Objectives To investigate whether CT signs of the xiphoid process, such as xiphisternal angle and evidence of soft tissue compression, are useful for diagnosing xiphodynia.

Design A case-control study within a cohort.

Setting/Participants Participants included 1560 individuals who visited a small urban hospital in Japan for chest or abdominal pain between January 2021 and September 2023. Those who underwent CT examinations including the xiphoid process were selected. Nine individuals diagnosed with xiphodynia were assigned to the case group, while 321 individuals diagnosed with other causes of pain were assigned to the control group.

Interventions The xiphisternal angle, evidence of soft tissue compression anterior to the xiphoid process, anatomical features at the tip of the xiphoid process, and anatomical morphology of the xiphoid process were compared between the two groups.

Results There was no significant difference in the xiphisternal angle between the two groups. No significant differences were observed in evidence of soft tissue compression anterior to the xiphoid process or anatomical features at the tip of the xiphoid process. New anatomical signs reveal that in approximately 70% of cases, the xiphoid process curves forward and then backward.

Conclusions The xiphoid process sternal angle is not useful for diagnosing xiphodynia. The curvature of the xiphoid process is frequently observed regardless of the presence of xiphodynia.

The authors have declared no competing interest.

The author(s) received no specific funding for this work.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

This study involves human participants and was approved by Kameyama Municipal Medical Center Medical Research and Ethics Committee (code No.2023092101).

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

Yes

I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.

Yes

Extra data can be accessed via the Dryad data repository at http://datadryad.org/ with the doi:[XXX].