In this anatomy lesson, ns going to cover the rib bones, likewise called costae in Latin. The ribs aid protect crucial organs in the thorax such as the heart and lungs, and also they aid with breathing.

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Don’t it is in fooled your long, curved shape! Rib bones are not share as lengthy bones. Instead, anatomists classify the ribs as flat bones, and also they are situated within the axial skeleton. Along with the sternum, thoracic vertebrae, and costal cartilages, the ribs type the thoracic cage, also called the bony thorax.

Ribs Anatomy

The typical skeleton consists of 24 separation, personal, instance ribs, developed in 12 pairs, and they are separated into three key categories: true ribs, false ribs, and also floating ribs.


True Ribs, False Ribs, and also Floating Ribs

The true ribs include rib bag 1-7, through each rib articulating posteriorly to the thoracic vertebrae and anteriorly come the sternum via costal cartilages. Because the true ribs connect to both the thoracic vertebrae and the sternum, anatomists occasionally splice those state together and call the true ribs “the vertebrosternal ribs.”The false ribs incorporate rib pairs 8-12. Like the true ribs, these false ribs articulate with thoracic vertebrae posteriorly. However, they do not affix directly to the sternum anteriorly, and also instead, attach to the costal cartilage the the preceding (superior) rib, except for false ribs 11-12, which room the floating ribs. Because the false ribs connect to the vertebrae posteriorly and also costal cartilage anteriorly, anatomists sometimes speak to the false ribs vertebrochondral ribs (vertebro = vertebrae; chondral = cartilage).The floating ribs (11-12) room the last 2 pairs that false ribs, yet unlike the other false ribs, they execute not attach to the cartilage of the coming before ribs on the anterior side. Instead, they connect posteriorly come the thoracic vertebrae and also “float” without attaching to the costal cartilage anteriorly, so anatomists simply speak to them “vertebral ribs.”

Intercostal Spaces

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


There room three main types of intercostal muscle, which facilitate chest movement: outside intercostal muscles, internal intercostal muscles, and also innermost intercostal muscles.

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

These intercostal spaces are crucial landmarks for nurses and other health care professionals, especially when assessing lung sounds and heart sounds.

As I pointed out 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 second intercostal space will be just listed below the second pair of ribs. From there, you have the right to count the intercostal spaces to locate the apical pulse, which is ~ above the left side of the chest in ~ the fith intercostal space, down the midclavicular line.

Other intercostal spaces will allow you come assess various chest assessment sounds.

Rib Bone Anatomy and Landmarks

When examining individual rib bones, you’ll an alert that part have different structures, so anatomists categorize ribs into two key types: typical and atypical.

Typical Rib Bones

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


The anterior extremity is concave and also porous, allowing for the attachment of the costal cartilage in ~ the former of the thoracic cage.The obelisk (body) of a common rib is flat but long, and also it curve sharply close to its posterior end, creating an angle known as the costal angle (or edge of the rib). A groove referred to as the costal groove extends under the worse (bottom) section of the rib’s shaft, which allows for the i of intercostal vessels and nerves. This groove create a sharp inferior border compared to the smoother remarkable border, which permits you to identify the appropriate orientation that the rib bone (sharper side constantly faces down).The tubercle is the small bumpy area where the human body meets the neck. The articular part of the tubercle articulates with the transverse process of the inferior vertebra, and the non-articular portion allows for the attachments of the ligament that the tubercle.The neck connect the body (shaft) of the rib to the head.The head is ~ above the posterior end, and also it articulates through vertebrae via two facets: a smaller upper facet, i m sorry articulates through the vertebra above, and a larger facet the articulates through the vertebra that the same rib number (example: rib three articulates v thoracic vertebra 3 at the worse 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 wider than all other ribs, and its broad, flat surface has grooves that support the subclavian vessels. Due to the fact that rib 1 articulates with very first thoracic vertebra only, there is a solitary facet top top its head (typical ribs have actually two facets, as discussed above). A scalene tubercle permits for the attachments of the scalene muscles.Rib 2 is likewise quite curved, but it is much longer than rib one and not as flat. The serratus anterior muscle originates from a roughened area near the middle of this rib, and it articulates v thoracic vertebrae 1 and 2 (T1 and T2).Rib 10 has only a solitary articular side on the head.Ribs 11 and 12 additionally have a solitary articular facet on the head, but 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 review our ribs anatomy video. In addition, you could want to clock our anatomy and physiology lectures top top YouTube, or examine our anatomy and also physiology notes.