thoracic outlet syndrome

noun

: any of a group of disorders that are marked by the compression of nerves (such as the brachial plexus) or blood vessels (such as the subclavian artery or vein) as they pass from the neck toward the armpit or proximal arm through a space in the upper thorax between the clavicle and the first rib and that typically result in pain, numbness, weakness, or cold sensitivity in the affected area

In August his arm suddenly went numb; he was shelled in two appearances before doctors figured out he was suffering from thoracic outlet syndrome, a condition in which his first rib was pressing upon an artery.

—Tom Verducci

The repetitive overhand motion done by weightlifters, gymnasts, swimmers and more, occasionally results in thoracic outlet syndrome …

—Steve Wood

—abbreviation TOS

Examples of thoracic outlet syndrome in a Sentence

Recent Examples on the Web

Festa’s current shoulder issue is unrelated to the thoracic outlet syndrome injury that ended his 2025 season but requires an injection and several weeks of shutdown, Twins athletic trainer Nick Paparesta said. —Dan Hayes, New York Times, 26 Feb. 2026

Festa was hampered by shoulder issues throughout 2025, eventually receiving Botox injections late last season to treat a case of thoracic outlet syndrome. —Betsy Helfand, Twin Cities, 18 Feb. 2026

Likewise, Guyon’s canal syndrome (ulnar nerve compression at the wrist) and thoracic outlet syndrome (pressure on nerves or blood vessels near the collarbone) can mimic cubital tunnel syndrome. —Scott Lafee, San Diego Union-Tribune, 17 Feb. 2026

While both syndromes cause numbness and tingling, only thoracic outlet syndrome causes the hands to become cold due to a lack of circulation. —Bestreviews, Mercury News, 5 Feb. 2026

But the Phillies' rotation would still be stacked without him, especially if Zack Wheeler returned from thoracic outlet syndrome early in the season. —Jackson Roberts, MSNBC Newsweek, 4 Dec. 2025

Despite his struggles, Buehler has a strong track record in the postseason and could still fortify a Phillies rotation that recently lost ace Zack Wheeler for the season due to thoracic outlet syndrome. —Mac Cerullo, Boston Herald, 31 Aug. 2025

Word History

First Known Use

1950, in the meaning defined above

Rhymes for thoracic outlet syndrome

• acrosome
• aerodrome
• catacomb
• centrosome
• chromosome
• cytochrome
• hippodrome
• honeycomb
• liposome
• meerschaum
• metronome
• microtome

Medical Definition

thoracic outlet syndrome

noun

: any of a group of neurovascular disorders that are marked by the compression of nerves (such as the brachial plexus) or blood vessels (such as the subclavian artery or vein) as they pass from the neck toward the arm through the thoracic outlet and that typically result in pain, numbness, weakness, or cold sensitivity in the neck, shoulders, or arms

Note: Common causes of thoracic outlet syndrome are anatomical anomalies (such as a cervical rib), traumatic injuries, or repetitive arm and shoulder movements.

—abbreviation TOS