Welcome to HCM.
This is a congenital defect. The extra rib arises from the the 7th cervical vertebra and is called cervical rib
. It is very rare occurring in approximately 0.2 % of population.
Most of the times it does not create any problem. Occasionally it may compress on the nerve
supplying the upper arm or the major artery
arising from the heart which supplies head and upper arm.