Interphlalangeal Articulation (Finger Joints)

Recap of the hand bones:

• Carpals: The bones of the wrist.
• Metacarpals: The bones of the center of the hand.
• Proximal Phalanges: The first bone of each finger.
• Intermediate Phalanges: The second bone of each finger.
• Distal Phalanges: The third bone on the four fingers of the hand.

Ligament: There are small volar ligaments that wrap around the end of each joint binding them.

Note: Many of the tendons and muscles are the same as the Metacarpophalangeal Joint (Knuckle) the only difference being that the tendons split off to connect at different points.

Mechanics: Because of the splitting tendons multiple movements can be controlled by the same muscle. Their strength is decent, making it useful for many things that we do. We can control them more precisely when the flexors and extensors are both used at the same time on the fingers.

Range of motion: Each joint in the fingers is able to flex and then extend only about 90 degrees.

Manipulation:

• Smashing the fingers with an object.
• Snapping the finger from a grab/grope.
• Grabbing the ring finger, which constricts the axis of forearm rotation.

Usage:

• The end of the distal phalanges (in conjunction with the nails) can be useful in scratching such as a tiger claw strike.
• Bending the distal and intermediate phalanges only makes use of the interphalangeal joint for a panther strike. This is useful in striking to the throat as it is a soft target for the small joints. This also keeps the hand "flatter" as most people keep their chin down in a fight, to actually strike to the throat when the fist wouldn't fit.
• For a spear hand strike the proximal phalange is extended to its max while the intermediate and distal phalanges are flexed slightly, this gives the fingers a rigidness for striking that can curl into a fist if the object is too hard.

Injury: Minor injuries to the fingers are likely to occur during training (especially with weapons) and can be severely hurt during sparing if open handed techniques are not uses properly.

For information on additional joints please refer back to the Joints page.