Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA, 02118, USA.
Surg Radiol Anat. 2021 Dec;43(12):2083-2086. doi: 10.1007/s00276-021-02840-4. Epub 2021 Sep 24.
During standard anatomical dissection for a medical anatomy course, we encountered an unusual bilateral variant of a unipennate flexor digitorum accessorius longus (FDAL) muscle, a supernumery muscle of the deep posterior leg and medial ankle.
We documented the muscles course and measured the diameter and length of the FDAL muscle belly, as well as the full length of its tendinous attachments.
On both right and left legs, the FDAL originated from the proximal posterior fibula and distal one-third of the flexor hallucis longus muscle. The tendon had a distal attachment on the flexor digitorum longus (FDL) tendon and traveled with the FDL tendon as it inserted on the third distal phalanx. The left FDAL full length was 42.54 cm; the length of the muscle belly was 16.26 cm; and the circumference of the muscle belly was 4.44 cm. The right FDAL full length was 44.20 cm; the length of muscle belly was 12.06; and the circumference (belly) was 4.44 cm. Surrounding musculature and neurovasculature follow standard anatomical courses.
This anatomical documentation provides opportunities for clinicians to consider mechanical influences of the FDAL on plantar foot function and further consider the accessory ankle muscles that have the potential to cause compressive neuropathies such as tarsal tunnel syndrome.
在医学解剖课程的标准解剖过程中，我们遇到了一种不寻常的单侧二头肌屈肌指深屈肌（FDAL）肌的双侧变体，这是一种深部后腿和内踝的额外肌肉。
我们记录了肌肉的行程，并测量了 FDAL 肌腹的直径和长度，以及其腱附着的全长。
在右腿和左腿上，FDAL 均发自近后腓骨和长屈肌的远端三分之一。肌腱在长屈肌腱（FDL）的远端附着，并随 FDL 肌腱一起插入第三远节指骨。左 FDAL 的全长为 42.54 厘米；肌腹的长度为 16.26 厘米；肌腹的周长为 4.44 厘米。右 FDAL 的全长为 44.20 厘米；肌腹的长度为 12.06 厘米；周长（腹部）为 4.44 厘米。周围的肌肉和神经血管遵循标准的解剖学课程。
这种解剖学记录为临床医生提供了考虑 FDAL 对足底足功能的机械影响的机会，并进一步考虑了可能引起压迫性神经病（如跗管综合征）的附加踝关节肌肉。
