2001;5(4):203–208.

Levator Palpebrae Superioris Muscle

The levator palpebrae superioris muscle arises at the orbital apex from the lesser wing of the sphenoid bone just superior to the annulus of Zinn. At its origin, the muscle blends with the superior rectus muscle inferiorly and with the superior oblique muscle medially. The levator palpebrae superioris passes anteriorly, lying just above the superior rectus muscle; the fascial sheaths of these 2 muscles are connected. The levator palpebrae superioris muscle becomes an aponeurosis in the region of the superior fornix. This muscle has both a cutaneous and a tarsal insertion. BCSC Section 7, Orbit, Eyelids, and Lacrimal System, discusses this muscle in detail.

Relationship of the Rectus Muscle Insertions

Starting at the medial rectus and proceeding to the inferior rectus, lateral rectus, and superior rectus muscles, the rectus muscle tendons insert progressively farther from the limbus. Drawing a continuous curve through these insertions yields a spiral, known as the spiral of Tillaux (Fig 3-4). The temporal side of each vertical rectus muscle insertion is farther from the limbus (ie, more posterior) than is the nasal side.

Figure 3-4 Spiral of Tillaux, right eye. Note: The insertion distances, given in millimeters, are maximum values. Insertion

distances vary in individuals. (Illustration by Christine Gralapp.)

Blood Supply of the Extraocular Muscles

Arterial System

The muscular branches of the ophthalmic artery provide the most important blood supply to the