Dictionary

undulant fever See Brucellosis.

unconsciousness, temporary A partial or complete loss of consciousness; interruption of awareness of oneself and one’s surroundings. When the loss of consciousness is temporary and recovery is spontaneous, it is referred to as syncope or, more commonly, fainting. Temporary unconsciousness may also occur with some types of seizures, from a head injury, or as part…

unconscious 1 Interruption of awareness of oneself and one’s surroundings; the lack of the ability to notice or respond to stimuli in the environment. A person may become unconscious due to oxygen deprivation, shock, injury, or use of central nervous system depressants such as alcohol and drugs. 2 In psychology, the part of thought and…

umbilical cord The cord that connects the developing fetus with the placenta while the fetus is in the uterus. The umbilical arteries and vein run within this cord. The umbilical cord is clamped and cut at birth, and its residual tip forms the bellybutton.

ultraviolet radiation Invisible rays that are part of the energy that comes from the sun. Abbreviated UV. UV radiation is made up of three types of rays: ultraviolet A (UVA), ultraviolet B (UVB), and ultraviolet C (UVC). UVC is the most dangerous type of UV light in its potential to harm life on earth, but…

ultraviolet C See ultraviolet radiation.

ultraviolet B See ultraviolet radiation.

ultraviolet A See ultraviolet radiation.

ultrasound, transvaginal See transvaginal ultrasound.

ultrasound High-frequency sound waves. Ultrasound waves can be bounced off tissues by using special devices. The echoes are then converted into a picture called a sonogram. Ultrasound imaging allows an inside view of soft tissues and body cavities without the use of invasive techniques. Ultrasound is often used to examine a fetus during pregnancy. There…

ultrasonic-assisted liposuction See liposuction, ultrasonic-assisted.

ulnar nerve A major nerve in the upper extremity that supplies both sensory and motor innervation to parts of the forearm and hand.