Detailed Anatomy of the Lateral Rectus Muscle-Superior Rectus Muscle Band

BACKGROUND: To elucidate the detailed anatomy of the lateral rectus muscle-superior rectus muscle (LR-SR) band by cadaver eye investigation. METHODS: In total, 48 eyes of 24 cadavers were observed macroscopically. The lateral rectus muscle (LRM) and superior rectus muscle (SRM) were dissected from their origins to their insertions under the dissecting microscope, and the location, width, length, and tensile strength of the LR-SR bands were measured. RESULTS: The LR-SR band is the thick ligament interconnecting LRM pulleys with SRM pulleys. The LR-SR band was covered by the orbital part of the lacrimal gland superiorly, and the intermuscular septum between the LRM and SRM was shown anterior to the LR-SR band. The length of the attachment site between the LR-SR band and the SRM was less at 8.64 ± 1.52 mm (p=0.040), its thickness was thinner at 0.74 ± 0.16 mm (p=0.002), and its tensile strength was weaker at 7.64 ± 1.82 N (p=0.028) compared to the attachment site between the LR-SR band and the LRM. CONCLUSIONS: This study revealed the detailed anatomy of the LR-SR band and provided helpful information to understand heavy eye syndrome and sagging eye syndrome.