Sternal foramen

Sternal foramen (or perforated sternum) is an oval foramen present at lower one-third of the sternum. It is a relatively common anatomical variation found in 6.5% of individuals.^[1]

Sternal foramen seen on three-dimensionally constructed CT scan

Structure

This variation is usually present at the lower one-third of the sternal body. It has an oval shape and a unique "bow tie" appearance when seen on axial computed tomography. The diameter of the sternal foramen ranges from 6 to 16 mm with an average diameter of 6.5 mm.^[2] Sometimes, the foramen can be present at the xiphod process. In extremely rare cases, the foramen is found at the manubrium.^[3]

Developmentally, sternal foramen results from the incomplete fusion of the sternal bars while they are still cartilaginous.^[4]

Clinical significance

Although sternal foramen is asymptomatic, it may entail a risk of serious complications from blinded sternal interventions. The foramen may be misdiagnosed as sternal fracture or a gunshot wound. Awareness of sternal foramen is also crucial in acupuncture to avoid cardiac tamponade.^[5]

Additional images

• 
  Sternal foramen on axial and sagittal CT. The "bow tie" appearance is seen on the axial view.
• 
  Sternal foramen and xiphoid foramen
• 
  Sternal foramen observed in dry skeleton
• 
  A 3D file showing a sternum with sternal foramen and xiphoid foramen

See also

• Sternum
• List of anatomical variation