Implants may be placed either above or below the pectoralis major (chest) muscle. Several factors are considered when selecting implant placement, including body habitus and amount of natural breast and soft tissues, aesthetic goals, and level of athleticism. If patients are quite slender and do not have adequate breast tissue to provide coverage for the implant, placement under the pectoralis major muscle (submuscular plane) may be recommended to improve the aesthetic result. If an implant is placed above the muscle in a patient with little natural breast tissue, there may be higher risk of implant visibility, rippling, and dissatisfaction with aesthetic outcome. If patients have adequate breast tissue to provide implant coverage – generally corresponding to 2cm of tissue when pinching the upper pole of the breast – implants may be placed above the muscle. This is referred to as the subglandular (under breast tissue, above muscle) plane. For patients who are quite physically active in upper body activities (for example, rowing, personal training), it is important to know that submuscular implants will shift with contraction of the pectoralis muscle.nIf wearing form-fitting clothing, you may notice the movement of the implants when performing these activities.