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Muscles of the Trunk
origin is lower 8 ribs, compresses abdomen; most external of abdominal muscles
compresses abdomen, middle layer; fibers point up to the head
Ilium, Linea alba and pubic crest, compresses abdominal wall
O: infraspinous fossa of scapula | I: greater tubercle of humerus | A: lateral rotation of humerus
Flexes lumbar region of vertebral column, producing forward bending at the waist. O: Pubic symphysis and superior margin of pubis. I: Xiphoid process, costal cartilages 5 - 7.
originates on external surface of lateral parts of ribs 1-8, inserts on anterior surface, medial border of scapula
• dense sleeve of fascia in thoracic and lumbar regions • site of muscle attachment (e.g., latissimus dorsi) • surrounds the intrinsic back muscles (see below)