Topics

Topic

design image
Xiphoid process of sternum

The xiphoid process is the smallest and most inferior part of the sternum, projecting downward from the body of the sternum at the xiphisternal joint (T9 vertebral level). It begins as a cartilaginous structure in youth and usually ossifies in adulthood. The xiphoid process varies greatly in size and shape—it may be pointed, bifid, curved, or broad. Anatomically, it serves as a key landmark for the lower border of the thoracic cage, the infrasternal angle, and the upper abdominal midline. It is closely related to the diaphragm, rectus abdominis, and linea alba, making it clinically important in thoracic and abdominal surgery, as well as in cardiopulmonary resuscitation (CPR) to avoid xiphoid fracture and visceral injury.

Synonyms

  • Xiphisternum

  • Metasternum

  • Processus xiphoideus

Function

  • Provides attachment for the diaphragm, rectus abdominis, and transversus thoracis muscles

  • Forms the inferior part of the sternum, contributing to thoracic cage stability

  • Acts as a surface landmark for the infrasternal angle, midline abdominal incisions, and CPR hand positioning

  • Contributes to the xiphisternal joint, which marks the lower limit of the thoracic cavity

Arterial Supply

  • Supplied by branches of the internal thoracic (mammary) artery

  • Additional contribution from the superior epigastric artery

Venous Drainage

  • Drains into tributaries of the internal thoracic vein and superior epigastric vein

Nerve Supply

  • Receives sensory supply from anterior cutaneous branches of lower thoracic intercostal nerves (T6–T7 region)

MRI Appearance

T1-weighted images:

  • In youth (cartilaginous phase), the xiphoid process appears as intermediate to low signal cartilage

  • In adults (ossified phase), it appears as low signal cortical bone with fatty marrow (high signal) centrally

  • Clear contrast against surrounding muscle and fat

T2-weighted images:

  • Cartilaginous xiphoid shows hyperintense signal relative to bone

  • Ossified xiphoid appears low signal cortical bone with variable marrow signal

  • Useful for detecting inflammation, fracture, or marrow edema

STIR (Short Tau Inversion Recovery):

  • Normal ossified xiphoid is low signal

  • Edema, trauma, or inflammatory changes appear as bright hyperintense signal

T1 Post-Contrast (Gadolinium-enhanced):

  • Normal xiphoid shows minimal enhancement

  • Pathology (infection, tumor, inflammation) demonstrates enhancement of cortical and surrounding soft tissues

CT Appearance

Non-contrast CT:

  • Ossified xiphoid appears as a hyperdense bony projection from the lower sternum

  • Variations (bifid, curved, elongated) are easily identified

  • In young patients, unossified cartilage appears as low-density tissue

Contrast-enhanced CT (CECT):

  • Defines the xiphoid margins clearly

  • Useful for evaluating pathological lesions, fractures, or postoperative changes

  • Demonstrates vascular and soft tissue relations around the diaphragm and upper abdomen

MRI images

Xiphoid process of sternum MRI coronal image -img-00000-00000

CT image

Xiphoid process of sternum CT coronal image -img-00000-00000

CT image

Xiphoid process of sternum CT SAG image -img-00000-00000