Final answer:
Neurological examination of the 3rd cranial nerve impairment reveals ptosis, dilated pupil, reduced or absent pupillary light reflex, an 'down and out' deviation of the eyeball, and restricted movements in eye muscles innervated by the oculomotor nerve.
Step-by-step explanation:
The neurological examination findings in a patient with an impairment of the 3rd cranial nerve (n.oculomotorius) would typically show the following:
- A. Eyelid cracks: The patient may present with ptosis, or drooping of the eyelid, due to weakness or paralysis of the levator palpebrae superioris muscle.
- B. Pupils: The affected pupil may be dilated (mydriasis) because the parasympathetic fibers running with the oculomotor nerve that constrict the pupil are impaired.
- C. Reaction of pupils to light: There will be a sluggish or absent pupillary light reflex on the side of the lesion as the fibers responsible for constriction in response to light are compromised.
- D. Position of eyeballs: Eyeball position may deviate 'down and out' due to unopposed action of the lateral rectus and superior oblique muscles, which are controlled by the abducens and trochlear nerves, respectively.
- E. Eyeball movements: Limitations in most movements of the eyeball will be apparent, excluding abduction (by the lateral rectus) and intorsion (by the superior oblique), as those are controlled by the abducens and trochlear nerves.