Abstract:
This case report describes the rare anomaly of an absent
right anterior scalene muscle presenting with the symptoms and signs
of the thoracic outlet syndrome. The thoracic outlet syndrome in our
patient can be attributed to the absence of the right anterior scalene
muscle, which resulted in the brachial plexus being in proximity to
the subclavian vein and artery in a narrowed and abnormal
interscalene space. In addition, the absence of the anterior scalene
muscle resulted in the neurovascular structures being compressed
onto the first rib in the costoclavicular space. The most likely cause of
the presentation is, however, the possibility of the presence of
aberrant muscle slips, which would cause compression of the
structures in the anterior (venous) and posterior (neurological)
sections of the thoracic outlet.
