Apofyser

Apofyser, also known as apophyses, are bony outgrowths that arise from separate ossification centers and serve as attachment sites for muscles or ligaments. Unlike the ends of bones that form joints (epiphyses), apophyses do not contribute to the joint surface. During adolescence these secondary ossification centers typically ossify and fuse with the main bone as growth ends. Apophyses are a normal part of skeletal development and help accommodate the pulling forces from tendons.

In youth, apophyseal regions are particularly susceptible to traction injuries when muscles or tendons pull on their attachment points. This condition is referred to as apophysitis and is common in active adolescents. Clinical presentation usually includes focal, localized pain at the site of the apophysis rather than joint pain. Notable examples include tibial tubercle apophysitis (Osgood-Schlatter disease) and calcaneal apophysitis (Sever’s disease). Other common sites include the pelvis (iliac crest, anterior superior iliac spine, and ischial tuberosity) and the greater trochanter. Imaging may show fragmentation, sclerosis, or widening of the apophysis, with symptoms often resolving with activity modification and targeted therapy as growth progresses.

Terminology varies by language; in English the term is apophysis with apophyses as the plural, while apofyser is used in some languages or contexts.