Brain stem examination120
| Response to pain | Flexion to supraocular pain | Diencephalic | |
| Extension to supraocular pain | Midbrain/upper pontine | ||
| None | Lower pontine | ||
| Posture | Normal | Brainstem intact | |
| Hemiparesis | Uncal herniation | ||
| Decorticate | Diencephalic | ||
| Decerebrate | Midbrain/upper pontine | ||
| Flaccid | Lower pontine | ||
| Tone/reflexes/plantars | Normal | Brainstem intact | |
| Unilateral pyramidal | Uncal herniation | ||
| Bilateral pyramidal | Diencephalic | ||
| Flaccid/extensor plantars | Lower pontine | ||
| Oculocephalic (doll's eye) | Saccadic eye movements | Normal forebrain control | |
| Exclude cord injury | Full deviation eyes away | Diencephalic | |
| Turn head from side to side, watch eyes | Minimal deviation eyes | Midbrain/upper pontine | |
| No movement eyes | Lower pontine | ||
| Oculovestibular (calorics) | Nystagmus | Normal forebrain control | |
| Exclude perforated eardrum | Full deviation eyes towards | Diencephalic | |
| Head in midline and 30° back | Minimal deviation eyes | Midbrain/upper pontine | |
| Inject 20 ml ice cold water into ear canal | No movement eyes | Lower pontine | |
| Pupil size | Normal midpoint | Midbrain/upper pontine | |
| Small | Diencephalic | ||
| Unilaterally large | Uncal herniation | ||
| Bilaterally large | Lower pontine | ||
| Pupil response to light | Brisk | Brainstem intact | |
| Bright torch | Unresponsive | Midbrain/upper pontine | |
| Respiratory pattern | Normal | Brainstem intact | |
| Cheyne–Stokes | Diencephalic | ||
| Hyperventilation | Midbrain/upper pontine | ||
| Ataxic, shallow | Lower pontine | ||
| Gasping, slow, irregular | Medullary | ||
Bold refers to clinical signs of potentially reversible cerebral herniation.