Understanding dual plane means you have to understand some basic concepts about the muscle anatomy of the chest wall.The chest wall muscle important in breast augmentation is called the pectoralis major muscle….otherwise known as the pec muscle. This muscle extends from the arm bone, called the humerus, near the shoulder, and attaches to the chest wall near the midline. How the implant is placed in relation to this muscle is important in determining the final long term result. The implant can be placed in front of the muscle. However, most surgeons choose to place the implants under the muscle which is often referred to as a subpectoral placement or “unders”. However, an implant placed under the muscle is never completely covered by muscle, with the lower part of the implant extending below the lower border of the muscle. Dual plane refers to implants that are partially covered by muscle and partially covered by breast tissue. Therefore, effectively ALL under the muscle implants are "dual plane". A standard subpectoral implant pocket is often referred to as a dual plane type 1 placement. The placement of the implant in a dual plane type 1 follows several steps:The lower end of the pec muscle is identified and then detached from the chest wall at the lower end to make room for the implant. However, as the muscle remains attached to the overlying breast tissue it doesn’t retract, or move too far.A space, or pocket, is then created under the pec muscle large enough to accommodate the chosen implant.Once the pocket is created, the implant is then inserted and positioned.In this situation the outer/lower aspect of the implant is not covered by muscle - "dual plane".However, as the muscle remains attached to the breast tissue and close to the lower curve of the breast, then as this muscle contracts it often pulls the skin in causing a groove along the lower breast curve. This is referred to as a dynamic double bubble and is quite common. Another form of under the muscle implant placement is the dual plane type 2. In this situation, many of the surgical steps are the same as the dual plane type 1. The lower end of the pec muscle is identified. However, unlike the dual plane type 1, the breast tissue is detached from the pec muscle approximately up to the level of the nipple.The space under the muscle is then opened and the lower end of the pec muscle is detached from the chest wall.With the muscle now detached from the both chest wall and the breast tissue, this segment of the pec muscle retracts upwards.With the under muscle pocket created, the implant is inserted and positioned and the wound is closed. The dual plane type 2 implant placement results in less of the implant covered by muscle along the lower half of the implant ….and this can have the benefit of a fuller more curvaceous underboob. It also significantly reduces the potential for a dynamic double bubble as this muscle is no longer close to the skin along the lower curve of the breast. One of the negative issues of a dual plane type 2 approach is that the detached segment of pec muscle is no longer functional…. so you can expect a slight reduction in pec muscle strength. However for the majority of people this is not noticeable. Pros and cons exist for each technique so speak to your plastic surgeon to find out what will give you the best outcome.