No raphe identified in the orbicularis oculi muscle

Area of Science:

• Anatomy
• Ophthalmology
• Surgical Anatomy

Background:

• The orbicularis oculi muscle plays a crucial role in eyelid function.
• The existence and anatomical significance of a raphe within this muscle remain unclear.
• Understanding the precise anatomical structures is vital for ophthalmic surgical procedures.

Purpose of the Study:

• To determine the presence or absence of the raphe of the orbicularis oculi muscle.
• To clarify the anatomical continuity and attachments of the lateral orbicularis oculi muscle.

Main Methods:

• Dissection of nine upper eyelids from six Oriental cadavers (ages 72-91).
• Gross anatomical observation of the lateral orbicularis oculi muscle and surrounding tissues.
• Histological examination of tissue sections stained with hematoxylin and eosin.

Main Results:

• The raphe of the orbicularis oculi muscle was not identified through either macroscopic or microscopic analysis.
• The lateral part of the orbicularis oculi muscle demonstrated continuous fibrous tissue, not a tendinous intercalation.
• Fibrous connective tissue, identified as lateral orbital thickening, was observed beneath the muscle, forming a band-like structure.

Conclusions:

• The study concludes that the raphe of the orbicularis oculi muscle does not exist.
• The physiological function of the lateral orbicularis oculi muscle is attributed to its attachment to the lateral orbital thickening, not a raphe.
• This finding refines the anatomical understanding of the orbicularis oculi muscle and its functional attachments.