Purpose: An anatomical and histological study of the conjoint fascial sheath of the levator and superior rectus (CFS) was carried out by using the cadavers for teaching.
Methods: Three adult Asian cadaver heads fixed in formalin were used. The CFS was exposed by the same surgeon in each case. Then the CFS was observed and measured in vivo and ex vivo. And the CFS, the levator and the frontal muscle were removed from the same eye for histological study.
Results: The CFS was located 2.1 ± 0.4 mm posterior to the fornix. A special muscle sheath of the levator was observed. The special muscle sheath and the tendon of the superior rectus were fused to the CFS through loose connective tissue. Hematoxylin-Eosin (HE) staining showed a large amount of connective tissue on examination of the CFS by microscopy. Double staining with Victoria-blue and Masson trichrome staining confirmed elastic fibers and collagen fibers in the CFS tissues.
Conclusions: If ptosis correction surgery is performed by looking for the CFS from the upper edge of the conjunctiva, in fact, only a special part of the muscle sheath of the levator in the CFS, but not the integral CFS, is used in the surgery. The histological results confirm that the CFS is a fibrous tissue membrane with both elasticity and toughness. Perhaps the best choice is to recombine the special muscle sheath of the levator in the CFS with the levator muscle tissue during ptosis correction surgery to suspend the eyelids.