Medical Apparatus: Imaging Guide to Orthopedic Devices

Glossary: G - I



Terms: Click below for the desired term





Medical Devices, Medical Procedures, and Foreign Bodies:
Abbreviations, Acronyms, and Definitions

by Tim B Hunter, MD, MSc and Mihra S. Taljanovic, MD, PhD



Gardner-Wells tongs.  A rigid, semicircular device that contains tongs applied to each side of the skull for skeletal traction to treat cervical spine injuries.

gastrostomy tube.  A tube surgically, percutaneously, or endoscopically placed into the stomach through the anterior abdominal wall and used for long-term administration of feedings.

gauge, gage.  The diameter of a slender object; a measuring instrument having a graduated scale.  The gauge of a firearm is a unit of measurement of the barrel diameter.  In the case of shotguns, the gauge is an inverse number for the fraction of a spherical pound of  lead that would fit the bore of the shotgun.  For example, a 1/12th pound ball fits a 12-gauge shotgun bore. 

GBCA. Gadolinium-based contrast agent(s).

GCS.See Glasgow coma scale.

Gehrung.  A type of pessary.

Gelfoam.  An absorbable gelatinous material used for hemostasis. It may be applied directly to a wound or injected intravascularly. See:

Gellhorn.  A type of pessary.

geometric artifact.  See linear artifact.

ghost track. A lucent hollow, usually long thin cylindrical space in bone representing the sequela of a previous fixation screw, fixation rod, or fixation nail.

Gianturco-Rosch Z-stent. A type of self-expanding metallic stent composed of round stainless steel.  It is used in the vascular and biliary systems to buttress areas of narrowing or obstruction.

Gibbs (truncation) artifact.  A frequency artifact produced by magnetic resonance imaging that is similar to chemical shift and magnetic artifacts. Gibbs artifacts are bright or dark lines parallel to borders of abrupt signal intensity changes. A Gibbs artifact may, for example, simulate a syrinx in the cervical spinal cord. Gibbs artifact is worse on coarse-matrix MR images (such as 128 X 128). Josiah W. Gibbs (1839 –1903) was a distinguished American physicist and chemist.

Glaser safety slug.  A type of bullet consisting of hundreds of pellets of number 12 bird shot in a copper cup with a non-radiopaque fiberglass Teflon cap.

Glasgow coma scale (GCS).  A standardized system for evaluating levels of consciousness and neurological status.

glass. A non-crystalline amorphous solid which is often transparent and exhibits a glass transition when heated toward the liquid state. The most common types of glass are the silicate glasses based on silica (silicon dioxide, quartz), a primary constituent of sand.

glass transition (glass-liquid) transition. A reversible transition in an amorphous material from a hard, relatively brittle state into a molten or rubber-like state as the material is heated.

glenosphere. Rounded metallic ball of a reverse total shoulder arthroplasty (RTSA or RSA) attached to a base plate (metaglene) fixed to the native glenoid region by screws.

GLF. Ground level fall.

GMP. Good manufacturing practices.

Gore-Tex.  A trademark of W. L. Gore & Associates, Inc.(Newark, DE).  It is a porous fluorocarbon polymer similar chemically to Teflon (polytetrafluoroethylene). Gore-Tex is best known for its use in sportswear, but it has also been utilized in the production of synthetic ligaments and other medical devices.

Gortex.  A corrupt spelling of Gore-Tex.

gossypiboma.  A term used to describe the foreign body reaction that develops around a retained surgical sponge.

GRAE.  Generally regarded as effective.

Graf artificial ligament system. A lumbar spine dynamic posterior stabilization system used in the treatment of degenerative spine disorders.

Grammont prosthesis. A type of reverse total shoulder arthroplasty (RTSA or RSA) with a large glenoid hemisphere with no neck and a small humeral cup.

graphite. The most stable form of carbon under standard conditions. Other well-known forms of carbon include diamonds, buckminsterfullerene, and graphene. Graphite is sometimes described as the highest grade of coal.

graphene. Pure carbon in the form of thin sheets one atom thick.

GraftRope. A tendon allograft system used for primary and secondary revision surgery in various joints including the knee, acromioclavicular joint, elbow, and ankle.

GRAS.  Generally regarded as safe.

Gravigards.  A type of intrauterine contraceptive device (IUD).

gravity drains.  Surgical drains that rely on gravity and fluid-tension dynamics  to drain fluids away from surgical beds and help tissue approximation and wound healing.

gravity suit (G suit).  A compression suit applied to a patient to control bleeding.

Greenfield filter.  A type of inferior vena cava filter for use in the prevention of clot propagation to the lungs.

Groshong catheter.  A specialized type of central venous catheter with a three-position valve near its tip. The valve allows fluid flow into and out of the catheter but remains closed when the catheter is not in use. This type of catheter does not require routine clamping or flushing with a heparin solution to keep it free of blood clots. It does require flushing with 0.9% normal saline solution on a periodic basis.

Grosse-Kempfe interlocking nail.  A type of intramedullary fracture fixation rod.

GSW.  Gunshot  wound.

GT.  Gastrostomy tube.

G-tube.  Gastrostomy tube.

GUDID. FDA's Global Unique Device Identification Database.

Gunther filter.  A type of inferior vena cava filter for use in the prevention of clot propagation to the lungs.

gutta-percha. A plastic dental filling derived from the latex of several species of Malaysian trees. It resembles rubber but contains more resin and is most commonly used as a permanent filling in root canals.


Back to Top


Hagie pin.  A partially threaded orthopedic fixation pin designed for hip fractures.

Halifax clamps.  A type of interlaminar clamp for posterior cervical spine fixation. Halifax clamps are generally used to stabilize a single level and are used in combination with bone grafting.

Hall-Kaster valve.  A type of prosthetic heart valve.

Halo vest.  An external cervical spine immobilization device used for unstable fractures and dislocations. A metallic ring (the halo) is fixed to the outer table of the skull with screws. The halo is connected to a padded fiberglass or plastic thoracic cast by means of metal rods (struts).

Hancock (porcine) valve.  A type of prosthetic heart valve manufactured from pig heart valves.

Hansen-Street nail.  A solid intramedullary nail used for femoral shaft fracture fixation.

Harrington rod.  A spinal fixation system that uses hooks in the lamina and facet joints of the spine to support the spine in cases of fracture, infection, scoliosis surgery, and tumor.

Harris tube.  A single-lumen tube with a mercury weight used in the study of the small intestine.  Its head is similar to that of the Miller-Abbott tube.

Hawkins catheter.  A self-retaining accordion catheter that assumes a Z configuration after the self-retaining device has been engaged.

HC.  See Hickman catheter.

HDE. Humanitarian device exemption, an FDA process to speed the approval of a medical device intended to benefit patients with a rare disease or condition that is manifested in fewer than 4,000 individuals in the United States per year.

HDO. Health care delivery organization.

hemiarthroplasty. An arthroplasty that involves only one side of a joint.

hemoclips.  Surgical clips of various sizes used to occlude bleeding vessels.

Herbert screw.  A modified orthopedic screw originally developed for the fixation of scaphoid fractures.  It is cannulated and has threads on both ends and an unthreaded central shank. The pitch of the threads is different on each end, which draws the fracture fragments together as the screw is being placed.

heterograft.  A graft of tissue or an organ from one species to another species.

Hertz (Hz).  Unit of frequency named in honor of physicist Heinrich Rudolf Hertz (1857-1894).  One hertz is 1 cycle/sec.

HHR. Humeral head replacement.

Hickman catheter.  A type of central venous catheter introduced Dr. R. O. Hickman. It is a trade name of C. R. Bard, Inc. (Murray Hill, NJ) and is often used as a generic term for any central venous catheter.

HLTx.  Heart and lung transplant.

HMPAO. Tc-hexamethylproyleneamine oxime, a radiopharmaceutical tracer compound labeled with technetium.

hollow point bullet.  A bullet with a hole in the jacket at the tip. The bullet is designed to deform into a mushroom shape in tissue to maximize tissue damage.

Holt nail-plate.  A type of fixed angle nail-plate used to treat hip fractures.

homograft.  A graft of tissue or an organ from a donor of the same species as the recipient.  Sometimes considered to be synonymous with allograft.

HPD.  Home peritoneal dialysis.

HPTP. High performance thermoplastic.

HTO. High tibial osteotomy.

HUD. Unites States Department of Housing and Urban Development; humanitarian use device. An humanitarian use device is a medical device intended to benefit patients with a rare disease or condition (fewer than 4,000 individuals in the United States per year).

Hulka clip.  A clip designed for tubal ligations.

Hunter tendon rod implant. A woven polyester core covered with barium impregnated silicone elastomer used for reconstruction of finger/forearm tendons. Wright Medical Technology (Memphis, TN).

HXLPE. Highly crosslinked polyethylene, which is believed to be more durable for joint arthroplasty than conventional polyethylene.

Hydrashok bullet.  See Federal Hydrashok bullet.

Hydroflex (AMS  Hydroflex).  A type of penile prosthesis.

HydroSet. A bone substitute of Stryker. It is a calcium phosphate cement used to fill bony voids, either surgically created or defects from a traumatic injury. It converts to hydroxyapatite, the principle mineral component of normal bone.

hydroxyapatite.  A fundamental inorganic constituent of bone matrix and teeth. It contains calcium, phosphate, and hydroxyl ions and is usually found in a crystalline form with a specific lattice configuration. Hydroxyapatite can also be manufactured as a bioactive ceramic material, which will form chemical bonds with bone.

hydroxyapatite implant.  A type of implant used to supplement bone defects in the jaw and facial bones.


Back to Top


IAB (intraaortic balloon), IABP (intraaortic balloon pump).  See intraaortic counter pulsation balloon pump.

IACB (IAC).  See intraaortic counter pulsation balloon pump.

IACD, ICD.  Implantable (automatic) cardioverter-defibrillator device; the same as an automatic implantable cardioverter defibrillator (AICD).

IACS. Intra-articular corticosteroid injections.

IARC. International Agency for Research on Cancer.

Id.  idem; Latin for “the same.”

ID.  Identification, infectious disease, inside diameter,  intradermal.

i.e. id est; Latin for “that is.”

IED. Improvised explosive devise.

IF.  Internal fixation, interstitial fluid, interventional fluoroscopy, intrinsic factor.

Ileo-B pouch.  A pouch device for collecting fluids from an ostomy site.

ILIF. Interlaminar lumbar instrument fusion; interlaminar lumbar instrumented fusion; instrumented lumbar interspinous fusion. A type of lumbar spine surgery for degenerative spinal stenosis which decompresses the spine and also fuses lumbar vertebrae together with donar bone placed between spinous processes and held in place by a small spinous process fixation plate. There may also be other lumbar fusion apparatus as well.

Ilizarov, device, technique.  A technique and device used most often in reconstructive settings to lengthen limbs, transport bone segments, and correct angular deformities. This technique was developed by Gavriil Abramovich  Ilizarov (1921–1992) through many years of hard work and experimentation under  difficult conditions in an isolated Siberian hospital during the 1940s and 1950s.

ILV. Independent lung ventilation, a system or device for ventilating the lungs independently of each other.

IMACS.  Image (management) archiving and communications system; the same as PACS.

iMar. Iterative metal artifact reduction techniques, which are used to decrease metal artifact on single energy CT.

IMBED. Ingestible micro-biologic electronic device.

IMD. Implantable medical device.

IMF. Intermaxillary fixation screws, maxillary screws used for fixation of mandibular fractures in combination with Erich Arch Bars for mandibulomaxillary fixation (MMF), basically wiring the jaw shut to obtain normal dental occlusion.

IMG. International medical graduate.

immobilization device.  Any device to immobilize a patient so that a procedure may be performed. Typical examples include a head holder for cranial computed tomographic studies and a Pigg-O-Stat device to restrain a child for chest radiography.

implant.  A generic term used for materials or devices placed in vivo for the treatment of medical or dental conditions.

Implantofix II.  A type of vascular access port.

INBONE. A total ankle replacement system (Wright Medical Technology).

Inferior vena cava filter; IVC filter.  A filtering device placed in the inferior vena cava to prevent thrombi from the pelvis or lower extremity propagating up the inferior vena cava into the heart or lungs or to prevent emboli from passing from the inferior vena cava into the heart and pulmonary arterial circulation. 

Infusaid Model 400, Infusaid Model 600.  Types of vascular access ports.

INFUSE Bone Graft. INFUSE is a product of Medtronic consisting of a naturally occurring human protein (rhBMP-2 {recombinant engineered human bone morphogenic protein -2}) and a carrier sponge manufactured from bovine collagen. INFUSE is designed to be used in place of autogenous bone grafts.

injection artifacts.  A type of nuclear medicine artifact that originates from the injection of radiotracer.

InQu. A bone graft extender and substitute product of ISTO Technologies, Inc. It combines attributes of poly(actide-co-glycolide) (PLGA) and hyaluronic acid (HyA). It is intended to form a scaffold for new bone formation. It is available as a paste mix or in granular form.

isotropy. The properties of a substance are the same in all directions, the opposite of anisotropy.

interference screw (Kurosaka screw). A short, broad, headless orthopedic screw designed to anchor anterior cruciate ligament grafts in the metaphysis of the tibia and femur.

interfragmentary (lag) screw.  An orthopedic screw that crosses a fracture line.

interlocking screws.  Screws used with intramedullary rods to “lock” the rods in place for control of fracture-fragment rotation and shortening.

Intestinal tube.  Any type of tube used to decompress the stomach, large, or small bowel, to obtain fluid samples, or to provide an access route for patient nutrition.

intraaortic counter pulsation balloon pump or device (IACB, IAB,  IABP, IAC).  A device used to support the circulation after cardiac surgery or acute myocardial infarction until the heart recovers adequate function of its own. The balloon is situated in the descending aorta just below the arch. It inflates during diastole and deflates during systole, thereby assisting blood flow into the coronary arteries during diastole and the systemic circulation during systole.

intracranial aneurysm clip.  A surgical clip used to occlude an intracranial aneurysm.

intramedullary rod.  An orthopedic rod inserted into the medullary space of a long bone to help with fracture fixation.

intrathecal (drug) delivery pump.  A device that consists of a battery-operated pump placed in a subcutaneous pocket and connected to a catheter situated in the spinal subarachnoid space. It is used for delivery of a carefully controlled volume of medication
to the spinal cord and nerve roots. The medication may be a chemotherapeutic agent or
an analgesic agent, depending on the patient’s condition. The pump can be refilled via a needle inserted into an access port in the pump, which lies just under the skin. Chemotherapeutic infusion pumps have a similar design and can be used to introduce chemotherapeutic agents into a variety of locations, such as the peritoneal cavity or the vasculature feeding an abdominal or pelvic malignancy.

intrauterine contraceptive device (IUD).  A small device placed in the uterus to prevent unwanted pregnancy. IUDs are popular contraceptive means in most of the world.

IOFB.  Intraocular or intraorbital foreign body.

Ionescu-Shiley valve.  A type of prosthetic heart valve.

IPD.  Intermittent peritoneal dialysis.

IPLF. Instrumented posterolateral lumbar fusion.

IPOP.  Immediate postoperative period or immediate postoperative prosthesis.

IPPB.  Intermittent positive-pressure breathing.

IPPF.  Immediate postoperative prosthetic fitting.

IPPV. Intermittent positive pressure ventilation.

iron  poisoning.  A common type of poisoning in children, who are highly sensitive to iron compounds. Iron poisoning is a large problem in the pediatric age group, because iron-containing medications are so widely used, and adults usually do not appreciate the potential toxicity of iron tablets.

I-S.—Ionescu-Shiley prosthetic heart valve.

ISO.  International Organization for Standardization. “ISO is a network of the national standards institutes of 162 countries, one member per country, with a Central Secretariat in Geneva, Switzerland, that coordinates the system” [see].   ISO was formed after World War II to coordinate equipment and later software standards worldwide.

ISO 13485. The standard for manufacturers of medical devices or medical device components. See ISO 13845.

ITAP. Intraosseous transcutaneous amputation prosthesis for limb salvage.

IUD,  IUCD.  See  intrauterine contraceptive device. IUD can also mean intrauterine death.

IVC.  Inferior vena cava.

Back to Top

Author contact information

Tim Hunter

All Rights Reserved

Publisher Contact Information

Main office: USA (New York)
Cambridge University Press
32 Avenue of the Americas
New York, NY 10013-2473

Phone: (212) 337-5000