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The subclavian artery (Figs 60.1 and 63.1)
nal jugular vein.
Arises from the brachiocephalic artery on the right and the arch of the
• The inferior sagittal sinus: begins near the origin of the superior
aorta on the left. It arches across the upper surface of the 1st rib to
sagittal sinus and runs in the free border of the falx cerebri. It is joined
become the axillary artery. It is in close contact with the apex of the which passes through the right jugular foramen to form the right inter-
lung and lies behind scalenus anterior at the root of the neck. by the great cerebral vein to form the straight sinus which lies in the
Branches: attachment of the falx to the tentorium cerebelli. The straight sinus
• The internal thoracic artery: see p. 13. turns to the left to form the left transverse sinus and then the sigmoid
• The vertebral artery: runs upwards to enter the foramen transver- sinus. The latter leaves the skull through the left jugular foramen.
sarium of the 6th cervical vertebra. It passes through corresponding • The cavernous sinus: this lies at the side of the pituitary fossa and
foramina in the other cervical vertebra to reach the upper surface of the contains the internal carotid artery. It receives the superior and inferior
atlas. Here it turns medially in a groove and then enters the cranial cav- ophthalmic veins and is connected to some smaller sinusesathe super-
ity through the foramen magnum. Here it joins its fellow of the opposite ior and inferior petrosal sinuses and the sphenoidal sinus. The two
side to form the basilar artery. It gives off the anterior and posterior cavernous sinuses are joined in front and behind the pituitary by the
spinal arteries which descend to supply the spinal cord, and the poster- intercavernous sinuses.
ior inferior cerebellar artery which supplies not only the cerebellum • The emissary veins: see p. 123.
but also the medulla. The basilar artery passes forwards on the under- • The internal jugular vein: passes down the neck from the jugular
surface of the medulla and pons and gives the anterior inferior cerebel- foramen, in the carotid sheath along with the internal and common
lar artery, branches to the brainstem and to the inner ear (the internal carotid arteries and the vagus nerve. It ends by joining the subclavian
auditory artery) and ends by dividing into the superior cerebellar and vein to form the brachiocephalic vein. It receives veins corresponding
posterior cerebral arteries. The latter is joined by the posterior com- to the branches of the external carotid artery ( facial, lingual, pharyn-
municating artery (p. 133). geal, and the superior and middle thyroid veins). The inferior thyroid
• The costocervical trunk: a small artery that passes backwards to veins pass downwards in front of the trachea to open into the left bra-
supply muscles of the back. It also supplies the superior thoracic artery chiocephalic vein.
(see Chapter 3). The facial vein communicates around the orbit with tributaries of the
• The thyrocervical trunk: gives off the superficial cervical and ophthalmic veins so that infections of the face may spread to the cav-
suprascapular arteries and then passes medially as the inferior thyroid ernous sinus if not properly treated.
artery across the vertebral artery to reach the middle of the posterior • The external jugular vein: begins in the parotid gland by the joining
border of the thyroid. It has a variable relation to the recurrent laryngeal of the retromandibular vein with other small veins. It passes obliquely
nerve, lying in front or behind them, but may branch early with the across sternomastoid to open into the subclavian vein. It receives the
nerve passing between the branches. transverse cervical, suprascapular and anterior jugular veins near its
• The dorsal scapular artery: usually given off from the third part lower end.
(Fig. 63.1). It descends along the medial border of the scapula but may • The anterior jugular vein: begins below the chin and runs down the
arise in common with the superficial cervical artery. neck near the midline. It then passes deep to sternomastoid to join the
external jugular vein.
The veins • The subclavian vein: lies in a groove on the 1st rib but is separated
The veins of the brain drain into dural venous sinuses (Fig. 60.2). The from the subclavian artery by the scalenus anterior. It receives the
most important of these are: external jugular vein, veins corresponding to the branches of the sub-
• The superior sagittal sinus: passes backwards in the midline in the clavian artery and, at its junction with the internal jugular vein, the thor-
attached border of the falx cerebri from just above the cribriform plate acic duct on the left and the right lymph duct on the right.
to the occipital region, where it communicates with the straight sinus, • The vertebral vein: this is formed at the level of the 6th foramen
and then turns to the right to form the right transverse sinus. It then transversarium from the vertebral plexus of veins that accompany the
winds down on the back of the petrous temporal as the sigmoid sinus vertebral artery.

The arteries II and the veins 135