The ability of each eye to move in all directions within its orbit is controlled

Question

The ability of each eye to move in all directions within its orbit is controlled by six extrinsic ocular muscles. Movement of the upper eyelid is controlled by a single muscle, the superior levator palpebrae. Figure 35.3, which is a lateral view of the right eye, reveals the insertions of all seven of these muscles. Their origins are one various bony formations at the back of the eye orbit. The muscle on the side of the eyeball that has a portion of it removed is the lateral rectus. Opposing is on the medical side of the eye is the medial rectus. The muscle that inserts on top of the tom of the eye is the inferior rectus. Just above the stub of the lateral rectus is seen the insertion of the superior oblique, which passes through a cartilaginous loop, the trochlea. Opposing the superior oblique is the inferior oblique, of which only a portion of the insertion can be seen. Materials: beef eye, preferably fresh dissecting instruments dissecting tray Examine the external surface of the eyeball identify the optic nerve and look for remnants of extrinsic muscle on the sides of the eyeball. Note the shape of the pupil. Is it round or elliptical? Identify the cornea. Holding the eyeball as shown in illustration 1, figure 35.4, make an incision into the sclerotic coat with sharp scalpel about one-quarter of an inch away from the cornea. Note how difficult it is to penetrate. Insert scissors into the incision and carefully cut all the way around the cornea, taking care not to squeeze the fluid out of the eye. Refer to illustration 2, figure 35.4. Gently lift the from portion off the eye and Place it on the tray with the inner surface upward The lens usually remains attached to the vitreous body, as shown in illustration 3. If the eye is preserved (not fresh), the lens may remain in the anterior portion of the eye. Examine the inner surface of the anterior portion and identify the thickened, black circular ciliary body. What function does the black pigment perform? Study the Iris carefully. Can you distinguish circular and radial muscle fibers'?

Explanation / Answer

Extrinsic muscles of eye parts :-

1.medial rectus muscle.

2.superior oblique muscle.

3.Trochlea.

4.superior levator palpebrae.

5.superior rectus muscle.

6.conjuctiva.

7.Lateral rectus.(2 places).

8.inferior oblique muscle.

9.inferior rectus muscle.

10.optic nerve.

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