General Features and Attachment Of

General Features and Attachments of Typical Ribs

Learning objectives:

At the end of the class, student should be able to :

 Classify the ribs.

 Mention the different parts of typical rib.

 Discuss the features of typical ribs.

Classification of Ribs

•Twelve pairs of ribs, each terminating anteriorly in a costal cartilage.

•True Ribs:

Costal cartilages of the upper seven ribs articulate directly with the sternum, known as TRUE RIBS.

•False Ribs: Costal cartilages lower five do not articulate directly to the sternum called as FALSE RIBS.

•Floating ribs:

Ribs 11th and 12th have no anterior connection with other ribs or with the sternum

Nomenclature

•Costal Margin:

Costal cartilages of 8th to 10th ribs articulate anteriorly with costal cartilages of the ribs above, forming a continuous margin, Costal Margin.

Typical Ribs:

•The Ribs 3rd to 9th or 10th have similar features and called as TYPICAL RIBS.

Typical rib consists of:

 A curved shaft with anterior and posterior ends.

Anterior end is continuous with its costal cartilage.

Posterior end articulates with the vertebral column and is characterized by a head, neck, and tubercle.

Head of Rib:

•Head is somewhat expanded.

•Presents two articular surfaces separated by crest.

•Smaller superior surface articulates with inferior costal facet on body of vertebra above,

•While larger inferior facet articulates with superior costal facet of its own vertebra.

Neck of Rib:

•Short flat region of bone.

•Separates the head from the tubercle.

Tubercle of rib:

•Projects posteriorly from the junction of the neck with the shaft.

•Consists of two regions

– An articular part and

– A non-articular part.

1. Articular part:

•It is medial.

• Has an oval facet for articulation with a corresponding facet on the transverse process of the associated vertebra;

2. non-articular part:

•Raised non-articular part is roughened by ligament attachments.

Shaft of Rib

•Shaft is generally thin and flat.

•Have two borders.

•Two surfaces.

•

Borders:

• Upper Border.

• Lower Border.

Surfaces:

•Outer Surface.

•Inner Surface.

•Superior margin is smooth and rounded,

• Inferior margin is sharp.

• Bends forward just laterally to tubercle at a site termed the angle.

•Has a gentle twist around its longitudinal axis.

•Inferior margin of internal surface is marked by a distinct costal groove.

References

GRAYS ANATOMY FOR STUDENTS 2004, -by Richard Drake, Wayne Vogl, Adam W.M. Mitchell

GRANT'S.ATLAS.OF.ANATOMY.12th. Anne M. R. Ager and Arther F. Delly

MOORE, KEITH L. - CLINICALLY ORIENTED ANATOMY, by Keith L. Moore and Keith L. Moore