Revisiting the arcade of Struthers: a cadaveric study to explore this debatable anatomical structure as a possible...

The study examines the gross morphology, morphometry, and histological architecture of the arcade of Struthers (AoS) and its anatomical interaction with the ulnar nerve (UN) to evaluate the possible role of the AoS as a site with features suggestive of chronic compressive changes in UN in cadaveric specimens. Forty-six upper limbs from 23 adult formalin-fixed cadavers (17 males and six females) were dissected to identify the AoS. Histological architecture was examined using Masson's Trichrome staining, with image analysis quantifying the composition of muscle and collagen fibres. The AoS was identified in 37 limbs (80.43%). Structurally, 23 (62.16%) were muscular, 11 (29.72%) aponeurotic, and 3 (8.11%) mixed. The mean arcade length was 5.23±1.13 cm. The UN passed beneath the arcade in 27 (72.97%), superficially in 7 (18.92%), and alongside in 3 (8.11%). Features suggestive of chronic compressive changes were observed in seven cases (all involving aponeurotic tissue), with histology revealing perineural and epineural fibrosis, increased collagen deposition, and endoneural fibrosis. Trichrome staining confirmed structural variation: muscular arcades showed 80%-90% muscle fibres, aponeurotic arcades had 85%-95% collagen, and mixed arcades had a balanced composition. The AoS is a prevalent anatomical structure, most commonly muscular, with the UN frequently passing beneath it. The aponeurotic arcades demonstrated a higher likelihood of causing chronic compressive changes in UN, confirmed by histological evidence to reflect a suggestive association with compression neuropathy.