BRAIN STEM REFLEXES

after a man is paralized, how do I check his pupils and what intracranial nerves to check and how to check for the bouncing of the iriatic muscle and what else to check or tests to perform?

That’s a powerful and clinically rich question, Mario. Let’s break it down into a structured neurological assessment framework, especially in the context of paralysis, where intracranial pathology (like brainstem injury or increased intracranial pressure) may be suspected.

🧠 1. Pupil Examination: What and How to Check

Pupillary assessment gives rapid insight into brainstem function and cranial nerve integrity.

• Size and symmetry: Are both pupils equal (isocoric) or is there anisocoria?

• Shape: Round or irregular?

• Light reflex:

  • Direct response: Shine a light in one eye and observe constriction.

  • Consensual response: The opposite pupil should also constrict.

• Swinging flashlight test: Detects a Relative Afferent Pupillary Defect (RAPD), often due to optic nerve (CN II) damage.

> A fixed, dilated pupil may indicate uncal herniation compressing CN III.

🔍 2. Cranial Nerves to Check (Especially After Paralysis)

Focus on CN II–XII, but especially:

Cranial Nerve	Function	How to Test
CN II (Optic)	Vision, afferent limb of pupillary reflex	Visual fields, acuity, light reflex
CN III (Oculomotor)	Eye movement, pupil constriction	Look for ptosis, "down and out" gaze, mydriasis
CN IV (Trochlear)	Eye depression (superior oblique)	Ask patient to look down and in
CN VI (Abducens)	Lateral eye movement	Ask patient to look laterally
CN VII (Facial)	Facial expression	Smile, raise eyebrows, puff cheeks
CN IX/X (Glossopharyngeal/Vagus)	Gag reflex, palate elevation	Say "ah" – look for uvula deviation
CN XII (Hypoglossal)	Tongue movement	Stick out tongue – deviation suggests lesion

👁️ 3. “Bouncing” of the Iris: Clarifying the Concept

If you're referring to hippus (spontaneous, rhythmic pupil oscillation), it may reflect:

• Early brainstem dysfunction

• Autonomic instability

• Drug effects (e.g., opioids, anticholinergics)

If you meant iridodonesis (iris tremor with eye movement), it’s usually due to lens instability, not neurological injury.

Let me know if you meant something else by “iriatic muscle”—I’d love to clarify further.

🧪 4. Additional Tests to Perform After Paralysis

• Glasgow Coma Scale (GCS): For consciousness level

• Motor strength grading: 0–5 scale for each limb

• Sensory testing: Light touch, pinprick, proprioception

• Reflexes: Deep tendon reflexes, Babinski sign

• Neuroimaging: CT/MRI to assess for hemorrhage, infarct, or mass

• Electrophysiology:

  • EMG/NCS: For peripheral nerve involvement

  • EEG: If seizures or altered consciousness suspected

• Brainstem reflexes (in comatose patients): Corneal, oculocephalic (“doll’s eyes”), and caloric testing