The subclavian arteries Fig 213

The left subclavian artery arises from the arch of the aorta, immediately behind the commencement of the left common carotid artery. It ascends against the mediastinal surface of the left lung and pleura laterally and the trachea and oesophagus medially to lie behind the sternoclavicular joint.

The right subclavian artery is formed behind the right sternoclavicular joint by the bifurcation of the brachiocephalic artery; beyond this point, the course of the two arteries is much the same.

The cervical course of the subclavian arteries is conveniently divided by the scalenus anterior muscle into three parts.

Recurrent laryngeal nerve

Vertebral artery Dome of pleura

Brachial plexus X

Common carotid artery

Trachea on oesophagus

Recurrent laryngeal nerve

Vertebral artery Dome of pleura

Brachial plexus X

Common carotid artery

Trachea on oesophagus

Thoracic Duct

Phrenic nerve Thoracic duct

Subclavian artery Subclavian vein

Sternohyoid on sternothyroid

Fig. 213 The root of the neck. For clarity, only the vagus nerve is shown on the right and only the phrenic nerve on the left, as this lies on scalenus anterior.

Phrenic nerve Thoracic duct

Subclavian artery Subclavian vein

Sternohyoid on sternothyroid

Fig. 213 The root of the neck. For clarity, only the vagus nerve is shown on the right and only the phrenic nerve on the left, as this lies on scalenus anterior.

The first part arches over the dome of the pleura and lies deeply placed beneath the sternocleidomastoid and the strap muscles. It is crossed at its origin by the carotid sheath and, more laterally, by the phrenic and vagus nerves. At this site, on the right side, the vagus gives off its recurrent laryn-geal branch which hooks behind the artery.

On the left side, the thoracic duct crosses the first part of the artery to open into the commencement of the left branchiocephalic vein.

The second part of the artery lies behind scalenus anterior which separates it from the subclavian vein. Behind lie scalenus medius and also the middle and upper trunks of the brachial plexus.

The third part extends to the lateral border of the first rib against which it can be compressed and its pulse easily felt, since here it is just below the deep fascia. Immediately behind the artery is the lower trunk of the brachial plexus which is, in fact, responsible for the 'subclavian groove' on the first rib. Its branches are:

1 The vertebral artery

2 The thyrocervical trunk:

(a) inferior thyroid artery

(b) transverse cervical artery

(c) suprascapular artery

3 The internal thoracic artery

• 2nd part — the costocervical trunk (supplying deep structures of the neck via its deep cervical branch, and the superior intercostal artery, which gives off the 1st and 2nd posterior intercostal arteries).

• 3rd part—gives no constant branch.

The vertebral artery

This is the most important of the branches of the subclavian artery. It crosses the dome of the pleura, traverses the transverse foramina of the upper six cervical vertebrae, then turns posteriorly and medially over the posterior arch of the atlas to enter the cranial cavity at the foramen magnum by piercing the dura mater. It then runs on the anterolateral aspect of the medulla to join its fellow in front of the pons to form the basilar artery

The following are the important branches of the vertebral artery:

1 anterior and posterior spinal arteries;

2 posterior inferior cerebellar artery. From the basilar:

3 anterior inferior cerebellar artery;

4 superior cerebellar artery;

5 posterior cerebral artery (supplying the occipital lobe and medial aspect of the temporal lobe; Fig. 211).

In addition, in the neck, the vertebral artery gives off spinal branches to the cervical spinal cord and vertebrae and muscular branches. Within the foramina transveraria it is accomparied by vertebral veins and a sympathetic plexus which, together with the carotid plexus, provides sympathetic fibres to the cranial contents.

Was this article helpful?

0 0
Back Pain Relief

Back Pain Relief

This informational eBook will present you with the most recent research and findings available so that you can learn more about Back Pain relief, covering as many bases as possible from A to Z.

Get My Free Ebook


Post a comment