Scalene triangle

The scalene triangle (also known as the interscalene triangle) is located laterally at the root of the neck and is the space through which the roots and trunks of the brachial plexus and the third part of the subclavian artery exit the neck.

Its anterior edge is formed by the scalenus anterior muscle, its posterior wall by the scalenus medius muscle and its base by the first rib.

It should not be confused with the colliscalene triangle located medial to the scalenus anterior muscle.