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Breast Implant Position: Above or Below the Muscle?
The purpose of this post is to educate patients in their choice of breast implant position as it relates the pectoralis major music during a breast augmentation.
Pectoralis Major Anatomy
The pectoralis major muscle is a fan-shaped muscle that partially spans the chest wall. It makes up the bulk of the chest muscles in the male and lies under the breast in the female. Often the pectoral muscle is referred to as “pecs,” the “pectoral muscle” or “chest muscle.”
Anatomical key points/terms
Insertion of the pectoralis muscle
- On the lateral (or side) groove of the humerus, a long bone in the arm running from shoulder to elbow.
- Deltoid tuberosity — a rough, triangular area on the front surface eof the middle of the humerus, to which the deltoid muscle attaches.
Origin of the pectoralis muscle
- Clavicular head—anterior (or front) surface of the medial (or middle) half of the clavicle.
- Sternal head— the central breast bone.
Function
The pectoralis major has four actions which are primarily responsible for movement of the shoulder joint.
- The first action is flexion of the humerus, as in throwing a ball side-arm or lifting a child.
- Secondly, it adducts the humerus, as when flapping the arms.
- Thirdly, it rotates the humerus medially, as occurs when arm-wrestling.
- Fourthly, it’s also responsible for keeping the arm attached to the trunk of the body.
Function/Strength After Sub-Pectoral Breast Implant Placement
A scientific study of strength performance of the pectoralis major muscle after sub-pectoral breast augmentation surgery (performed and authored by S.P. Beals, K.A. Golden and M. Basten — reported in Aesthetic Surgery Journal 2003; 23: 92-97) documented what most plastic surgeons and patients have found. They concluded that sub-pectoral breast implant placement did not produce statistically significant long-term loss of upper-extremity strength performance, and no permanent loss of pectoralis muscle strength resulted from sub-pectoral breast implant placement after breast augmentation.
Technique
Using any of the three most-common access incisions (inframammary, periareolar or axillary), the lateral edge of the pectoralis muscle is identified and gently detached (not cut) off the chest wall, leaving both the muscle insertion and origin in tact; this maintains muscle functionality. In reality, it’s nearly impossible to have the pectoralis major muscle completely cover the breast implant. Thus the name/term “dual plane” describes the breast implant is being covered (in the upper portion) with the pectoralis muscle and the lower portion by only breast tissue.
Breast Implant Placement
1. Sub-pectoral (dual plane)
Pros
- Less chance for internal scarring (capsular contracture)
- Padding from the muscle, therefore less chance of implant palpability
Cons
- Varying degree of animation upon pectoralis major contraction (breasts moving)
- Longer immediate recovery
2. Supra-pectoral
Pros
- In borderline ptosis (breast sag), placement on top of the pectoralis muscle can be an alternative to having a corrective mastopoxy (or breast lift procedure) done.
- Faster immediate recovery
Cons
- Increased chance of internal scarring (capsular contracture)
- Increased potential for breast implant palpability (no muscle coverage)
Conclusion
In my practice, based on data and my experience, I personally and almost always place implants under the muscle (dual plane) unless the patient is a professional weightlifter (animation issues).
The Staff of Imagine Plastic Surgery serving many of the communities of the greater Inland Empire including but limited to Riverside, CA and Inland Empire, Redlands, Rancho Cucamonga, Ontario, Corona, Upland, and Chino Hills.