Thus Mr. Beebe in the paper referred to says: "Birds have early learned to take clams or mussels in their beaks or claws at low tide and carry them out of the reach of the water, so that at the death of the mollusk, the relaxation of the adductor muscle would permit the shell to spring open and afford easy access to the inmate."
"Ways of Nature"
John Burroughs
The lower fragment passes upward, and is rotated laterally by the weight of the limb; the displacement is aggravated by the contraction of the flexor and adductor muscles.
"Manual of Surgery Volume Second: Extremities--Head--Neck. Sixth Edition."
Alexander Miles Alexis Thomson
In advanced cases the deformity can only be corrected by open operation, which consists in dividing the femur obliquely downwards and medially through the great trochanter, and, the adductor muscles having been ruptured or divided, the limb is put up in the abducted position along with, if required, powerful weight extension.
"Manual of Surgery Volume Second: Extremities--Head--Neck. Sixth Edition."
Alexander Miles Alexis Thomson