THORACIC OUTLET SYNDROME ⠀ PECTORALIS MINOR SYNDROME ⠀ [ANATOMY AND PATHOLOGY] ⠀ The pec minor originates on the coracoid process on the front of the scapula and splits into three sections that travel diagonally downward and medial to attach to the 3rd to 5th ribs. ⠀ Contraction of the pec muscle pulls the shoulder blade downward (depression) and forward (protraction) on the ribcage. Conversely, if the shoulder is held in place by the levator scapulae and trapezius muscles, contraction of the pec minor can elevate the upper ribcage and assist in inhalation. ⠀ Chronic tension in the pec minor can produce “winging of the scapula” in which the vertebral edge and lower tip of the scapula stick out from the rib cage and become visually prominent. ⠀ Tension in this muscle can also cause it to compress (entrap) the nerves of the brachial plexus in the shoulder region, where the neurovascular bundle passes between the tendon of pec minor and the coracoid process of the scapula, producing neurogenic pain and numbness that is experienced in the forearm, hand, and fingers, like that associated with carpal tunnel syndrome. It may also restrict blood flow to arm by compressing the axillary artery and lead to a weak or absent pulse at the wrist of the affected arm. Because of these entrapments, trigger point activity in this muscle can be a major contributor to thoracic outlet syndrome (along with scalene trigger points). ⠀ Pec minor trigger points can lead to pain patterns start in the front of shoulder and can extend down the inside of the arm, elbow, forearm, palm of the hand, and into the pinky, ring, and middle fingers