extra ocular muscle

**Extraocular Muscles: Function and Anatomy**

The extraocular muscles are a group of six muscles responsible for controlling the movements of the eyeballs. These muscles are essential for maintaining proper eye alignment and facilitating precise eye movements. Let's explore their function and anatomy in this short lecture:

**Function of Extraocular Muscles:**

1. **Lateral Rectus Muscle:** This muscle abducts the eyeball, meaning it moves the eye away from the midline of the face, allowing for outward eye movement.

2. **Medial Rectus Muscle:** The medial rectus muscle adducts the eyeball, bringing the eye back to the midline of the face, enabling inward eye movement.

3. **Superior Rectus Muscle:** This muscle elevates the eyeball, moving it upward.

4. **Inferior Rectus Muscle:** The inferior rectus muscle depresses the eyeball, moving it downward.

5. **Superior Oblique Muscle:** This muscle primarily intorts the eyeball (rotating it inward) and also depresses and abducts the eye.

6. **Inferior Oblique Muscle:** The inferior oblique muscle extorts the eyeball (rotating it outward) and also elevates and abducts the eye.

**Anatomy of Extraocular Muscles:**

The extraocular muscles originate from the common tendinous ring, also known as the annulus of Zinn, which surrounds the optic nerve at the back of the eye. From the common tendinous ring, the muscles insert onto the surface of the eyeball. The six extraocular muscles are:

1. **Lateral Rectus Muscle:** Originates from the common tendinous ring and inserts on the lateral side of the eyeball.

2. **Medial Rectus Muscle:** Originates from the common tendinous ring and inserts on the medial side of the eyeball.

3. **Superior Rectus Muscle:** Originates from the common tendinous ring and inserts on the superior aspect of the eyeball.

4. **Inferior Rectus Muscle:** Originates from the common tendinous ring and inserts on the inferior aspect of the eyeball.

5. **Superior Oblique Muscle:** Originates from the sphenoid bone, near the common tendinous ring, and inserts on the upper part of the eyeball's posterior surface.

6. **Inferior Oblique Muscle:** Originates from the maxillary bone, near the anterior inferior orbital rim, and inserts on the lower part of the eyeball's posterior surface.

**Clinical Significance:**

Disorders of the extraocular muscles can result in various eye alignment and movement problems, including strabismus (crossed eyes) and diplopia (double vision). Ophthalmologists and orthoptists play a crucial role in diagnosing and managing these conditions through various treatment options, including eye exercises, prism glasses, and, in some cases, surgical intervention.

In conclusion, the extraocular muscles are vital for controlling eye movements and maintaining proper alignment of the eyeballs. Their coordinated action allows for precise and coordinated eye movements, enabling us to focus on objects and navigate the world around us effectively.

MCQs on Extraocular Muscles

Q1. Which muscle is responsible for moving the eye away from the midline of the face?

Q2. The muscle responsible for moving the eye toward the midline of the face is:

Q3. The muscle responsible for elevating the eyeball is:

Q4. Which muscle is responsible for depressing the eyeball?

Q5. The muscle that primarily intorts the eyeball (rotating it inward) is:

Q6. The muscle that extorts the eyeball (rotating it outward) is:

Q7. The insertion point of the Lateral Rectus Muscle is on the:

Q8. The muscle responsible for supporting the aryepiglottic folds is:

Q9. Which muscle is responsible for abducting the eyeball and moving it upward?

Q10. The origin of the Medial Rectus Muscle is from the: