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Decrypt joint activity: Why do fingers feel so different when stretching?
Every stretch and bend of the finger, there are complex anatomical structures and physiological mechanisms hidden behind it.The movement of the finger mainly depends on the "interphalangeal joint" connecting the phalanx, which includes two groups of joints proximal and distal.The characteristics of these joints allow us to feel completely different touch and flexibility when performing daily movements.
Structure of interfinal joints
Each finger has two sets of interphalangeal joints (except for one with the thumb), namely "Proximal Interphalangeal Joint" (PIP) and "Distal Interphalangeal Joint" (DIP).These joints operate in a hinge manner, providing bending toward the palm.
"These structures are designed to keep your fingers stable and flexible when stretching and bent."
Anatomical Characteristics of Joint
The PIP joints are particularly stable when stretching.Compared to other joints in the palm, the transverse diameter of the PIP joint is larger than the anterior and posterior diameter, and the strong lateral ligaments remain tight in various positions when bending.Although DIP joints are also stable, they are limited in size and mobility.
Combination of tendons and ligaments
Above the PIP joint, the stretching mechanism is divided into three bands, the central band attached to the back of the middle finger bone, and the bands on both sides continue to extend to the back.The exquisite design of these structures allows the fingers to move flexibly, avoiding injuries when overstretched.
"The difference in sensory during stretching is mainly related to the tension of the ligament and the coordination of the tendon."
Range of motion of stretching and bending
The interfinal joints mainly perform bend and stretching.In PIP joints, the bending range can reach 100°, while in DIP joints it is slightly limited, about 80°.The stability of these joints depends largely on the tendons surrounding them.
Clinical significance
In clinical practice, rheumatoid arthritis often ignores the effects of DIP joints, so when DIP joints are stiff or painful, it often prompts the possibility of other joint lesions, such as osteoarthritis or psoriasis arthritis .
Conclusion
Understanding the structure and function of interphalangeal joints can help us better understand the flexibility of fingers and their importance in our daily lives.Such knowledge is particularly important for athletes, physical therapists and professional medical staff.Are finger extension and bends merely the result of muscle movement?Or are they closely related to our quality of life?
