Webster's New World Medical Dictionary

thoracic outlet syndrome
A condition that is
due to compromise of blood vessels or nerve fibers
between the armpit (axilla) and the base of the
neck, because of compression by adjacent tissues.
Symptoms include pain, arm weakness, and numb-
ness in the hands and fingers. Thoracic outlet syn-
drome can be caused by muscle development from
some types of manual work or exercise, injury, or
malformation. Treatment involves physical therapy
and use of anti-inflammatory medication, and some-
times by surgery.
thoracic vertebrae
The 12 vertebrae situated
between the cervical (neck) vertebrae and the
lumbar vertebrae. The thoracic vertebrae provide
attachment for the ribs and make up part of the
back of the thorax (chest). The thoracic vertebrae
are represented by the symbols T1 through T12.
See also 
vertebra; vertebral column.
thoracotomy
An operation to open the chest,
usually in order to gain access to the lungs or heart.
thorax
The area of the body that is located
between the abdomen and the neck. Within the tho-
rax are the lungs, the heart, and the first section of
the aorta. Also known as chest.
thrive, failure to
See 
failure to thrive.
thrombectomy
A procedure to remove a clot
(thrombus).
thrombi
Plural of thrombus.
thrombin
An enzyme that presides over the con-
version of a substance called fibrinogen to fibrin,
which promotes blood clotting.
thrombinogen
See 
prothrombin.
thrombocyte
See 
platelet.
thrombocythemia
An abnormally high number of
platelets in the blood. Also known as thrombocytosis.
thrombocytopenia–absent radius syndrome
See 
TAR syndrome.