The four structures that can cause nerve compression or impingement for thoracic outlet syndrome are?

The four structures that can cause nerve compression or impingement for thoracic outlet syndrome are:

- cervical rib, which is an extra rib that can form above the first rib and compress the nerves and blood vessels in the thoracic outlet.

- scalene muscles, which are a group of muscles located in the neck that can become tight and compress the nerves and blood vessels in the thoracic outlet.

- pectoralis minor, which is a muscle that connects the chest bone to the shoulder blade and can become tight and compress the nerves and blood vessels in the thoracic outlet.

- costoclavicular ligaments, which connect the first rib to the clavicle. These ligaments can become inflamed or thickened, which can compress the nerves and blood vessels in the thoracic outlet.