Pectoralis Minor Syndrome

Abstract

Pectoralis minor syndrome (PMS) is a subset of neurogenic thoracic outlet syndrome (TOS) that can cause upper extremity symptoms of pain, paresthesia, and/or weakness due to compression of the neurovascular bundle by the pectoralis minor muscle (PM). The most distinguishing symptoms and signs of PMS include pain and/or tenderness in the subclavicular anterior chest wall and axilla. The clinical diagnosis of PMS can be con fi rmed by an improvement in symptoms and physical fi ndings following a PM muscle block with local anesthetic. Treatment begins with PM stretching exercises. If this is insuf fi cient, PM tenotomy (PMT) is a low risk operation, which can be performed as an outpatient. When PMS is the only diagnosis the success rate of PMT is 90 %, but when PMS is accompanied by nerve compression at the level of the scalene triangle the success rate of isolated PMT is only 35 %. PMS should also be considered in all patients with recurrent neurogenic TOS, as this condition has been found in a substantial proportion of such patients.

Images in Vascular Medicine Pectoralis minor syndrome – A forgotten vascular compression syndrome

“…About 82% of PMS cases are secondary to trauma and 70% of patients evaluated for neurogenic thoracic outlet syndrome (TOS) also have PMS. 1,2 PMS is often thought to be a subset of TOS, but they must be distinguished as treatment for TOS does not relieve symptoms due to compression of the axillary neurovascular bundle. Conservative management with physical therapy can be pursued for those with only neurogenic PMS.…”

“…Those who fail physical therapy or have vascular compression can be successfully treated with relatively risk-free nerve blocks or PM tenotomies, thereby avoiding more invasive thoracic outlet operations and their potential complications. [1][2][3] Over 90% of patients with isolated PMS have resolution of symptoms with tenotomy, whereas about 35% of patients with PMS and TOS require both tenotomy and thoracic outlet surgery. 2 Patients A and B underwent PM tenotomy with symptom improvement.…”

“…About 82% of PMS cases are secondary to trauma and 70% of patients evaluated for neurogenic thoracic outlet syndrome (TOS) also have PMS. 1,2…”

“…[1][2][3] Over 90% of patients with isolated PMS have resolution of symptoms with tenotomy, whereas about 35% of patients with PMS and TOS require both tenotomy and thoracic outlet surgery. 2 Patients A and B underwent PM tenotomy with symptom improvement. Management for Patient C is ongoing.…”