The arcade of Struthers: An anatomical study with potential neurosurgical significance

Abstract

Background:Significant controversy exists regarding the existence of the so-called arcade of Struthers and whether this structure is involved in some cases of proximal ulnar nerve entrapment. Therefore, the aim of the present study was to further elucidate this anatomy.Methods:Fifteen cadavers (30 sides) underwent dissection of the medial arm with special attention to the course of the ulnar nerve and its relationships to the soft tissues of this region.Results:We identified a thickening in the inferior medial arm that crosses the ulnar nerve and is consistent with the so-called arcade of Struthers in 86.7% of sides. On 57.7% of the sides, the arcade was found to be due to a thickening of the brachial fascia and was classified as a type I arcade. On 19.2% of the sides, the arcade was due to the internal brachial ligament and these were classified as type II arcades. On 23.1% of the sides, the arcade was due to a thickened medial intermuscular septum and these were classified as type III arcades. The mean length of the arcade was 4.3 cm and the distal end of the arcade was, on average, 6.8 cm above the medial epicondyle. Although the presence of an arcade of Struthers was slightly more common in female specimens, this did not reach statistical significance. However, arcades were found more often on right side (P < 0.001).Conclusions:Based on our findings, the arcade of Struthers is an anatomical band of connective tissue in the medial distal arm that crosses the ulnar nerve. This structure was found in the majority of our specimens and may need to be evaluated in proximal ulnar neuropathies. We believe that past studies that have not observed the arcade and past studies with varied findings are due to the various definitions used for this anatomical structure. Using the classification system as demonstrated in the present study may make future communications regarding the arcade of Struthers more exact.

An anatomical investigation of rare upper limb neuropathies due to the Struthers’ ligament or arcade: a meta-analysis

“…The results of the study herein suggest that the SA can be found in most individuals, but that its presentation is highly variable, described in Tables 8-11. Al-Qattan and Murray [2], Mirza et al [27], Siqueira and Martins [32] and Tubbs et al [38], all describe at least some occurrence of an atypical SA, differing by the source of the thickened fascia or musculotendinous band. Even more inconsistency lies in the morphology of the SA, where most tended to be musculotendinous, but a large proportion was still found to be solely tendinous or muscular.…”

“…Similarly to the analysis of the SL, assessment of the SA was divided by subgroups -geographical prevalence, atypical prevalence, atypical type, morphology, relation to the ulnar nerve, and ulnar nerve compression. [38] 2011…”

“…The formal description of the SA by Kane et al [24] (a fibrous canal with a roof formed by a deep fascial thickening, an anterior border at the medial intermuscular septum, and a lateral border at the humerus and the muscular fibre covering of the triceps brachii) did not always apply to the findings of certain included studies due to its variability in presentation [2,27,32,38]. The variant definitions of the SA can be found in Table 8.…”

Ulnar Neuropathy at the Elbow: From Ultrasound Scanning to Treatment

“…Mizia et al (8) estimated its prevalence as 53%. Tubbs et al (9) described three types of Struthers' arcade. Type I was described as the most common, where thickening of the brachial fascia formed the arcade.…”

“…Type I was described as the most common, where thickening of the brachial fascia formed the arcade. In type II, the arcade is related to the internal brachial ligament (aponeurotic continuation of the brachialis muscle), and type III arcade is due to thickened MIS (9).…”