Registered Nurse RN

Registered Nurse, Free Care Plans, Free NCLEX Review, Nurse Salary, and much more. Join the nursing revolution.

  • RN
    • Nursing Clinical Skills
  • Nursing Videos
  • Blog
  • Nursing School
  • Nursing Care Plans
  • Nursing Quizzes
  • Nursing
  • Nursing Jobs
  • NCLEX Review
  • Store

Rib Anatomy

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

Don’t be fooled their long, curved shape! Rib bones are not classified as long bones. Instead, anatomists classify the ribs as flat bones, and they are located 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 average skeleton contains 24 individual ribs, formed in 12 pairs, and they are divided into three main categories: true ribs, false ribs, and floating ribs.

true ribs, false ribs, floating ribs, anatomy, rib bones, bones anatomy

True Ribs, False Ribs, and Floating Ribs

  • The true ribs include rib pairs 1-7, with each rib articulating posteriorly to the thoracic vertebrae and anteriorly to the sternum via costal cartilages. Because the true ribs attach to both the thoracic vertebrae and the sternum, anatomists sometimes splice those terms together and call the true ribs “the vertebrosternal ribs.”
  • The false ribs include rib pairs 8-12. Like the true ribs, these false ribs articulate with thoracic vertebrae posteriorly. However, they do not attach directly to the sternum anteriorly, and instead, attach to the costal cartilage of the preceding (superior) rib, except for false ribs 11-12, which are the floating ribs. Because the false ribs attach to the vertebrae posteriorly and costal cartilage anteriorly, anatomists sometimes call the false ribs vertebrochondral ribs (vertebro = vertebrae; chondral = cartilage).
  • The floating ribs (11-12) are the last two pairs of false ribs, but unlike the other false ribs, they do not attach to the cartilage of the preceding ribs on the anterior side. Instead, they attach posteriorly to the thoracic vertebrae and “float” without attaching to the costal cartilage anteriorly, so anatomists simply call them “vertebral ribs.”

Intercostal Spaces

The space between each rib is called the intercostal space, and there are 11 intercostal spaces in the thoracic cage, which are filled with nerves, lymph nodes, arteries, veins, and muscles. In fact, when you eat ribs at a restaurant, you’re eating the intercostal muscles of an animal.

intercostal space, intercostal muscles, intercostal spaces numbered

There are three main types of intercostal muscle, which facilitate chest movement: External intercostal muscles, internal intercostal muscles, and innermost intercostal muscles.

Each intercostal space is numbered after the rib directly above it. So the first intercostal space will be the space just below the first rib; the second intercostal space is the space below the second rib, and so on.

These intercostal spaces are important landmarks for nurses and other healthcare professionals, especially when assessing lung sounds and heart sounds.

As I mentioned in my sternum anatomy video, the second pair of ribs meet at the junction between the manubrium and the body of the sternum, forming the sternal angle (or angle of Louis). The second intercostal space will be just below the second pair of ribs. From there, you can count the intercostal spaces to locate the apical pulse, which is on the left side of the chest at 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, so anatomists categorize ribs into two main types:  typical and atypical.

Typical Rib Bones

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

rib bones,rib anatomy, head, tubercle,neck,costal angle

  • The anterior extremity is concave and porous, allowing for the attachment of the costal cartilage at the front of the thoracic cage.
  • The shaft (body) of a typical rib is flat but long, and it curves sharply near its posterior end, forming an angle known as the costal angle (or angle of the rib). A groove called the costal groove extends down the inferior (bottom) portion of the rib’s shaft, which allows for the passage of intercostal vessels and nerves. This groove creates a sharp inferior border compared to the smoother superior border, which allows you to identify the proper orientation of the rib bone (sharper side always faces down).
  • The tubercle is the small bumpy area where the 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 attachment of the ligament of the tubercle.
  • The neck connects the body (shaft) of the rib to the head.
  • The head is on the posterior end, and it articulates with vertebrae via two facets: a smaller upper facet, which articulates with the vertebra above, and a larger facet that articulates with the vertebra of the same rib number (example: rib three articulates with thoracic vertebra 3 at the inferior facet and vertebra 2 and the superior facet). These facets are separated by a bony crest, to which the intra-articular (or interarticular) ligament attaches.

Atyipcal Rib Bones

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

typical ribs, atypical ribs, anatomy, rib anatomy, rib bones, anatomy

  • Rib 1 is usually shorter and wider than all other ribs, and its broad, flat surface contains grooves that support the subclavian vessels. Because rib 1 articulates with first thoracic vertebra only, there is a single facet on its head (typical ribs have two facets, as mentioned above). A scalene tubercle allows for the attachment of the scalene muscles.
  • Rib 2 is also quite curved, but it is 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 with thoracic vertebrae 1 and 2 (T1 and T2).
  • Rib 10 has only a single articular facet on its head.
  • Ribs 11 and 12 also have a single articular facet on the head, but no necks or tubercles.

Free Quiz and More Anatomy Videos

Take a free ribs anatomy quiz to test your knowledge, or review our ribs anatomy video. In addition, you might want to watch our anatomy and physiology lectures on YouTube, or check our anatomy and physiology notes.

Please Share:

  • Click to print (Opens in new window)
  • Click to share on Facebook (Opens in new window)
  • Click to share on Twitter (Opens in new window)
  • Click to share on Pinterest (Opens in new window)
  • More
  • Click to share on Reddit (Opens in new window)
  • Click to share on LinkedIn (Opens in new window)
  • Click to share on WhatsApp (Opens in new window)
  • Click to share on Pocket (Opens in new window)
  • Click to share on Telegram (Opens in new window)
  • Click to share on Skype (Opens in new window)
Nursing Gear

RSS Latest YouTube Videos

  • Barbiturates Pharmacology Nursing NCLEX Review Mechanism of Action
  • Circumduction Movement: Hip, Shoulder, Thumb, Fingers, Wrist, Ankle, Toes, Head
  • Vial Coring Prevention Needle Technique Nursing Skill Medication Administration
  • Abduction and Adduction of Wrist, Thigh, Fingers, Thumb, Arm | Anatomy Body Movement Terms

Recent Posts

  • Barbiturates Pharmacology Nursing NCLEX Review on Anxiolytic, Sedative-Hypnotic
  • Circumduction
  • Circumduction Quiz
  • Vial Coring Prevention

Disclosure and Privacy Policy

This website provides entertainment value only, not medical advice or nursing protocols. We strive for 100% accuracy, but nursing procedures and state laws are constantly changing. By accessing any content on this site or its related media channels, you agree never to hold us liable for damages, harm, loss, or misinformation. See our full disclosure and privacy policy. Copyright Notice: Do not copy this site, articles, images, or its contents without permission.

Important Links

  • Advertise
  • Contact Us

Follow Us on Social Media

  • Facebook Nursing
  • Instagram Nursing
  • Twitter Nursing
  • YouTube Nursing

Get Free Email Updates:

Enter your email address below and hit "Submit" to receive free email updates and nursing tips.

Copyright © 2021 RegisteredNurseRN.com. All Rights Reserved.