Category: A

In an infant, extension of one or both extremities on the side to which the head is forcibly turned. Flexion of the extremities occurs on the other side.  

Two or more reflexes initiated simultaneously in different receptors that involve the same motor center but produce opposite effects.  

Contraction of the anal sphincter, following irritation or stimulation of the skin around the anus. This reflex is lost if the second to fourth sacral nerves are injured.  

Reflexes initiated by several stimuli originating in widely separated receptors whose impulses follow the final common path to the effector organ and reinforce one another.  

Contraction of the adductor muscles of the thigh on applying pressure to, or tapping, the medial surface of the thigh or knee.  

Forearm flexion with internal rotation of the hand as a result of a quick blow to the acromion; elicited in hyper-reflexic states.  

Involuntary closure of the eyelids after exposure to a sharp, sudden noise. This is a normal startle response that may be exaggerated in patients with anxiety disorders or hyperacusis or blunted in infants or adults with a hearing disorder or facial nerve paralysis.  

A change in heart rate, usually a slowing, resulting from mechanical stimulation of abdominal viscera.  

A device or surface that reflects waves, radiant energy, or sound.  

A laboratory technique for analyzing thin layers of objects, such as biological membranes or layered metallic surfaces. It is performed by exposing an object to neutrons or x-rays, and measuring their scatter from the layered surface.