shaft

Last reviewed 01/2018

The shaft of a rib is the longest section:

• begins at neck passing inferolaterally and obliquely
• passes inferomedially from angle to distal anterior end
• elongated, blade-like
• concave surface facing inwards to the thoracic cavity in contact with parietal pleura
• convex external surface:
• relatively superficial under skin from angle projecting anteriorly
• serratus anterior attached to superior margin in superior 8 ribs
• superior margin:
• rounded and relatively broad
• external intercostal muscle attached laterally
• more deeply, internal intercostal muscle attached from sternal end to angle
• as a continuation, internal intercostal membrane attached from angle to tubercle
• subcostal muscles attached in deeper plane
• inferior margin is thinner and runs to a sharp edge:
• external intercostal muscle attached to outer surface of margin
• internal intercostal muscle attached more deeply from subcostal groove progressing anteriorly
• internal intercostal membrane attached from angle to tubercle
• internal surface near to inferior margin houses costal groove which tapers out to a rounded, smooth edge with no recess upon reaching the anterior third of the rib