ss removed from the side of the
thorax. While the arm hangs close to the side, the axillary space does
not (properly speaking) exist; and in this position, the axillary
vessels and nerves make a general curve from the clavicle at the point
K, Plate 14, to the inner side of the arm, the concavity of the curve
being turned towards the thoracic side. But when the arm is abducted
from the side, and elevated, the vessels which are destined to supply
the limb follow it, and in this position they take, in reality, a
serpentine course; the first curve of which is described, in reference
to the thorax, from the point K to the head of the humerus; and the next
is that bend which the head of the humerus, projecting into the axilla
in the elevated position of the member, forces them to make around
itself in their passage to the inner side of the arm. The vessels may be
readily compressed against the upper third of the humerus by the finger,
passed into the axilla, and still more effectually if the arm be raised,
as this motion will rotate the tuberous head of the humerus downwards
against them.

The vessels and nerves of the axilla are bound together by a fibrous
sheath derived from the membrane called costo-coracoid; and the base or
humeral outlet of this axillary space, described by the muscles C, K, E,
G, Plate 13, is closed by a part of the fascial membrane, g, extended
across from the pectoral muscle, E, to the latissimus dorsi tendon, K.
In the natural position of the vessels at that region of their course
represented in the Plates, the vein A overlies the artery B, and also
conceals most of the principal nerves. In order to show some of these
nerves, in contact with the artery itself, the axillary vein is drawn a
little apart from them.

The axillary space gives lodgment to numerous lymphatic glands, which
are either directly suspended from the main artery, or from its
principal branches, by smaller branches, destined to supply them. These
glands are more numerous in the female axilla, Plate 14, than in the
male, Plate 13, and while they seem to be, as it were, indiscriminately
scattered here and there through this region, we observe the greater
number of them to be gathered together along the axillary side of the
great pectoral muscle; at which situation, h, in the diseased condition
of the female breast, they will be felt to form hard, nodulated masses,
which frequently extend as far up through the axillary space as the r