extensor retinaculum การใช้

• The extensor retinaculum is attached laterally to the lateral margin of the radius.
• Its tendon passes through a compartment of the extensor retinaculum, posterior to distal radio-ulnar joint, then divides into two as it crosses the dorsum of the hand, and finally joins the extensor digitorum tendon.
• In length, the tendon passes through a long and superficial synovial sheath which, passing obliquely from the radial border of the foremarm into the thumb, extends from the proximal border of the extensor retinaculum to the first carpometacarpal joint.
• The tendon, after passing under the superior extensor retinaculum of foot and inferior extensor retinaculum of foot in the same canal as the extensor digitorum longus, is inserted into the dorsal surface of the base of the metatarsal bone of the fifth digit.
• The tendon, after passing under the superior extensor retinaculum of foot and inferior extensor retinaculum of foot in the same canal as the extensor digitorum longus, is inserted into the dorsal surface of the base of the metatarsal bone of the fifth digit.
• The superior extensor retinaculum binds down the tendons of extensor digitorum longus, extensor hallucis longus, peroneus tertius, and tibialis anterior as they descend on the front of the tibia and fibula; under it are found also the anterior tibial vessels and deep peroneal nerve.
• The muscle passes under the superior and inferior extensor retinaculum of foot in company with the fibularis tertius, and divides into four slips, which run forward on the dorsum of the foot, and are inserted into the second and third phalanges of the four lesser toes.
• The inferior fibres are continuous in front with those of the inferior extensor retinaculum of the foot; behind they are attached to the lateral surface of the calcaneus; some of the fibers are fixed to the calcaneal tubercle, forming a septum between the tendons of the peroneus longus and peroneus brevis muscles.
• The fibres end approximately at the middle of the forearm in the form of a flat tendon, which is closely connected with that of the extensor carpi radialis longus, and accompanies it to the wrist; it passes beneath the abductor pollicis longus and extensor pollicis brevis, beneath the extensor retinaculum, and inserts into the lateral dorsal surface of the base of the third metacarpal bone, with a few fibres inserting into the medial dorsal surface of the second metacarpal bone.