Phalanges are the bones that form the skeletal framework of the fingers and toes. They provide support and enable movement, facilitating a wide array of daily activities.
Location and Structure
Phalanges are located within the hands and feet, forming the digits. Each hand and foot contains 14 phalanges, resulting in a total of 56 phalanges in the human body. In both the hand and foot, the thumb and big toe (hallux) each possess two phalanges: a proximal phalanx and a distal phalanx. The remaining fingers and toes each have three phalanges: a proximal, a middle (or intermediate), and a distal phalanx.
Each phalanx consists of three main parts: a base (proximal end), a shaft (middle part), and a head (distal end). The proximal phalanges are closest to the palm or sole, articulating with the metacarpal bones in the hand and metatarsal bones in the foot. The middle phalanges are situated between the proximal and distal ones, while the distal phalanges are the outermost bones, forming the tips of the fingers and toes. These bones articulate at interphalangeal joints, which allow for movement.
Role and Common Issues
Phalanges play a significant role in the function of both hands and feet. In the hands, these bones enable dexterity, facilitating actions such as gripping, pinching, writing, typing, and manipulating objects. The joints between the phalanges allow for flexion, extension, and some rotation, contributing to the hand’s versatility.
In the feet, phalanges are equally important, contributing to balance, propulsion during walking, and supporting overall body weight. The toes, particularly the big toe, assist in maintaining balance and pushing off the ground during movement. This structure provides a stable base of support for standing, walking, and running, and helps absorb impact during locomotion.
Despite their importance, phalanges are susceptible to various issues, including fractures and dislocations. Fractures can result from direct impact, crush injuries, or repetitive stress. Dislocations often occur at the proximal interphalangeal (PIP) joints, where bones move out of their normal alignment. Arthritis, including both osteoarthritis and inflammatory types like rheumatoid arthritis, can affect the joints within the phalanges, leading to pain, stiffness, and reduced mobility. Other common foot issues involving phalanges include hammertoe and bunions.