A

• Ankle Clonus

  • Definition: Involuntary, rhythmic muscle contractions and relaxations in response to sudden dorsiflexion of the foot.

  • Clinical significance: Indicates upper motor neuron (UMN) lesion (e.g., stroke, spinal cord injury).

  • Exam tip: Test by briskly dorsiflexing the ankle and holding; observe for repetitive beats.

• Atrophy

  • Definition: Loss of muscle bulk due to denervation or disuse.

  • Significance: Suggests lower motor neuron (LMN) lesions, peripheral neuropathy, or chronic disuse.

  • Exam tip: Compare muscle bulk bilaterally, especially in calf and thigh.

B

• Babinski Sign

  • Definition: Upgoing plantar reflex where the big toe dorsiflexes and other toes fan out when the lateral sole is stroked.

  • Significance: Indicative of UMN lesion affecting corticospinal tract.

  • Exam tip: Use a blunt object to stroke the sole firmly from heel to toes.

• Balance

  • Definition: Ability to maintain posture and equilibrium.

  • Exam tip: Assess using Romberg test (standing feet together, eyes closed) and gait assessment.

C

• Clonus

  • See Ankle Clonus.

• Coordination

  • Definition: Smooth, accurate, and controlled muscle movements.

  • Exam: Heel-to-shin test for lower limb coordination to assess cerebellar function.

D

• Deep Tendon Reflexes (DTRs)

  • Common lower limb reflexes:

    • Patellar reflex (L3-L4): Knee jerk elicited by tapping patellar tendon.

    • Achilles reflex (S1): Ankle jerk elicited by tapping Achilles tendon.

  • Clinical relevance:

    • Increased reflexes → UMN lesion.

    • Reduced/absent reflexes → LMN lesion or peripheral neuropathy.

• Dermatomes

  • Definition: Areas of skin innervated by sensory fibers of a single spinal nerve root.

  • Exam: Test light touch, pinprick, and temperature along L2-S2 dermatomes to localize sensory deficits.

F

• Foot Drop

  • Definition: Inability to dorsiflex the foot due to weakness of the anterior tibialis muscle.

  • Causes: Peroneal nerve palsy, L5 radiculopathy, stroke.

  • Exam tip: Assess dorsiflexion strength and gait (steppage gait).

G

• Gait

  • Types: Normal, ataxic, spastic, steppage, waddling.

  • Exam: Observe walking normally, on heels and toes, and tandem gait (heel-to-toe).

  • Significance: Different gait patterns indicate different neurological or muscular pathologies.

H

• Hypotonia

  • Definition: Decreased muscle tone resulting in floppy limbs.

  • Significance: Suggests LMN lesion, cerebellar disease, or acute peripheral neuropathy.

I

• Inversion & Eversion of Foot

  • Definition: Movements controlled by different nerve roots and peripheral nerves.

  • Clinical relevance: Weakness may localize lesions to L4-L5 (inversion) or L5-S1 (eversion).

M

• Muscle Power

  • Assessment: Graded 0 to 5 (0 = no movement; 5 = normal strength).

  • Key muscle groups:

    • Hip flexors (L2-L3),

    • Knee extensors (L3-L4),

    • Ankle dorsiflexors (L4-L5),

    • Plantar flexors (S1).

  • Exam tip: Compare bilaterally and test against resistance.

• Muscle Tone

  • Definition: Resistance to passive movement.

  • UMN lesion: Increased tone (spasticity).

  • LMN lesion: Decreased tone (flaccidity).

P

• Plantar Reflex

  • See Babinski Sign.

• Proprioception

  • Definition: Awareness of limb position in space.

  • Exam: Move patient’s big toe up or down with eyes closed and ask direction.

  • Significance: Loss suggests dorsal column dysfunction.

R

• Reflexes

  • See Deep Tendon Reflexes.

• Romberg Test

  • Definition: Assessment of proprioception and balance.

  • Exam: Patient stands with feet together and eyes closed; loss of balance indicates proprioceptive or vestibular dysfunction.

S

• Sensory Testing

  • Modalities: Light touch, pain (pinprick), temperature, vibration, and proprioception.

  • Exam tip: Test systematically on lower limbs to identify pattern of sensory loss (e.g., dermatomal, stocking-glove).

• Spasticity

  • Definition: Velocity-dependent increase in muscle tone.

  • Significance: Classic UMN sign.

• Straight Leg Raise (SLR) Test

  • Purpose: Assess for lumbar radiculopathy, especially L5-S1 nerve roots.

  • Positive test: Reproduction of sciatic pain between 30-70 degrees of leg elevation.

T

• Tone

  • See Muscle Tone.

• Tendon Reflexes

  • See Deep Tendon Reflexes.

V

• Vibration Sense

  • Exam: Use a 128 Hz tuning fork on bony prominences (e.g., medial malleolus).

  • Significance: Loss seen in peripheral neuropathy, dorsal column disease.

Key Clinical Pearls

• UMN lesions → increased tone, hyperreflexia, positive Babinski, clonus, spasticity.

• LMN lesions → decreased tone, hyporeflexia, muscle atrophy, fasciculations.

• Sensory deficits help localize lesions: dermatomal patterns suggest nerve root pathology; stocking-glove pattern suggests peripheral neuropathy.

• Gait assessment provides valuable clues for lesion localization and severity.