Akkadian

matnu - sinew, tendon (CAD M₁ 412, AHw. 633)

PS
*matn- (1) - sinew, tendon; nerve (Held 1965: 405; SED I No. 191; Kogan 2011: 215)

Usually unseparated from the forms meaning ‘hip, loin’, etc. (see *matn- (2) - hip, loins, small of the back) which are semantically difficult to compare. Note, however, that a semantic contamination with metathetic *mV(ˀ)n(-at)- - tendon, sinew; muscle (No. 183) is possible.