Windisch G
Institut für Anatomie, Karl-Franzens-Universität Graz, Harrachgasse 21, A-8010 Graz, Austria.
Surg Radiol Anat. 2000;22(3-4):213-5. doi: 10.1007/s00276-000-0213-1.
Usually the four lumbrical muscles arise from the tendons of flexor digitorum profundus and insert into the extensor expansions on the radial side of the corresponding fingers. This special case showed a very rare variation of a unipennate fourth lumbrical muscle of the right hand; the muscle fibre bundles originated on the radial side of the flexor digitorum profundus and coursed horizontal on its radial side, deep to the palmar aponeurosis and in front of the deep transverse metacarpal ligament over the fifth metacarpophalangeal joint. At the level of this joint, its tendon divided into one radial and one ulnar slips. Both heads surrounded the tendons of the flexor digitorum superficialis and profundus muscles, and found their insertion into the flexor digitorum superficialis tendon, as well as their bony attachment into the proximal and even more into the middle phalanx.
通常，四块蚓状肌起自指深屈肌腱，止于相应手指桡侧的指背腱膜。此特殊病例显示右手单羽状第四蚓状肌出现非常罕见的变异；肌纤维束起自指深屈肌桡侧，在其桡侧水平走行，位于掌腱膜深面且在掌骨深横韧带前方，跨越第五掌指关节。在该关节水平，其肌腱分为一条桡侧支和一条尺侧支。两支均环绕指浅屈肌和指深屈肌肌腱，并止于指浅屈肌肌腱，以及其在近节指骨甚至中节指骨的骨性附着处。
