging to the 

 different toes and fingers. Upon the phalanges 

 the synovial sheath is firmly bound down by 

 a dense unyielding fibrous membrane, a cir- 

 cumstance well worthy of remark; for, as we 

 shall presently see, it modifies in a very im- 

 portant degree the characters of inflammation 

 occurring here. Besides these, we have a re- 

 markable vaginal bursa connected with the long 

 head of the biceps muscle; and smaller ones 

 are found investing the tendons of the circum- 

 flexus palati, obturator internus, &c. 



Having thus considered the forms and rela- 

 tions of the different sorts of bursse, we may 

 next proceed to offer a few remarks applicable 

 alike to all, upon their structure, contents, uses, 

 development, and diseases. Here, however, our 

 labour is much abridged by the fact already 

 alluded to, and now admitted upon all hands, 

 that the membrane forming the bursae, and the 

 synovial membrane of joints, are anatomically 

 and physiologically the same. They are, in 

 fact, the same in form, being both shut sacs ; 

 the same in structure, being both essentially 

 composed of cellular membrane; the same in 

 function, for they are both designed to facilitate 

 the motion of contiguous organs ; and, as we 

 shall presently see, they are both similarly af- 

 fected by disease. Were we to enter at length 

 into these particulars upon the present occasion, 

 we should but anticipate details belonging pro- 

 perly to a more general head, that, namely, of 

 synovial membrane. Hence the few remarks we 

 are now about to offer must be received as merely 

 supplementary to those found under that article. 



