In this anatomy lesson, i’m going come cover the rib bones, also called costae in Latin. The ribs aid protect critical 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, bent shape! Rib bones room not share as lengthy bones. Instead, anatomists classify the ribs as level bones, and also they are located within the axial skeleton. Along with the sternum, thoracic vertebrae, and costal cartilages, the ribs form the thoracic cage, additionally called the bony thorax.

Ribs Anatomy

The mean skeleton includes 24 individual ribs, created in 12 pairs, and also they are separated into three key categories: true ribs, false ribs, and floating ribs.


True Ribs, False Ribs, and also Floating Ribs

The true ribs include rib pairs 1-7, with each rib articulating posteriorly come the thoracic vertebrae and also anteriorly come the sternum via costal cartilages. Due to the fact that the true ribs connect to both the thoracic vertebrae and the sternum, anatomists periodically splice those terms together and call the true ribs “the vertebrosternal ribs.”The false ribs encompass rib pairs 8-12. Prefer the true ribs, this false ribs articulate v thoracic vertebrae posteriorly. However, they carry out not attach directly come the sternum anteriorly, and also instead, attach to the costal cartilage that the preceding (superior) rib, other than for false ribs 11-12, which are the floating ribs. Since the false ribs affix to the vertebrae posteriorly and also costal cartilage anteriorly, anatomists sometimes call the false ribs vertebrochondral ribs (vertebro = vertebrae; chondral = cartilage).The floating ribs (11-12) room the last 2 pairs the false ribs, yet unlike the other false ribs, they carry out not affix to the cartilage of the coming before ribs on the anterior side. Instead, they connect posteriorly to the thoracic vertebrae and also “float” without attaching to the costal cartilage anteriorly, so anatomists simply contact them “vertebral ribs.”

Intercostal Spaces

The space between every rib is referred to as the intercostal space, and there room 11 intercostal spaces in the thoracic cage, which are filled with nerves, lymph nodes, arteries, veins, and 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 m sorry facilitate chest movement: outside intercostal muscles, inner intercostal muscles, and innermost intercostal muscles.

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

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

As I discussed in mine sternum anatomy video, the 2nd pair the ribs satisfy at the junction between the manubrium and the body of the sternum, creating the sternal angle (or angle of Louis). The second intercostal room will it is in just listed below the second pair of ribs. Native there, you deserve to count the intercostal spaces to locate the apical pulse, i m sorry is ~ above the left next of the chest in ~ the fith intercostal space, under the midclavicular line.

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

Rib Bone Anatomy and Landmarks

When examining 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 incorporate ribs 3-9, and they attribute a column (or body), head, neck, groove, tubercle, and anterior extremity.


The anterior extremity is concave and also porous, permitting for the attachment of the costal cartilage at the front of the thoracic cage.The shaft (body) of a common rib is flat however long, and it curve sharply close to its posterior end, forming an angle well-known as the costal angle (or angle of the rib). A groove called the costal groove extends under the inferior (bottom) part of the rib’s shaft, which permits for the i of intercostal vessels and also nerves. This groove create a sharp inferior border contrasted to the smoother remarkable border, which enables you to recognize the ideal orientation the the rib bone (sharper side constantly faces down).The tubercle is the small bumpy area whereby the body meets the neck. The articular component of the tubercle articulates through the transverse process of the inferior vertebra, and also the non-articular section 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 upper facet, i m sorry articulates v the vertebra above, and a bigger facet that articulates through the vertebra the the very same rib number (example: rib 3 articulates through thoracic vertebra 3 in ~ the inferior facet and vertebra 2 and the remarkable facet). This facets space separated through a bony crest, come which the intra-articular (or interarticular) ligament attaches.

Atyipcal Rib Bones

The atypical ribs incorporate ribs 1, 2, 10, 11, and also 12.


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

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Free Quiz and an ext Anatomy Videos

Take a complimentary ribs anatomy quiz to test her knowledge, or evaluation our ribs anatomy video. In addition, you can want to watch our anatomy and physiology lectures top top YouTube, or inspect our anatomy and also physiology notes.