IDIOPATHIC SCOLIOSIS - Structural
lateral curvature of an unknown cause.
ILIAC BONE - A part of the pelvic bone that is above
the hip joint and from which autogenous bone grafts
are frequently obtained.
ILIAC CREST - The large, prominent portion of the pelvic
bone at the belt line of the body.
ILIOPSOAS MUSCLE - Large muscles starting at L-1 and
becoming wider as it picks up segments from the lower
lumbar spine; combines with the iliacus muscle before
attaching to the lesser trochanter of the hip.
IMMOBILIZATION - Limitation of motion or fixation of
a body part usually to promote healing.
INFANTILE SCOLIOSIS - Lateral curvature of the spine
that begins before age 3.
INFRATENTORIAL - Beneath the tentorium.
INFUNDIBULUM - A stalk extending from the base of the
brain to the pituitary gland.
INSTRUMENTATION - the use of instruments such as metal
screws or braces during a surgical procedure to support
bone as it heals.
INTERBODY - between the bodies of two adjacent vertebrae
INTERCOSTALS - The muscles between the ribs.
INTERNAL FIXATION - The immobilization of bone fragments
or joints with implants in order to promote healing
INTERSPINOUS LIGAMENT - Ligament between each of the
INTERSPINOUS PSEUDARTHROSIS - Formation of a false
joint between two spinous processes.
INTERVERTEBRAL DISC - See Disc (Intervertebral).
INTERVERTEBRAL DISC NARROWING - Narrowing of the space
between any two vertebral bodies.
INTRA-AORTIC BALLOON COUNTER PULSATION DEVICE - A pump
which is inserted into the main vessel of the body,
the aorta, to help the heart deliver blood to critical
organs such as the brain or kidneys.
INTRACEREBELLAR - Within the cerebellum.
INTRA-ARTERIAL CATHETERIZATION ANGIOGRAPHY - An invasive
study in which a catheter (a small tube) is placed in
the artery and contrast material is injected to which
makes the blood vessels visible on an X-Ray image. The
catheter is inserted in the groin into the femoral artery
(the artery to the leg) through a needle, and is guided
into the arteries in the neck and head. This study is
associated with a very small (less than 0.05 % chance
of serious complications) and requires the patient to
lie in bed for approximately six hours to allow the
leg vessel to heal.
INTRACEREBRAL - Within the cerebrum.
INTRACEREBRAL HEMATOMA - A blood clot within the brain.
INTRACRANIAL - Within the cranium of the skull.
INTRACRANIAL PRESSURE (ICP) - The overall pressure
inside the skull.
INTRAOPERATIVE CISTERNOGRAPHY - Administration of a
contrast dye into the ventricles which are chambers
in the brain that contain brain fluid.
INTRAMEDULLARY - Refers to medullaris, marrow; (1)
withing the medulla oblongata of the brain, (2) within
the spinal cord, and (3) within the marrow cavity of
INTRINSIC - Situated entirely within or pertaining
exclusively to a part.
IN VITRO - Describing biological phenomena that are
made to occur outside the living body traditionally
in a test tube. In vitro is Latin for in glass.
IN VIVO - Within a living body. In vivo is Latin for
INFERIOR - Situated below or directed downward.
INFORMED CONSENT - Consent of the patient who has received
sufficient information to have surgery, receive medication,
or participate in a clinical study.
INSTITUTIONAL REVIEW BOARD (IRB) - A committee designated
by an institution, such as a hospital, to review and
approve research projects; e.g., clinical studies in
INVESTIGATIONAL DEVICE EXEMPTION (IDE) - A FDA regulatory
status which permits the human use of an unapproved
medical device for the purposes of collecting clinical
data under strictly controlled conditions.
ISCHEMIA - Inadequate circulation of blood generally
due to a blockage of an artery.
ISOLA - A posterior fixation device.
ISOMETRIC - Of equal dimensions. In physiology, denoting
the condition when the ends of a contracting muscle
are held fixed so that contraction produces increased
tension at a constant overall length.
ISOTONIC - Relating to isotonicity or isotonia. Having
equal tension; denoting solutions possessing the same
osmotic pressure; more specifically, limited to situations
in which cells can neither swell nor shrink.
ISTHMIC - The lesion is in the pars interarticularis.
Three types occur: lytic, fatigue fracture of the pars
interarticularis; elongated but intact pars interarticularis;
and acute fracture of the pars interarticularis.
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