TSE ANTEBIOB LIMBS. 



73 



Angles. — The anterior or cervical angle is the thinnest of the three. The 

 posterior or dorsal angle is thick and tuberous, The inferior or humeral 

 angle is the most voluminous, and is separated from the remainder of the 

 bone by a slight constriction, which constitutes the nech of the scapula. It 

 exhibits : 1, The glenoid cavity, an oval diarthrodial surface, excavated to a 

 slight extent to receive the head of the humerus, notched on the inner side, 

 and bearing on the external margin of the ridge which surrounds it a small 

 tubercle of insertion ; 2, The coracoid process, situated in front, and at a 

 certain distance from the glenoid cavity. This is a large eminence 

 in which may be distinguished two parts : the hase, a thick rugged process ; 

 and the summit, a kind of beak curved inwards. 



Structure and development. — ^Like all the wide bones, the scapula is 

 formed of two compact lamellffl separated by spongy tissue. The latter is 

 yery scanty towards the centres of the supra and infraspinous fossas, where it 

 is often altogether wanting ; it is most abundant in p. ^-^ 



the angles. The scapula is developed from two centres 

 of ossification, one of which forms the coracoid pro- 



cess. 



ABM. 



This region has only one bone, the Jiumerus, 



Sumerus. 



The "humerus is a long single bone, situated between 

 the sc^ula and the bone of the fore-arm, in an oblique 

 direction downwards and backwards. Like all the long 

 bones, it offers for study a body and two extremities. 



Body. — The body of the humerus looks as if it 

 had been twisted on itself from within to without in 

 its superior extremity, and from without to within at 

 the opposite end. It is irregularly prismatic, and is 

 divided into four faces. The anterior face, wider, 

 above than below, has in its middle and inferior por- 

 tions some muscular imprints. The posterior, smooth 

 and rounded from one side to the other, becomes 

 insensibly confounded with the neighbouring faces. 

 The external is excavated by a wide furrow, which 

 entirely occupies it, and turns round the bone ob- 

 liquely from above to below and behind to before , 

 it is to the presence of this o'lannel ihat the humerus 

 owes its apparent twist, aSprf^^s 'in consequence 



designated the furrow of tor 

 humerus. 



This furrow is separat 

 by a salient border, the a 

 of torsion, which ends inf 

 fossa, and superiorly, tow- 

 bone, by the imprint. 

 roughened, very pro 

 and behind, anrl ' 

 torsion ; by-it'' 

 a curved ¥zi 

 base r'. 



the body of the 



1 the anterior face 



f^st of the furrow 



the coronoid 



ihird of the 



,This is a 



hflfe(5e 



ANTERO-EXTERNAL VIEW 

 OE EISHT HUMERUS. 



1, Trochlear or bioipita 

 ndges; 2, External 

 deltoid tuberosity ; 

 Head or articular '' 

 face ; 4, Externa'' "^ 

 cle;&^iW 

 its 



Artf.' 

 cori 

 % 



