Sternalis muscle: an uncommon finding during aesthetic breast surgery

Bilateral Sternalis Muscles: The Clinical Significance of This Rare Discovery

This case report explores the physical characteristics and clinical significance of the sternalis muscle, an uncommon anatomical variation of the anterior thoracic wall. If present, the sternalis muscle may distort diagnostic images and can be associated with incorrect interpretation of such medical images, misdiagnoses, and even surgical complications. As such, enhancing clinicians' knowledge of this muscle and improving its recognition is of the utmost importance. In this case report, a rare bilateral sternalis muscle that was discovered during an educational human cadaveric dissection of a 73-year-old Black male is described. The right sternalis muscle fibres extended from the mid-sternal level to the right sternocostal arch, measuring 11.5 cm in length and 3.4 cm at its largest width. In contrast, the smaller left sternalis muscle fibres measured only 5.6 cm in length and 1.2 cm at its greatest width. This rare bilateral presentation of the sternalis muscle is documented in approximately one-third of all reported sternalis cases with an associated estimated prevalence as low as 1.7% among the general population. Serving as a reminder of the intricate anatomical complexities that continue to challenge and intrigue medical professionals, this report advocates for continued education of anatomical variations to enhance patient care and medical practices.

Sternalis is muscle: An anatomic variation and its clinical implications

This report presents a case description of sternalis muscle which is an accessory muscle of anterior thoracic wall. A 56-year-old woman underwent mastectomy for breast cancer along with free flap reconstruction, revealing the presence of aberrant sternalis muscle. It was divided transversely during partial rib resection to expose internal mammary vessels. The case proceeded with successful flap transfer. Clinical implications of this anatomic variation is discussed. The authors conclude that plastic surgeons should be aware of this muscular anomaly.

Improvement in Existing Chest Wall Irregularities During Breast Reconstruction

Mastectomies for both cancer resection and risk reduction are becoming more common. Existing chest wall irregularities are found in these women presenting for breast reconstruction after mastectomy and can pose reconstructive challenges. Women who desired breast reconstruction after mastectomy were evaluated preoperatively for existing chest wall irregularities. Case reports were selected to highlight common irregularities and methods for improving cosmetic outcome concurrently with breast reconstruction procedures. Muscular anomalies, pectus excavatum, scoliosis, polythelia case reports are discussed. Relevant data from the literature are presented. Chest wall irregularities are occasionally encountered in women who request breast reconstruction. Correction of these deformities is possible and safe during breast reconstruction and can lead to improved cosmetic outcome and patient satisfaction.

Sternalis muscle, what every anatomist and clinician should know

The sternalis muscle is a well documented but rare muscular variation of the anterior thoracic wall. It lies between the superficial fascia and the pectoral fascia and is found in about 8% of the population. It presents in several morphological variants both unilaterally and bilaterally and has no apparent physiological function. There is still much disagreement about its nerve supply and embryological origin. With the advent of medical imaging and thoracic surgery the clinical importance of this muscle has been re-emphasized. It has been implicated in misdiagnosis of breast masses on routine mammograms owing to its parasternal location and relative unfamiliarity among radiologists. When undetected before any thoracic surgery, it has the potential to interfere with and prolong such procedures. When present and detected preoperatively it can be used as a muscular flap in reconstructive surgeries of the breast and neck. This article will present the sternalis muscle with special emphasis on its morphology, homology, and clinical significance.

Prevalence and variance of the sternalis muscle: a study in the Chinese population using multi-detector CT

OBJECTIVE

To analyze the prevalence, anatomical features, as well as variance of the sternalis muscle in the Chinese population using multi-detector computed tomography (MDCT).

METHODS

We retrospectively reviewed 6,000 adult axial MDCT images to determine the overall and gender prevalence of the sternalis muscles. We also analyzed the side prevalence and anatomical features, including shape, size, location and course.

RESULTS

The sternalis muscle was present in 347 (5.8 %) of 6,000 adults. This muscle was more common in males (6.0 %, 187/3091) than in females (5.5 %, 160/2909). Among the 347 adults, 118 (34.0 %) had bilateral sternalis muscles; 148 (42.7 %) had right sternalis muscles; and 81 (23.3 %) had left sternalis muscles. The sternalis muscle was either flat or nodular and located superficial to the major pectoral muscles on CT axial transverse images. According to the muscle morphology and course, we classified sternalis muscles as three different types and nine subtypes. The muscles appeared with a single head and single belly in 58.5 %, double or multiple heads in 18.1 %, and double or multiple bellies in 23.4 %. The mean length, width and thickness were 111.1 ± 33.0, 17.7 ± 9.9 and 4.1 ± 1.7 mm measured on MDCT.

CONCLUSION

The sternalis muscle was highly prevalent in normal Chinese adults. MDCT is an effective method to demonstrate this muscle in vivo.