We identified 89 studies from our initial search. Only 11 of the articles provided a description of the technique involving the use of the pectoralis major muscle flap in the reconstruction of the sternoclavicular defects. 5 of the articles were excluded because they described the exact same procedures that has been previously described by a different author.
The pectoralis major muscle advancement flap ( Fig. 2A): The use of this flap for sternoclavicular defect reconstruction was first described by Munoz et al in 1996  and its modification, total release of humeral attachments by Opoku et al in 2019 . In this procedure, the skin overlying the pectoralis in the midline is incised and carried down to the subcutaneous tissue. The ipsilateral
pectoralis muscle is dissected and lifted off the chest wall from medial to lateral. The pectoralis is also released inferiorly from its attachment to the serratus. The Thoracoacromial artery and its pectoral branch is identified and preserved. After completely undermining the flap, it is mobilized superiorly and medially to cover the sternoclavicular joint defect. The PM muscle is sutured to the platysma and sternal fascia. If adequate muscle bulk and length cannot be obtained to provide adequate coverage. the pectoralis can be released from its humeral attachments resulting in a completely detached pectoralis except for its attachment to the vascular pedicle . In this configuration, the muscle is not split, none of the major branches of the Thoracoacromial artery is sacrificed, however, the pectoral perforator of the internal mammary are sacrificed.
Split pectoralis major muscle flap (Fig.2B): First described by Zehr et al. in 1996 
After Sternoclavicular resection, the superior aspect of the pectoralis major is already exposed by the dissection. Skin hooks are placed on the inferior skin edge. A skin flap is elevated inferiorly exposing the pectoralis major to the level of the fourth interspace and laterally toward the edge of the deltoid. The superior one-half of the muscle fibers are transected by electrocautery at the extreme lateral region of exposure. The muscle fibers are then split longitudinally toward the origin of the muscle. At the same time, the muscle flap is dissected free from the underlying pectoralis minor. Extension of this medial dissection to the medial vascular perforators creates a split pectoral major flap, which can be easily rotated 45 to 60 degrees to fill the defect superiorly. The flap is sewn into place superiorly to the platysma fascia and medially to the sternal fascia. This configuration has ample muscle for soft tissue coverage. It is well vascularized from the intact sternal perforators of the IMA. The TAA is sacrificed.
Partial pectoralis major muscle advancement flap (Fig.2C): First described by Song et al in 2002 .
After SCJ resection, a skin incision was made over the manubrium as far caudad as the level of the third costal cartilage in the midline and carried a variable distance . A flap of skin and subcutaneous tissue is raised to allow mobilization of approximately the upper one third of the pectoralis major muscle laterally as far as the deltopectoral groove. This portion of the muscle is mobilized from its superior attachments to the clavicle and its medial attachments to the sternum as far caudad as approximately the third intercostal space. The medial intercostal perforators to this portion of the muscle were divided. The muscle is separated from the underlying pectoralis minor and advanced into the defect on the basis of its thoracoacromial artery vascular supply. It is then tacked to surrounding structures with interrupted absorbable sutures. Subcutaneous tissues and skin were closed. The resulting flap is a large flap with robust blood supply dependent on the TAA. The sternal perforators are sacrificed.
The islandized hemipectoralis major muscle flap (Fig. 2D): First described by Schulman et al in 2007 . After SCJ resection or debridement, the skin and subcutaneous tissue are elevated. caudally, exposing the pectoralis major muscle. The interval between the clavicular and sternocostal portions of the pectoralis major muscle was identified and split in the direction of its fibers. Muscular attachments to the sternum medially and the clavicle superiorly were divided. The clavicular segment was then reflected superiorly, exposing the underlying thoracoacromial vessels. A Doppler probe was used to verify the patency of this pedicle. The muscle was divided 3 cm lateral to the thoracoacromial vessels, completely islandizing it on the vascular pedicle. The pedicle was freed from surrounding tissue, which maximized the length and allowed adequate mobilization. The muscle is advanced medially and superiorly to fill the defect and was secured in place without tension with sutures. This configuration has a small to moderate amount of muscle dependent on the TAA. It has a robust blood supply.
Deltoid branch-based clavicular head of pectoralis major muscle flap (Fig.2E) : First described by Al-Mufarrej et al in 2013 . It is basically a partial islandized pectoralis flap based on just the deltoid branch of the TAA. The branches of the TAA are not sacrificed.
Following clavicular resection, the TAA is dissected and visualized. The fascial plane separating the clavicular and sternocostal heads is identified. The muscle fibers are carefully spread apart with a Schnidt. The thoracoacromial pedicle running underneath the muscle, along with its deltoid and pectoral branches, is identified. Once the pedicle has been identified under the muscle, the clavicular head muscle fibers are divided lateral to the pedicle with bipolar. After visualization of the fatty tissue around the TAA through a lateral split in the muscles, the artery is palpated along its course and its entrance into the muscle is identified. Muscle fibers are then split along their natural course cephalad to that point. If the muscle is being harvested without a skin paddle, dividing the acromial branch of the deltoid artery will improve the muscle flap arc of rotation. Lateral to medial subpectoral dissection is then performed with release of the caudad muscle attachments. Any remaining attachments to the sternum are divided.
Once the muscle is islandized, the flap is delivered into the defect and secured in place.