198 SKELETON OF THE DOG 
unites with the rest of the bone at six to eight months. The shoulder has a great 
range of movement on the chest wall. 
The humerus is relatively very long, rather slender, and has a slight spiral 
twist. The shaft is somewhat compressed laterally, especially in its proximal two- 
thirds; this part is curved in varying degree, convex in front. The deltoid tuber- 
osity has the form of a low ridge, and it is continued by a crest which runs up- 
ward and backward and bears a tubercle on its proximal part. Another line runs 
from it down the anterior aspect and forms.the medial boundary of the very shallow 
musculo-spiral groove. The nutrient foramen is about in the middle of the posterior 
surface. A slight elevation on the proximal third of the medial surface represents 
the teres tubercle. The head is long and strongly curved from before backward. 
The neck is better marked than in the horse. The undivided lateral tuberosity is 
placed well forward and extends little above the level of the head. The medial tu- 
Cartilage 
Cartilage 
Serratus 
Pos- 
ae Pose 
angle - 
g terior 
angle 
Infra- 
spinous 
fossa 
Supra- ~ Spine 
spinous ~ : 
fossa Posterior 
border 
Neck - 4 
Neck 3 
Tuber bay Tuber ( ee 
| : : C 
scapule | Glenoid cavity scapule : | 
Acromion Glenoid cavity 
Fig. 216.—Lerr Scaputa oF Dog; Larerau View. Fig. 217.—Rieut Scaputa or Doc; Meprau View. 
berosity is small. The intertuberal or bicipital groove is undivided and is displaced 
to the medial side by the extension forward of the lateral tuberosity. The distal 
end bears an oblique trochlear articular surface for articulation with the radius and 
ulna, the lateral part of which is the more extensive and is faintly grooved. The epi- 
condyles are prominent. The coronoid and olecranon fossee often communicate 
through a large supratrochlear foramen. The proximal end unites with the shaft 
at about one year, the distal at six to eight months. 
The two bones of the forearm are relatively long and articulate with each other 
at each end in such a manner as to allow of slight movement. A narrow inter- 
osseous space separates their shafts. The radius is flattened from before back- 
ward and increases in size distally. The shaft forms two curves, so that it is con- 
vex dorsally and medially. The dorsal surface is convex in both directions and is 
marked in its distal half by a groove for the oblique extensor of the carpus. The 
volar surface presents the nutrient foramen in its proximal third, and bears a rough 
