Can the Xiphoid Process Grow with Age?
No, the xiphoid process does not truly "grow" with age in adults; rather, it undergoes progressive ossification of pre-existing cartilage throughout adulthood, which can make it appear larger or more prominent on imaging and physical examination.
Normal Developmental Changes
The xiphoid process contains cartilage (xiphoidal cartilage) that is normal anatomy, not an anatomical variant as previously thought 1. This cartilage undergoes gradual ossification:
- Most xiphoid processes (85%) contain both bone and cartilage components in adults, with only 15% showing complete ossification 1
- The ossification process occurs gradually during the third to fifth decades of life, with complete fusion of the xiphisternal joint occurring at a mean age of 46.31 years in males and 45.57 years in females 2
- Four types of ossification patterns exist: Type I (no ossification, <1/3) in 45%; Type II (minor ossification, 1/3-1/2) in 20%; Type III (major ossification, 1/2-2/3) in 20%; Type IV (complete ossification, >2/3) in 15% 1
Clinical Implications
The progressive ossification can create the appearance of growth:
- Previously cartilaginous portions become radiographically visible as they ossify, which may be misinterpreted as new growth on serial imaging 1
- The xiphoid process shows significant anatomical variations including bifid, trifid, curved, or deflected configurations that can be mistaken for masses 3, 4
- Plain radiographs are recommended as first-line imaging to identify bone involvement or anatomical variations 5
Pathological Growth
True pathological enlargement can occur but is distinct from normal ossification:
- Heterotopic ossification after surgical trauma to the xiphoid region has been reported, representing actual new bone formation rather than normal developmental ossification 6
- Post-traumatic elongation can occur years after abdominal surgery, requiring surgical excision if symptomatic 6
Key Clinical Pitfall
Studies using skeletal specimens or CT imaging alone likely underestimate or overestimate xiphoid size because they cannot adequately visualize the cartilaginous component that comprises the majority of the structure in many adults 1. This explains why the xiphoid may appear to "grow" on serial imaging as cartilage ossifies and becomes radiographically apparent.