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66 SECTION I III The Birds

be in place beforehand to reduce examination time and
the length of the anesthesia.

III THE SKELETALLY IMMATURE WING

Grossly, the wings of nestlings appear almost vestigial
compared with those of adolescent and adult birds
(Figure 6-1). Their short, thick, fringelike feathers belie
even the remotest possibility of future fl ight (Figure
6-2).
The skeletally immature wing is characterized by
the abbreviated appearance of its long bones, a conse-
quence of its as yet unossified cartilaginous epiphyses,

which are nearly transparent to radiation. Accordingly,
there are no visible joints per se, merely widely sepa-
rated, blunted bone ends (Figures 6-3 and 6-4). Failing
to recognize this normal radiographic appearance in a
nestling can lead to an incorrect diagnosis such as dis-
location, infection, or even metabolic or nutritional
bone disease.

Shoulder

The immature shoulder or humeral joint is comprised
of four bones: the humerus, coracoid, scapula, and
clavicle. The clavicle does not actually form a part of
the joint but rather acts as a contiguous medial stabi-
lizer. In the spread-wing, VD position, the unossifi ed
proximal humerus appears to stand off from the rest Figure 6-2 • Ventrodorsal view (soft tissue technique) of the
of the shoulder bones, which overlap one another uninjured left wing of the nestling owl in Figure 6-1 shows the
short, stubby feathers that characterize this stage of development.
medially (Figure 6-5).

Humerus
The immature humerus has a gently recurved body,

blunted ends, and ill-defined or invisible epiphyses.

Figure 6-1 • The anesthetist extends the

small, flipperlike wing of a nestling owl,
which fell from its nest while being banded,
breaking its right ulna.

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