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Abstract
The flexor digitorum superficialis (FDS) muscle is located in the intermediate layer of the muscles in the anterior compartment of the forearm. Variable but individual variations have been reported in the FDS regarding the number of head and the origin, distribution and interconnections of muscle slip and insertion to finger. In this case, we report a concomitant complex variation in FDS which was observed in a cadaver during a routine dissection classes for the undergraduate medical students. It includes the variation which is the separation of the tendon of FDS into the super-ficial and deep layers, the structural variations in muscle slips and associated tendon variations, the finding of Gantzer' muscle leading to flexor pollicis longus muscle. These complex variations in FDS are very rare case and this report summarizes the related phylogenetic and embryological significance.
References
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Fig. 1.
Cadaveric dissection showing left flexor digitorum superficialis. Superficial layer (A) and deep layer (B) of left flexor digitorum su-perficialis. SM, superficial-medial muscle slip; SL, superficial-lateral muscle slip; HH, humeral head of superficial-lateral muscle slip; RH, radial head of superficial-lateral muscle slip; MN, median nerve; RN, radial nerve; BR, brachioradialis (cut); DM, deep-medial muscle slip; DL, deep-lateral muscle slip; AM, additional muscle slip; AT, additional tendon; GM, Gantzer's muscle; FPL, flexor pollicis longus.
Table 1.
Concomitant variations in flexor digitorum superficialis in this report.
| 1. Separation of superficial and deep layers of flexor digitorum superficialis |
| 2. Structural variation of muscle slips and associated tendon changes |
| A. Irregular merge between muscle slips B. Variation of origin in muscle slips |
| a. Weak radial origin of superficial lateral muscle slip∗∗ |
| b. Additional humeral origin of superficial lateral muscle |
| C. Additional muscle slip a. Additional muscle slip across two muscle slips |
| b. Tendons on both ends of additional muscle slip |
| 3. Flexor pollicis longus-related accessory muscle (Gantzer's muscle) |
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