Dorsal Scapular Artery Variations and Relationship to the Brachial Plexus, and a Related Thoracic Outlet Syndrome Case.

Helen Pearson,Justin Brown,Afshin Karimi,Anthony Pastore,Daniela Alexandru,Frank Daly,Anne-Marie Verenna,Geoffrey Bove,Mary Barbe

doi:10.1055/s-0036-1583756

Abstract

Rationale Knowledge of the relationship of the dorsal scapular artery (DSA) with the brachial plexus is limited. Objective We report a case of a variant DSA path, and revisit DSA origins and under-investigated relationship with the plexus in cadavers. Methods The DSA was examined in a male patient and 106 cadavers. Results In the case, we observed an unusual DSA compressing the lower plexus trunk, that resulted in intermittent radiating pain and paresthesia. In the cadavers, the DSA originated most commonly from the subclavian artery (71%), with 35% from the thyrocervical trunk. Nine sides of eight cadavers (seven females) had two DSA branches per side, with one branch from each origin. The most typical DSA path was a subclavian artery origin before passing between upper and middle brachial plexus trunks (40% of DSAs), versus between middle and lower trunks (23%), or inferior (4%) or superior to the plexus (1%). Following a thyrocervical trunk origin, the DSA passed most frequently superior to the plexus (23%), versus between middle and lower trunks (6%) or upper and middle trunks (4%). Bilateral symmetry in origin and path through the brachial plexus was observed in 13 of 35 females (37%) and 6 of 17 males (35%), with the most common bilateral finding of a subclavian artery origin and a path between upper and middle trunks (17%). Conclusion Variability in the relationship between DSA and trunks of the brachial plexus has surgical and clinical implications, such as diagnosis of thoracic outlet syndrome.

Highlights

The dorsal scapular artery (DSA) supplies the levator scapulae and rhomboid muscles, and contributes to the arterial anastomosis around the scapula
We examined the path of the DSA relative to the brachial plexus trunks in 158 sides of 106 cadaveric specimens and how the paths differ by DSA origin
Case Report of a DSA Compressing the Lower Trunk of the Brachial Plexus A 17-year-old right-handed male patient presented to the neurosurgery clinic for evaluation of right upper limb pain and paresthesia of 4-year duration

Summary

Introduction

The dorsal scapular artery (DSA) supplies the levator scapulae and rhomboid muscles, and contributes to the arterial anastomosis around the scapula. Arterial compression of nerves resulting in pain or dysfunction is a phenomenon recognized to occur both intracranially[8,9] and extracranially.[10,11,12] TOS is frequently a result of anatomical variations in the region of the brachial plexus and is typically characterized by pain and paresthesias in the upper limb, accompanied occasionally by weakness.[13,14,15,16] Mechanical compression of the brachial plexus by anomalous cervical ribs, fibrous bands, or hypertrophied scalene muscles is commonly implicated as the etiology of TOS.[15,17,18,19,20] Upper limb symptoms can result from mechanical compression of components of the brachial plexus by subclavian vessels or its branches as they pass through the outlet.[13,15,17,20,21] The DSA is the most frequently implicated artery in this type of compression of the plexus, with a location between the middle and lower trunks of the plexus cited as the most problematic variant.[22,23,24] Besides direct compression by subclavian vessels,[25] compression of the brachial plexus by vascular branches has been reported in the literature, only rarely.[26]

Methods

Results

Discussion

Conclusion