Mandaic

giṭra - ligament (of the body); joint, bond, knot (MD 90)

g-­ < *ḳ-­ by dissimilation of two «emphatic» stops, the process likely inherited by Mnd. from the Akk. substratum

PS
*ki/uṯ̣r- - joint (of the ribs, fingers, etc.) (SED I No. 155)
Though reconstructed as an anatomic term on the PS level, the present root is likely related to, or rather derived from, Sem. *k(ʷ)ṯ̣r ‘to bind, knot, fix’