The tendons of the palmaris longus (PL) and radial carpal extensor (RCE) muscles have extensive applications in surgery, yet despite their constant use, information about their morphological and morphometric characteristics remains limited. The aim of this study was to describe the morphological and morphometric characteristics of the PL and RCE muscle tendons and compare them to each other in 30 upper limbs of adult individuals with no apparent deformations from anatomy units at four universities in Chile. The anterior side and lateral margin of the forearm and the back of the hand as far as the tendon plane were dissected. The average length, width at origin level and at the level of the radiocarpal joint line of the PL muscle tendon were 125.48 mm ± 8.93, 4.76 mm ± 1.35 and 3.76 mm ± 0.91, respectively. The average length, width at the levels of origin and insertion of the extensor carpi radialis longus muscle tendon were 180.46 mm ± 15.03, 14.69 mm ± 3.72 and 7.76 mm ± 1.44 respectively, whereas for the extensor carpi radialis brevis muscle they were 115.23 mm ± 11.81, 9.53 mm ± 2.58 and 7.33 mm ±1.17, respectively. The most common origin of the tendons of the PL and extensor carpi radialis longus muscles was at the level of the middle third of the forearm, whereas the most common origin of the extensor carpi radialis brevis muscle tendon was at distal third level. The shape of the tendons of the PL and RCE muscles was broad and flat along their entire length. Simulating the longitudinal division of the tendons of the RCE muscles in two halves, the radial half of the tendons of both muscles has morphological and morphometric characteristics similar to the PL muscle tendon, such that it could be used as a graft in the case of agenesis of the PL muscle, or for tendon transfer where elongation of a tendon in the region is required.
KEY WORDS: Palmaris longus muscle; Extensor carpi radialis muscles; Extensor carpi radialis longus muscle; Exten- sor carpi radialis brevis muscle; Upper limb; Tendon transfer surgery.