- A quarter. For example, the liver is in the right upper quadrant of the abdomen.
* * *One quarter of a circle. In anatomy, roughly circular areas are divided for descriptive purposes into quadrants. The abdomen is divided into right upper and lower and left upper and lower quadrants by a horizontal and a vertical line intersecting at the umbilicus. Quadrants of the ocular fundus (superior and inferior nasal, superior and inferior temporal) are demarcated by a horizontal and a vertical line intersecting at the optic disk. The tympanic membrane is divided into anterosuperior, anteroinferior, posterosuperior, and posteroinferior quadrants by a line drawn across the diameter of the drum in the axis of the handle of the malleus and another intersecting the first at right angles at the umbo. [L. quadrans, a quarter]
* * *quad·rant 'kwäd-rənt n1) an arc of 90° that is one quarter of a circle2) any of the four more or less equivalent segments into which an anatomic structure may be divided by vertical and horizontal partitioning through its midpoint <pain in the lower right \quadrant of the abdomen>
* * *quad·rant (kwodґrənt) [L. quadrans quarter] 1. one quarter of a circle; that portion of the circumference of a circle that subtends an angle of 90 degrees. 2. any one of four corresponding parts or quarters, as of the abdominal surface, the field of vision, the dentition, or the tympanic membrane.
Quadrants of the abdomen. RUQ, Right upper quadrant; LUQ, left upper quadrant; RLQ, right lower quadrant; LLQ, left lower quadrant.
Medical dictionary. 2011.