(trī'seps )

[ tri- + L. -ceps, -cipit-from caput, stem capit-, head]

A muscle arising by three heads with a single insertion.

t. brachii The muscle of the posterior arm with three points of origin (one on the scapula, two on the humerus) and one insertion on the ulna. It extends the forearm and is controlled by the radial nerve.

SEE: arm for illus.

t. skin fold The thickness of the skin including subcutaneous fat as measured on the skin over the triceps muscle of the arm. Comparison of the value obtained from a patient to stand ard values (or the comparison of this value with skin fold measures from other body areas) helps to provide an estimate of body fat. It is used in assessing and documenting both malnutrition and obesity.

t. surae The muscle group formed by the two heads of the gastrocnemius and the single head of the soleus muscles.