3. The external jugular (p. 319). Remove the skin from the side of the
face and trace its branches (Fig. 131). The internal jugular, vena
facialis profunda, the submentalis, and the deep terminal branches of
the posterior facial cannot be followed at this time; veins shown on
Fig. 131 should all be found, however.
4. Trace the thyrocervical axis and its branches (p. 293). Add them to
your diagram of the subclavian.
5. Follow the common carotid artery (p. 283) and internal jugular vein
(p. 320). Find the division of the common carotid into its terminal
branches and then dissect its lateral branches and those of the internal
jugular (see Fig. 119).
6. The external carotid (p. 285, and Fig. 119). Follow its branches
with the exception of the internal maxillary.
7. The internal maxillary (p. 287). Find its inferior alveolar branch
first and follow it by cutting away with bone-forceps the ventral border
of the lower jaw. To follow its other branches and those of the carotid
plexus, remove the zygomatic arch, cut the temporal, masseter, and
pterygoid muscles, and cut the mandible behind the incisor teeth and
remove it. The branches which pass into the skull are not to be followed
at present. The posterior facial vein (p. 323), the vena facialis
profunda (p. 323), and the submental vein (p. 323) may be followed at
the same time.
8. The internal carotid (p. 285). Follow it to the point where it
enters the cranium.
9. Trace the other branches of the costocervical axis (p. 292). To do
this, cut the arteries and nerves of the axilla on the side on which
they have been dissected, allowing the arm to fall backward. Then trace
the branches of the costocervical axis with tracer, scalpel, and
bone-forceps, taking care not to injure the vertebral artery. Add these
branches to your diagram of the subclavian.
10. The vertebral artery (p. 291). Trace it to the foramen
transversarium of the sixth cervical vertebra. Then with bone-forceps
follow it to the atlas and into the atlantal foramen. Add this to your
diagram of the subclavian.
11. The basilar artery (p. 291) and the other arteries of the brain (p.
289) are best studied on a preparation, similar to that shown in Fig.
121. To obtain such a preparation it is only necessary to remove the
brain (for directions, see p. 462) of a specimen in which the arteries
have been injected.
(12. Veins of the brain and dura mater (p. 324). These can be worked out
only with much difficulty, except on specimens injected with gelatine.
The skull must be chipped away and the veins followed without destroying
them.)
13. Trace the pulmonary veins (p. 315) (filled with red injection) and
the pulmonary artery (p. 280).