【Anatomy】A list of eye muscles and the nerves they innervate

Ocular appendages

Eyelids, conjunctiva, lacrimal organs, extraocular muscles, orbits

eye socket

1.
It is composed of 7 skulls, forming a quadrangular pyramid

2.
The orbit and paranasal sinuses are adjacent

3.
Holes, fissures and fossa of the orbit

Orbital contents

Eyeball, optic nerve, extraocular muscles, lacrimal glands, blood vessels, nerves, fascia, fat

Orbicularis oculi muscle

1.
Ring-shaped

2.
Innervated by the facial nerve

3.
Eyelid closure

Lift the eyelid muscles

1.
Innervated by the oculomotor nerve

2.
Raise the upper eyelids

Muller's muscle

Innervated by sympathetic nerves, the palpebral fissure widens when contracted

Tear vessel

1.
Lacrimal gland: in the lacrimal fossa above the outer orbit, tear fluid is secreted

2.
Lacrimal duct: lacrimal gland points, lacrimal tubules, lacrimal sacs, nasolacrimal ducts

Secretion and discharge of tears

Physiological functions of tears

1.
Moisten the cornea and conjunctiva

2.
Cleaning effect

3.
Bactericidal effect on extraocular muscles

Each eye has six and eye movements

Innervation of extraocular muscles

External rectus muscle – abductor innervation

Superior oblique muscle – trochlear nerve innervation

Oculomotor innervation – superior rectus, inferior rectus, medial rectus, inferior oblique

Four rectus muscles and two oblique muscles

Superior rectus muscle (pulls the eye up) Inferior rectus muscle (pulls the eye down)

Internal rectus muscle (pulls the eye inward) External rectus muscle (pulls the eye outward)

Superior oblique (pulls the eye outward and downward) Inferior oblique (pulls the eye inward upward)

The superior rectus and inferior rectus muscles are in tug-of-war

The medial rectus and external rectus muscles are in tug-of-war

The superior and inferior oblique muscles are in tug-of-war

Ocular motor nerve walking (lateral view)

Ocular motor nerve walking (back view)

The starting and ending point of the eye muscles:

1.
The inferior oblique muscle originates from the inner and lower edge of the orbital wall

2.
The remaining muscles originate from the orbital apical general tendon ring

3.
Each muscle stops at the sclera at different distances after the angular scleral margin

Ciliary ganglia

1.
Between the optic nerve and the lateral rectus muscle, 10 mm in front of the optic nerve foramen

2.
Sensory nerve (the first trigeminal nerve), parasympathetic nerve (oculomotor nerve), sympathetic nerve (cervical sympathetic nerve)

When the nerves are damaged, the muscles that innervate them become weaker

Abductor innervates the external rectus muscle

Function of the abductor nerve: pulling the eye straight outward

Abductor nerve palsy: weakness of the lateral rectus muscle, greater relative strength of the medial rectus muscle, and the eyeball is pulled inward

The trochlear nerve innervates the superior oblique muscle

Trochlear nerve paralysis >> a relative increase in upper oblique muscle weakness >> lower oblique muscle strength>> counterclockwise turning of the eyeball>> diplopia>> patients tilt their head (or to the left or vice versa for right paralysis) >> improve symptoms

The oculomotor nerve innervates the remaining 4 extraocular muscles

Oculomotor palsy causes abduction and trochlear innervation of relatively strong muscles (rectus lateral and superior oblique), which turn the eye outward and downward
.

By understanding the extraocular muscles and neuroanatomy that govern eye activity, we can understand the dysfunction of the eye muscles caused by the associated nerve damage
.
Diplopia occurs when both eyes are looking in the same direction and the corresponding eye muscles cannot move in the same direction, which can be accompanied by changes
in head position.

Oculomotor motor innervation of the upper eyelid muscle

Oculomotor nerve palsy, causing the eyelids to droop

The parasympathetic motor branch of the oculomotor nerve controls pupil size and lens shape

The oculomotor nerve is damaged, resulting in dilated pupils and increased curvature of the lens

If the parasympathetic motor branch of the unilateral oculomotor nerve is damaged, the ipsilateral eye directly reflexes to light disappear, indirect to light reflexes, and regulatory reflexes disappear.

Roll your big watery eyes and think about which muscles are moving and which nerves are innervating
.

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