ABSTRACT
Introduction In 1927 Adson and Coffey described clinically what they called “scalene anticus syndrome” where the subclavian artery vessel could be compressed by the anterior scalene muscle.1
In 1958, Rob and Standeven introduced the term “thoracic outlet compression syndrome.”2 However, the definition needs to be explained in order to address the syndromes that pertain to the upper opening of the chest cavity. The opening comprises the space between the manubrium of the sternum the first rib and the T1 vertebral body (Figure 43.1 and 43.2). “Outlet” means that some structures or organs come out of the chest cavity either to the arms or to the neck. The only structures exiting the chest cavity are the innominate and subclavian arteries. The subclavian veins, on the contrary, enter the thoracic cavity at the front of this space and therefore it is called the “thoracic inlet,” because the flow of blood goes from the outside to the inside of the chest cavity. The brachial plexus going to the arms originates in the cervical spine and only the last branch comes from between C7 and T1.3 Nevertheless, since these trunks run parallel to the subclavian artery the compression of both structures fall under the term “thoracic outlet syndrome.” The anterior scalene muscle separates these compartments. Compression at the inlet therefore entails obstruction or pinching of the subclavian vein only. Causes includes Paget-Schroetter syndrome, and obstruction by catheters or other endovascular devices. In summary, the anterior portion of the upper opening of the chest cavity is considered to be the inlet and the posterior area is considered the outlet separated by the anterior scalene muscle.
