Sir,
Gynecomastia correction is one of the commonest aesthetic surgeries performed by a
plastic surgeon. The sternalis muscle is a rare chest wall muscle, usually described
in the literature by anatomists, during cadaveric dissections.[1] There are only a few clinical case reports regarding the same in aesthetic breast
surgeries.[2] The position of the muscle adjacent to the medial border of breast tissue makes
it significant in all types of breast surgeries. We describe our clinical experience
of encountering this muscle during gynecomastia surgery.
A 29-year-old male bodybuilder with bilateral Simon grade 2a gynecomastia was planned
for chest liposuction followed by gland excision. After liposuction, gland excision
proceeded with the inferior periareolar incision. During right-side gland excision,
a parasternal vertical bulge of muscle was noted, anterior to the pectoralis major
([Figs. 1] and[2]). The orientation of those muscle fibers was perpendicular to the pectoralis major
and it was found to be a separate muscle. The same finding was noted on the opposite
side, though smaller in size. These extra muscle fibers were left alone and gland
excision was completed. Postoperatively it was explained to the patient. We did some
literature search for the same, and from previous case reports and cadaveric study
data, it was found to be a muscle named “STERNALIS.” A mild medial chest prominence
was noted postoperatively, which can be attributed to the hypertrophied sternalis
muscles in this patient.
Fig. 1 Vertical muscle fibers: right parasternal region, anterior to the pectoralis major
muscle fibers.
Fig. 2 Orientation of muscle fibers of the sternalis and pectoralis major (white arrows).
First described in detail by Dupuy (1726), the incidence of this muscle in cadaveric
studies varies depending on the region and race. In the Indian population, its incidence
is 4 to 8% in both genders.[3] The origin of the muscle is variable and is postulated to arise from adjacent muscles
like the sternocleidomastoid/rectus abdominis/pectoralis major. The sternalis muscle
is described to be innervated from external/internal thoracic nerves/intercostal nerves.[4] Is significance in plastic surgery, especially breast surgery, is multifold like
interference with mammography interpretation,[5] interference with internal mammary artery (IMA) pedicle dissection in breast reconstruction,
and interference with submuscular pocket dissection in augmentation mammoplasty.[5] It can coexist with pectoralis major defects.[4]
The sternalis muscle, a rare chest wall muscle, is known more by anatomists than surgeons.
The clinical presence of this muscle should be identified and reported. More light
has to be shed on the vascular anatomy and innervation of the muscle for its clinical
use. The clinical significance of this muscle in relation to aesthetic breast surgeries
should be studied.
