Morphometric Parameters of the Fibrous Arch of Flexor Digitorum Superficialis: A Cross-sectional Cadaveric Study in the Indian Population

Abstract

Introduction: The Flexor Digitorum Superficialis arch (FDS arch) serves as a connection between the humero-ulnar and radial heads of the FDS muscle. This arch can potentially compress the median nerve, leading to the development of pronator syndrome. Aim: To describe the morphometric parameters of the FDS arch in the Indian population. Materials and Methods: A two-year cross-sectional cadaveric study was conducted at the Department of Anatomy, Christian Medical College, Vellore, India, from December 2018 to November 2020. Thirty-four forearms from 17 adult cadavers (8 male and 9 female) were included in the study after excluding those with forearm deformities caused by trauma, congenital malformations, or scars. Measurements were taken for the distance from the medial epicondyle to the apex of the FDS arch and the thickness of the arch. The type of FDS arch (tendinous or muscular, distinct or indistinct) was also observed. Descriptive statistics, including means, standard deviations, and range, were calculated using STATA/IC 16.0. Results: Among the specimens, the FDS arch was tendinous in 20 (58.8%) and muscular in 14 (41.2%) cases. The mean distance from the medial epicondyle to the apex of the FDS arch was 65.8±12.8 mm, and the mean thickness was 0.80±0.43 mm. A distinct arch was observed in 25 (73.53%) specimens, while an indistinct arch was found in 9 (26.47%) specimens. Conclusion: The findings of this study contributed valuable insights for surgical interventions aimed at decompressing the median nerve entrapment in the proximal forearm.

Keywords

• entrapment neuropathy
• forearm
• median nerve
• pronator syndrome