Phalanges are the bones that form the foundational structure of our fingers and toes. Present in both the hands and feet, they play an integral role in fine motor actions and overall body support.
Anatomy of Phalanges
There are 14 phalanges in each hand and 14 in each foot, resulting in a total of 56 phalanges in the human body. These bones are classified as long bones, despite their relatively small size, each comprising a shaft, a proximal base, and a distal head.
Digits in both the hands and feet generally contain three phalanges: a proximal, a middle (or intermediate), and a distal phalanx. The proximal phalanx is closest to the palm or sole, the middle phalanx lies in between, and the distal phalanx forms the fingertip or toe tip. The primary exceptions to this arrangement are the thumb and the big toe, each of which possesses only two phalanges: a proximal and a distal phalanx, lacking a middle one.
These bones connect to the metacarpals in the hand and metatarsals in the foot, forming metacarpophalangeal and metatarsophalangeal joints, respectively. Phalanges also articulate with each other through interphalangeal joints, allowing for movement within the digits. The proximal phalanges are typically the largest, while the middle and distal phalanges progressively decrease in size.
Role in Movement and Dexterity
Phalanges are key to the hand’s ability to perform tasks, contributing to gripping, grasping, and fine motor skills. Their articulated structure allows for movements such as flexion (bending), extension (straightening), and some rotation, which are essential for activities like writing, typing, or manipulating small objects. The precise coordination of these bones with muscles, tendons, and ligaments enables the hand’s remarkable dexterity.
In the feet, phalanges contribute to balance, propulsion, and weight-bearing during locomotion. They provide a stable base of support for standing, walking, and running. The toes, particularly the big toe, play an important part in maintaining balance and pushing off the ground, enabling efficient movement. The arrangement of these bones in the foot offers both flexibility and stability, which is necessary for supporting body weight and absorbing impact during various physical activities.
Common Injuries and Conditions
Phalanges, due to their exposed location, are susceptible to various injuries, with fractures and dislocations being common occurrences. A fracture refers to a break or crack in the bone, often resulting from direct trauma, crush injuries, or impacts sustained during sports activities. These breaks can range in severity, from simple cracks to comminuted fractures where the bone breaks into multiple pieces, or intra-articular fractures that extend into a joint.
Dislocations happen when the bones forming a joint move out of their normal alignment. In the fingers, dislocations frequently occur at the proximal interphalangeal (PIP) joint, which is the middle joint of the finger. Such injuries often result from sudden forces, hyperextension, or axial loading, commonly seen in sports.