Thyrocervical trunk

At a glance

English

Thyrocervical trunk

Latin (TA2)

Truncus thyreocervicalis

System

Artery

Region

Trunk

Side

Paired, left and right

About the thyrocervical trunk

The thyrocervical trunk is a stubby, thick vessel at the root of the neck. It comes off the upper side of the first part of the subclavian artery, the stretch from the start of the subclavian to the medial edge of scalenus anterior. Along the subclavian it lies beyond the vertebral artery, which arises first, and before the costocervical trunk, which leaves the second part of the artery behind scalenus anterior.

The trunk rises only a few millimetres before it divides. Its classic branches are the inferior thyroid artery, the suprascapular artery and the transverse cervical (cervicodorsal) artery, and the ascending cervical artery usually comes off the inferior thyroid close to its start. The arrangement is highly variable: the transverse cervical artery may arise directly from the subclavian, and its two branches, the superficial cervical and dorsal scapular arteries, often arise separately. The older name truncus thyrobicervicoscapularis reflects this crowd of branches.

The branches fan out in different directions. The inferior thyroid artery climbs medially behind the carotid sheath and then loops down to reach the lower part of the thyroid gland, also supplying the parathyroid glands, larynx, trachea and oesophagus. The suprascapular and transverse cervical arteries run laterally, passing in front of scalenus anterior and the phrenic nerve, to the shoulder and the back of the scapula. The ascending cervical artery runs up on the front of the cervical transverse processes and sends spinal branches into the vertebral canal.

Taken together, the trunk helps supply the muscles of the neck and shoulder girdle, the thyroid and nearby viscera, and the spinal cord in the lower neck. Its scapular branches join the scapular anastomosis, which can bring blood to the arm if the axillary artery is blocked. The inferior thyroid artery lies close to the recurrent laryngeal nerve, a relation surgeons respect during thyroid operations.

Course and supply

Arises from

The upper surface of the first part of the subclavian artery, medial to scalenus anterior, between the vertebral artery and the costocervical trunk.

Ends in

Divides almost at once into the inferior thyroid, suprascapular and transverse cervical arteries, with the ascending cervical artery arising from the inferior thyroid.

Supplies

Supplies the thyroid and parathyroid glands, the larynx, trachea and oesophagus, the deep and superficial muscles of the neck, the shoulder muscles around the scapula and part of the cervical spinal cord.