Bodily Oddities

Cervical rib

Also called: Neck rib · Extra rib

An extra rib above the normal top rib, growing from the lowest bone in the neck. About 1 in 100 people have one, and most never know.

Bones and joints Nerves Variation Structural
Not an emergency Genetic

How common

About 1% of people Uncommon · 1–10% More common in women. Often on one side only.

Do you have this?

These are answers from visitors, not a study.

How it works

People normally have twelve pairs of ribs. Each pair grows from a bone of the spine in the chest. The neck has seven bones of its own, called cervical vertebrae. In the embryo, every vertebra has a small rib-like bud. In the chest the buds grow into ribs. In the neck they normally stop and merge into the vertebra1. In some people the bud on the seventh neck vertebra keeps growing and becomes an extra rib1.

A cervical rib can be a short stub of bone, a full rib that curves round to join the first normal rib, or a band of fibrous tissue that does not show on X-ray1. It sits above the collarbone, close to the nerves and the artery that run from the neck into the arm.

A large review of X-ray and dissection studies puts the frequency at about 1.1% of people1. It is more common in women and is often on one side only1. Most cervical ribs cause nothing at all. They are found by accident, on a chest X-ray taken for something else.

Is it a problem?

Usually not. In a small number of people the extra rib presses on the nerves or blood vessels going to the arm. This is one cause of thoracic outlet syndrome2. The signs are tingling, numbness, or aching in the arm and hand, or a hand that goes pale and cold, especially with the arm raised. If you have a known cervical rib and these symptoms, see a doctor. The rib can be removed by surgery if it is the cause2. Without symptoms, nothing needs to be done.

History and culture

Some snakes and lizards have ribs on every vertebra from the neck down. The human cervical rib is a reminder that the plan for a rib is present on every vertebra and is simply switched off in most of them1.

Sources and further material

  1. Encyclopedia Cervical rib
  2. Encyclopedia Thoracic outlet syndrome
Bones Variation

Accessory ossicles

Small extra bones, most often in the foot, that form when a growth centre never fuses with its main bone. They are harmless but can be mistaken for fractures on an X-ray.

Up to 1 in 5 feet
Skin Variation

Supernumerary nipples

An extra nipple, usually small and flat, on a line running from the armpit to the groin. Between 1 in 500 and 1 in 18 people have one, and most think it is a mole.

0.2–5.6% of people
Nerves Involuntary

Pins and needles

The prickling, buzzing feeling in a limb after you sit on it or lean on it. It happens when pressure comes off a nerve and the nerve fibres restart at different speeds.

Everyone
Nerves Reflex

Referred pain

Pain from an internal organ often shows up somewhere else, like the left arm during a heart attack or the shoulder from a gallbladder. The nerves from the organ and from that patch of skin share a line into the spinal cord.

Everyone