IV.] 



SKELETON OF UPPER LIMB. 



ossification The coracoid ossification contributes to form 

 the glenoid cavity. 



3- The CLAVICLE is a long cylindrical bone with a slightly 

 sigmoid curvature, placed transversely on each side of the 

 neck and connecting the acromion with the manubrium of 

 the sternum. Its outer end, in childhood, bears a cartilage 

 termed the meso-scapular cartilage (which ultimately ossifies), 

 and is connected with the acromion by a synovial joint. The 

 inner end has a distinct centre of ossification (as an epiphysis) 

 and unites with the sternum by 

 a joint in which is interposed a 

 fibro-cartilage (the omosternum} 

 having a synovial membrane on 

 each side of it. The clavicle is 

 connected with the coracoid by 

 ligament only. . " 



4. The HUMERUS (os humeri} 

 is the largest and longest bone 

 of the upper limb, and extends 

 from the shoulder to the elbow- 

 joint. It is imperfectly cylindri- 

 cal, with an expansion at each 

 end. We may consider it in the 

 position in which it is placed 

 when the arm is dependent and 

 the palm turned forwards. 



The cylindrical part (or shaft) 

 has its anterior surface marked 

 above by a longitudinal depres- 

 sion, termed the bicipital groove, 

 because it lodges the tendon of 

 a muscle called the Biceps. 

 Below and external to this is a 

 roughened elevated tract for the 

 insertion of the deltoid muscle. 



The lower part of the shaft 

 has its anterior surface sepa- 

 rated from the posterior surface 

 by two lines (or ridges), one on 

 each side, which become well marked as they approach Q 

 lower end of the bone. The outer of these two ridges is 

 termed the supinator, or external condyloid, ridge (for reasons 

 which will appear), while the inner one is named the i 

 condyloid, or pronator ridge. 



L 2 



FIG. 124. FRONT VIEW of THE 

 RIGHT HUMERUS OF MAN. 



b, bicipital groove ; cf, coronoid 

 fossa ; ec, external condyle ; gt, 

 great, or radial tuberosity ; //, 

 head of the humerus : ic, internal 

 condyle ; lh, capitellum ; //, 

 lesser or ulnar tuberosity; /, 

 trochlea. 



