IXJ 



]' i.i I lie lower figures are the first two ribs seen from above. The upper figure is from a dissection to show the course <,t 

 tin contents of the axillary sheath. Observe that these go backwards as well as outwards from the first rib. so that they 

 come to lie on the Serratus magnus at once, even though this muscle arises comparatively far back on the two upper ribs. 

 This leaves the front portions of the ribs uncovered by either the muscle or the vessels, and here the pectoral stru 

 must eiime into relation with the ribs : the first rib is here in relation with the costo-coracoid membrane and the second rib 

 with IN x toralis minor. Areas for both these structures may be seen on the -ecoml rib. a* is shown in the lowest figure, and the 

 anterior angle marks the continuity of the two areas. The lower figures require little comment, but it may IK- pointed out 

 that tlu- Subclavian and rhomboid attachments on the tirst rib appear there largely because there is some calcification of the 

 ilage, that the sharp groove for the 1st dorsal nerve is not always evident, and the posterior part of Scalcnus mcdius 

 insertion, marked oft by a dotted line and labelled LC, probably represents the Levator costa? found as a separate muscle 

 lower down. 



