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

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Don’t it is in fooled their long, curved shape! Rib bones room not classified as long bones. Instead, anatomists divide the ribs as flat bones, and also they are situated within the axial skeleton. In addition to the sternum, thoracic vertebrae, and costal cartilages, the ribs kind the thoracic cage, also called the bony thorax.

Ribs Anatomy

The median skeleton includes 24 individual ribs, formed 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 anteriorly come the sternum via costal cartilages. Because the true ribs affix 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 encompass rib pairs 8-12. Favor the true ribs, these false ribs articulate v thoracic vertebrae posteriorly. However, they carry out not attach directly to the sternum anteriorly, and instead, affix to the costal cartilage of the preceding (superior) rib, except for false ribs 11-12, which room the floating ribs. Due to the fact that the false ribs connect to the vertebrae posteriorly and costal cartilage anteriorly, anatomists sometimes speak to the false ribs vertebrochondral ribs (vertebro = vertebrae; chondral = cartilage).The floating ribs (11-12) are the last 2 pairs that false ribs, yet unlike the other false ribs, they perform not attach to the cartilage that the preceding ribs ~ above the anterior side. Instead, they attach posteriorly to the thoracic vertebrae and “float” there is no attaching to the costal cartilage anteriorly, therefore anatomists simply speak to them “vertebral ribs.”

Intercostal Spaces

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


There are three main species of intercostal muscle, i m sorry facilitate chest movement: outside intercostal muscles, inner intercostal muscles, and innermost intercostal muscles.

Each intercostal room is numbered ~ the rib directly over it. For this reason the very first intercostal space will be the room just listed below the very first rib; the 2nd intercostal an are is the an are below the 2nd rib, and so on.

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

As I stated in mine sternum anatomy video, the second pair of ribs meet at the junction between the manubrium and also the body of the sternum, creating the sternal angle (or edge of Louis). The second intercostal room will it is in just listed below the 2nd pair that ribs. Indigenous there, you deserve to count the intercostal spaces to situate the apical pulse, i beg your pardon is ~ above the left next of the chest in ~ the fith intercostal space, down the midclavicular line.

Other intercostal spaces will allow you to assess different chest assessment sounds.

Rib Bone Anatomy and Landmarks

When examining individual rib bones, you’ll notice that some have different structures, for this reason anatomists categorize ribs into two main types: typical and atypical.

Typical Rib Bones

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


The anterior extremity is concave and also porous, permitting for the attachment of the costal cartilage in ~ the front of the thoracic cage.The shaft (body) the a usual rib is flat but long, and it curve sharply near its posterior end, creating an angle well-known as the costal angle (or edge of the rib). A groove called the costal groove extends down the worse (bottom) section of the rib’s shaft, which allows for the i of intercostal vessels and nerves. This groove creates a spicy inferior border compared to the smoother superior border, which allows you to recognize the suitable orientation that the rib bone (sharper side constantly faces down).The tubercle is the tiny bumpy area where the body meets the neck. The articular part of the tubercle articulates v the transverse procedure of the worse vertebra, and the non-articular section allows for the attachment of the ligament of the tubercle.The neck connect the body (shaft) that the rib to the head.The head is on the posterior end, and also it articulates through vertebrae via two facets: a smaller sized upper facet, which articulates through the vertebra above, and a bigger facet that articulates with the vertebra the the exact same rib number (example: rib three articulates through thoracic vertebra 3 in ~ the worse facet and also vertebra 2 and also the exceptional facet). These facets space separated through a bony crest, come which the intra-articular (or interarticular) ligament attaches.

Atyipcal Rib Bones

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


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

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Free Quiz and much more Anatomy Videos

Take a free ribs anatomy quiz to test her knowledge, or evaluation our ribs anatomy video. In addition, you might want to clock our anatomy and physiology lectures on YouTube, or inspect our anatomy and physiology notes.