EXTREMITY. 



147 



only tliis portion of the muscle which separates 

 this jKirt of the scapula from the common inte- 

 guments, and to this superficial position is at- 

 tributed the more frequent occurrence of frac- 

 tures from direct violence in this- than in any 

 other portion of the bone. 



The angle between the cervical and axillary 

 borders is truncated, and presents many points 

 of great interest. We here notice an articular 

 concavity, destined to contribute to the for- 

 mation of the shoulder-joint, commonly known 

 under the name of the glenoid cavity, (sinus 

 articular'u.J This cavity, which is a very 

 superficial one, is oval; the long axis of the 

 oval being vertical in its direction, the acute 

 extremity of the oval is situated superiorly, 

 and here the edge of the bone is cut and 

 rounded off towards the posterior part, where 

 is inserted the tendon of the biceps. The 

 cavity is surrounded by a thick lip of bone, 

 to which in the recent state the fibre-cartilage, 

 called glenoid ligament, is applied. At the 

 internal or anterior part of this border, is a 

 notch for the passage of the tendon of the sub- 

 scapularis muscle. The aspect of the glenoid 

 cavity when the scapula is quiescent is outwards 

 and slightly upwards and forwards. This cavity 

 is connected with the rest of the bone by a thick 

 but contracted portion denominated the neck 

 of the scapula. The neck of the scapula is 

 surmounted by a remarkable curved process, 

 called the coracoid process, (xopal-, corvus.) 

 This process, well compared to a semiflexed 

 finger, is directed forwards and outwards, it is 

 connected to the scapula by a thick portion, 

 which seems to arise by two roots, one posterior, 

 thick and rough, lying immediately in front 

 of the notch in the cervical border, the other 

 anterior and thin, and connected with the apex 

 of the glenoid cavity. The concave surface 

 of the coracoid process is directed downwards 

 and outwards, and in the recent state projects 

 over the upper and internal part of the shoul- 

 der-joint : its convex surface is rough, and has 

 inserted into it the ligaments by which the 

 clavicle is tied to it. The coracoid process 

 affords attachment by its internal edge to the 

 pectoralis minor muscle ; to its outer edge is 

 affixed the ligament which, with the acromion 

 process, completes the osseo-ligamentous arch 

 over the shoulder-joint, and by its summit it 

 gives insertion to the short head of the biceps 

 and to the coraco-brachialis. 



It remains only to examine the surfaces of 

 this bone. The anterior surface forms in the 

 greatest part of its extent a shallow fossa, fossa 

 mbieapttlaru, which is limited above and be- 

 hind by the superior and posterior margins of 

 the bone, and in front by a smooth and rounded 

 ridge, which extends from the glenoid cavity 

 to the inferior angle. This fossa is frequently 

 intersected in various directions by bony ridges. 

 Cruveilhier remarks, that in a well-formed per- 

 son, this surface ought to be exactly adapted 

 to the thorax; but when the chest is contracted, 

 as in phthisical patients, the scapula not par- 

 ticipating to a proportionate extent in the con- 

 traction, there follows such a change of re- 

 lation that the scapulae become very prominent 



behind, and are in some degree detached from 

 the ribs like wings, whence the expression 

 scapula alatf, applied to the projection of the 

 shoulders in phthisical patients. The whole 

 fossa has lodged in and inserted into it the 

 subscapularis muscle, whence its name. At 

 the superior posterior angle and the inferior 

 one, are rough surfaces into which are inserted 

 the superior and inferior fibres of the serratus 

 magnus muscle. 



The posterior surface is remarkable for its 

 division into two portions by a large process 

 which projects from it nearly horizontally back- 

 wards and slightly upwards. This process, called 

 the spine of the scapula, is fixed to the bone 

 at the line of union of its superior and mid- 

 dle thirds ; it commences at the triangular 

 surface already noticed at the termination of 

 the superior fourth of the vertebral border of 

 the scapula, thence it proceeds outwards, in- 

 clining a little upwards, and just where the 

 neck of the scapula is united with the rest 

 of the bone, this spine ceases to be connected 

 with the scapula, and is continued outwards in 

 a slightly arched form, as a broad and flattened 

 process, denominated the acromion process, 

 (axgo;, summits, tifxo;, humerus.) The spine 

 presents posteriorly a thick and rough edge, 

 which by its superior border gives attachment 

 to the trapezius muscle, and by its inferior to 

 the deltoid, the intervening space being covered 

 by the aponeurotic expansion which connects 

 the muscles last-named. The superior surface 

 of the spine looks nearly directly upwards ; it 

 is concave, and contributes to form the fossa 

 supra-spinata. The inferior surface, on the 

 other hand, forming part of the fossa supra- 

 spinata, is convex anteriorly and slightly con- 

 cave posteriorly, and looks downwards and 

 backwards ; on each surface we observe a large 

 nutritious foramen. The posterior edge of the 

 spine is quite subcutaneous, and the physician 

 often finds it desirable to practise percussion 

 upon it. 



Above the spine of the scapula is \hejbssa 

 supra-spinata, which lodges the muscle of the 

 same name, formed in front by the scapula, 

 behind by the spine, both surfaces being 

 slightly concave. Below the spine is the fossa 

 supra-spinata much larger than the preceding, 

 slightly convex, except towards its anterior 

 part. This fossa is formed by the scapula 

 below and the inferior surface of the spine 

 above ; it is limited in front by a ridge which 

 proceeds downwards and backwards, from the 

 glenoid cavity to the inferior angle, and bounds 

 behind a surface which gives attachment to 

 the teres major and minor muscles. Into this 

 ridge itself is inserted a fibrous fascia, which 

 separates the attachment of the last-named 

 muscles from the fossa infra-spinata and the 

 insertion of the muscle of the same name. The 

 two fossae, thus separated by the spine, com- 

 municate through a channel formed on the 

 posterior part of the neck of the scapula and 

 bounded behind by the spine ; through this 

 channel pass the arterial and nervous ramifica- 

 tions from the superior to the inferior fossa. 



The acromion process is evidently continu- 



