The extraocular muscles are the six muscles that control movement of the eye
What is the function of the 6 muscles of the human eye?
EXTRAOCULAR MUSCLES:
There are six muscles that attach to
the eye to move it
. These muscles originate in the eye socket (orbit) and work to move the eye up, down, side to side, and rotate the eye. The superior rectus is an extraocular muscle that attaches to the top of the eye.
What are the six intrinsic eye muscles?
The six muscles in this group are:
medial rectus, lateral rectus, superior rectus, superior oblique, inferior rectus and inferior oblique
.
What are extrinsic muscles in the eye?
Extrinsic eye muscles (also called extraocular muscles) are
attached to the outside of the eyeball
and enable the eyes to move in all directions of sight. There are six extraocular eye muscles and one muscle that controls movement in the upper eyelid.
What are the 6 extrinsic eye muscles and their functions?
- Lateral Rectus. Moves eye laterally, VI Abducens.
- Medial Rectus. Moves eye medially, III Occulomotor.
- Superir Rectus. Elevates the eye, Turns eye medially. III Occulomotor.
- Inferior Rectus. Depresses the eye, Turns the eye medially. …
- Inferior Oblique. Elevates the eye. …
- Superior Oblique. Depresses eye.
What controls 4 of the 6 extrinsic eye muscles?
The annulus of Zinn
is a tendinous ring that surrounds the optic nerve and serves as the origin for four of the six extraocular muscles, excluding the inferior oblique muscle and superior oblique muscle.” (We got that quote from Wikipedia.)
What controls extrinsic eye muscles?
Most of the muscles of the eye are innervated by
the oculomotor nerve (cranial nerve III)
. The lateral rectus is innervated by the abducens nerve, CN IV, which causes abduction of the eye. The trochlear nerve, CN VI, innervates the superior oblique.
What is the strongest muscle in the human body?
The strongest muscle based on its weight is
the masseter
. With all muscles of the jaw working together it can close the teeth with a force as great as 55 pounds (25 kilograms) on the incisors or 200 pounds (90.7 kilograms) on the molars.
Can we control our eye muscles?
Three cranial nerves carry signals from the brain to control the extraocular muscles. These are the
oculomotor nerve
, which controls the majority of the muscles, the trochlear nerve, which controls the superior oblique muscle, and the abducens nerve, which controls the lateral rectus muscle.
Can you control eye muscles?
Three cranial nerves
are responsible for controlling the eye muscles. These are the third cranial nerve (oculomotor nerve), the fourth cranial nerve (trochlear nerve), and the sixth cranial nerve (abducens nerve). The secondary names of these nerves kind of give away what muscles they control.
What are the two intrinsic eye muscles?
Any of the muscles associated with the functioning of the eye, which are divided into two groups. The intrinsic muscles, which are involuntary, are situated inside the eyeball and comprise the ciliary muscle (see ciliary body)
and the iris
.
How do eye muscles work?
The muscles are attached to the sclera of the eye at one end and are anchored to the bony orbit of the eye at their opposite ends. Contraction of the muscles produce
movement of the eyes within the orbit
. The cranial lower motor neurons innervate these muscles and thereby control their contractions.
What causes the ciliary muscles in your eyes to involuntarily relax?
Parasympathetic activation of the M3 muscarinic receptors
causes ciliary muscle contraction. The effect of contraction is to decrease the diameter of the ring of ciliary muscle causing relaxation of the zonule fibers, the lens becomes more spherical, increasing its power to refract light for near vision.
What is the difference between intrinsic and extrinsic muscles?
The intrinsic muscles lie entirely within the tongue, while the extrinsic muscles attach the tongue to other structures. The extrinsic muscles reposition the tongue, while the intrinsic muscles
alter the shape of the tongue for talking and swallowing
.
Where are the extrinsic muscles?
The extrinsic muscles of the
shoulder originate from the trunk
, and attach to the bones of the shoulder – the clavicle, scapula, or humerus. They are located in the back, and are also known as the superficial back muscles. The muscles are organised into two layers – a superficial layer and a deep layer.
Which extrinsic eye muscle is responsible for turning the eye inferiorly?
The superior oblique muscle, or obliquus oculi superior
, is a fusiform muscle originating in the upper, medial side of the orbit (i.e. from beside the nose) which abducts, depresses and internally rotates the eye. It is the only extraocular muscle innervated by the trochlear nerve (the fourth cranial nerve).
