Harrington rod:  An old type of spinal instrumentation used to correct scoliosis.

 

health maintenance organization:  A type of insurance coverage for medical care in which all care is given by a group of doctors who are under contract to provide services at a reduced fee.

 

herniated disc:  A lumbar intervertebral disc in which a portion of the nucleus pulposus has moved to an abnormal position.

 

hologram:  A three-dimensional image projection.