![]() The non-articular portion is a rough elevation and affords attachment to the ligament of the tubercle. The articular portion is the lower and more medial of the two and presents a small, oval surface for articulation with the transverse costal facet on the end of the transverse process of the lower of the two vertebrae to which the head is connected. On the posterior surface at the neck, is an eminence-the tubercle that consists of an articular and a non-articular portion. Its upper border presents a rough crest ( crista colli costae) for the attachment of the anterior costotransverse ligament its lower border is rounded. Its anterior surface is flat and smooth, whilst its posterior is perforated by numerous foramina and its surface rough, to give attachment to the ligament of the neck. The neck of the rib is the flattened part that extends laterally from the head. The crest gives attachment to the intra-articular ligament. The transverse process of a thoracic vertebra also articulates at the transverse costal facet with the tubercle of the rib of the same number. The upper region articulates with the inferior costal facet on the vertebra above, and the larger region articulates with the superior costal facet on the vertebra with the same number. It is marked by a kidney-shaped articular surface which is divided by a horizontal crest into two articulating regions. The head of the rib is the end part closest to the vertebra with which it articulates. They are numbered to match the vertebrae they attach to – one to twelve, from top (T1) to bottom. All ribs are attached posteriorly to the thoracic vertebrae. Parts of rib Įach rib consists of a head, neck, and a shaft. The spaces between the ribs are known as intercostal spaces they contain the intercostal muscles, and neurovascular bundles containing nerves, arteries, and veins. These ribs are relatively small and delicate, and include a cartilaginous tip. ![]() The phrase floating rib or vertebral rib ( Latin: costae fluctuantes) refers to the two lowermost, the eleventh and twelfth rib pairs so-called because they are attached only to the vertebrae–and not to the sternum or cartilage of the sternum. Their elasticity allows rib cage movement for respiratory activity. There are three pairs of vertebrochondral ribs (eighth to tenth) that connect indirectly to the sternum via the costal cartilages of the ribs above them. The false ribs include both vertebrochondral ribs and vertebral ribs. The first seven rib pairs known as the fixed or vertebrosternal ribs are the true ribs ( Latin: costae verae) as they connect directly to the sternum the next five pairs (eighth to twelfth) are the false ribs ( Latin: costae spuriae). The terms true ribs and false ribs describe rib pairs that are directly or indirectly attached to the sternum. The rib cage intrinsically holds the muscles of respiration ( diaphragm, intercostal muscles, etc.) that are crucial for active inhalation and forced exhalation, and therefore has a major ventilatory function in the respiratory system. Together with the skin and associated fascia and muscles, the thoracic cage makes up the thoracic wall and provides attachments for extrinsic skeletal muscles of the neck, upper limbs, upper abdomen and back. A typical human thoracic cage consists of 12 pairs of ribs and the adjoining costal cartilages, the sternum (along with the manubrium and xiphoid process), and the 12 thoracic vertebrae articulating with the ribs. The sternum, together known as the thoracic cage, is a semi-rigid bony and cartilaginous structure which surrounds the thoracic cavity and supports the shoulder girdle to form the core part of the human skeleton. The rib cage, as an enclosure that comprises the ribs, vertebral column and sternum in the thorax of most vertebrates, protects vital organs such as the heart, lungs and great vessels.
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