a deep tendon reflex elicited when the Achilles tendon is stretched and then struck with a tendon hammer. The normal response is reflex contraction of the calf muscles and plantar flexion of the ankle. The ankle jerk may be increased if the spinal cord is compressed above the level of the first sacral spinal nerve (which arises at the level of the second lumbar vertebra). If the nerve itself is cut or compressed the reflex is reduced or absent.
The joint between the leg bones (TIBIA and FIBULA) above, and the TALUS (the Roman dice-bone) below. It is a very strong joint with powerful ligaments binding the bones together at either side, and bony projections from the leg bones, which form large bosses on either side, called the outer and inner malleoli, extending about 12 mm (half an inch) below the actual joint. Two common injuries near the ankle are a sprain, on the inner side, consisting of tearing of the internal ligament; and fracture of the ?bula (Pott’s fracture) on the outer side. (See also JOINTS, DISEASES OF.)... ankle
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).... biceps jerk
a tendon reflex that acts at the level of the seventh cervical spinal nerve. With the elbow flexed and relaxed, the triceps tendon is struck just above the elbow, causing contraction of the triceps and extension of the elbow. This reflex is increased in upper *motor neuron lesions and absent in lower motor neuron lesions.... triceps jerk
Health Encyclopedia