Ultrasonic Observation and Clinical Application of Arcade of Struthers in the Mid-Arm

The mid-arm structure named arcade of Struthers has been shrouded in controversy since it was identified. Most specimens in previous studies were European. The occurrence, component, extent, and position of this structure in the xanthoderm are not clear. Moreover, research into the arcade of Struthers has been at the anatomic level and there has been no ultrasonic research. The aim of this study was to elucidate and measure this anatomy by both anatomic dissection and ultrasonic observation to provide clear and definite criteria to classify the arcade of Struthers, as well as operation guidelines for identifying the arcade of Struthers in ultrasonic imaging and surgical decompression.

Sixty-four upper limb specimens of 32 adult cadavers were dissected. The tendinous arcade of Struthers (TAS) and muscular arcade of Struthers (MAS) were observed and measured, as well as the position at which the medial intermuscular septum was pierced by the ulnar nerve. The position at which the concomitant blood vessel began to accompany the ulnar nerve was also recorded. Twenty healthy adult participants were enrolled for ultrasonic research. The ulnar nerve was scanned from the cubital tunnel to the fossa axillaris for the anatomic structure crossing it. Once the arcade of Struthers was found, the distal and proximal limits were marked on the skin and it was then measured.

Anatomic study showed TASs in 21 limbs, and MASs were found in 16 limbs. The total incidence of the arcade of Struthers was 57.8%. The length of TAS (2.12 ± 0.62 cm) and MAS (4.46 ± 1.96 cm) had a significant difference and the distance between its proximal limit and the medial humeral epicondyle were 8.93 ± 1.38 cm and 9.50 ± 1.69 cm, respectively. Ultrasonic study showed that the incidence of the arcade of Struthers was 50.0%. The distance between its proximal limit and the medial humeral epicondyle was 8.52 ± 1.88 cm and 9.45 ± 1.76 cm. The length was 1.85 ± 1.8 cm and 4.23 ± 1.93 cm, respectively.

We believed that an arcade of Struthers described by multiple investigators did exist in Chinese people, and based on our study, it was classified into 2 types: TAS and MAS. Caution should be used to preserve the superior ulnar collateral artery when incising the arcade of Struthers. Ultrasonography can detect the existence ratio, dimension, and location of the arcade of Struthers.