Certified Ophthalmic Medical Technologist (COMT) Practice Exam

Which extraocular muscle inserts anterior at 5.5mm to the limbus and comprises the start of the Spiral of Tillaux?

1. Medial Rectus

2. Lateral Rectus

3. Superior Rectus

4. Inferior Rectus

The correct answer is: Medial Rectus

The medial rectus muscle is the extraocular muscle that inserts at approximately 5.5 mm from the limbus and is an integral component of the Spiral of Tillaux. This spiral is a concept that describes the positioning of the four rectus muscles in relation to the eyeball as they converge at the sclera to create a coordinated movement of the eye. The medial rectus is responsible for adduction of the eye and is located closest to the midline of the orbit, playing a key role in lateral movements. Its insertion point at 5.5 mm anterior to the limbus is characteristic of its anatomy and differentiation from the other rectus muscles, which have varying insertion locations. Understanding the anatomy of the extraocular muscles, including their insertions, is crucial for the assessment and treatment of ocular motility disorders, making this knowledge essential for any certified ophthalmic medical technologist.