Bones and Joints of the Thorax

Flashcards covering the anatomical features, classifications, and clinical conditions related to the bones and joints of the thorax, including the sternum, ribs, and thoracic vertebrae.

Sternum

Commonly known as the breast bone, it is an elongated flat bone about $17\,cm$ long situated in the anterior median part of the chest wall.

Manubrium sterni (Episternum)

The thickest and strongest part of the sternum, which is quadrilateral in shape and lies opposite the third and fourth thoracic vertebrae.

Sternal angle (Angle of Louis)

A transverse ridge on the anterior aspect of the sternum formed by the junction of the manubrium and the body, located about $5\,cm$ below the suprasternal notch.

Body of sternum (Mesosternum)

The longest part of the sternum, composed of four fused segments called sternebrae, which articulates with the second through seventh costal cartilages.

Xiphoid process (Metasternum)

The smallest and lowest part of the sternum, providing attachment for the rectus abdominis and the linea alba.

Sternal puncture

A clinical procedure for bone marrow aspiration, typically performed on the upper part of the manubrium sterni because it is subcutaneous and accessible.

Pectus excavatum (Funnel chest)

A condition where the thoracic cage is compressed anteroposteriorly and the sternum is pushed backward, which may compress the heart.

Pectus carinatum (Pigeon chest)

An abnormal shape of the thoracic cage where the chest is compressed side-to-side and the sternum projects forward like a boat's keel.

True ribs (Vertebrosternal ribs)

The first seven pairs of ribs ($1^{st}-7^{th}$) which articulate posteriorly with the vertebrae and anteriorly with the sternum via costal cartilages.

False ribs

The $8^{th}$ through $12^{th}$ ribs that do not articulate directly with the sternum.

Floating ribs (Vertebral ribs)

The $11^{th}$ and $12^{th}$ ribs whose anterior ends are free and tipped with cartilage.

Typical ribs

Ribs $3^{rd}-9^{th}$ that share common features, including a head, neck, tubercle, and a shaft with a costal groove.

Costal groove

A groove on the inner surface near the lower border of a rib that lodges the intercostal vein, artery, and nerve (VAN).

First rib

The shortest, broadest, and most acutely curved rib, featuring a scalene tubercle on its inner border and lacking a costal groove.

Cervical rib

An elongation of the costal element of the $C7$ vertebra that may compress the lower trunk of the brachial plexus and the subclavian artery.

Flail chest (Stove-in-chest)

A condition resulting from ribs being fractured at two sites, causing the segments to be sucked in during inspiration and pushed out during expiration (paradoxical respiration).

Thoracic vertebrae

Twelve vertebrae characterized by the presence of costal facets on the sides of their bodies for articulation with the heads of the ribs.

Costovertebral joints

Synovial plane joints formed between the heads of the ribs and the costal facets on the bodies of thoracic vertebrae.

Costotransverse joints

Synovial plane joints formed by the articulation of a rib tubercle with the transverse process of the numerically corresponding vertebra.

Manubriosternal joint

A secondary cartilaginous joint (symphysis) between the manubrium and the body of the sternum that permits slight movement during respiration.