Which structures course between the anterior and middle scalene muscles?

Which structures course 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 through which the subclavian artery and the roots/trunk of the brachial plexus pass en route to the axilla. This area marks the junction where the artery and the lower brachial plexus emerge from the neck to supply the upper limb. Phrenic nerve runs on the anterior surface of the anterior scalene, not between the scalene muscles. The subclavian vein lies mainly anterior to the anterior scalene, not between the two scalene muscles. The carotid artery and internal jugular vein sit in the carotid sheath deeper and medial, not between the scalene muscles. The vagus nerve and thoracic duct are not between the scalene muscles either.

The space between the anterior and middle scalene muscles is the interscalene region through which the subclavian artery and the roots/trunk of the brachial plexus pass en route to the axilla. This area marks the junction where the artery and the lower brachial plexus emerge from the neck to supply the upper limb.

Phrenic nerve runs on the anterior surface of the anterior scalene, not between the scalene muscles. The subclavian vein lies mainly anterior to the anterior scalene, not between the two scalene muscles. The carotid artery and internal jugular vein sit in the carotid sheath deeper and medial, not between the scalene muscles. The vagus nerve and thoracic duct are not between the scalene muscles either.