**3.8 Flexor digitorum superficialis (FDS)**

Draw the first line between the mid-elbow flexor crease to the mid-wrist crease, second line from the medial epicondyle to the pisiform bone. Select the middle onethird between these two lines and make a rectangular box (as in **Figure 17**). Then, again divide this rectangle (with line 3) into equal medial and lateral halves. Now, 2nd finger FDS is more superficial at/near the distal part of 3rd line, 3rd FDS at the proximal part of 3rd line. 4th FDS and 5th FDS falls near just medial to 2nd line. 4th FDS superomedial to 3rd FDS and 5th FDS infero-medial to 2nd FDS. Avoid going near or crossing the first line laterally to avoid inadvertent injury to the neurovascular

#### **Figure 16.**

*Flexor carpi radialis(FCR): A, B, C, D – as stated above in Figure 15. Distal plus sign denotes FCR injection point, proximal (left one) marked for PT.*

#### **Figure 17.**

*Flexor digitorum superficialis(FDS): L1- the line between the mid-elbow flexor crease to the mid-wrist crease. L2- medial epicondyle to pisiform bone. The central big rectangle represents the middle one-third of the medial forearm. L3- equally divide this rectangle into equal medial and lateral half. s2- 2nd finger FDS, s3- 3rd FDS, s4- 4th FDS, s5- 5th FDS. Plus at s2, s3, s4, & s5 denoted vertical entry point for respective FDS slips.*

bundle. So, we should focus on the medial rectangle. This is the author's practice method based on adult cadavers as described by Bickerton LE et al. [10].
