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Q-1 (IMG_2089) - 1984 Nobel Prize in Physiology or Medicine

• Myeloma cells (TK-) are HAT-sensitive - they die because aminopterin blocks the de novo DNA synthesis pathway, and they lack TK to use the salvage pathway
• Splenic B-cells are mortal - they die on their own
• Only the fused hybridoma cells (TK+) survive - they are immortal AND can use the salvage pathway

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Q-2 (First image) - Nobel Prize in Physiology or Medicine

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Q-4 (Third image)

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Complete CNS (Central Nervous System) Examination

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OVERVIEW - ORDER OF EXAMINATION

1. Higher Mental Functions (consciousness, cognition)
2. Cranial Nerves (CN I-XII)
3. Motor System (tone, power, reflexes, coordination)
4. Sensory System (primary + cortical modalities)
5. Gait & Cerebellar

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PART 1: HIGHER MENTAL FUNCTIONS

Bare minimum: Level of consciousness + orientation to time, place, person.

A. Level of Consciousness

• Ranges from fully awake to comatose
• Describe the minimum stimulus needed to elicit a response:
  • Verbal commands
  • Squeeze of trapezius muscle (brief pain)
• Distinguish purposeful responses (reaching toward pain, eye contact) from reflex spinal responses (triple flexion: ankle + knee + hip flexion to plantar stimulus)

B. Orientation

• Name (person)
• Location (place)
• Day of week + date (time) - time is usually the first to be lost

C. Speech vs. Language

1. Name components of a watch or pen (increasingly detailed)
2. Repeat "No ifs, ands, or buts"
3. Follow a 3-step verbal command
4. Write a sentence
5. Read and respond to a written command

D. Memory (3 Time Scales)

E. Fund of Information

• Ask about major historic or current events
• Adjust for educational level and life experience

F. Insight & Judgment

• Detected during interview
• Formal test: "What would you do if you found a wallet on the sidewalk?"

G. Abstract Thought

• Similarities: "How are an apple and an orange alike?"
• List items with shared attributes: "Name four-legged animals"

H. Calculation

• Age/education appropriate tasks
• Serial 7s (subtract 7 from 100 repeatedly) or serial 3s from 20
• Simple word problems

Cognitive Domains & Localization (Goldman-Cecil)

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PART 2: CRANIAL NERVE (CN) EXAMINATION

Bare minimum: Check fundi, visual fields, pupils (size & reactivity), extraocular movements, facial movements.

Test CNs in numerical order; group CN III, IV, VI together (all control eye movements).

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CN I - Olfactory

• Often omitted unless inferior frontal lobe disease (e.g., meningioma) suspected
• Eyes closed - patient sniffs a mild odorant (toothpaste, coffee) and identifies it

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CN II - Optic

• Visual acuity: Snellen chart (with glasses/contacts)
• Visual fields by confrontation:
  • Face patient at 0.6-1.0 m; hands at periphery of your own visual fields
  • Patient looks at center of your face; indicates when/where they see movement
  • Screen both eyes simultaneously; test each separately if abnormality found
• Fundoscopy: Inspect optic disc, macula, vessels

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CN III, IV, VI - Oculomotor, Trochlear, Abducens

• Pupillary light reflex (CN II afferent / CN III efferent): direct & consensual
• Extraocular movements: Ask patient to follow finger in an "H" pattern
  • CN III: up, down, medial gaze; elevates lid
  • CN IV: depression when eye adducted (reading)
  • CN VI: lateral gaze
• Check for nystagmus and diplopia in eccentric gaze

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CN V - Trigeminal

• Sensation: Light touch in V1 (forehead), V2 (cheek), V3 (jaw) - both sides
• Corneal reflex: Light cotton wisp to cornea (V1 afferent / CN VII efferent)
• Motor: Clench jaw - palpate masseter; open jaw against resistance (pterygoids)
• Jaw deviates toward the weak side with unilateral lesion

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CN VII - Facial

• Upper face (forehead wrinkling, eye closure) - spared in UMN lesions (bilateral cortical innervation)
• Lower face (show teeth, puff cheeks, smile) - affected in both UMN and LMN lesions
• Asymmetry is the key finding

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CN VIII - Vestibulocochlear

• Hearing: Whispered voice test; finger rub
• Weber test: Tuning fork on vertex - lateralizes to affected ear (conductive loss) or good ear (sensorineural loss)
• Rinne test: AC > BC (normal); BC > AC in conductive hearing loss

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CN IX, X - Glossopharyngeal & Vagus

• Observe palate elevation with "Aah" - uvula deviates away from the lesion
• Gag reflex: Touched posterior pharynx (IX afferent / X efferent)
• Assess voice quality (hoarseness = vagal lesion)
• Swallowing evaluation

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CN XI - Spinal Accessory

• Shoulder shrug against resistance (trapezius - C3/C4 + CN XI)
• Head rotation against resistance to each side (sternocleidomastoid)

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CN XII - Hypoglossal

• Inspect tongue for atrophy and fasciculations at rest
• Protrusion: Tongue deviates toward the weak (LMN lesion) side
• Strength: push tongue against inner cheek on each side

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PART 3: MOTOR EXAMINATION

Bare minimum: Look for muscle atrophy + check tone. Assess upper limb: pronator drift + wrist/finger extensors. Lower limb: toe extensors.

A. Appearance

• Inspect muscle groups under good lighting
• Look for:
  • Fasciculations (LMN/anterior horn cell disease)
  • Atrophy or hypertrophy
  • Tenderness
• Involuntary movements:

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B. Tone

• Upper limb: Rapid pronation-supination + flexion-extension at wrist
• Lower limb (supine): Place hands behind knees, rapidly raise them - normal tone = heel drags before lifting; increased tone = heel lifts immediately

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C. Muscle Strength (MRC Scale)

• Pronator drift (very sensitive screen): Arms extended, parallel, eyes closed for 10 sec - pronation/flexion or asymmetry = weakness
• Test major muscle groups in proximal → distal order

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D. Reflexes

• Reinforcement: Jendrassik maneuver (hook fingers and pull) for ankle reflex; teeth-clenching for upper limb
• Test both sides sequentially; record minimum stimulus needed

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PART 4: SENSORY EXAMINATION

Bare minimum: Light touch + temperature in each distal extremity. Double simultaneous stimulation. Romberg test.

Primary Sensory Modalities (test all in each limb)

• Test distal to proximal (abnormal findings guide how far to proceed)
• Compare right vs. left, proximal vs. distal, upper vs. lower limbs

Cortical Sensory Modalities (require intact primary sensation + parietal lobe processing)

Romberg Test (proprioception/dorsal column)

• Patient stands with feet together, arms at sides
• Eyes open first (balance maintained)
• Then eyes closed: swaying/falling = positive Romberg (dorsal column or vestibular disorder)
• A positive Romberg is not a cerebellar sign (cerebellar ataxia is present even with eyes open)

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PART 5: GAIT & COORDINATION (CEREBELLAR)

Gait Observation

• Ask patient to walk normally, then turn, then tandem walk (heel-to-toe)

Cerebellar Tests

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UMN vs. LMN - Key Distinguishing Features

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Quick Reference: Pupillary Findings in Coma

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1. Higher Mental Functions - consciousness/GCS, orientation (person/place/time), speech vs. language, memory (immediate/short-term/long-term), insight, abstract thought, calculation, cognitive domain localization
2. Cranial Nerves (CN I-XII) - step-by-step testing method, what each reflex tests, key abnormal findings (e.g., uvula deviation, tongue deviation direction, facial nerve UMN vs. LMN distinction)
3. Motor System - appearance/fasciculations, tone types (spasticity vs. rigidity vs. cogwheel vs. paratonia), MRC 0-5 power grading, deep tendon reflexes with levels, cutaneous reflexes (Babinski, abdominal, cremasteric, anal), primitive reflexes (grasp, suck, palmomental)
4. Sensory System - all 5 primary modalities with their pathways, cortical sensation (stereognosis, graphesthesia, two-point discrimination, double simultaneous stimulation), Romberg test
5. Gait & Cerebellar - gait patterns with localization, finger-nose, heel-shin, dysdiadochokinesia, rebound