Corpus: Subclavian artery
1. Definition
2. Origin
The left subclavian artery originates from the aortic arch, the right subclavian artery has its common origin with the common carotid artery in the brachiocephalic trunk.
3. Course
The subclavian artery runs through the scalene gap formed by the anterior and medial scalene muscels and, after crossing the lateral edge of the first rib, is called the axilarry artery.
The subclavian artery can be divided into three sections:
3.1. First section
3.1.1. Right subclavian artery
After the right subclavian artery leaves the brachiocephalic trunk, it runs behind the sternoclavicular articulation to the medial edge of the scalenus anterior muscle. It slightly exceeds the level of the clavicle. The artery is covered anteriorly by the integument, the superficial body fascia, the patysma, the deep cervial fascia and the clavicular origin of the sternocleidomastoid muscle, the sternohyoid muscle and the sternothyroid muscle. It is crossed by the internal jugular vein and the vertebral vein as well as the vagus nerve and its cardiac branches. Behind the right subclavian artery is the pleura, the border cord, the longus colli muscle and the first thoracic vertebral body. The right recurrent laryngeal nerve winds around the lower and posterior part of the vessel.
3.1.2. Left subclavian artery
The left subclavian artery originates from the aortic arch behind the left common carotid artery at the level of the fourth thoracic vertebra. It then ascends to the medial border of the anterior scalene muscle. The artery is connected to the vagus nerve and the phrenic nerve at the front. The internal jugular vein and the vertebral vein run parallel to it. The left subclavian artery is also covered by the sternothyroid, sternohyoid, and sternocleidomastoid muscles. Posterior to the left subclavian artery are the esophagus, the thoracic duct, the left recurrent laryngeal nerve, and the longus colli muscle.
3.2. Second section
The second section of the subclavian artery lies behind the anterior scalene muscle. In this area, the artery is also covered anteriorly by the skin, the superficial fascia, the platysma, the deep cervical fascia and the sternocleidomastoid muscle. On the right side, the phrenic nerve is separated from the artery by the anterior scalene muscle; on the left side, the nerve crosses the artery. Behind the vessel are the pleura and the medial scalene muscle, above the brachial plexus and below the pleura. The subclavian vein lies below and in front of the artery, separated from it by the anterior scalene muscle.
3.3. Third section
The third segment of the subclavian artery runs downwards and laterally from the lateral edge of the anterior scalene muscle to the outer edge of the first rib. In this area, the superficial artery is covered by the skin, the superficial fascia, the platysma, the supraclavicular nerves, and the deep cervical fascia. The external jugular vein crosses the artery. In the last part, the artery lies behind the clavicle and the subclavian muscle. The subclavian vein is located anterior to the artery.
4. Branches
The artery gives off the following branches:
- vertebral artery: The vertebral artery runs cranially through the transverse foramina of the cervical spine to the foramen magnum of the skull. After connecting with the vertebral artery on the opposite side to the basilary artery, the vessel supplies the brain stem, cerebellum, and occipital sections of the terminal brain.
- internal thoracic artery: Runs caudally parallel to the sternum at a distance of approx. 1 cm and supplies the anterior chest wall, the upper parts of the abdominal wall, the mediastinum, the pericardium, and the diaphragm.
- thyreocervical trunk: The inferior thyroid artery, the transverse colliac artery, and the suprascapular artery originate from this vascular trunk. As a variation, the ascending cervical artery, which normally arises from the inferior thyroid artery, also originates here.
- costocervical trunc: The suprascostal artery and the profunda cervical artery originate from the dorsal and caudal vascular trunk.
There are numerous variations of the arterial branches of the subclavian artery.
5. Function
The subclavian artery supplies the upper extremities and parts of the neck and thoracic region with arterial blood. The vessel is also involved in cerebral perfusion via the vertebral artery.
6. Clinic
The scalene gap represents a narrowing of the subclavian artery in which blood flow can be impaired. This is known as scalene syndrome.
The subclavian artery is used for the surgical treatment of aortic coarctation, among other things. The procedure is called subclavian artery reversoplasty.
An aberrant right subclavian artery is referred to as a lusoria artery.