Sternoclavicular defects are rare in clinical practice. These defects are usually a result of surgical resection of the medial head of the clavicle and the manubrium for sternoclavicular joint infection or resection of tumors. These resulting defects are usually reconstructed with soft tissue. The pectoralis major muscle flap has been the workhorse flap for this type of reconstruction [1-3]. The first use of the pectoralis major muscle flap for reconstruction of chest defects was reported by Heuston in 1977  and its first use in sternoclavicular defect reconstruction was described by Munoz . Munoz essentially used the whole pectoralis major muscle as an advancement flap for the reconstruction of a sternoclavicular defect. The use of the whole muscle has been associated with loss of function of the pectoralis major muscle, aesthetic concerns related to the bulky appearance of reconstruction, and large access incisions. Since the use of the PM flap by Munoz in 1996, there have been multiple configurations of the PM flap to address these concerns. The various configurations have been termed differently in the reported literature for e.g., “compound pectoralis flap,” “split pectoralis flap,” “pectoralis advancement flap,” “islandized pectoralis flap,” etc. The names can be very confusing. For example, the islandized flap described by Schulmam and the deltoid branch flap described by Faisal et al. are both islandized flaps but differ based on the blood supply to the flap. There currently exists no classification system for the different configuration of the pectoralis flap for these reconstructions. We have classified the different configurations of the PM flap for sternoclavicular defects based on the reported cases in our literature review. The most obvious limitation of our study is that there may be studies that were missed in our search published in other language other than the English language.
Type 1: Whole muscle advancement
Type 1 configuration of the PM flap for sternoclavicular defect reconstruction includes procedures that use the whole pectoralis major muscle for reconstruction. It includes the pectoralis advancement flap in which the whole muscle is detached from its sternal clavicular attachments, mobilizing it laterally and advancing it medially to cover the defect [Fig. 2A]. This flap is based on the TAA. Included in this category is the flap when released from its humeral attachment to allow for more advancement
Type 2: Hemipectoralis muscle flap
Type 2 configuration includes splitting the pectoralis muscle and using the upper part of the muscle, usually the clavicular part for reconstruction. This configuration is subcategorized:
Type 2A is a hemipectoralis rotated flap. In this configuration, the pectoralis muscle is split and the upper (sternoclavicular) portion is released from its insertion laterally. The flap is then rotated to fill the defect [Fig. 2B]. The flap is supplied by the internal mammary sternal perforators.
Type 2B is a hemipectoralis advancement flap in which the upper part of the pectoralis major is split, and its sternoclavicular attachment is released. The muscle is then advanced to cover the defect. [Fig. 2C]. This flap is supplied by the TAA.
Type 3: Islandized pectoralis flap
Type 3 configuration includes procedures in which a portion of the clavicular head of the pectoralis major muscle is split and then islandized by releasing all of its attachments.
Type 3A is an islandized flap where the flap is supplied by the TAA. In this flap configuration, the distal part of the TAA is sacrificed [Fig. 2D]
Type 3B is an islandized flap where the flap is supplied by the deltoid branch of the TAA. The TAA remains wholly intact without sacrificing distal blood flow [Fig. 2E].