Department of Anatomy, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand.
Surg Radiol Anat. 2020 Aug;42(8):935-938. doi: 10.1007/s00276-020-02439-1. Epub 2020 Feb 19.
Anatomical variants in the posterior compartment of forearm and hand are not uncommon. Physicians should be aware of variations in this region for correct diagnosis and treatment of diseased hands.
During a routine dissection at our department, an extremely rare case of deep hand extensor muscle was discovered.
A complete extensor digitorum profundus complex was found in the fourth extensor compartment in addition to the extensor indicis proprius. The complex consisted of two muscle bellies originating from the lateral aspect of distal ulna and the adjacent interosseous membrane. The first belly resembled the conventional extensor indicis proprius. The second belly gave off two tendon slips: one inserted to the index and middle fingers and the other formed aponeurosis before inserting to the ring and little fingers.
To our knowledge, a complete extensor digitorum profundus complex which inserts to all medial four digits has never been reported in humans. Awareness of variations in this region is critical for surgeons operating in the forearm and hand. The present case also provides insights into the evolutionary and developmental origin of these structures.
前臂和手部后间隔的解剖变异并不少见。医生应了解该区域的变异情况，以便正确诊断和治疗手部疾病。
在我们部门的一次常规解剖中，发现了一个非常罕见的深部手部伸肌病例。
除了固有示指伸肌外，在第四伸肌间隔还发现了一个完整的指深伸肌复合体。该复合体由两个肌腹组成，起源于远端尺骨的外侧和相邻的骨间膜。第一个肌腹类似于传统的固有示指伸肌。第二个肌腹发出两条肌腱：一条插入食指和中指，另一条在插入环指和小指之前形成腱膜。
据我们所知，在人类中，从未报道过插入所有内侧四个手指的完整指深伸肌复合体。了解该区域的变异情况对在前臂和手部进行手术的外科医生至关重要。本病例还提供了对这些结构的进化和发育起源的深入了解。
