MEDULLA CROSS-SECTION

Draw in 30 seconds. One image = 3 syndromes.

THE IMAGE TO MEMORIZE

DORSAL Gracilis • Cuneatus • Vestibular LATERAL SpThalamic Sp V nucleus Nuc Ambiguus Inf Cer Ped Sympathetics↓ LATERAL IX, X, XI Horner's Ataxia Vertigo MEDIAL Pyramid (CST) Medial Lemniscus CN XII (Hypoglossal) MLF ASA Anterior Spinal Artery PICA PICA POSTERIOR ANTERIOR

DRAW IT IN 4 STROKES

1

Draw an oval

2

Horizontal line → top = DORSAL

3

Two vertical lines → sides = LATERAL

M L L D
4

Label: D top, L sides, M center

BLOCK A VESSEL → NAMED SYNDROME

🟢 MEDIAL MEDULLARY (Dejerine)

Vessel: ASA (Anterior Spinal Artery)

The 4 M's:

Motor — contralateral hemiplegia (pyramid)

Medial lemniscus — contralateral proprioception/vibration loss

MLF — internuclear ophthalmoplegia

Motor of tongue — ipsilateral tongue deviation (CN XII)

💡 Tongue points TO the lesion. Body weak on OTHER side.

🔴 LATERAL MEDULLARY (Wallenberg)

Vessel: PICA (Post. Inferior Cerebellar A.)

Everything except motor:

• Ipsilateral face pain/temp loss (Sp V nucleus)

• Contralateral body pain/temp loss (SpThal tract)

• Dysphagia + hoarseness (Nucleus Ambiguus → IX, X)

• Ipsilateral Horner's (descending sympathetics)

• Vertigo + nystagmus (vestibular nuclei)

• Ipsilateral ataxia (inferior cerebellar peduncle)

💡 NO hemiplegia. Pyramid is spared (it's medial).

THE ONE RULE:
Medial = Motor (pyramid lives medially → hemiplegia)
Lateral = everything else (sensory, cerebellar, autonomic, cranial nerves)

CROSSED PATTERN: Face = ipsilateral, Body = contralateral (in BOTH syndromes)

WHICH CRANIAL NERVES LIVE HERE?

MIDBRAIN III, IV PONS V, VI, VII, VIII MEDULLA IX, X, XI, XII 2 4 4 ← 2-4-4
2-4-4 rule: Midbrain = 2 nerves (III,IV) • Pons = 4 nerves (V-VIII) • Medulla = 4 nerves (IX-XII)

In Wallenberg: IX, X hit → dysphagia, hoarse voice, absent gag reflex
In Dejerine: XII hit → tongue deviates toward lesion

5 RETENTION ANCHORS

  1. Oval → 3 zones: Dorsal (top), Lateral (sides), Medial (center-bottom). That's your whole diagram.
  2. ASA feeds Medial, PICA feeds Lateral. Two vessels, two syndromes. Done.
  3. Medial = Motor (4 M's). Pyramid is medial → hemiplegia. Lateral = everything EXCEPT motor.
  4. Wallenberg has NO hemiplegia. If there's limb weakness, it's NOT Wallenberg — it's Dejerine or pontine.
  5. 2-4-4: Midbrain 2 (III,IV), Pons 4 (V-VIII), Medulla 4 (IX-XII). Wallenberg = IX,X. Dejerine = XII.