臂弯
the inside part of your arm where it bends
She sat back in the armchair and settled the baby in the crook of her arm.
You should try to sneeze into the crook of your arm rather than your hands.
They walked side by side, her hand in the crook of his arm.
I got a mosquito bite right in the crook of my arm.
Her two children lay with her, in the crook of each arm.
See also: crook noun (BEND)