What is the thoracic outlet?
Nerves and blood vessels travel from the neck to the upper limb through a series of three tunnels, known collectively as the thoracic outlet. (Picture 1) Picture 1: Diagram of the thoracic outlet. The nerves and blood vessels pass through three triangular channels which make up the thoracic outlet: (A) the triangular space between the scalene muscles; (B) the costoclavicular space; and (C) a space beneath the pectoralis minor muscle. Obstruction to the electrical conduction down the nerves, or blood flow through the arteries, or veins can lead to symptoms in the arm and hand, known as the thoracic outlet syndrome (TOS). Most patients with the thoracic outlet syndrome have three features: numbness, weakness, and a sensation of swelling in the hand and arm. Most commonly, the complaints arise from altered posture that causes mild compression with intermittent symptoms and no alarming features. Depending upon the cause, and presentation, three types of TOS are recognized: • Neurogenic – I
