Page 264 - Canine Lameness

236 15 Shoulder Region

(A) (C) (E)

SHOULDER REGION

(B) (D) (F)

Figure 15.9 Shoulder luxation: (A, B) patient with traumatic medial shoulder luxation; (C, D) patient with
Salter-Harris Type I fracture of the proximal humerus; and (E,F) patient with glenoid dysplasia. (A) The
humeral head (black arrow) is obviously displaced medially to the glenoid cavity (white arrow) of the
scapula on the craniocaudal radiographs, which is (B) less obvious on the lateral view. However, the caudal
aspect of the glenoid has significant overlap with the caudal humeral head, indicating displacement. (C) A
physeal fracture of the proximal humerus may be mistaken for traumatic luxation. The fracture line (white
arrow) and the remaining proximal humerus (black arrow) may mimic the appearance of a luxation.
However, the humeral head within the glenoid cavity can be visualized radiographically (compare (C) to (A));
(D) the lateral view clearly depicts the humeral head within the glenoid cavity, while the diaphysis of the
humerus is displaced caudally. (E) Medial luxation secondary to glenoid dysplasia; the glenoid cavity (white
arrow) is lacking a distinct concave surface (glenoid fossa) and the humeral head (black arrow) is
abnormally shaped (compare (E) to (A)). (F) The lateral view shows significant overlap of the humeral head
over the glenoid and abnormal osseous anatomy.