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72 SECTION I III The Birds

Figure 6-11 • Close-up, lateral view (wings-up) of a hawk
with a shattered shoulder joint including a severely displaced
proximal humeral fracture that wasn’t visible in the
ventrodorsal view because of superimposition.

hanging drop view, where the scapula, coracoid, and ble oblique views. As the bird is being positioned for the
humerus can all be seen clearly with only minimal VD view, one or both wings may be rolled unintention-
overlapping (Figure 6-12). ally, causing the distal humeral metaphysis and associ-
ated condyle to appear abnormally wide when compared
to a true lateral projection.
Humerus
Perhaps the best indication of elbow obliquity is the
The adult humerus, while clearly the stoutest and defining of the lateral and medial halves of the distal

strongest of the avian wing bones, is not the longest; humeral condyle, which are not normally appreciable
the adjacent radius and ulna are the longest avian in a true lateral projection because of superimposition.
wing bones (Figure 6-13). The proximal humerus is a When oriented obliquely, the lateral half of the humeral

distinctive bone that resembles the profile of an opening condyle can appear even larger than it actually is when
lily, which is the result in great part of the graceful arch compared with its medially situated counterpart. But
of the humeral crest. The humeral shaft curves gently projectional illusion aside, the deliberate oblique posi-
downward and then abruptly broadens into a wide tion of the elbow typically provides the clearest view
condyle featuring a disproportionately large lateral of the humeroulnar and humeroradial joints, a distinct
element that articulates with the ulna and a compara- diagnostic advantage when articular injury is sus-
tively small medial element that articulates with the pected (Figure 6-14).
radius.
Radius and Ulna
Elbow
There are two common projectional variants of the
Just as with mammals, the avian elbow is capable of radius and ulna as seen in VD projections, both of
providing a variety of different looks when viewed which are related to obliquity at the shoulder. In one
ventrodorsally. These projectional differences are caused variation, both the radial and ulnar bodies appear
by rotation of the shoulder, which in turn leads to rota- bowed, while their distal counterparts appear rela-
tion of the elbow, thus accounting for a variety of possi- tively straight (Figure 6-15). In the second, featuring

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