Bizepsreflex

Bizepsreflex, also known as the biceps reflex or musculocutaneous reflex, is a deep tendon reflex that assesses the function of the C5–C6 spinal cord segments and the musculocutaneous nerve. A brisk tap on the biceps brachii tendon normally elicits elbow flexion, sometimes with a brief forearm supination.

Anatomy and mechanism: The reflex arc involves afferent fibers from the biceps tendon traveling via the musculocutaneous nerve to the spinal cord, where they synapse with motor neurons that project back to the biceps muscle. The biceps brachii is primarily innervated by the musculocutaneous nerve, with C5–C6 providing the key motor input.

Technique: The patient sits with the forearm supported and the elbow flexed about 90 degrees, slightly supinated. The clinician palpates or visually identifies the biceps tendon in the antecubital fossa and taps it with a reflex hammer. A normal response is a brisk elbow flexion, often accompanied by minor forearm supination.

Interpretation: A symmetric normal reflex is expected in healthy individuals. A diminished or absent biceps reflex suggests dysfunction of the C5–C6 roots or musculocutaneous nerve, such as radiculopathy or peripheral neuropathy. Hyperreflexia may indicate an upper motor neuron lesion above the reflex arc. Findings should be interpreted in the context of other neurological signs and patient age.

Clinical relevance: The biceps reflex is part of a standard upper limb examination and helps localize lesions affecting the cervical spine or peripheral nerves, particularly around the C5–C6 level.