Visual fields, muscles, innervations and movement Flashcards
What does RAPD stand for?
Relative Afferent Pupil Defect
How do you check for nerve damage if one pupil is un-observable due to, hypothetically say, blood?
Even if the pupil is un-observable, light will still penetrate to the back of the eye and the pupil of the good eye should be observed for reaction.
A light is shined into both eyes. when in the right eye both pupils are reactive. On the left there is a bilateral lack of miosis. what does this mean?
That there is complete damage to the optic nerve of the Left eye.
A light is shined into both eyes. when in the right eye both pupils are reactive. When shone into the left eye the pupil appears to dilate. what does this mean?
It is relative afferent pupil defect (RAPD) also called Marcus Gunn pupil. The optic nerve of the left eye is damaged or impeded meaning that even though the left pupil is actually constricting, it is doing so to a lesser degree than the right and so appears to dilate.
Give an example of an afferent pupil defect and its method of detection?
Marcus Gunn pupil or relative afferent pupillary defect (RAPD) is a medical sign observed during the swinging-flashlight test whereupon the patient’s pupils constrict less (therefore appearing to dilate) when a bright light is swung from the unaffected eye to the affected eye.
Give an example of a cause of an efferent pupil defect?
Apical lung tumour (pankost tumour).
What would you expect from a visual field diagram when someone is blind is one eye and where would the problem be?
It is complete vision loss in one field. It is damage or an optic nerve leision.
What would a visual field diagram look like for someone with bitemporal hemianopia and what would cause it?
It is loss of half of the visual field on the lateral sides of vision. It can be caused by optic chiasm tumour, pituitary tumour or craniopharyngioma. It can also be the result of an aneurysm.
What would a visual field diagram look like for someone with homonymous hemianopia and what would cause it?
Homonymous hemianopsia is when half of 2 same side is obscured. It can be congenital, but is usually caused by brain injury to the optic tract. Stroke, trauma, tumors, infection, or following surgery.
What would a visual field diagram look like for someone with left homonymous inferior quadrantanopia and what would cause it?
Lower left quadrant loss. Leision of the left parietal radiation.
What would a visual field diagram look like for someone with homonymous superior quadrantanopia and what would cause it?
Upper quadrant loss caused by a leision to the temporal radiation/Meyers loop
What would a visual field diagram look like for someone with homonymous hemianopia with central sparring and what would cause it?
Homonymous sided vision loss with central sparring. caused by an Occipital liesion/stroke.
A patient cant see from the left side of both eyes? What has happened to them and where is the problem?
They have homonymous hemianopia that has been caused by an infarct or liesion to the right optic tract
A person cannot see the outside half of either eye. What is it and where is the problem?
It is bitemporal hemianopia and it is caused by a liesion pressing on the optic chiasm. think pituitary.
What is the pink muscle, what does it do and what is its innervation?
Superior rectus muscle. It pulls gaze upwards and laterally. (in conjunction with the inferior oblique muscle it raises gaze directly up. It is inervated by the CN 3.
What is the red muscle, what does it do and what is its innervation?
Superior oblique muscle. It pulls gaze medially and down. It is innervated by CN4. (SO4+LR6+everything else)
What is the green muscle, what does it do and what is its innervation?
It is the inferior obliques muscle. It pulls gaze medially and up. It is innervated by CN3.
What is the cyan muscle, what does it do and what is its innervation?
It is the inferior rectus muscle. It pulls the eye down and laterally. It is innervated by CN3. It works with the superior olique to look directly down.
What is the Blue muscle, what does it do and what is its innervation?
It is the lateral rectus muscle. It pulls gaze laterally. it is innervated by CN6.
