182 OSTEOLOGY. 
erosses the back of the body obliquely in a direction outwards and sheghtly 
upwards, extending from the vertebral border near the lower limit of its upper 
fourth towards the centre of the posterior glenoid edge, from which, however, it 
is separated by the great scapular notch, which here corresponds to the posterior 
aspect of the neck. The surfaces of the spine, which are directed upwards and 
downwards, are concave, the upper entering into the formation of the supraspinous 
fossa, which lies above it, the lower forming the upper wall of the infraspinous fossa, 
which lies below it. The two fosse are in communication with each other round 
the free external concave border of the spine, where that curves over the great 
scapular notch. The posterior free border of the spine is subcutaneous throughout 
its entire length. Its upper and lower edges are strongly lipped, and serve—the 
superior, for the attachment of the trapezius; the inferior, for the origin of the 
deltoid. The inter- 
vening surface varies 
in width—broad and 
triangular where it be- 
comes confluent with 
the vertebral border, 
it displays a smooth 
surface, over which 
the tendinous fibres of 
the trapezius play; 
narrowing rapidly, it 
forms a surface of 
varying width which 
blends externally with 
a flattened process, 
the two forming a 
compressed plate of 
bone which arches 
across the scapular 
notch above and be- 
hind, and then curves 
forwards, upwards, and 
outwards to overhang 
the glenoid fossa. The 
internal border of this 
process is continuous 
with the upper mar- 
gin of the spine, and 
is gently curved. The 
external border, more 
curved than the inner, 
with which it is united 
in front, is confluent 
with the inferior edge 
of the spine, with 
INFERIOR ANGLE which it forms an 
Fic. 126.—TuHe RicHr SCAPULA AS SEEN FROM THE FRONT‘. abrupt bend, termed 
the acromial angle. 
The bone included between these two borders is called the acromion process. Of 
compressed form, it much resembles the acromial end of the clavicle, with which 
it articulates by means of a facet (facies articularis acromil) which is placed on its 
internal border near its anterior extremity. The superior surface of the acromion, 
which is broad and expanded, is subcutaneous, and is directed upwards and back- 
wards, and in the normal position of the bone outwards as well. Its internal 
edge, where not in contact with the clavicle, has attached to it the fibres of the 
trapezius, whilst its external margin affords origin to the central part of the 
deltoid. At its anterior extremity it is connected with the coracoid process by  — 
ACROMION CLAVICULAR FACET 
CoRACOID PROCESS 
Pectoralis 
minor 
SUPERIOR ANGLE 
Deltoid 
Omo-hyoid 
NOTCH 
BN SupRASCAPULAR 
GLENOID of 
FOSSA 
NECK 
Triceps 
Biceps (short head) and coraco-brachialis 
ARTERIAL FORAMEN 
Serratus magnus 
SUBSCAPULAR FOSSA—__ ¥ 
Subscapularis ——~ \ 
VERTEBRAL BORDER 
AXILLARY BORDER _ 
