The exact answer to why your ring finger knuckle may look sunken in, based on the provided information, is because of a specific injury to the bone.
A sunken ring finger knuckle is typically the result of an injury where the broken head of the metacarpal bone is pushed in toward the palm. This displacement of the bone is the primary reason the knuckle appears sunken.
Understanding the Metacarpal Bone
Your knuckles are formed by the ends of the long bones in your palm called metacarpal bones where they meet the bones of your fingers (phalanges). The joint connecting the metacarpal to the finger is the metacarpophalangeal (MCP) joint, and the prominence you see on the back of your hand is the head of the metacarpal bone.
The Impact of Injury
When the head of the metacarpal bone is broken and pushed inward towards the palm, it changes the normal structure and contour of the hand.
- The broken head of the metacarpal bone is pushed in toward the palm, causing the knuckle overlying it to lose its usual rounded shape and project less prominently.
- This displacement creates a visual “sunken” appearance at the knuckle joint on the back of your hand.
Related Effects
Beyond the sunken appearance, an injury like this can have other lasting effects:
- There is also a possibility that the affected finger will appear shorter than it did, even after the site has healed. This is because the bone fragment has shifted, effectively shortening the overall length from the knuckle joint.
In summary, if your ring finger knuckle looks sunken, it is likely due to a broken head of the metacarpal bone beneath that has been pushed inwards towards the palm.
