Which structures pass between the anterior and middle scalene muscles?

Which structures pass between the anterior and middle scalene muscles?

• A. Phrenic nerve and subclavian vein
• B. Carotid artery and internal jugular vein
• C. Vagus nerve and thoracic duct
• D. Brachial plexus and subclavian artery

Answer: (D)

The space between the anterior and middle scalene muscles is the interscalene region where the brachial plexus trunks pass together with the subclavian artery as it moves toward the upper limb. The subclavian vein does not travel through this gap; it lies anterior to the anterior scalene. The phrenic nerve runs on the surface of the anterior scalene, not within the interscalene space, and the vagus nerve with the thoracic duct occupy different compartments (carotid sheath and posterior mediastinum) rather than passing between the scalene muscles. So the structures that pass between the anterior and middle scalene muscles are the brachial plexus and the subclavian artery.

The space between the anterior and middle scalene muscles is the interscalene region where the brachial plexus trunks pass together with the subclavian artery as it moves toward the upper limb. The subclavian vein does not travel through this gap; it lies anterior to the anterior scalene. The phrenic nerve runs on the surface of the anterior scalene, not within the interscalene space, and the vagus nerve with the thoracic duct occupy different compartments (carotid sheath and posterior mediastinum) rather than passing between the scalene muscles. So the structures that pass between the anterior and middle scalene muscles are the brachial plexus and the subclavian artery.