Distal phalanx

Distal Phalanx is the smallest and most terminal bone located in the fingers of the hand and the toes of the foot in humans and many other animals. Each finger and toe has three phalanges, with the exception of the thumb and big toe, which typically have only two. The distal phalanx is situated at the tip of each digit, distal to both the proximal phalanx and the middle phalanx in digits that have them.

Structure

The distal phalanx bone is characterized by its small size and is composed of a base, shaft, and head. The base is the proximal end of the bone that articulates with the middle phalanx or, in the case of the thumb and big toe, the proximal phalanx. The shaft is the elongated, cylindrical part of the bone. The head of the distal phalanx is the part that forms the tip of the digit and is often characterized by a tuft or tuberosity that provides attachment for the fingernail or toenail.

Function

The primary function of the distal phalanx is to support the nails on the fingers and toes, providing protection and enhancing sensation and manipulation abilities of the digits. The presence of the distal phalanx is crucial for the tactile sensation and fine motor skills that are essential for daily activities, such as writing, grasping objects, and walking.

Clinical Significance

Injuries to the distal phalanx are common and can range from minor bruises to fractures. Such injuries are often painful and may affect the nail bed or disrupt the growth of the nail. Treatment depends on the severity of the injury and may include immobilization, pain management, and, in severe cases, surgery.

Fractures of the distal phalanx can be classified into several types, including tuft fractures, shaft fractures, and base fractures. Tuft fractures are the most common and occur at the tip of the digit. Management of distal phalanx fractures aims to relieve pain, restore function, and prevent complications such as infection or deformity.

Development

The distal phalanges, like other bones in the body, develop from cartilage through a process known as endochondral ossification. This process begins in the late fetal stage and continues through childhood and adolescence, with the distal phalanges being among the last bones to complete ossification.

See Also

• Phalanx bone
• Hand anatomy
• Foot anatomy
• Bone fracture