Anatomy Questions: Finger Extensors & Wrist Movement - Seeking Clarification

Question
Mikey,
      I have several questions regarding anatomy. I have a good understanding of human anatomy (constantly referring to my Frank Netter books) but some things confuse me. Do the finger extensors cover the wrist extensors completely? Also if I flex my index finger and middle finger individually (and looking at their tendon movement at the wrist crease) I notice that index finger flexion causes movement more medial than middle finger flexion. Do the tendons cross? Thanks for your help!

Answer
Hello Rick,

I'm glad you're having fun exploring!

The flexor digitorum profundis flexes the fingers, and there are separate tendons for each finger - the lateral aspect of it flexes the ring and pinky fingers and the medial aspect flexes the index and middle finger.  The tendons shouldn't cross (but anything is possible) but what comes to mind is that some times the index finger tendon has a separate muscle belly and that may be causing what you are seeing.

Best Wishes!