168 SPECIAL ANATOMY OF THE SKELETON 



in front, so that the two bends of the same rib are almost parallel. Coincident with this, the 

 ribs on the opposite side, on the concavity of the curve, are sunken and depressed behind and 

 bulging and convex in front. In addition to this the ribs become occasionally welded together 

 by bony material. 



The ribs are frequently the seat of caries leading to abscesses and sinuses, which mav burrow 

 to a considerable extent over the wall of the thorax. The only special anatomical point in con- 

 nection with abscesses and sinuses is that care must be taken in dealing with them that the 

 intercostal space is not punctured and the pleural cavity opened or the intercostal vessels 

 w'ounded, as the necrosed portion of bone is generally situated on the internal surface of the rib. 



In cases of empyema the thorax requires opening to evacuate the pus. There is considerable 

 difference of opinion as to the best position to do this. Probably the best place for intercostal 

 drainage is between the fifth and sixth ribs, in or a little in front of the mid-axillary line. This 

 is the last part of the cavity to be closed by the expansion of the lung; it is not thickly covered 

 by soft parts; the space between the two ribs is sufficiently great to allow of the introduction of 

 a fair-sized drainage tube, and when the patient is confined to bed he does not lie upon the 

 drainage tube as he does when the opening is posterior. Better than intercostal drainage in the 

 vast majority of cases is rib resection and drainage. A portion of the fifth or sixth rib should 

 be removed in the mid-axillary line. In chronic empyema the lung becomes shrunken and ad- 

 herent, and simple drainage w T ill not bring about a cure. It is necessary in such cases to do an 

 operation that will permit of collapse of the chest wall. Estlander's operation consists in resect- 

 ing a portion of every rib which overlies the cavity of the empyema. Schede's operation consists 

 in removing ribs from the second rib down over the empyema cavity. The ribs are removed 

 from cartilages to angles, and intercostal muscles and the parietal layer of the pleura are also 

 taken away. Fowler and de Lorme not only practise extensive rib resection and remove the 

 parietal layer of the pleura, but also remove pulmonary pleura (total pleurectomy or pulmonary 

 decortication). 



THE EXTREMITIES. 







The extremities, or limbs, are those long, jointed appendages of the body 

 which are connected to the trunk by one end and free in the rest of their extent. 

 They are four in number: an upper or thoracic pair, connected with the thorax 

 through the intervention of the shoulder and subservient mainly to prehension; 

 and a lower or pelvic pair, connected with the pelvis, intended for support and 

 locomotion. Both pairs of limbs are constructed after one common type, so that 

 they present numerous analogies, while at the same time certain differences are 

 observed between the upper and lower pair, dependent on the peculiar offices 

 they have to perform. 



The bones by which the upper and lower limbs are attached to the trunk are 

 named, respectively, the shoulder and pelvic girdles, and they are constructed on the 

 same general type, though presenting certain modifications relating to the different 

 uses to which the upper and lower limbs are respectively applied. The shoulder 

 girdle is formed by the scapula? and clavicles, and is imperfect in front and behind. 

 In front, however, the girdle is completed by the upper end of the sternum, with 

 which the inner extremities of the clavicle articulate. Behind, the girdle is widely 

 imperfect and the scapula is connected to the trunk by muscles only. The pelvic 

 girdle is formed by the innominate bones, and is completed in front through the 

 symphysis pubis, at which the two innominate bones articulate with each other. 

 It is imperfect behind, but the intervening gap is filled in by the upper part of 

 the sacrum. The pelvic circle, therefore, presents, with the sacrum, a complete 

 ring, massive and comparatively rigid, in marked contrast to the lightness and 

 mobility of the shoulder girdle. 



THE UPPER EXTREMITY. 



T 



he bones of the upper extremity consist of the clavicle and scapula (pectoral 

 girdle), the humerus (arm), the radius and ulna (forearm), the carpal bones 

 (wrist), the metafcacssi bones (palm), and the phalanges (digits). 



