대한흉부영상의학회 Korean Society of Thoracic Radiology

Discussion

Diagnosis With Brief Discussion

Diagnosis

Sternalis muscle

Radiologic Findings

CT scans show band-like, tubular structure surrounded fat tissue overlying the anterior surface of the pectoralis muscle along medial margin of the muscle.

Brief Review

The sternalis muscle is an uncommon anatomic variant of the chest wall musculature that is of uncertain teleology or function. It runs from the infraclavicular region inferiorly to approximately the caudal aspect of the sternum. Cadaveric studies have shown that the muscle is present in approximately 8% of both males and females and is twice as often unilateral as bilateral. Its longitudinal and parasternal location would make it logical to assume that it represents an aberrant extension of the rectus abdominis muscle; however, it is more superficial than the rectus abdominis and is not contiguous with it.
The recognition of normal variants is important to reduce the number of patients subjected to recall, follow-up examinations, or biopsies.
Occasionally, the muscle is included in medial aspect of the craniocaudal mammogram, and it could produce some diagnostic difficulty. The correct diagnosis is suggested by the location, configuration, and lack of a corresponding abnormality on the lateral views.

References

1. The sternalis muscle: an unusual normal finding seen on mammography. AJR 1996; 166:33-36

2. Barlow RN. The sternalis muscle in American whites Negroes. Anat Rec 1935; 61:413-426

Keywords

Chest wall, Congenital,