The Crossed Extensor Reflex (CER; also known as the crossed cord reflex) is a protective response that apparently begins at about the 28th week of gestation and is functionally integrated one to two month after delivery. It is functionally significant in back-and-forth (or reciprocal) muscle actions. Its dysfunction can interfere with activities like running and […]

The Idea: Human physiological reflexes have a predictable display. Either they work according to their original design or they are pathological. There are no other choices. If a reflex displays itself in ways other than according to its preprogrammed format, it must be considered to be pathological, and it increases the risk of injury. Reflex […]

Striking a tendon has an almost instant display. A quick stretch to the patellar tendon, for xample, should register with an involuntary jerk of the knee; the foot kicks. This “knee jerk” deep tendon reflex (DTR) test is a common part of even the most basic neurological exam. It assesses the functional integrity of the […]

The neck receptors give rise to a primitive reflex—the Tonic Neck Reflex (TNR)—found in newborn humans. Books say that the TNR normally vanishes by the child’s first birthday, but that appears to be functionally and demonstrably untrue. The TNR persists throughout life and is a fundamental tool for neurological examination. The TNR is fundamental to […]