In this anatomy lesson, ns going come cover the rib bones, additionally called costae in Latin. The ribs help protect critical organs in the thorax such together the heart and also lungs, and also they aid with breathing.

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Don’t be fooled their long, bent shape! Rib bones space not share as long bones. Instead, anatomists share the ribs as level bones, and also they are situated within the axial skeleton. In addition to the sternum, thoracic vertebrae, and also costal cartilages, the ribs kind 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 divided into three key categories: true ribs, false ribs, and floating ribs.


True Ribs, False Ribs, and Floating Ribs

The true ribs include rib bag 1-7, v each rib articulating posteriorly come the thoracic vertebrae and also anteriorly to the sternum via costal cartilages. Because the true ribs connect to both the thoracic vertebrae and also the sternum, anatomists occasionally splice those terms together and also call the true ribs “the vertebrosternal ribs.”The false ribs include rib pairs 8-12. Favor the true ribs, this false ribs articulate v thoracic vertebrae posteriorly. However, they do not attach directly come the sternum anteriorly, and instead, connect to the costal cartilage the the preceding (superior) rib, except for false ribs 11-12, which room 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) room the last two pairs that false ribs, but unlike the various other false ribs, they do not attach to the cartilage the the coming before ribs top top the anterior side. Instead, they affix posteriorly to the thoracic vertebrae and also “float” there is no attaching to the costal cartilage anteriorly, for this reason anatomists simply speak to them “vertebral ribs.”

Intercostal Spaces

The an are between each rib is dubbed the intercostal space, and there are 11 intercostal spaces in the thoracic cage, which room filled v 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 room three main types of intercostal muscle, i beg your pardon facilitate chest movement: external intercostal muscles, inner intercostal muscles, and also innermost intercostal muscles.

Each intercostal space is numbered after the rib directly over it. Therefore the very first intercostal space will be the room just listed below the first rib; the second intercostal space is the space below the 2nd rib, and also so on.

These intercostal spaces are important landmarks for nurses and also other medical care professionals, particularly when assessing lung sounds and heart sounds.

As I mentioned in my sternum anatomy video, the second pair the ribs accomplish at the junction in between the manubrium and also the body of the sternum, creating the sternal edge (or edge of Louis). The 2nd intercostal space will be just below the second pair that ribs. From 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, under the midclavicular line.

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

Rib Bone Anatomy and also Landmarks

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

Typical Rib Bones

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


The anterior extremity is concave and porous, enabling for the attachments of the costal cartilage at the former of the thoracic cage.The pillar (body) of a common rib is flat yet long, and it curves sharply close to its posterior end, forming an angle recognized as the costal angle (or angle of the rib). A groove referred to as the costal groove extends down the worse (bottom) portion of the rib’s shaft, which permits for the i of intercostal vessels and nerves. This groove create a sharp inferior border contrasted to the smoother superior border, which enables you to identify the ideal orientation the the rib bone (sharper side always faces down).The tubercle is the tiny bumpy area wherein the human body meets the neck. The articular component of the tubercle articulates with the transverse procedure of the inferior vertebra, and also the non-articular part allows for the attachment of the ligament the the tubercle.The neck associate the human body (shaft) of the rib come the head.The head is ~ above the posterior end, and also it articulates through vertebrae via two facets: a smaller sized upper facet, i beg your pardon articulates through the vertebra above, and also a bigger facet the articulates with the vertebra of the very same rib number (example: rib three articulates through thoracic vertebra 3 at the inferior facet and vertebra 2 and the remarkable facet). This facets room separated by a bony crest, to which the intra-articular (or interarticular) ligament attaches.

Atyipcal Rib Bones

The atypical ribs encompass ribs 1, 2, 10, 11, and 12.


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

See more: How To Find The 3Rd Angle Of A Triangle, How To Find The Third Angle Of A Triangle

Free Quiz and an ext Anatomy Videos

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