Generality
The rib cage is the considerable bony structure, located between the neck and the diaphragm muscle, which includes: the 12 pairs of ribs, the sternum and the 12 thoracic vertebrae of the spinal column.
The ribs constitute the left and right lateral portions, and a fair part of the anterior portion; the sternum constitutes its central anterior portion; finally, the thoracic vertebrae represent the posterior portion.
On some bones of the thoracic cage important muscles of the human body are inserted, including: the pectoralis major muscle, the sternocleidomastoid muscle, the rectus abdominis muscle and the intercostal muscles.
The rib cage has at least 3 important functions, which are: protection against the heart, lungs, esophagus, aorta, hollow veins and spinal cord; support of the human body, in particular with the thoracic vertebrae; finally, support for breathing, thanks to the upward movements of the ribs that expand the volume inside the rib cage.
The rib cage can be subject to: bone fractures (a typical example is a fractured rib), cartilage inflammation (such as Tietze syndrome and costochondritis) and malformations (such as pectus excavatum or the faired chest).
What is the rib cage?
The thoracic cage is the bone structure, which is part of the trunk of the human body, the 12 pairs of ribs, the sternum and the 12 thoracic vertebrae of the vertebral column participate in its constitution.
Anatomy
The rib cage is the portion of the human body, which lies between the neck, above, the diaphragm muscle, below, and the two shoulders, laterally.
Anatomically, it corresponds to the chest (or thorax) and the upper back region.
In composing the rib cage:
- The 12 thoracic vertebrae represent the posterior portion;
- The two sets of 12 ribs constitute the left and right lateral portions, and a fair part of the anterior portion;
- The sternum represents its central anterior portion.
STERNUM
Located in the center of the thorax, the sternum is the long, flat, uneven bone on which the first 7 pairs of ribs are inserted by means of the so-called costal cartilages.
By convention, anatomists divide it into three regions, named: manubrium, body, and xiphoid process.
The handlebar it is the highest region of the sternum, therefore closest to the neck. Trapezoidal in shape, the manubrium of the sternum has, on both sides and with a direction from "top to bottom," an incisura and two depressions: on each incisura, the internal (or medial) ends of the clavicles are inserted; on the two depressions, on the other hand, the first two pairs of ribs are connected (N.B: the depressions for the second pair of ribs are shared with the body).
The body it is the intermediate sternum region, located between the manubrium and the xiphoid process. The body of the sternum has an elongated shape and, thanks to a series of depressions on both sides, offers a total anchorage with 4 pairs of ribs (from the third pair to the sixth pair) and a partial anchorage with 2 pairs of ribs (the second pair, which is shared with the dumbbell, and the seventh pair, which is shared with the xiphoid process).
Finally, the xiphoid process it is the lowest sternum region, therefore more distant from the neck and closer to the abdomen. Mainly cartilaginous in nature up to the age of 40, the xiphoid process presents, on both sides, a small depression shared with the overlying body , within which the seventh pair of ribs is welded.
RIBS
The ribs are the 24 tapered and curved bones (or arched ribbon-like), which, arranged in pairs, arise on both sides of the 12 thoracic vertebrae and project almost to the anterior area of the thorax.
From this description, it appears that each of the 12 thoracic vertebrae is the point of origin of a pair of ribs.
The ribs retain a bony nature for most of their course; they change composition only in the final anterior projections, in which they present the aforementioned costal cartilages.
Looking at a classic frontal image of the rib cage from top to bottom, it is immediately clear that:
- The first 7 pairs of ribs find direct insertion into the sternum, through the costal cartilages;
- The eighth, ninth and tenth pair of ribs hook onto the costal cartilages of the immediately preceding pair of ribs. That is, the eighth pair of ribs attaches to the costal cartilages of the seventh pair of ribs; the ninth pair of ribs attaches to the costal cartilages of the eighth pair of ribs; and so on;
- The eleventh and twelfth pair are free and also much shorter than the previous pairs.
In a generic rib, anatomists recognize three main regions, which are: the posterior end, the anterior end and the body.
L"rear end of a rib is the region of connection with the vertebra from which the rib in question originates; it has two particular areas, called the head and neck.
L"anterior end of a rib is the region of connection with the costal cartilages; the costal cartilages are integral parts of the ribs, but, given their cartilage nature, anatomical experts have preferred to distinguish them with a specific denomination.
The body of a rib, finally, is the region between the posterior end and the anterior end.
Every two overlapping ribs there is an empty space, which in specialist jargon is called intercostal space. In the various intercostal spaces take place the so-called intercostal muscles, the so-called intercostal nerves, arterial blood vessels and venous blood vessels.
