Reflex hammer

A handheld neurological examination instrument with a soft head, used to tap tendons and assess muscle stretch reflexes.

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Deep tendon reflex: A muscle contraction elicited by briefly stretching its tendon, commonly tested during neurological examinations. The hammer is used to evoke these reflexes by tapping their tendons.
Muscle spindle: A sensory receptor within skeletal muscle that detects changes in muscle length and the speed of stretching. Tendon impact briefly stretches muscle fibers, activating these receptors.
Taylor reflex hammer: A triangular-headed reflex hammer with a flexible handle, commonly used for tendon-reflex testing. Its distinctive design is one familiar form of the instrument.
Superficial reflex: A reflex elicited by stimulating the skin or mucous membrane rather than stretching a tendon. Unlike tendon reflexes, these responses begin with cutaneous stimulation.
Patellar reflex: Knee extension caused by tapping the patellar tendon and stretching the quadriceps muscle. A standard hammer test that checks the reflex arc serving the quadriceps.
Ia afferent fiber: A fast sensory nerve fiber that carries muscle-spindle stretch signals into the spinal cord. It conveys the stimulus produced by the hammer toward the spinal reflex circuit.
Queen Square reflex hammer: A long-handled reflex hammer with a weighted, disk-shaped head used in neurological examinations. Its weight and handle provide an alternative way to deliver a tendon tap.
Hoffmann sign: Finger flexion after a brief flick of the distal middle finger, sometimes used as a sign of upper motor neuron dysfunction. It is elicited by a finger maneuver, not by striking a tendon with a hammer.
Achilles reflex: Downward movement of the foot after tapping the Achilles tendon and stretching the calf muscles. This tendon is another common site tested with a reflex hammer.
Alpha motor neuron: A spinal motor neuron that sends signals to skeletal muscle fibers to produce contraction. The reflex response reaches muscle through this neuron’s motor output.