The classification of synarthroses includes fibrous synarthroses and cartilaginous synarthroses. Fibrous synarthroses are further subdivided into sutures, syndesmoses and gomphoses. Sutures link flat bones of the skull and are typical of the membranous skull region. Syndesmoses involve bone-to-bone bridging by ligaments, such as the interosseous membrane between tibia and fibula. Gomphoses unite tooth roots to the alveolar bone by a fibrous attachment. Cartilaginous synarthroses include synchondroses, where epiphyseal cartilage connects bones, such as the spheno-occipital synchondrosis of the skull.
Typical examples include the sutures of the cranial vault, the gomphosis anchoring teeth, the syndesmosis of the distal tibiofibular joint, and the synchondroses of the growth plates in infants. These joints exhibit a high degree of ossification over time, often transforming into articular cartilage or bone as the organism matures. Additionally, some synarthroses, like the interosseous membrane, support both stability and load-bearing during locomotion.
During embryonic development, many synchondroses serve as transient structures that later ossify into diarthrodial joints or fused bones. For instance, the proximal tibiofibular synchondrosis becomes a fibrous syndesmosis after birth. The preservation of immobile joints in the adult skeleton underscores their importance in maintaining mechanical resilience and preventing microtrauma across weight-bearing axes.
In clinical contexts, synarthroses are associated with conditions such as craniosynostosis, where premature suture closure affects skull development, or distal tibiofibular syndesmotic injuries that compromise ankle stability. Proper management of these joints involves imaging, surgical alignment, or reconstructive techniques depending on severity. Understanding synarthrosis anatomy is essential for orthopedic, dental and forensic investigations.