Deep layer of the lower neck
1. Superior trunk of brachial plexus
2. Middle trunk of brachial plexus
3. Inferior trunk of brachial plexus
4. Subclavian artery
5. Scalenus anterior and phrenic nerve
6. Internal thoracic artery
7. Thyrocervical trunk
8. Ansa subclavia
9. Inferior thyroid veins
9. Inferior thyroid veins
10. Inferior parathyroid gland
11. Brachiocephalic trunk
12. Common carotid artery
13. Cupula of the pleura
Deep layer of the lower neck. At left, observe the superior (1), middle (2) and inferior trunks (3) of the brachial plexus, while at right the subclavian artery (4). Notice the Scalenus anterior and the phrenic nerve (5) lying on it. The thyrocervical trunk (7) is slightly unusual. Medial to it, find the ansa subclavia (8). Study the internal thoracic artery (6) pulling downwards on the cupula of the pleura and in the centre of the picture the inferior thyroid veins (9), the right inferior parathyroid gland (10) and the brachiocephalic trunk (11). At the right side of the picture the left common carotid artery (12) and the cupula of the pleura (13) are labelled.