Rib Anatomy and Classification

Practice flashcards covering the anatomical features, classifications, and specific characteristics of typical and atypical ribs based on the lecture material.

7th rib

The longest rib, resulting from the progressive increase in rib length.

8th rib

The rib with the greatest lateral projection because the transverse diameter of the thorax increases from the $1st$ to the $8th$ rib.

Vertebrosternal ribs (1st-7th)

Ribs that articulate posteriorly with vertebrae and anteriorly with the sternum.

Vertebrochondral ribs (8th-10th)

Ribs that articulate posteriorly with vertebrae and anteriorly join their cartilages to the cartilage of the higher rib.

Vertebral (floating) ribs (11th-12th)

Ribs that articulate posteriorly with the vertebrae but have free anterior ends.

Typical rib anterior end

Contains a small cup-shaped depression that joins with costal cartilage to form a primary cartilaginous costochondral joint.

Typical rib head

Part of the posterior end with a lower larger facet for the body of the numerically corresponding vertebra and an upper smaller facet for the next higher vertebra.

Rib Tubercle

A projection at the junction of the neck and shaft divided into a medial articular part and a lateral non-articular part.

Angle of the rib

The point approximately $5\,cm$ away from the tubercle where the rib shaft abruptly changes its direction.

Costal groove

A groove on the inner surface near the lower border that lodges the Intercostal Vein, Intercostal Artery, and Intercostal Nerve (Mnemonic: VAN).

Characteristic features of a typical rib (Mnemonic: CAT)

Curve (curved along entire extent), Angle (two bends located $5\,cm$ from the tubercle and $2\,cm$ from the anterior end), and Twist (two ends cannot touch the same horizontal plane).

First Rib

The shortest, broadest, and most acutely curved rib; it has a single articular facet on the head and no costal groove.

Internal intercostal muscle

Muscle attached to the floor of the costal groove, situated between the bone and the intercostal nerves and vessels.

Intercostalis intimus

Muscle attached to the upper border of the costal groove.

Second Rib

A rib characterized by a highly curved shaft and a length that is twice that of the first rib.