1066 DISSECTION OF THE THORAX. 



of the last-mentioned muscle, the posterior interosseous nerve ; and on, 

 the interosseous membrane the posterior interosseous artery, with its re- 

 current branch ; they are both to be traced to their distribution (pp. 654 

 and 391). The lower part of the radial artery which has hitherto been hid 

 from view may also now be studied : its posterior carpal and its meta- 

 carpal branch will be seen, together with the dorsal branches of the 

 thumb and index finger (p. 398). The termination on the back of the 

 wrist of the anterior interosseous artery after passing through the inter- 

 osseous membrane is also to be noticed. Finally, the interossei muscles 

 are to be dissected on both the palmar and dorsal aspects of the hand 

 (p. 227). 



10. Articulations of the Fore-arm and Hand. The dissector may now 

 return to an examination of the elbow-joint and other articulations of the 

 upper limb. In connection with the elbow-joint, he will first make a revi- 

 sion of the relations of the soft parts to the joint, such as those of the 

 triceps, brachialis aiiticus, and supinator brevis muscles, the muscles attached 

 to the outer and inner condyles of the humerus, and the median, muRculo- 

 spiral, and ulnar nerves, together with the anastomoses of the superior and 

 inferior profunda and the anastomotic branches of the brachial, with the two 

 ulnar, the radial, and the interosseous recurrent arteries. The dissector will 

 then proceed to examine in detail the internal and external lateral ligaments, 

 the anterior and the thin posterior ligaments, the orbicular ligament, the syno- 

 vial membrane, and the cartilaginous surfaces of the bones (p. 138). The 

 dissector should carefully observe the different kinds of motion of which the 

 parts are capable, and the variations in the tightness of the ligaments and 

 in the relations of external parts induced by these motions. In examin- 

 ing the lower radio-ulnar articulation, the dissector will particularly study 

 the relations of the triangular fibro-cartilage, and the nature of the move- 

 ments in prouation and supination of the hand ; and, in the carpal joints, 

 the extent of the synovial cavities and the position of the cartilage and in- 

 terosseous ligaments. 



III. THORAX. 



The right and left sides of this region constitute each a part. Its dissec- 

 tion may be completed within three weeks. It includes the deep dis- 

 section of the thoracic parietes, the viscera of the thoracic cavity, 

 together with the upper surface of the diaphragm. It is indispensable 

 that the dissectors of opposite sides should be present together and act in 

 concert. 



1. Parietes and Pleura. The dissection is to be commenced on the fifth 

 day after the subject has been placed upon its back, that is, the tenth 

 day after it has been first placed in the rooms. The external and internal 

 intercostal muscles, and the intercostal arteries and nerves in the anterior 

 part of their course, together with the parietal pleura, are to be first dissected 

 (pp. 240, 402 and 655). Then let the internal mammary artery on the 

 right side be laid bare by the removal of the 2nd, 3rd, 4th, 5th and 6th 

 costal cartilages, in order that its relation to the sternum, and its anterior 

 intercostal and perforating branches may be observed (p. 374). The corre- 

 sponding costal cartilages on the left side may then be divided close to the 

 ribs, and the ribs belonging to those cartilages on both sides are then to be 

 divided as smoothly as possible about three inches beyond their angles ; in 

 doing which the dissectors must be careful to avoid injuring their hands 

 upon the sharp spicula of the sawn extremities of the ribs. The anterior 



