90 



THE BONES. 



elevated, is followed by an acromion whose extremity reaches to above the scapulo- 

 humeral articulation. The latter is separated from the remainder of the spine by a 

 constriction called the pedicle of the acromion. The coracoid process is voluminous, and 

 resembles a semi-flexed finger. The clavicle extends from the acromion to the sternum ; 

 it is flattened above and below, and flexed like an italic S. This inflexion of the 

 clavicle is more pronounced in the male than the female. 



B. AKM. The humerus of Man is much longer than that of animals. Its dinphysis 

 is prismatic and divisible into three faces; the deltoid imprint lias the form of a V with 

 its point directed downwards. The voluminous articular head is turned inwards ; the 



Fig. 55. 



Fig. 56. 



EIGHT HUMAN HUMERUS; ANTERIOR 

 SURFACE. 



1, Shaft ; 2, Head ; 3, Neck ; 4, Greater 

 tuberosity ; 5, Lesser tubemsity ; 6, Bici- 

 pital groove ; 7, Interior bicipital groove ; 

 8, Posterior bicipital ridge ; 9. Rough sur- 

 face for insertion of deltoid ; 10, Nutrient 

 foramen; 11, Eminentia capitata; 12, 

 Trochlea; 13, External condyle ; 14, In- 

 ternal condyle ; 15, External condyloid 

 ridge; 16, Internal condyloid ridge; 17, 

 Fossa for the coronoid process of ulna. 



HUMAN ARM-BONES ; FRONT VIEW. 



1, Shaft of ulna ; 2, Greater sigmoid 

 notch; 3, Lesser sigmoid notch; 4 Ole- 

 cranon process ; 5, Coronoid process ; 6, 

 Nutrient foramen; 7, Ridges for inser- 

 tion of interosseous membrane; 8, Capi- 

 talum ulnae; 9, Styloid process; 10, 

 Shaft, of radius; 11, Its head; 12, Its 

 neck; 13, Its tuberosity; 14, Oblique 

 line; 15, Lower end of bone; 16, Styloid 

 process. 



bicipital groove is single, and looks outwards. The inferior articular surface resembles 

 that of animals, except that the condyle is more distinct. 



C. FORE-ARM. The two bones of the fore-arm, as we have already seen, only articu- 

 late by their extremities : they are separated from one another in their middle part. 

 The superior extremity of the radius corresponds to the condyle of the humerus ; that of 

 the ulna articulates with the humeral trochlea. The coronoid process belongs to the 

 ulna. At the lower extremity of the fore-arm it is remarked : 1, That the radius cor- 

 responds to the greater portion of the carpus, while the ulna only articulates with the 

 pyramidalis ; 2, That the radio-carpal articulation is protected outwardly and inwardly 

 by two small osseous prolongations, the styloid processes of the ulna and radius. 



D. HAND. 1. Carpus. The carpus of Man is composed of eight bones four in each 



