first rib

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first rib

the highest rib of the thoracic cage. It moves about the axis of its neck, raising and lowering the sternum. First rib movement during quiet breathing is negligible, but under conditions of stress it can increase the anteroposterior diameter of the chest.
References in periodicals archive ?
Abbreviated variables include last lumber backfat (LLBF), 10th rib backfat (BF10), 1st rib backfat (BF1) and loin muscle area (LMA); [L.
This is a congenital abnormality located above the 1st rib that typically produces no symptoms and requires no therapy.
A hot summer calls for hot wheels -- the 1st Ribs 'n' Soul Festival Classic Car Show is sure to attract an audience of car lovers that cross generations.