Anatomical basis for the clinical application of the arterial supply of musculus pectoralis major.

The pattern of arterial supply to the various parts (clavicular, sternocostal and aponeurotic) of the pectoralis major muscle was studied in 7 cadaver dissections and 10 angiograms by injecting a radio-opaque substance. Three main arteries supplied the muscle, i.e. the pectoral branch of the thoracoacromial trunk (TAT-PB), the lateral thoracic artery and the perorating branch of the internal thoracic artery, supported by other branches of the TAT and the superior thoracic artery. It is observed that the TAT-PB, a chief vascular pedicle, anastomoses freely with other arteries and supplies most parts of the muscle. The present study is mainly focussed on the exclusion of the chief vascular pedicle of muscle to eliminate the confusion of previous studies and prevent the unnecessary hindrance and complications of the muscle flap.     

The nerve supply to the clavicular part of the pectoralis major muscle: an anatomical study and clinical application of the function-preserving pectoralis major island flap

The purpose of this study was to investigate the nerve supply to the clavicular part of the pectoralis major muscle so that the innervation to this part can be maintained in the muscle-preserving pectoralis major island-flap transfer. Although methods have been described that include a limited portion of the muscle while leaving the upper parts undisturbed with an intact motor innervation, reports on anatomical studies of this nerve supply are brief. The distal distribution of the nerves, the spatial relationship to the main vascular pedicle, and the ways to preserve them during surgical procedures remain unclear. Surgically relevant features of the clavicular part of the pectoralis major muscle were studied by dissection. The nerve supply to this part was examined on 11 sides of eight formalin-fixed cadavers. Two fresh cadavers were used for dissection, intraarterial polymer injection, and application of a nerve-preserving surgical technique. In all subjects, a separate nerve innervated the clavicular and upper medial sternocostal portions of the pectoralis major muscle. This nerve arises craniomedial to the main vascular pedicle of the flap and divides into several branches. These branches run in a fascia on the deep surface of the pectoralis major muscle, superficial to the origin and distal course of the vascular pedicle. Most branches to the clavicular part end medial to the coracoid process. The course of the branches to the upper sternocostal part is more medial. Based on their anatomical findings, the authors propose a surgical technique for transfer of the pectoralis major island flap to the head and neck area through a tunnel in the deltopectoral groove, lateral to the origin of the vascular pedicle. Head and neck reconstruction was performed using this technique. The presented method is a muscle-preserving procedure that maintains maximal donor-site function and morphology.     

Myocutaneous vascular territory of the thoracoacromial artery. A topographical and morphometric study of the arterial vascularization of the pectoralis major myocutaneous flap

In order to clarify the vascularization of the pectoralis major muscle by the pectoral branch of the thoracoacromial artery, morphometric investigations and selective injection studies of the vessel were performed. A comparison with the anatomical orientation points clinically used for locating the vessel and its course confirms that the origin of the artery is at a constant spot at half the sternoacromial distance; the main vessel axis, however, deviates considerably from the clinically used acromioxiphoid axis in lateral direction. The lumen of the thoracoacromial artery has a range of more than 150% of the smallest vessel. Atherosclerotic alterations are not the reason for this variety but only an additional handicap for the vessel capacity. Two types of muscle-perforating arteries were found, and the cutaneous area of blood supply was defined.     

The pectoralis major myocutaneous flap. A versatile flap for reconstruction in the head and neck.

A compound flap is described that utilizes skin from the anterior chest on a narrow segment of pectoralis major muscle, with its underlying axial neurovascular bundle. This flap has been used successfully to reconstruct large defects in 4 consecutive patients. Our experience with this flap suggests that it may be more versatile than the deltopectoral flap.     

Branches of the right pulmonary artery supplying the basal segments of the lung.

The studies were carried out on 100 right lungs taken from dead human bodies of both sexes whose age varied from 16 to 81 years. The pulmonary artery and the bronchus were injected with a 65% solution of duracryl and then digested in sulfuric acid. The specimens obtained were then examined to determine the number and dimensions of the branches of the basal portion of the right pulmonary artery (RPA) penetrating into the basal segments of the right lower pulmonary lobe. Their length was 52 mm at the most, and their diameter 14 mm. Three types of ramification of the basal portion of the RPA were distinguished on the basis of the trunks, segmental and subsegmental branches present. In 72% of the cases the branches penetrating into the basal segments showed a tree-like type, in 2% of the cases a bushy-like type and in 26% of the cases a middle type.     

Intrinsic nerves of the pectoralis major and minor in man

In the human intraorganic nerves of the thoracic muscles amyelin fibers make 62% and myelin ones--38%. In transversal sections ultrastructure of the myelin and amyelin fibers varying in their diameters has been studied. In the myelin and amyelin fibers the amount of various organells is not equal: in the amyelin fibers the arrangement density of microtubules is greater than that of neurofilaments, there is a reverse dependence between the amount of the microtubules and the neurofilaments on the one hand, and the fibrilar diameter, on the other hand. In the myelin fibers with the increasing diameter, the amount of the neurofilaments increases, while that of the microtubules decreases.     

The pectoralis major for single-stage reconstruction of the difficult wounds of the orbit and pharyngoesophagus

This paper reports the results of reconstructions of difficult wounds in the head and neck area with musculocutaneous flaps in 20 patients. Twelve patients had reconstructions following cranial and orbital resections, and eight patients had reconstructions of the pharyngoesophagus. There were four wound complications, all of which healed without further surgical procedures. The pectoralis major musculocutaneous flap continues to be the most versatile flap for reconstructions at a variety of sites in the head and neck area. Contrary to other reports, it has not been bulky, it has been used without previous delays of the skin paddle, it has not required skin grafts to close the donor sites, and it has been used without difficulty in five female patients.     

Unilateral absence of the trapezius and pectoralis major muscle: a variant of Poland syndrome

We report a female patient with unilateral absence of the trapezius and pectoralis major muscles without other associated limb abnormalities. We believe that this anomaly belongs to the spectrum of anomalies resulting from disruption of the blood supply in the embryonic subclavian and vertebral arteries, as suggested in Poland syndrome.     

Use of pectoralis major muscle flaps to repair defects of anterior chest wall.

We closed defects of the anterior chest wall in 6 patients, using either unilateral or bilateral pectoralis major muscle flap transpositions. In 4 of these patients the defect was stabilized with autogenous rib grafts, and none of these had a flail chest. All of the transposed muscle flaps remained viable and innervated. The deformities and the functional disturbances resulting from the transpositions were minimal.     

Reconstruction of the mediastinal trachea with a tubed pectoralis major myocutaneous flap

A young patient with a massive postirradiation recurrence of thyroid cancer invading the larynx and mediastinal trachea had been treated by resecting the larynx and trachea to within three rings of the carina. A mediastinal tracheostomy was avoided by using a tubed pectoralis major myocutaneous flap to replace the ablated trachea. The flap, transferred into the mediastinum subclavicularly, was connected to the tracheal stump and exteriorized as a cervical tracheostomy. This resulted in direct closure of the donor site and primary healing. Four years after the operation, the patient remains free of disease and is tolerating the neotrachea without difficulty or complications. The technique described is offered as an alternative to conventional mediastinal tracheostomy methods, which have acknowledged shortcomings.     

Further experiences with the pectoralis major myocutaneous flap for the immediate repair of defects from excisions of head and neck cancers.

In our experience with 14 pectoralis major myocutaneous flaps they have been very reliable for reconstructions in a variety of clinical situations--especially in the repair of defects from extensive cancer resections in the head and neck area, including orbital exenterations. The flaps can be transferred immediately, without a delay.     

Inspiratory and expiratory patterns of the pectoralis major muscle during pulmonary defensive reflexes

Experiments wereconducted to determine the discharge pattern of the pectoralis majormuscle during pulmonary defensive reflexes in anesthetized cats(n = 15). Coughs andexpiration reflexes were elicited by mechanical stimulation of theintrathoracic trachea or larynx. Augmented breaths occurredspontaneously or were evoked by the same mechanical stimuli.Electromyograms (EMGs) were recorded from the diaphragm, rectusabdominis, and pectoralis major muscles. During augmented breaths, thepectoralis major had inspiratory EMG activity similar to that of thediaphragm, but during expiration reflexes the pectoralis major also hadpurely expiratory EMG activity similar to the rectus abdominis. Duringtracheobronchial cough, the pectoralis major had an inspiratory patternsimilar to that of the diaphragm in 10 animals, an expiratory patternsimilar to that of the rectus abdominis in 3 animals, and a biphasicpattern in 2 animals. The pectoralis major was active during both the inspiratory and expiratory phases during laryngeal cough. We conclude that, in contrast to the diaphragm or rectus abdominis muscles, thepectoralis major is active during both inspiratory and expiratory pulmonary defensive reflexes.