K.K) 



THE SKELETON 



TIk' si'venth rib and its costal cartilage give attachment to the following 

 muscles : — 



Internal intereostals (sixth and seventh). 

 External intercostals (sixth and seventh). 

 Levatores costarum (seventh). 

 Infracostal (when present). 

 Diaphragm. 

 Transversalis. 



External oblique abdominis. 

 Rectus abdominis (costal cartilage). 

 Triangularis sterni (costal cartilage). 

 8erratus magnus. 

 Ilio-costalis, or sacro-lumbalis. 

 Musculus accessorius. 



Longissimus dorsi. 

 It gives attachment to the folloAving ligaments : — 



Anterior costo-vertebral or costo- 



central (stellate). 

 Middle costo-transverse (interosseous) 

 The capsular. 



Fig. 109.— First and Second Ribs 



Superior costo-transverse. 



Posterior costo-transverse (rhomboid). 



The interarticular. 



Levator eostje and 

 accessorius 



Scalenus medius 



GROOVE fOR SUBCLAVIAN 

 ARTERY 



Scalenus antieu; 



GROOVE FOR SUBCLAVIAN 

 VEIN 



Levator eostae 

 Accessorius 



(insertion) 

 Cervicalis ascendens 



(origin) 

 Serratus posticus 



superior 



'insertion) 



Scalenus posticus 



Third digitation of 

 serratus magnus 



External 

 intercostals 



Blood-supply. — Tlie ril)s are very vascular and derive numerous branches from 

 the intercostal arteries. The branches in the shaft run towards the rib-head. Those 

 of the head and neck take a contrary direction, and run, as a rule, towards the 

 shaft. In tlie neighljourhood of the tuberosity the vessels seem to run in any 

 direction. 



Peculiar ribs. — Several of the ribs differ in many particulars from tliis general 

 description. Tlicy are the first, second, tenth, eleventh, and twelfth. 



The first rib is the broadest and most sharplv curved. The head is small, and, 

 as a rule, is furnished with only one articular "facet. The tubercle is large and 

 l.roininent, the neck narrow. The shaft is broad, has no angle, and is curved 

 around a vertical axis only. The upper surface presents two shallow grooves 

 separated near the inner border by a rough surface (Lisfranc's or Scalene tubercle) 



