Humans are normally equipped with 24 symmetrical ribs to protect the vital organs, but around 1 in 500 people are born with an extra rib extending from the neck and shoulder section, known as the thoracic outlet. The cervical rib, or in even rarer cases, extra pair may interfere with the blood supply to the arm, causing a loss of pulse when the arm is moved in certain directions. The vestigial rib is believed to be connected with genes that suppress cancer risks, but the nature of this effect unknown. In some cases, complications include numbness, tingling, coldness in the hands and most disturbingly, a protruding sensation in the arm. The ribs are useful in other mammals, but are vestigial in humans.
Posted on: Thu, 13 Jun 2013 05:31:14 +0000
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