How do I measure a patient's height if he/she is bed-ridden?

Height can be estimated in bedridden patients using knee-length prediction equations. Measurements are taken using a simple device called a knee-height caliper or a broad-blade caliper. With the patient lying supine, and the knee bent at a 90-degree angle, one blade of the caliper is placed over the anterior surface of the left thigh, above the condyles of the femur and just proximal to the patella. The caliper shaft is held parallel to the shaft of the tibia. Pressure is applied to compress the tissue. Two readings should be taken and should agree within +/-0.5 cm. Height is then calculated using equations; sex and age are also required for the equations.

-Nancy Collins, PhD, RD, LD/N, FAPWCA