interfalangeal

The term *interphalangeal* refers to the joints and regions located between the phalanges, which are the bones that form the fingers and toes in the human hand and foot. The phalanges are segmented into three distinct parts in each digit: the distal, middle, and proximal phalanges, with the exception of the thumb and big toe, which have only two phalanges (distal and proximal). The joints connecting these bones are classified as interphalangeal joints.

In the hand, there are two primary interphalangeal joints: the proximal interphalangeal (PIP) joint, located between the proximal and middle phalanges, and the distal interphalangeal (DIP) joint, situated between the middle and distal phalanges. The thumb has only one interphalangeal joint, known as the interphalangeal joint of the thumb (IP), which connects its proximal and distal phalanges. Similarly, the big toe features a single interphalangeal joint, though it is often referred to as the distal interphalangeal joint of the hallux.

Interphalangeal joints are hinge-type synovial joints, allowing primarily flexion and extension movements. They are essential for fine motor skills, such as grasping and manipulating objects, as well as for weight-bearing and stability in the foot. Conditions affecting these joints, such as arthritis, fractures, or dislocations, can significantly impact hand and foot function, often requiring medical intervention or physical therapy for management.

The term is also used anatomically to describe structures located between the phalanges, including ligaments, tendons, and blood vessels that support joint mobility and stability. Proper care and maintenance of interphalangeal joints are crucial for overall hand and foot health, particularly in activities that involve repetitive motion or physical strain.