When the man saw that he could not overpower Jacob, he struck the socket of Jacob’s hip and dislocated it as they wrestled.
KJV
And when he saw that he prevailed not against him, he touched the hollow of his thigh; and the hollow of Jacob’s thigh was out of joint, as he wrestled with him.
ASV
And when he saw that he prevailed not against him, he touched the hollow of his thigh; and the hollow of Jacob’s thigh was strained, as he wrestled with him.