The eyelid is composed of a fibrous inner membrane ending in a stiff arch near the border, a muscle to close the lid, another to open it, the skin externally, and the conjunctival mucous membrane internally.
"Special Report on Diseases of Cattle"
U.S. Department of Agriculture J.R. Mohler
A black eye is to be distinguished from the effusion which sometimes follows such injuries as fracture of the anterior fossa of the skull, fracture of the orbital ridges, or a bruise of the frontal region of the scalp, chiefly by the facts that in the former the discoloration comes on within a very short time of the injury, the swelling appears simultaneously in both lids, and the sub-conjunctival ecchymosis, when present, is coeval with the ecchymosis of the lids.
"Manual of Surgery Volume Second: Extremities--Head--Neck. Sixth Edition."
Alexander Miles Alexis Thomson