Certified Surgical First Assistant (CSFA) Practice Test

Which rectus muscle is responsible for moving the eyeball upward and medially?

1. Lateral rectus

2. Superior rectus

3. Inferior rectus

4. Medial rectus

The correct answer is: Superior rectus

The superior rectus muscle is primarily responsible for moving the eyeball upward and medially. This muscle is one of the extraocular muscles, which are responsible for controlling eye movements. When the superior rectus contracts, it pulls the eyeball upward while also contributing to adduction (movement toward the midline) due to its orientation. This dual function of upward movement and medial rotation is crucial for activities that require focused vision on objects that are positioned above and toward the center of the visual field. In contrast, the lateral rectus muscle is responsible for moving the eyeball laterally (away from the midline), while the inferior rectus muscle moves the eyeball downward and can assist in lateral movements. The medial rectus muscle, on the other hand, is specifically involved in moving the eyeball medially but does not contribute to upward movement. Understanding the distinct functions of these rectus muscles is crucial for comprehending overall eye movements and their implications in both health and various medical conditions.