Thoracic outlet syndrome is described as a disorder caused by compression of nerves and blood vessels in which location?

• A. Between the clavicle and the first and second ribs at the brachial plexus
• B. In the neck
• C. In the abdomen
• D. In the leg

Answer: (A)

Thoracic outlet syndrome happens when the nerves and blood vessels that supply the arm are squeezed as they pass through a narrow passage inside the thoracic outlet. The critical spot is the space between the clavicle (collarbone) and the first rib, where the brachial plexus nerves and the subclavian vessels travel from the neck into the arm. When compression occurs there—due to posture, muscle tension, or anatomical differences—it can cause numbness, tingling, weakness, or changes in color and pulse in the arm. The abdomen and leg are not involved in this specific bottleneck, and while the neck is related to the origin of the nerves, the characteristic compression for this condition is at that space beneath the clavicle in front of the first rib.