[The 2 key muscles in thoracotomy for excision of the lung. The latissimus dorsi and the levator scapulae muscles].

Anatomical data related to the thoracotomies performed most frequently in lung surgery are described in some detail: continuity between serratus anterior and levator scapulae as a vide muscular sheet possessing a common deep aponeurosis (thoracolumbar fascia) extending Gilis' space to the vertebral column as the levator scapulae-thoraci space; presence of a "composite aponeurosis" in the posterior angle between serratus anterior and levator scapulae, covering the 8th rib triangle or triangle of auscultation; long costal insertion area and presence of two differently orientated muscle layers for the digitations, particularly of apical bundle. Supplied by a rich vascularization of multiple sources, the serratus anterior and latissimus dorsi are two muscles with single longitudinal nerve pedicles derived from brachial plexus. It is certainly the denervation which is responsible for the distal atrophy of these muscles "sectioned on the right of the selected ribs" following conventional thoracotomy. To avoid esthetic and functional sequelae this innervation must be preserved as far as possible by: interrupting division of serratus anterior anterior to long thoracic nerve and avoiding inclusion of axillary border of latissimus dorsi during lateral thoracotomy; sectioning the latissimus dorsi as low as possible--the other muscles being simply freed and inclined--during lateral thoracotomy.