The capitellum is a rounded, knob-like projection located on the distal end of the humerus (the long bone in the upper arm). It articulates with the radius, one of the two bones in the forearm, and is crucial for elbow joint movement. More specifically, it is a semispherical protuberance arising from the anterior and lateral aspect of the distal humerus.
In more detail:
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Location: The capitellum is found on the anterior (front) and lateral (outer) side of the distal humerus (the end of the humerus closer to the elbow).
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Structure: It has a rounded, almost ball-like shape, allowing for smooth articulation and a wide range of motion.
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Function: The capitellum is a key component of the elbow joint. It articulates primarily with the head of the radius, enabling movements like flexion (bending) and extension (straightening) of the elbow, as well as pronation (turning the palm down) and supination (turning the palm up) of the forearm.
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Clinical Significance: The capitellum is susceptible to injuries, such as fractures (capitellum fractures) and osteochondritis dissecans (a condition where cartilage and bone separate). These injuries can lead to pain, stiffness, and limited range of motion in the elbow.
