THE SCAPULA, 83 



The acromion 2^^'ocess, projecting ontwards and forwards from tho 

 extremity of the spine over tlie glenoid cavity, forms the summit of 

 the shoulder. It is an ex]3anded process, compressed from above down- 

 wards. Its superior surface, rough and subcutaneous, is continuous 

 with the prominent border of the spine ; its inferior surface, smooth 

 and concave, is continuous with the superior surface and external 

 border of the spine. On its internal border anteriorly is a narrow 

 oval surface for articulation with the clavicle. 



The ffJenoidcarii If is, a slightly concave surface, looking outwards 

 and forwards. It i i pyriform in shape, with the narrow end upper- 

 most, and gently incurved in front. Its rim is flattened, and in the 

 recent state, it 'is covered by a fibrous band, the glenoid ligament, 

 which deepens its concavity ; at its upper extremity is a slight rough- 

 ness, marking the attachment of the long head of the biceps muscle. 



The ncc/c, supporting the glenoid cavity, is most distinct posteriorly, 

 where it forms with the sjiine the great scapular notch or groove, leading 

 from the supraspinous to the infraspinous fossa. The line of the neck, 

 as described by anatomists, passes superiorly between the glenoid 

 cavity and the coracoid process, but that of the part described as neck 

 by surgeons passes internal to the coracoid process. 



The coracoid process, thick, strong, and hook-like, rises for a short 

 distance almost vertically from the superior border of the bone, above 

 the glenoid cavity, and then bending at a right angle, is directed 

 forwards and outwards. Its superior surface, towards the base, is 

 rough and uneven, giving origin to the coraco-clavicular hgaments ; 

 on its outer border is attached the coraco-acromial ligament, at its 

 extremity the coraco-brachialis muscle^'and short head of the biceps, 

 and on the inner edge the pectoralis minor. 



The borders or costct of tlie scapula are three in number. The 

 superior border is the shortest ; it extends from the superior angle 

 outwards and downwards to the coracoid process, at the base of which 

 it presents a rounded sjiprasa^mlar notch, which is converted into a 

 foramen by a ligament or occasionally by a spiculum of bone, and is 

 traversed by the suprascapular nerve. The external, axillary, or inferior 

 border presents at its upper part, beneath the glenoid cavity, a rough 

 ridge, above an inch long, to which the long^head of the triceps nmsclc 

 is attached : below this there is usuall}' a slight groove, where the 

 dorsal branch of the subscapular artery passes backwards : and at its lower 

 extremity the border is thick, and rounded over into the space from 

 which the teres major muscle arises. The internal or posterior border, 

 called also tlie base, is the longest of the three, and is divisible into 

 three parts, viz., a short one opposite the triangular surface of origin 

 of the prominent border of the spine, and the portions above and below 

 that space, both of which incline outwards as they recede from the 

 spine. The upper part gives attachment to the levator anguli scapula3 

 muscle, the middle to the rhomboideus minor, and the lower to the 

 rhomboideus major muscle. 



^"Texture. — The triangular part of the scapula is in great part thin 

 and translucent, and contains little cancellated tissue. The neck, the 

 coracoid and acromion processes, the prominent border of the spine, 

 and the part near the inferior angle, derive their greater thickness and 

 strength from increased thickness of the compact bony substance in 

 some parts, and from cancellated tissue in others. A vascular foramen 



G 2 



