into internal and external
carotids.

S S. Great pectoral muscles.

T T. Lesser pectoral muscles.

U. Mediastinal pleura of right side.

V. Right auricle of the heart.

[Illustration: Upper body, showing internal organs of neck and chest.]
Plate 1

PLATE 2.

A. Right ventricle of the heart. A a. Pericardium.

B. Pulmonary artery. B b. Pericardium.

C. Ascending aorta. C c. Transverse aorta.

D. Right auricle.

E. Ductus arteriosus in the loop of left vagus nerve, and close to
phrenic nerve of left side.

F. Superior vena cava.

G. Brachio-cephalic vein of left side.

H. Left common carotid artery.

I. Left subclavian vein.

K. Lower end of left internal jugular vein.

L. Right internal jugular vein.

M. Right subclavian vein.

N. Innominate artery--brachio-cephalic.

O. Left subclavian artery crossed by left vagus nerve.

P. Right subclavian artery crossed by right vagus nerve, whose inferior
laryngeal branch loops under the vessel.

Q. Right common carotid artery

R. Trachea.

S. Thyroid body.

T. Brachial plexus of nerves.

U. Upper end of left internal jugular vein.

V V. Clavicles cut across and displaced downwards.

W W. The first ribs.

X X. Fifth ribs cut across.

Y Y. Right and left mammae.

Z. Lower end of sternum.

[Illustration: Upper body, showing internal organs of neck and chest.]
Plate 2

COMMENTARY ON PLATES 3 & 4.

THE SURGICAL FORM OF THE SUPERFICIAL CERVICAL AND FACIAL
REGIONS, AND THE RELATIVE POSITION OF THE PRINCIPAL
BLOOD-VESSELS, NERVES, &c.

When the neck is extended in surgical position, as seen in Plates 3 and
4, its general outline assumes a quadrilateral shape, approaching to a
square. The sides of this square are formed anteriorly by the line
ranging from the mental symphysis to the top of the sternum, and
posteriorly by a line drawn between the occiput and shoulder. The
superior side of this cervical square is drawn by the horizontal ramus
of the lower maxilla, and the inferior side by the horizontal line of
the clavicle. This square space, R 16, 8, 6, Plate 4, is halved by a
diagonal line, drawn by the sterno-cleido-mastoid muscle B, which cuts
the square into two triangles. In the anterior triangle, F 16, 6, Plate
4, is located the superficial common carotid artery, C, and its
branches, D, with accompanying nerves. In the posterior triangle, 9, 8,
6, Plate 4, is placed the superficial subclavian artery, A, its