A 24-year-old man presents with coldness and pallor of the left hand and recent episodes of small painful black areas in his fingertips. A chest radiograph shows a complete cervical rib on the left. Doppler reveals post-stenotic dilatation of the left subclavian artery with mural thrombus. Which structure compressed by the rib explains these findings?

• A Subclavian vein at the costoclavicular ligament
• B Lower trunk of the brachial plexus against the first rib
• C Subclavian artery between the anterior and middle scalene muscles ✓
• D Axillary nerve in the quadrangular space

Explanation

Arterial thoracic outlet syndrome results from compression of the subclavian artery, usually by a cervical or anomalous first rib, producing post-stenotic dilatation, mural thrombus, and digital embolisation presenting as ischaemic fingertips. Neurogenic TOS compresses the lower trunk of the brachial plexus and causes pain and paraesthesia without ischaemia. Venous TOS produces effort thrombosis of the subclavian vein with arm swelling. Definitive treatment is excision of the rib with first rib resection and repair of any arterial aneurysm.

Reference: Bailey & Love's Short Practice of Surgery, 28th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.