Ribs. The Classification of Human Ribs.

The upper seven ribs are so-called "true ribs" as they have their cartilages directly attached to the sternum. Other (from 8^th to 12^th) are called "false ribs" as they attach to the sternum via other ribs cartilage. The last two (11^th & 12^th) are not attached to the sternum at all and, therefore, are called "floating ribs."

Other classifications subdivide ribs into typical and atypical. Typical ribs (from the 3^rd to 9^th) have common features that make it challenging to identify their position (for example, to distinguish between 6^th and 7^th ribs, etc.). In contrast, atypical could be identified with relative ease.

The frontal view of the rib cage with comments — The front view of the thorax. True, false, floating, typical, and atypical ribs.

Top view of the typical rib and thoracic vertebra with comments — Top view of the right and left typical rib (7^th) with the thoracic vertebra VII.
The list of terms:
*Costa* – Rib
*Vertebra thoracica* – Thoracic vertebra
*Caput costae* – Head of rib
*Collum costae* – Neck of rib
*Tuberculum costae* – Costal tubercle
*Corpus costae* – Body (shaft) of the rib

Typical rib and articulating thoracic vertebra with the terminology comments — Oblique view of the typical (7^th) rib.

The list of terms:
*Costa vera* – True rib
*Vertebra thoracica* – Thoracic vertebra
*Caput costae* – Head of rib
*Facies articularis capitis costae* – Articular surface on head of rib
*Collum costae* – Neck of rib
*Corpus costae* – Body of rib
*Angulus costae* – Angle of rib
*Sulcus costae* – Costal groove

Costovertebral joints. Articulation surfaces with comments — The relations between a typical rib and thoracic vertebrae.
The head of each typical rib articulates with two thoracic vertebrae, and the articular facet of costal tubercle articulates with the transverse process of the lower vertebra.
The list of terms:
*Fovea costalis inferior* – Inferior costal facet
*Fovea costalis superior* – Superior costal facet
*Facies articularis capitis costae* – Articular surfaces on head of rib
*Crista capitis costae* – Interarticular crest on head of rib
*Facies articularis tuberculi costae* – Articular facet of costal tubercle
*Fovea costalis processus transversi* – Costal facet of transverse process

Head and neck of the rib with terminology comments — The back view of the typical rib
Note the two articular surfaces on the rib's head that articulates with two adjacent vertebrae and the interarticular crest facing the vertebral disc.
The list of terms:
*Caput costae* – Head of rib
*Facies articulares capitis costae* – Articular surfaces on head of rib
*Crista capitis costae* – Interarticular crest on head of rib
*Collum costae* – Neck of rib
*Crista colli costae* – Crest of neck of rib
*Facies articularis tuberculi costae* – Articular facet of costal tubercle
*Tuberculum costae* – Costal tubercle
*Angulus costae* – Angle of rib
*Sulcus costae* – Costal groove

Anatomical structures of the first and second ribs — The top view of the 1^st and 2^nd rib
Both ribs are atypical: the first rib is short and flat, and has no interarticular crest on the head since it articulatee with only one thoracic vertebra. But the second rib has prominent rounded tuberosity for attachment of the serratus anterior muscle.
The list of terms:
*Costa prima* – First rib
*Tuberculum musculi scaleni anterioris* – Tubercle for anterior scalene muscle
*Sulcus arteriae subclaviae* – Groove for subclavian artery
*Sulcus venae subclaviae* – Groove for subclavian vein
*Costa secunda* – Second rib
*Tuberositas musculi serrati anterioris* – Rougheness for serratus anterior muscle

Download PNG image — Dorsal view of the two lowermost ribs
Both are atypical since they lack the neck, the costal tubercle, and the articular facet of the costal tubercle. Also, the head of the 11^th and 12^th rib has no interarticular crest because of the articulation with the single corresponding vertebra.

Eleven and twelve rib — Dorsal view of the two lowermost ribs
Both are atypical since they lack the neck, the costal tubercle, and the articular facet of the costal tubercle. Also, the head of the 11^th and 12^th rib has no interarticular crest because of the articulation with the single corresponding vertebra.

360° rotation of the human ribs

First published: 15/Jun/2020
Last update: 26/Nov/2020