« 1. Flexor tendonsThe flexor tendons in the fingers occur because the muscles of the forearms become tendons as they enter the carpel tunnel into the hand.As you can see from the first image we have a bunch of other muscles of the forearm that affect motion of the hand and wrist. Well ignore those for now! First up is the Flexor digitorum superficialis or FDS. Swipe ️ and see it visualized again with its interaction with its deeper counterpart. The Flexor digitorum profundus or FDP is the deeper muscle that extends to the finger tip and helps us with flexing the entire fingerFDS is a tendon that splits into a V to allow the deeper FDP to run between it right to the tip! It inserts into the middle phalanx and flexes primarily the PIP joint. The design of these two tendons contribute to why we have such fine motor control at our fingers but it&;d be a shame if these tendons didn&;t have anything strong to hold them down! Next up. Pulleys.
[Finger anatomy series 3/3] 3.The Proximal Interphalangeal joint or PIPNow that you know about the flexor tendons, the function of the pulleys and where they tend to pull, you should be able to guess why the PIP joint is so important!The PIP is the main joint that dictates the forces along the pulleys due to the position and angle of pull from the forces of the tendons.Demonstrated here is more of a hanging grip or an open handed grip. The angle of the PIP in this image is quite large and thus the resultant forces on the pulleys is minimal !! The SMALLER angle in the PIP = GREATER forces on the pulleys! Take this into consideration when thinking about how you grip your holds! I&;ll demonstrate with some more pictures in the following posts! »