A deep tendon reflex mediated by the fifth cervical spinal nerve (C5). The examiner’s thumb or index finger is placed over the patient’s biceps tendon in the elbow crease and struck sharply with a tendon hammer; the normal response is a reflex contraction of the biceps and flexion of the elbow. The jerk is exaggerated in upper motor neuron lesions, such as a stroke, and reduced or absent in lower motor neuron lesions, such as a disc herniation, peripheral nerve injury, or peripheral neuropathy (e.g. diabetes, alcoholism).
Subjects: Medicine and Health.