SDL 2: Jaw and eye muscles Flashcards
List the 6 muscles involved in the movement of the eye.
Superior rectus Inferior rectus Lateral rectus Medial rectus Superior oblique Inferior oblique
Which of the extra-ocular muscles are innervated by the oculomotor nerve (CNIII)?
Superior rectus
Inferior rectus
Medial rectus
Inferior oblique
Which extra-ocular muscle is innervated by the trochlear nerve (CNIV)?
Superior oblique
Which extra-ocular muscle is innervated by the abducens nerve (CNVI)?
Lateral rectus
How would you test the function of the oculomotor nerve (CNIII)?
Ask the patient to look medially. Check the upper eyelid is fully retracted on upward gaze.
How would you test the function of the trochlear nerve (CNIV)?
Ask the patient to look medially then downwards. Isolated region very rare.
How would you test the function of the abducens nerve?
Ask the patient to look laterally.
What is the function of the levator palpabrae superior?
Retract the upper eyelid.
Which muscle malfunctions during ptosis?
Levator palpebrae superioris
What is Horner’s syndrome?
Combination of symptoms that arises when the sympathetic trunk is damaged. The signs and symptoms occur on the same side as the lesion of the sympathetic trunk. It is characterized by miosis (a constricted pupil), ptosis (a weak, droopy eyelid), apparent anhidrosis (decreased sweating), with or without enophthalmus (inset eyeball).
Why does mild ptosis occur in Horner’s syndrome?
Loosthe superior tarsal muscle which produces ptosis
What are the actions of each of the 6 extra-ocular muscles controlling the eye?
Superior rectus - elevation (primarily - also intorsion and adduction)
Inferior rectus - depression (primarily - also extorsion and adduction)
Lateral rectus - abduction
Medial rectus - adduction
Superior oblique - intorsion, depression and abduction
Inferior oblique - extorsion, elevation and abduction
Which two visual reflexes would be absent in a patient with unilateral oculomotor nerve damage. Which other cranial nerve is involved in these reflexes.
Pupillary light reflex
Accommodation reflex
(CNII also involved)
What is the role of the ciliary ganglion?
Provides autonomic innervation to the sphincter pupillae constricts the pupil, a movement known as Miosis. The opposite, Mydriasis, is the dilation of the pupil.
Also innervates the ciliaris, causing it to contract, releasing tension on the Zonular Fibers, making the lens more convex, also known as accommodation.
Which bony structure acts with the lateral ligament to prevent dislocation of the TMJ?
The articular tubercle
Which two other functional ligaments can be found within the TMJ?
Collateral (lateral and medial)
Capsular
NB: Everywhere I look gives different answers and I can’t find the attachments
What are the four principle muscles of mastication?
Masseter
Temporalis
Lateral pterygoid
Medial pterygoid
Which muscle(s) are responsible for elevation of the mandible (closing the mouth)?
Temporalis
Masseter
Medial pterygoid (minor role)
Which muscle(s) are responsible for depression of the mandible (opening the mouth)?
Lateral pterygoid (assisted by digastric)
Which muscle(s) are responsible for protrusion of the mandible?
Lateral pterygoid
Which muscle(s) are responsible for retrusion of the mandible?
Temporalis
Which muscle(s) are responsible for lateral movements of the mandible?
Medial pterygoid
What is the nerve supply to the muscles of mastication?
Motor component of the mandibular division of the trigeminal nerve (V3).
What foramina does this nerve branch pass through?
Foramen ovale
