extremiteter

Extremiteter, or extremities, are the distal parts of the limbs used for manipulation and locomotion. In humans they are divided into upper extremities (arms) and lower extremities (legs). The term derives from Latin extremitas, meaning outermost part, and is commonly used in anatomical and clinical contexts.

Anatomy: Extremiteter consist of bones, joints, muscles, nerves, blood vessels, and connective tissue. The upper extremity includes the shoulder girdle, arm (humerus), forearm (radius and ulna), and hand (carpals, metacarpals, and phalanges). The lower extremity includes the pelvis and hip, thigh (femur), leg (tibia and fibula), and foot (tarsals, metatarsals, and phalanges). Major joints include the shoulder, elbow, wrist, hip, knee, and ankle, with numerous smaller joints in the hands and feet. Nerves such as the brachial plexus and lumbosacral plexus provide motor and sensory innervation; arteries and veins supply blood; muscles generate movement and provide stability.

Development and variation: Limb development is governed by genetic signaling during embryogenesis, leading to the patterned formation of bones, joints, and soft tissues. Common congenital variations include polydactyly (extra digits) and syndactyly (fused digits). Trauma, disease, or aging can alter structure and function.

Function: The extremiteter enable reaching, grasping, manipulating objects, locomotion, balance, and environmental interaction. They also house dense sensory receptors that convey touch, temperature, and proprioception.

Clinical relevance: Extremiteter are frequently affected by fractures, dislocations, tendon or ligament injuries, nerve or vascular damage, and inflammatory or degenerative conditions. Management focuses on restoring function through immobilization, rehabilitation, and, when needed, surgical intervention.