'Joints' in the Bible

Then Ebed-melech the Cushite said to Jeremiah, "Please put {the rags} and {worn-out clothes} under the joints of your arms under the ropes," and Jeremiah did so.

Then his face changed and his thoughts terrified him, and {his hip joints gave way} and {his knees knocked together}.

For the word of God [is] living and active and sharper than any double-edged sword, and piercing as far as the division of soul and spirit, both joints and marrow, and able to judge the reflections and thoughts of the heart.