TOPIC 2- 24. Functions of the external eye muscles. The neural control of the eye movements

- Ciliary muscle
- Sphincter pupillary muscle
- Dilator pupillary muscle
- Superior tarsal muscle

Which are the intraocular muscles of the eye?

Smooth muscle

What type of muscles are the intraocular muscles?

- Ciliary muscle
- Sphincter pupillary muscle

Which of the intraocular muscles are innervated by oculomotor nerve?

Oculomotor nerve

What is the innervation of ciliary muscle?

Oculomotor nerve

What is the innervation of sphincter pulillare muscle?

- Dilator pupillary muscle
- Superior tarsal muscle

Which of the intraocular muscles are innervated by sympathetic NS?

Postganglionic fibers from the superior cervical ganglion

What is the innervation of dilator pupillary muscle?

Postganglionic fibers from the superior cervical ganglion

What is the innervation of superior tarsal muscle?

- Superior rectus muscle
- Inferior rectus muscle
- Lateral rectus muscle
- Medial rectus muscle

- Superior oblique muscle
- Inferior oblique muscle

- Levator palpebral superioris

Which are the extraocular muscles of the eye?

- Equator plane
- Vertical meridian
- Horizontal meridian

What are the planes that make up the octants?

8 octants

What does the Equator plane, vertical meridian, horizontal meridian divide the eye ball into?

- Sagittal
- Transverse
- Vertical

Around which axis does the extraocular muscles move the eye around?

Abduction and adduction

Which movements of the eye are around the vertical axis?

Elevation and depression

Which movements of the eye are around the transverse axis?

External rotation and internal rotation

Which movements of the eye are around the sagittal axis?

- Inferior oblique
- Superior rectus
- Medial rectus
- Inferior rectus

Which extraocular muscles are innervated by oculomotor nerve?

Superior oblique

Which extraocular muscles are innervated by trochlear nerve?

Lateral rectus

Which extraocilar muscles are innervated by abducent nerve?

- Adduction
- Internal rotation
- Elevation

Which kinds of movements does the rectus superior do?

Adduction

Which kinds of movements does the rectus medius do?

- Adduction
- External rotation
- Depression

Which kinds of movements does the rectus inferior do?

Abduction

Which kinds of movements does the rectus lateralis do?

- Depression
- Internal rotation
- Abduction

Which kinds of movements does the superior oblique muscle do?

- External rotation
- Abduction
- Elevation

Which kinds of movements does the inferior oblique muscle do?

- Common tendinous ring
- Anterior, superior, medial/lateral octants

Origin and insertion of the superior rectus?

- Common tendinous ring
- Anterior, inferior, medial/lateral octants

Origin and insertion of the inferior rectus?

- Common tendinous ring
- Anterior, lateral, superior/inferior octants

Origin and insertion of lateral rectus?

- Common tendinous ring
- Anterior, medial, superior/inferior octants

Origin and insertion of medial rectus?

- Common tendinous ring (goes through the trochlear ring, which will be the original origin of the tendon)
- Posterior, superior, lateral octant

Origin and insertion of superior oblique?

- Maxilla
- Posterior, inferior, lateral octant

Origin and insertion of inferior oblique?

- Right lateral rectus muscle
- Left medial rectus muscle

Looking to the right?

- Superior rectus muscle
- Inferior oblique muscle

Looking up?

- Inferior rectus muscle
- Superior oblique muscle

Looking down?

The intact muscle will pull

What happens in case of a nerve lesion?

- Ptosis of the eyelid
- Depression and abduction of the eye
- Fully dilated pupil
- Diplopia

What happens if there is a complete oculomotor nerve palsy?

Dilated pupil

What happens if there is a partial lesion of the oculomotor nerve?

Double vision

What is diplopia?

- Inability to look down and laterally
- Diplopia

What happens if there is a trochlear palsy?

- Inability to look laterally
- Diplopia

What happens if there is an abducent nerve palsy?

- Ptosis of the eyelid
- Myosis (loss of dialator pupillae muscle function)

What happens if there is a lesion of the superior cervical ganglion?

- Frontal eye field, br. 8
- Parieto-occipital eye field, br. 7

What are the cortical areas for controlling eye movements?

Center for voluntary saccades

What is frontal eye field's function?

Center for smooth pursuit movements
- fixation center

What is parieto-occipital eye field's function?

- Superior colliculus
- Pretectal area
- Paramedian pontine reticular formation

To where does the frontal eye field send efferents?

Eyes deviate to the same side as the lesion

What happens if there is a lesion of the corticopontine pathway?

Eyes deviate to the opposite side as the lesion

What happens if there is a lesion of the paramedian pontine reticular formation?

The eye on the contralateral side can be abducted

What happens if there is a lesion of the medial longitudinal fasciculus?

- Pretectal area
- Rostral interstitial nucleus of the MLF
- Interstitial nucleus of Cajal

What are the centers that control vertical eye movements?

Control upward eye movements

What is the function of the pretectal area?

Direct the gaze downwards

What is the function of the rostral interstitial nucleus of MLF?

Rotatory eye movements

What is the function of the interstitial nucleus of Cajal?

Palsy of upward gaze

What is the symptom of Parinaud syndrome?

Parinaud syndrome

Palsy of upward gaze