Internal Medicine Glossary

1. Muscle Tone

  • Definition: The resistance of muscle to passive stretch during resting state.

  • Types:

    • Normal tone: Slight resistance felt when passively moving the limb.

    • Hypertonia: Increased tone, seen in upper motor neuron lesions. Subtypes:

      • Spasticity: Velocity-dependent increase in tone (e.g., stroke, MS).

      • Rigidity: Uniform resistance (e.g., Parkinson’s disease).

    • Hypotonia: Decreased tone, common in lower motor neuron lesions or acute UMN lesions.

  • Assessment: Passively move shoulder, elbow, wrist, and fingers; note resistance.


2. Muscle Strength

  • Definition: The force a muscle can exert voluntarily.

  • Grading (Medical Research Council scale):

    • 0: No contraction

    • 1: Flicker or trace of contraction

    • 2: Movement with gravity eliminated

    • 3: Movement against gravity

    • 4: Movement against some resistance

    • 5: Normal power

  • Testing:

    • Shoulder abduction/adduction (C5-C6)

    • Elbow flexion/extension (C5-C7)

    • Wrist extension/flexion (C6-C8)

    • Finger grip (C8-T1)

    • Finger abduction (ulnar nerve, T1)


3. Reflexes

  • Definition: Automatic muscle responses to specific stimuli, assessing integrity of reflex arcs and CNS pathways.

  • Upper Limb Reflexes:

    • Biceps reflex (C5-C6): Strike biceps tendon; forearm flexion indicates intact reflex.

    • Brachioradialis reflex (C6): Strike radius near wrist; forearm flexion and supination.

    • Triceps reflex (C7-C8): Strike triceps tendon; elbow extension.

  • Abnormal findings:

    • Hyperreflexia: Indicates UMN lesion.

    • Hyporeflexia/absent reflex: Suggests LMN lesion or peripheral neuropathy.

    • Clonus: Repetitive reflex beats, suggests UMN lesion.


4. Sensory Examination

  • Modalities to test:

    • Light touch (via cotton wool or brush)

    • Pain (pinprick)

    • Temperature (cold tuning fork or test tubes)

    • Proprioception (position sense of fingers)

    • Vibration (128 Hz tuning fork on bony prominences)

    • Discriminative sensation:

      • Stereognosis: Identifying objects by touch

      • Graphesthesia: Recognizing numbers drawn on skin

      • Two-point discrimination

  • Nerve distributions: Assess median, ulnar, radial nerves and dermatomes C5-T1.


5. Coordination Tests

  • Purpose: Assess cerebellar function and proprioception.

  • Tests:

    • Finger-to-nose test: Patient touches your finger then their own nose repeatedly.

    • Rapid alternating movements (pronation/supination of hands): Look for dysdiadochokinesia.

    • Finger tapping: Speed and rhythm assessment.

  • Abnormalities: Dysmetria (overshoot or undershoot), intention tremor, irregular movements.


6. Special Signs

  • Pronator Drift:

    • Test: Patient holds arms outstretched, palms up, eyes closed.

    • Positive: One arm pronates and drifts downward, indicating contralateral corticospinal tract lesion.

  • Tinel’s Sign (at wrist):

    • Test: Tap over median nerve at the wrist.

    • Positive: Tingling sensation in median nerve distribution, suggesting carpal tunnel syndrome.

  • Phalen’s Test:

    • Test: Patient flexes wrists fully, pressing backs of hands together for 60 seconds.

    • Positive: Tingling in median nerve distribution, indicating median nerve compression.


7. Nerve Stretch Tests

  • Purpose: Detect nerve root irritation or radiculopathy.

  • Examples:

    • Spurling’s test: Extension and rotation of neck to the affected side to elicit radicular arm pain.

    • Upper limb tension tests: Various maneuvers to stretch brachial plexus or cervical nerve roots.


8. Peripheral Nerve Examination

  • Median nerve:

    • Motor: Thumb opposition and abduction

    • Sensory: Palmar aspect of lateral 3.5 fingers

  • Ulnar nerve:

    • Motor: Finger abduction/adduction, flexion of 4th and 5th digits

    • Sensory: Medial 1.5 fingers

  • Radial nerve:

    • Motor: Wrist and finger extension

    • Sensory: Posterior arm and dorsum of hand (lateral 3 fingers except fingertips)


9. Clinical Correlation

  • Upper Motor Neuron Lesion (UMN):

    • Weakness with increased tone and hyperreflexia, positive Babinski, no muscle atrophy initially.

  • Lower Motor Neuron Lesion (LMN):

    • Weakness with hypotonia, hyporeflexia, muscle wasting, fasciculations.

  • Peripheral neuropathy:

    • Symmetrical distal sensory loss, decreased reflexes.

  • Radiculopathy:

    • Dermatomal sensory loss, motor weakness in nerve root distribution, positive nerve stretch tests.

  • Plexopathy or Mononeuropathy:

    • Mixed motor and sensory deficits following peripheral nerve distribution.


10. Practical Examination Tips

  • Ensure patient comfort and privacy.

  • Use systematic side-to-side comparison.

  • Start with observation for atrophy, fasciculations, tremors.

  • Always correlate findings with patient history.

  • Document muscle strength and tone carefully.

  • Note asymmetry and focal deficits.

  • Repeat reflex tests if uncertain; confirm with reinforcement techniques.

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