What is the motor function of the oculomotor nerve?
The oculomotor nerve is the third cranial nerve (CN III). It allows movement of the eye muscles, constriction of the pupil, focusing the eyes and the position of the upper eyelid. Cranial nerve III works with other cranial nerves to control eye movements and support sensory functioning.
How do you assess CN III?
Inability to follow and object in direction of CN III (the quickest test is to observe upward gaze which is all CN III; the eye on the affected side does not look upward) Inability to open the eyelid. CN III dysfunction causes the eyelid on the affected side to become “droopy”. This is called ptsosis.
Is oculomotor nerve sensory or motor?
Somatic Motor
| Nerves in Order | Modality | Function |
|---|---|---|
| Olfactory | Special Sensory | Smell |
| Optic | Special Sensory | Vision |
| Oculomotor | Somatic Motor Visceral Motor | Levator palpebrae, superioris, superior, medial & inferior recti muscles Parasympathetic to ciliary & pupillary constrictor muscles |
| Trochlear | Somatic Motor | Superior oblique muscle |
What muscles does oculomotor control?
The oculomotor nerve controls several muscles:
- Levator palpebrae superioris – raises the upper eyelid.
- Superior rectus muscle – rotates the eyeball backward, “looking up”
- Medial rectus muscle – adducts the eye, “looking towards your nose”
- Inferior rectus muscle – rotates the eyeball forwards, “looking down”
What is the function of the oculomotor nerve quizlet?
What are the functions of the oculomotor nerve? Nerve III controls muscles that turn eyeball up,down, and medially as well as controlling the iris, lens, and the upper eyelid.
What are cranial nerves 3/4 and 6?
Cranial nerves (CN) III, IV, and VI are motor (efferent) nerves that control the six muscles of the eye (three pairs of antagonistic muscles). CN VI innervates the lateral rectus muscle, while CN IV innervates the superior oblique muscle.
Which cranial nerves have motor functions only?
Cranial nerves III, IV, VI, XI, and XII are pure motor nerves.
Which cranial nerves have significant motor and sensory function?
The trigeminal nerve is the largest of your cranial nerves and has both sensory and motor functions.
What is the common function of cranial nerves III IV and VI?
Cranial nerves III (CNIII) (oculomotor), IV (trochlear), and VI (abducens) control the position of the eyeballs; CNIII influences the position of the eyelids and the size of the pupils.
How do you test for CN 2?
2nd Cranial nerve For the 2nd (optic) cranial nerve, visual acuity is tested using a Snellen chart for distance vision or a handheld chart for near vision; each eye is assessed individually, with the other eye covered.