Abstract
The thoracic skeleton consists of twelve ribs on each side, connected to the sternum by means of costal cartilages. Costal
cartilages are bar-shaped hyaline cartilages which articulate with corresponding ribs and articular facet on sternum forming
costochondral & chondrosternal joints respectively. The 1st sternochondral joint between the manubrium and the first
costal cartilage is an unusual form of synarthrosis and is often called as synchondrosis. Thick perichondrium of chondral
cartilages are continuous with the periosteum of the ribs, which can get partially calcified in old age. Fusion of 1st costal
cartilage may be due to normal mineralization which can occur at puberty. Some congenital abnormalities, traumatic
injuries and other chronic inflammation around joints can lead to osteogenesis and fusion. Mineralization and osteogenesis
in the 1st costal cartilage may be physiological age-related change.
During routine survey of our osteology lab of Department of Anatomy, a bilateral fusion of first rib with the sternum was
found which resemble a bull horn. These types of anomalies may cause pain and swelling in the concerned area and
difficulty in respiration. Awareness of this bony complex is important for physicians, orthopedic surgeons, radiologists and
dermatologists.

Key words: rib, costochondral joint, synchondrosis, synostosis