Xiphoid Process

The xiphoid process is the small, inferior-most part of the sternum. It is a thin, cartilaginous structure in youth that typically ossifies and becomes bony in adulthood. Although the smallest portion of the sternum, it serves as an important anatomical landmark and provides attachment for several muscles involved in respiration and abdominal wall support.

Location

The xiphoid process is located at the inferior end of the sternum, below the body of the sternum, at the level of the T9 vertebra. It forms the inferior boundary of the anterior thoracic wall and marks the center of the costal arch.

Structure

The xiphoid process is highly variable in shape—flat, pointed, curved, or bifid—and typically measures 2–5 cm in length. In early life, it is composed of hyaline cartilage and later ossifies with age. Complete fusion with the body of the sternum (xiphisternal joint) may occur in older adults.

Key Features

• Xiphisternal joint: Cartilaginous joint between the xiphoid and body of sternum; may ossify with age
• Costal arch connection: Lies at the midline where the right and left costal margins meet

Articulations

• Sternal body: Joins superiorly via the xiphisternal joint (symphysis type)

Muscle Attachments

• Diaphragm: Attaches posteriorly
• Rectus abdominis: Inserts on the anterior surface
• Transversus thoracis: Originates from the posterior surface

Function

• Provides structural support to the lower thoracic cage
• Serves as a key muscular attachment point for respiration and abdominal wall function
• Marks anatomical landmarks for clinical procedures (e.g., CPR hand placement just above it)

Blood Supply

• Arterial supply: Branches of the internal thoracic artery and anterior intercostal arteries
• Venous drainage: Into the internal thoracic and subcostal veins

Innervation

• Overlying skin is supplied by anterior cutaneous branches of the lower thoracic intercostal nerves

Clinical Relevance

• Xiphoidalgia: Pain arising from trauma or inflammation of the xiphoid process
• CPR complications: Improper hand placement during chest compressions can fracture the xiphoid, potentially damaging liver or diaphragm
• Xiphoid ossification: Often misinterpreted as an abnormal mass on imaging or palpation if ossified irregularly
• Surface landmark: Marks the inferior border of the thoracic cavity and central tendon attachment of the diaphragm