Tendon reflexes and their pathological alterations

1. Big picture

Tendon reflexes, also called deep tendon reflexes or own reflexes, are one of the most objective parts of the neurological examination. They need little patient cooperation and give direct information about the integrity of the reflex arc and the influence of the upper motor neuron system on spinal motor neurons.

For the exam, the key idea is simple:

Decreased or absent tendon reflex → problem in the reflex arc / lower motor neuron system. Increased tendon reflex ± clonus → upper motor neuron / pyramidal tract lesion, after the acute phase.

Always interpret tendon reflexes together with muscle tone, muscle power, atrophy, fasciculations, sensory findings, Babinski sign and symmetry.