Developmental anomalies at the thoracic outlet: An analysis of 200 consecutive cases

Abstract

Anatomic observations were made during 200 consecutive transaxillary surgical procedures performed in 175 patients because of unremitting signs and symptoms of nerve or vascular compression at the thoracic outlet. There were 160 cases of brachial plexus compression and 40 cases of arterial or venous occlusion. In 132 (66%) of these cases, single or multiple abnormalities were recognized that represented developmental variations previously described in anatomic dissections or in embryologic studies. There were 17 cases of cervical rib or first thoracic rib abnormalities and 20 supernumerary scalene muscles. Developmental variations were identified in 86 scalene and 39 subclavius muscles or their insertions. Comparisons revealed a higher percentage of developmental anomalies in this group of patients than in consecutive anatomic investigations reported in unselected populations. This information was interpreted in light of recent embryologic studies and histochemical and morphometric ultrastructural studies of scalene muscle. The preponderance of evidence suggests that neurovascular compression in the region of the thoracic outlet derives from a combination of these factors: predisposing morphologic variations, structural modifications conditioned by functional requirements, and changes in fiber type or myosin isoform consequent to trauma. The correlation of clinical syndrome with morphologic characteristics alone was significant only for the Paget-Schroetter syndrome.

Bilateral anatomic variation in the relation of the upper trunk of the brachial plexus to the anterior scalene muscle

“…The upper extremities' buds develop from the mesenchyme during the fourth week of foetal development. The neck muscles arise from the premuscle mass of the shoulder girdle [12].…”

Compressão da artéria subclávia por pseudoartrose de clavícula: apresentação na quinta década de vida

“…8,9 It can also be caused by repetitive use of the upper limb, as occurs in some professional and sporting activities. Arterial complications caused by post-traumatic pseudarthrosis are uncommon, [3][4][5][6][7] but can be severe. 8 The mechanism of injury is the result of chronic constriction of the subclavian artery and repeated microtraumas.…”

“…1,2 The location of the clavicle means that a pseudarthrosis may cause compression of structures in the thoracic outlet. Compression of the subclavian artery is rare [3][4][5][6] and when it occurs it is the result of bone disorders in 88% of cases. 5 The symptoms are generally variable and slow to appear.…”

Recurrent thoracic outlet syndrome and surgical treatment

“…Kolların elevasyonunu, başın üstüne kaldırılmasını ya da öne doğru uzatılmasını gerektiren araba kullanmak, bilgisayarda yazı yazmak ya da bir şey taşımak gibi etkinlikler semptomları kötüleşti-rir. Üst ekstremitenin nötral pozisyona getirilmesi ile semptomlar hızla düzelir (1)(2)(3).…”