Synonyms
Medical: Costa vertebralis, Costae vertebrales
Introduction
The ribs as a whole form the thorax. Two ribs each are connected via the spinal column and the sternum. Most people have 12 pairs of ribs (the number of ribs can vary), which are all connected to our thoracic spine and determine the shape of the thorax. The upper 10 ribs (true and false ribs, see below) are additionally connected to the sternum in an articulated manner, the lower two ribs (rudimentary ribs, see below) are free.
Anatomy of the ribs
These 12 ribs (costae) are divided into three groups: All ribs consist of a bony and a cartilaginous part. The ribs originate at the spine in bones and become cartilaginous at their end at the sternum. The first rib is short and broad, protecting the rib cage from above.
It is largely covered by the collarbone (clavicle). The 8th – 10th ribs are called false ribs because they do not reach the sternum directly, but merge with the 7th rib in a cartilaginous way. The ribs fused to the sternum are also called the costal arch.
The 11th and 12th ribs are only stubby and do not end at the costal arch (rudimentary ribs). In about 0.5% of all people, a mostly insignificant malposition of the 5th, 6th and 7th cervical vertebrae with a so-called cervical rib, which is often discovered only by chance, occurs. In rare cases, a lumbar rib can also be formed on the first lumbar vertebral body, but often only as a stubby extension of the transverse process of the vertebral body.
- True ribs (1st – 7th rib = costae verae)
- Incorrect ribs (8th – 10th rib = costae spuriae)
- Rudimentary ribs (11th and 12th rib = costae fluctuantes)
So that the ribs can move along with the respiratory movements, there are rib joints on the sternum and the spine: Together with the vertebrae of the spine, the bony end of the ribs forms the costovertebral joints, so-called ball joints. The round rib head lies in a hollow of the vertebral body. The joints between the sternum and rib are called rib-chestal joints (sternocostal joints).
The first pair of ribs is attached to the sternum handle (manubrium sterni) and the 2nd -7th rib to the sternum body. The space between two ribs is called the intercostal space. This is where the intercostal muscles are located.
In addition, nerves and vessels also run here on the inner underside of the ribs.
- Rib-vertebral joints
- Rib-chest joints
- Collarbone (Clavicle)
- Breastbone (sternum)
- Ribs (Costae)
Rib cartilage is physiological and a component of our ribcage. Anatomically, the rib cartilage connects our bony rib bodies (corpus costae) with the sternum.
Consequently, the rib cartilage is located at the front, to the side of the sternum. We have a total of twelve pairs of ribs. Of these, the first seven pairs of ribs are directly connected to the sternum via the rib cartilage.
For this reason they are also called “true ribs” (Costae verae). The next three pairs of ribs (8th to 10th pair of ribs) are not individually connected to the sternum like the “true ribs”, but join the higher rib pair in cartilage. So also the designation “false ribs” (Costae spuriae) explains itself.
The last two pairs of ribs have no connection to the sternum, so that they are also called rudimentary ribs (Costae fluctuantes). The rib cartilage has a special significance for the elasticity of the thorax, which is very important for breathing. Due to the cartilaginous connection between ribs and sternum, the thorax can widen during inhalation, but also shrink again during exhalation.
You can read more detailed information on this topic here:
- Rib Cartilage
- What diseases of the rib cartilage are there?
There are several rib muscles that play an important role, especially in breathing. A large muscle group is the intercostal muscles, which are made up of several muscles. On the one hand, there are the outer, inner and innermost intercostal muscles (Musculi intercostales externi, interni and intimi), which are stretched between the individual ribs like a fish bone.
Their task is to widen the thorax during inhalation (inspiration) and to shrink it during exhalation (expiration).On the other hand, the subcostal muscles (Musculi subcostales) lie under the ribs. These also belong to the intercostal muscles and are a division of the Musculi intercostales interni. Consequently, they also lower the ribs and thus help with exhalation.
Another muscle that belongs to the group of intercostal muscles is the Musculus transversus thoracis. This muscle tenses the cartilaginous costal arch and thus increases resistance during inhalation. There are also respiratory auxiliary muscles that support the intercostal muscles when necessary.
These include a number of muscles, such as the major and minor pectoralis muscles, the anterior serratus muscle and the posterior superior muscle. These support overall inhalation. During exhalation, the various abdominal muscles are increasingly used.
