The Anatomy of a Floating Rib

Floating rib injuries are caused, in part, by a vulnerability in human anatomy. That's because the rib cage, made up of 12 pairs of ribs, doesn't fully attach to other bones in the same way at all points.

Seven pairs of ribs attach directly to the sternum, at the front of the chest, through cartilage that forms at the end of each rib. The next three pairs, called the false ribs, only attach to the cartilage of the rib above. And the last two pairs of ribs, the floating ribs, do not attach to the sternum at all, making them more prone to injury.

Rib Anatomy and Structure

Your ribs are located in the chest, also called the thoracic cavity. Each rib has five parts: head, neck, body (or shaft), tubercle, and angle. The 12 pairs of ribs in the body are numbered based on their attachment to the sternum, a bony process at the front of the rib cage, which serves as an anchor point.

The first rib attaches to the sternum below the clavicular attachment; it is shorter and more curved than the others. The next six ribs are both longer and become progressively more open (rather than curved) as the rib cage continues down the length of the torso.

The remaining ribs (8 through 12) are called "false ribs" as they do not attach to the sternum directly. Instead, they are attached to the costal cartilage of the sternum.

However, the last two pairs of ribs at the very bottom, also known as "floating ribs," do not attach at the front of the rib cage at all—only to the vertebrae in the back.

Rib Cage Function

The ribs are part of what's called the axial skeleton and are classified as flat bones. The primary job of flat bones is to protect your internal organs.

Other flat bones in the human body are found in the pelvis and skull. Red blood cells are made in the marrow of flat bones.

The thoracic cage (or rib cage) has the critical mission of protecting the heart and lungs, which are among the body's most vital organs.

Slipping Rib Syndrome

While it is not as common as an injury to the chest wall, "slipping rib syndrome" is an ailment that can cause distress for people who have it but are not aware of why it occurs.

Slipping rib syndrome, also called Cyriax syndrome, occurs when the false ribs move. The movement of these lower ribs is often felt as a slipping, clicking, or popping sensation. Similar pain can, rarely, be seen in the floating ribs.

The sensation typically only occurs on one side of the rib cage (unilateral). There is usually a sudden onset of pain that can be localized or can radiate through the rib cage on the affected side.

The syndrome seems to be reported most often by females, though cases have occurred in people of all ages. The exact cause of slipping rib syndrome isn't known, but common risk factors are:

• Rib trauma from things like contact sports or a car accident
• High-intensity athletic activities, such as running, rowing, lacrosse, and field hockey

Broken or Bruised Ribs

As with any bone in the human body, ribs can fracture or break. They also may be referred to as bruised when the fascia surrounding the rib cage is injured.

In terms of broken or fractured ribs, these two terms refer to the same injury—one that occurs in the bone. While a bruised rib might not sound as severe as a broken rib, injury to the tissues that surround and support the rib cage can be extremely painful.

Although ribs commonly fracture due to injury, they also can break due to reasons like the pressure of prolonged coughing. Older people, and people with certain underlying health conditions like osteoporosis, may be more at risk of a rib fracture.

The key difference between broken, bruised, and fractured ribs is whether the bones of the rib cage are involved or if the injury was primarily to the tissue of the chest wall. In some cases, both are involved.

Floating Rib Diagnosis

Floating rib symptoms may be suspected when a healthcare provider has ruled out other causes for a person's discomfort, such as:

• Rib fracture
• Esophagitis
• Pleuritic chest pain

The gold standard for diagnosing the condition is a simple hooking maneuver, which can be performed in the office, that can help to determine if the lower ribs are hypermobile.

Floating Rib Treatment

Treatment depends on the severity of the associated pain. Unlike other bones of the body, such as an arm or leg, the chest cannot be immobilized if a bone is broken. There are limits to how much mobility can be reduced because the chest needs to move as a person breathes.

These injuries usually heal on their own, given adequate time and supportive care and pain management. The primary focus is on controlling pain and any exacerbating factors, such as a cough. Treatment may include:

• Using heat or ice packs at the pain site
• Limiting activity
• Stabilizing the ribs with a chest bandage wrap

If a person with slipping rib syndrome has continued pain that is not well controlled with over-the-counter pain relievers, temporary activity limitations, and the use of ice packs, a healthcare provider may prescribe nerve blocks.

Summary

The last two pairs of ribs are called floating ribs because they don't attach to the sternum at the front of the chest. Floating ribs are associated with a rare and painful condition called "slipping rib syndrome," where the floating ribs move, causing a slipping, clicking, or popping sensation. Injured floating ribs usually heal on their own with time, rest, ice packs, and pain relievers.