Physical examination maneuver
Physical Exam
Achilles Deep Tendon Reflex
also known as Ankle jerk
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Video coming September 2026
How to Perform
With the ankle relaxed and the foot slightly dorsiflexed (e.g., the leg crossed over the opposite knee, or the patient kneeling on a chair), strike the Achilles tendon just above its calcaneal insertion with the reflex hammer. The normal response is reflex plantarflexion of the foot.
How to Interpret
Showing 7 of 11 findings
Hypothyroidism
Hung-up Achilles reflex
Rule in
Somewhat helpful
Rule out
—
Evidence:Limited
Peripheral Neuropathy
Lower-extremity bedside cluster positive (≥2 of 3: Achilles reflex absent despite facilitation, vibration <10 seconds at toe with 128-Hz tuning fork, or position sense <8 of 10 1-cm trials at toe)
Rule in
Helpful
Rule out
Very helpful
Evidence:Limited
Rule in
Very helpful
Rule out
Minimally helpful
Evidence:Limited
Hyporeflexia (≤1+) at Achilles
Rule in
Somewhat helpful
Rule out
Helpful
Evidence:Limited
Lower-extremity hyporeflexia pattern (Achilles + patellar both impaired)
Rule in
Somewhat helpful
Rule out
Somewhat helpful
Evidence:Limited
S1 Radiculopathy
Hyporeflexia (≤1+) at Achilles
Rule in
Not helpful
Rule out
Not helpful
Evidence:Limited
Upper Motor Neuron Lesion
Hyperreflexia (≥3+) at Achilles
Rule in
Helpful
Rule out
Somewhat helpful
Evidence:Limited