Shoulder & Brachial Plexus LO2

2. Identify and list the parts and branches of the subclavian artery and vein, and describe their course in the neck.

The subclavian artery arises from the brachiocephalic trunk (right side) or the aortic arch (left side) and becomes the axillary artery distally. The subclavian artery is divided into three parts by the anterior scalene muscle.

1st part of subclavian a.: medial to the anterior scalene m. and gives off the following branches:

    • vertebral a. - travels through the foramina of the transverse processes of C1 through C6 to enter the cranial cavity through the foramen magnum.
    • internal thoracic a. – to the thorax.
    • thyrocervical trunk - four branches:
      • inferior thyroid a.
      • ascending cervical a.
      • transverse cervical a.
      • suprascapular a.

2nd part of the subclavian a.: posterior to the anterior scalene m. and only has one branch:

    • costocervical trunk.

3rd part of the subclavian a.: lateral to the anterior scalene m. and only has one branch:

    • dorsal scapular a.

The subclavian a. becomes the axillary a. at the lateral (inferior) margin of the first rib.

The subclavian vein begins at the lateral border of the 1st rib and is a continuation of the axillary vein. It unites with the internal jugular vein to form the brachiocephalic vein. This union is known as the venous angle and is the site where the thoracic duct and right lymphatic duct drain their lymph into the venous circulation. The subclavian vein also receives the external jugular vein.