Structure of the Ribcage and Ribs

Author: Scott A. Sheffield MS

Last update: Nov 2nd, 2022

Introduction to the Structure of the Ribcage and Ribs:

There are twelve (12) pairs of ribs and all articulate posteriorly with the thoracic vertebrae.

1. The true ribs (ribs 1-7) attach to the sternum by costal cartilages. The flexible (hyaline) cartilage, makes the breathing process easier.

2. The false ribs (ribs 8-10) attach to the costal cartilage of rib 7, not directly to the sternum.

3. The floating ribs (ribs 11-12) have no anterior attachment with the sternum.

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Ribs 3-9 share many structural characteristics.

In comparison, the first two ribs are shorter and more curved. Rib 1 is also flattened horizontally. The heads of ribs 1, 10, 11, and 12 have a single facet for articulation with the bodies of the thoracic vertebrae. Ribs 11 and 12 do not have necks or tubercles and the anterior tips of their bodies lack an articular surface.

Bone Markings of Ribs 3-9:

1. Body or shaft – long, curved portion of the rib. [Add/Remove vertebrae]

2. Angle – area of shaft with the greatest curvature. [Add/Remove vertebrae]

3. Costal groove – elongated depression along the inferior surface of the rib. The channel provides a pathway for the intercostal blood vessels and nerves run. [Add/Remove vertebrae]

4. Head – medioposterior end of the rib. It contains the facets that articulate with the vertebral bodies of the thoracic vertebrae. [Add/Remove vertebrae]

5. Superior articular facet – upper of two small depressions on the head. It forms the are of articulation with the inferior costal (or demi) facet on the vertebra above. [Add/Remove vertebrae]

6. Inferior articular facet – lower of the two small depressions on the head. It forms the are of articulation with the superior costal (demi) facet on the vertebra below. [Add/Remove vertebrae]

7. Neck – area between the head and the tubercle. [Add/Remove vertebrae]

8. Tubercle – small elevation on the posterior surface of the rib at the junction of the head and neck. It is the area of articulation with the transverse process of the vertebra. [Add/Remove vertebrae]

9. Sternal end – region of the rib that attaches to the costal cartilage. [Add/Remove vertebrae]

Test yourself:

Anterior view of the ribcage and ribs: [Show/Hide answers]

Test yourself:

Medial view of the right ribs: [Show/Hide] answers.

Interactive quiz about the ribs