In this anatomy lesson, i’m going to cover the rib bones, additionally called costae in Latin. The ribs help protect vital organs in the thorax such as the heart and lungs, and also they aid with breathing.

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Don’t be fooled their long, bent shape! Rib bones space not divide as long bones. Instead, anatomists divide the ribs as level bones, and they are situated within the axial skeleton. Together with the sternum, thoracic vertebrae, and costal cartilages, the ribs form the thoracic cage, also called the bony thorax.

Ribs Anatomy

The median skeleton contains 24 separation, personal, instance ribs, created in 12 pairs, and they are split into three key categories: true ribs, false ribs, and also floating ribs.


True Ribs, False Ribs, and Floating Ribs

The true ribs include rib pairs 1-7, through each rib articulating posteriorly to the thoracic vertebrae and anteriorly come the sternum via costal cartilages. Due to the fact that the true ribs connect to both the thoracic vertebrae and also the sternum, anatomists periodically splice those terms together and call the true ribs “the vertebrosternal ribs.”The false ribs incorporate rib pairs 8-12. Choose the true ribs, these false ribs articulate v thoracic vertebrae posteriorly. However, they execute not connect directly to the sternum anteriorly, and instead, attach to the costal cartilage the the coming before (superior) rib, except for false ribs 11-12, which space the floating ribs. Because the false ribs attach to the vertebrae posteriorly and also costal cartilage anteriorly, anatomists sometimes contact the false ribs vertebrochondral ribs (vertebro = vertebrae; chondral = cartilage).The floating ribs (11-12) are the last two pairs that false ribs, but unlike the other false ribs, they carry out not attach to the cartilage of the coming before ribs top top the anterior side. Instead, they attach posteriorly come the thoracic vertebrae and also “float” there is no attaching come the costal cartilage anteriorly, therefore anatomists simply speak to them “vertebral ribs.”

Intercostal Spaces

The room between every rib is referred to as the intercostal space, and there are 11 intercostal spaces in the thoracic cage, which space filled through nerves, lymph nodes, arteries, veins, and also muscles. In fact, once you eat ribs in ~ a restaurant, you’re eating the intercostal muscles of an animal.


There are three main varieties of intercostal muscle, i beg your pardon facilitate chest movement: exterior intercostal muscles, interior intercostal muscles, and innermost intercostal muscles.

Each intercostal an are is numbered ~ the rib directly above it. So the an initial intercostal space will be the room just listed below the first rib; the 2nd intercostal room is the an are below the 2nd rib, and also so on.

These intercostal spaces are necessary landmarks because that nurses and also other healthcare professionals, specifically when assessing lung sounds and heart sounds.

As I mentioned in mine sternum anatomy video, the second pair that ribs meet at the junction in between the manubrium and also the human body of the sternum, developing the sternal edge (or angle of Louis). The 2nd intercostal room will be just listed below the 2nd pair the ribs. Native there, you can count the intercostal spaces to situate the apical pulse, which is ~ above the left next of the chest in ~ the fith intercostal space, down the midclavicular line.

Other intercostal spaces will permit you come assess different chest evaluate sounds.

Rib Bone Anatomy and also Landmarks

When analyzing individual rib bones, you’ll notification that part have various structures, so anatomists categorize ribs right into two key types: typical and atypical.

Typical Rib Bones

Typical ribs include ribs 3-9, and they function a column (or body), head, neck, groove, tubercle, and anterior extremity.


The anterior extremity is concave and porous, permitting for the attachment of the costal cartilage at the former of the thoracic cage.The shaft (body) of a usual rib is flat yet long, and it curves sharply near its posterior end, creating an angle well-known as the costal angle (or angle of the rib). A groove dubbed the costal groove extends down the inferior (bottom) part of the rib’s shaft, which permits for the i of intercostal vessels and also nerves. This groove creates a sharp inferior border contrasted to the smoother exceptional border, which permits you to determine the ideal orientation that the rib bone (sharper side constantly faces down).The tubercle is the little bumpy area where the human body meets the neck. The articular part of the tubercle articulates with the transverse procedure of the inferior vertebra, and the non-articular part allows for the attachments of the ligament of the tubercle.The neck connects the human body (shaft) that the rib come the head.The head is ~ above the posterior end, and also it articulates through vertebrae via 2 facets: a smaller sized upper facet, i m sorry articulates through the vertebra above, and also a bigger facet that articulates through the vertebra that the very same rib number (example: rib three articulates v thoracic vertebra 3 in ~ the worse facet and also vertebra 2 and the premium facet). This facets room separated through a bony crest, to which the intra-articular (or interarticular) ligament attaches.

Atyipcal Rib Bones

The patent ribs include ribs 1, 2, 10, 11, and 12.


Rib 1 is usually shorter and broader than all various other ribs, and also its broad, flat surface consists of grooves that support the subclavian vessels. Because rib 1 articulates with first thoracic vertebra only, over there is a solitary facet top top its head (typical ribs have actually two facets, as mentioned above). A scalene tubercle enables for the attachment of the scalene muscles.Rib 2 is likewise quite curved, but it is longer than rib one and also not together flat. The serratus anterior muscle originates native a roughened area close to the center of this rib, and also it articulates through thoracic vertebrae 1 and also 2 (T1 and T2).Rib 10 has only a solitary articular facet on its head.Ribs 11 and also 12 likewise have a solitary articular side on the head, yet no necks or tubercles.

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Free Quiz and much more Anatomy Videos

Take a complimentary ribs anatomy quiz to test your knowledge, or testimonial our ribs anatomy video. In addition, you might want to watch our anatomy and also physiology lectures top top YouTube, or check our anatomy and physiology notes.