S / serpĕrastra
noun

serpĕrastra

gen. serpĕrastrōrum · gender neuter · decl. 2nd
(), , perh. from serpo - rastrum, creepingsplints
knee-splints; knee-bandages
knee-splints or knee-bandages for straightening the crooked legs of children. *
Lit.: pueris in geniculis alligare, Varr. L. L. 9, § 11 Müll.—*
by extension
Transf., humorously of officers, who hold the soldiers in check: de serperastris cohortis meae nihil est quod doleas, Cic. Att. 7, 3, 8.