1. Anterior Muscles of Trunk, Shoulder, Arm
Figure 6.16a

2. Muscles of Trunk, Shoulder, Arm
Anterior muscles
Pectoralis major—adducts and flexes the humerus
Intercostal muscles
External intercostals—raise rib cage during inhalation
Internal intercostals—depress the rib cage to move air out of the lungs when you exhale forcibly

3. Anterior Muscles of Trunk, Shoulder, Arm
Figure 6.16a

4. Anterior Muscles of Trunk, Shoulder, Arm
Figure 6.16b

5. Muscles of Trunk, Shoulder, Arm
Muscles of the abdominal girdle
Rectus abdominis—flexes vertebral column and compresses abdominal contents (defecation, childbirth, forced breathing)
External and internal obliques—flex vertebral column; rotate trunk and bend it laterally
Transversus abdominis—compresses abdominal contents

6. Anterior Muscles of Trunk, Shoulder, Arm
Figure 6.16b

7. Muscles of Trunk, Shoulder, Arm
Posterior muscles
Trapezius—elevates, depresses, adducts, and stabilizes the scapula
Latissimus dorsi—extends and adducts the humerus
Erector spinae—back extension
Quadratus lumborum—flexes the spine laterally
Deltoid—arm abduction

8. Muscles of Posterior Neck, Trunk, Arm
Figure 6.17a

9. Muscles of Posterior Neck, Trunk, Arm
Figure 6.17b