Understanding Palmar Flexion and Dorsiflexion
Palmar flexion and dorsiflexion are two essential movements of the wrist that involve upward and downward motions. While radial abduction and ulnar adduction refer to side-to-side movements, palmar flexion and dorsiflexion focus on vertical movements.
During palmar flexion, the hand moves in a way that brings the palm closer to the forearm. This movement also causes the proximal carpal bones to shift towards the back of the hand. On the other hand, dorsiflexion involves the proximal carpal bones shifting towards the palm. To facilitate these motions, the lunate bone and the capitate bone act as axis points.
By understanding these movements, one can gain a deeper knowledge of the intricate mechanics and functionalities of the wrist.
Development
During the development of a fetus, the bones are not initially hard and rigid like they will eventually become. Instead, the bones go through a process called ossification to become hardened. Specifically, the carpal bones undergo a type of ossification known as endochondral ossification, which involves the internal hardening of the bones. The centers of ossification for the carpal bones only appear after birth and follow a spiral pattern. The first bones to harden are the capitate and hamate, followed closely by the triquetrum. The ossification process then continues with the lunate, trapezium, trapezoid, and scaphoid. Finally, the pisiform is the last bone to fully develop.