Trunk Muscles

Anterior Muscles Name: Pectoralis Major Origin: Sternum, clavicle, & 1 st to 6 th rib Insertion: Proximal humerus Primary action: Adducts and flexes humerus

Anterior Muscles Name: Intercostal muscles Location: Found between the ribs Primary action: Raise the ribcage for breathing

Muscles of Abdominal Girdle Name: Rectus abdominis Origin: Pubis Insertion: Sternum and 5 th to 7 th rib Primary action: Flexes vertebral column

Muscles of Abdominal Girdle Name: External Oblique Origin: Lower 8 ribs Insertion: Iliac crest Primary action: Flexes and rotates vertebral column

Muscles of Abdominal Girdle Name: Internal Oblique Origin: Iliac crest Insertion: Last 3 ribs Primary action: Paired muscles deep to external obliques Flex and rotate vertebral column

Muscles of Abdominal Girdle Name: Transverus abdominis Origin: Lower ribs and iliac crest Insertion: Pubis Primary action: Compresses abdominal contents

Posterior Muscles Name: Trapezius Origin: Occipital bone and all cervical / thoracic vertebrae Insertion: Scapular spine and clavicle Primary action: Extends neck and adducts scapula

Posterior Muscles Name: Latissimus Dorsi Origin: Lower spine and iliac crest Insertion: Proximal humerus Primary action: Extends and adducts humerous

Posterior Muscles Name: Erector Spinae Origin: Iliac crest, ribs 3-12, and vertebrae Insertion: Ribs thoracic / cervical vertebrae Primary action: Extends back

Posterior Muscles Name: Deltoid Origin: Scapular spine and clavicle Insertion: Humerus (deltoid tuberosity) Primary action: Abducts humerus