While all races have two pairs of floating ribs, some ethnic groups, especially Japanese have three pairs of floating ribs or tenth rib is a floating rib. No, it is not related to evolution. It is just that Japanese have high tendency to choose or to get tenth rib as true floating rib.
In several ethnic groups, most significantly the Japanese, the tenth rib is sometimes a floating rib, as it lacks a cartilaginous connection to the seventh rib.
Floating ribs are four atypical ribs (two lowermost pairs, XI-XII) in the human ribcage. They are called so because they are attached to the vertebrae only, and not to the sternum or cartilage coming off of the sternum. Some people are missing one of the two pairs. Others have a third pair.
There are twelve pairs of ribs, all of which articulate with the vertebral column. However, only seven have a direct articulation with the sternum. As such, ribs can be allocated to one of three distinct types; true (vertebrosternal) ribs, false (vertebrochondral) ribs and floating (vertebral, free) ribs.
The false ribs are the ribs that indirectly articulate with the sternum, as their costal cartilages connect with the seventh costal cartilage; by the costochondral joint; They are the eighth, ninth, and tenth ribs.
The last two pairs of ribs are known as the floating ribs, i.e. 11th and 12th pair.
Most people have a pair of floating ribs at the bottom of the ribcage (ribs 11 and 12), but a few have a third stubby little floating rib (13), and even fewer — yours truly included — have a 10th rib that floats free. Free to cause some trouble! See below for more on this one.
Lumbar (or 13th) ribs are a rare anatomical variant and represent transitional vertebrae at the thoracolumbar junction with a prevalence of ~1% 1.
If you have broken or cracked three or more adjacent ribs in two places, you may experience a condition called “flail chest.” With flail chest, your upper rib cage separates from the rest of the chest wall and can't hold its shape when you breathe.
The last two, the floating ribs, have their cartilages ending in the muscle in the abdominal wall. The configuration of the lower five ribs gives freedom for the expansion of the lower part of the rib cage and for the movements of the diaphragm, which has an extensive origin from the rib cage and the vertebral column.
When someone breaks three or more ribs in two or more places, it can lead to a serious condition called flail chest. People with flail chest will find it hard to breathe and need immediate medical attention.
Background: Twelfth rib syndrome, or slipping of the 12th rib, is an often overlooked cause for chronic chest, back, flank, and abdominal pain from irritation of the 12th intercostal nerve. Diagnosis is clinical and follows the exclusion of other causes of pain.
Most people are born with 12 ribs on each side of the body, making a total of 24 ribs. Some people are born with more than 24 ribs. These extra ribs are called supernumerary ribs. When people are born with less than 24 ribs, it is called agenesis of the ribs.
The floating ribs are commonly extracted during plastic surgery procedures, to equip patients with reduced waist size.
This syndrome usually occurs in 8th to 10th ribs (also known are false ribs) at the lower part of your rib cage. These ribs are not connected to the chest bone (sternum). Fibrous tissue (ligaments), connect these ribs to each other to help keep them stable.
The idea was that, if you remove the floating ribs, there's less in the way when you try to drastically adjust your internal organs by squeezing them into a corset and, as a result, your waist automatically appears abnormally slender.
Can you fly with broken ribs? As cracked ribs cannot be easily supported during the healing process, flying in the days, or even weeks, following the break can be very painful. For this reason, it is important to take advice from your doctor and speak to your airline if you break ribs less than a week prior to flying.
You'll be surprised as to how much you could lose and still live. You can still have a fairly normal life without one of your lungs, a kidney, your spleen, appendix, gall bladder, adenoids, tonsils, plus some of your lymph nodes, the fibula bones from each leg and six of your ribs.
“It's not entirely unheard of for coughing or sneezing to cause a rib fracture, but usually that happens in the elderly, people with specific medical illnesses, or reduced bone density,” said Adam Shiroff, MD, FACS, director of the Penn Center for Chest Trauma and an associate professor of Surgery.
The vast majority of people are born with 12 pairs of ribs, for a total of 24, no matter their sex. The exception to this anatomy rule are people born with specific genetic anomalies. These can take the form of too many ribs (supernumerary ribs) or too few (agenesis of ribs).
The lower five pairs of ribs (ribs eight to twelve) are known as false ribs because their costal cartilages do not articulate directly with the sternum.
In normal development, a baby is born with 12 pairs of ribs. The number is the same for males and females. The top seven ribs (called the true ribs) connect with cartilage to the breastbone (sternum).
Each adult has 206 bones, 24 of which are ribs (12 on each side), but approximately one out of every 200 people have an extra rib. This rib is referred to as the cervical rib.
About 1 in 100 people are born with an extra rib called a cervical rib. About 1 in 10 people who have a cervical rib develop thoracic outlet syndrome. The thoracic outlet is a space, or passageway, that lies just above your first rib and behind your collarbone (clavicle).
Slipping rib syndrome is a painful and rare disorder that is known by many other names, including floating rib syndrome, lost rib syndrome, costal chondritis or costochondritis, and Tietze syndrome.