O. Facial artery seen through fibres of platysma.
P. Mastoid half of sterno-mastoid muscle.
Q. Locality beneath which the commencements of the subclavian and carotid arteries lie.
R. Locality of the subclavian artery in the third part of its course.
S. Locality of the common carotid artery at its division into internal and external carotids.
Plate 3
PLATE 4.
A. Subclavian artery passing beneath the clavicle, where it is crossed by some blood-vessels and nerves.
B. Sternal attachment of the sterno-mastoid muscle, marking the situation of the root of common carotid.