This bifid rib was found incidentally on CT chest. Bifid ribs are not uncommon, more frequently unilateral. Usually asymptomatic, they may cause musculoskeletal pain or intercostal nerve entrapment. If of the 1st rib, then may be an uncommon cause of thoracic outlet syndrome.
Bifid ribs are also seen in Gorlin (nevoid basal cell carcinoma) syndrome.
K. Cağli “Thoracic outlet syndrome in an adolescent with bilateral bifid ribs.” Clin Anat. 2006 Sep;19(6):558-60.
Credit: Dr Frank Gaillard