The subclavian arteries arise from the brachiocephalic trunk on the right and the aortic arch on the left. They arch laterally over the pleura and divide into branches before becoming the axillary arteries. The branches of the subclavian arteries include the vertebral, internal thoracic, and thyrocervical trunk arteries. The thyrocervical trunk further divides into the inferior thyroid, suprascapular, and superficial cervical arteries.

1. Subclavian arteries
Dr. Mohammad Mahoud Mosaed

2. SUBCLAVIAN ARTERY
• Origin:
• The right artery arises from the brachiocephalic trunk.
• The left artery arises from the aortic arch.
• The subclavian artery arches upward and laterally over the pleura
and between the scalenus anterior and medius muscles
• Termination: at the outer border of the first rib, where the artery
becomes the axillary artery.
• Course: the course of the artery is divided into;
• First part from its origin to the medial border of scalenus anterior
• Second part behind this muscle
• Third part from the lateral margin of scalenus anterior to the outer
border of the first rib, where the artery becomes the axillary artery.

5. BRANCHES OF THE SUBCLAVIAN ARTERY
• 1. Branches Of The First Part
VERTEBRAL ARTERY.
INTERNAL THORACIC ARTERY.
THYROCERVICAL TRUNK.
• 2. BRANCHES OF THE SECOND PART
COSTOCERVICAL TRUNK
• 3. BRANCHES OF THE THIRD PART
Dorsal scapular artery

8. VERTEBRAL ARTERY
• It ascends in the neck through the foramina in the
transverse processes of the upper six cervical
vertebrae. It passes medially above the posterior
arch of the atlas and then ascends through the
foramen magnum into the skull, at the level of the
lower border of the pons it joins the vessel of the
opposite side to form the basilar artery.
• The basilar artery ascends in a groove on the
anterior surface of the pons. It gives off branches to
the pons, the cerebellum, and the internal ear. It
finally divides into the two posterior cerebral
arteries.

9. Branches
• Extracranial branches
• 1. The spinal branches enter the vertebral canal via
the intervertebral foramina, and supply the spinal
cord and its membranes.
• 2. Muscular branches
They supply the deep muscles of the suboccipital
region
• Intracranial branches:
• Meningeal branches
• Anterior and posterior spinal arteries
• Posterior inferior cerebellar artery
• Medullary arteries

12. INTERNAL THORACIC ARTERY
• The internal thoracic artery descends into
the thorax behind the first costal cartilage
and in front of the pleura. It descends
vertically one fingerbreadth lateral to the
sternum; in the sixth intercostal space, it
divides into the superior epigastric and
the musculophrenic arteries.

13. THYROCERVICAL TRUNK
• The thyrocervical trunk is a short wide
artery which arises near the medial
border of scalenus anterior.
• It divides into;
Inferior thyroid artery
Suprascapular artery
Superficial cervical artery.

14. Inferior thyroid artery
• It ascends to the posterior
surface of the thyroid
gland, where it is closely
related to the recurrent
laryngeal nerve. It supplies
the thyroid and the
inferior parathyroid glands

15. Suprascapular artery
• It runs laterally over the scalenus anterior and the
brachial plexus and follows the suprascapular
nerve onto the back of the scapula.
Superficial cervical artery
• It crosses anterior to the brachial plexus.
• It crosses the floor of the posterior triangle
• It supplies the trapizius with the adjoining muscles
and the cervical lymph nodes.

17. BRANCHES OF THE SECOND PART
• COSTOCERVICAL TRUNK arches back above
the cervical pleura to the neck of the first rib,
where it divides into;
• 1. Superior intercostal artery which give the
first and the second posterior intercostal
arteries in the first and the second intercostal
spaces
• 2. Deep cervical artery which supplies the
deep muscles of the neck.

19. BRANCHES OF THE THIRD PART
• The third part of the subclavian artery usually
has no branches. Occasionally gives Dorsal
scapular artery which gives off a small branch to
scalenus anterior.
• It passes laterally through the brachial plexus in
front of scalenus medius and then deep to levator
scapulae to the superior scapular angle .

20. • In one third of the subjects the superficial
cervical artery is replaced by the
transverse cervical artery that arises
from the thyrocervical trunk, and divided
into superficial branch (which replace the
superficial cervical artery) and a deep
branch (which replace the dorsal scapular
artery).