29) Muscular walls of the thorax and abdomen are composed of A) spinal erector muscles. B) muscles of mastication. C) oblique and rectus muscles. D) glossal muscles. E) pectoralis muscles. Answer: 30) Each of the following muscles is involved in the process of chewing or manipulating food in the mouth except the A) masseter. B) temporalis. C) pterygoid. D) omohyoid. E) genioglossus. Answer: 31) Damage to the pectoralis major would interfere with a person's ability to A) extend the forearm. B) abduct the humerus. C) Flexion of the humerus D) elevate the scapula. E) rotate the elbow. Answer: 32) The spinous processes of the upper thoracic vertebrae are the origin of the A) levator scapulae. B) rhomboid major. C) trapezius. D) supraspinatus. E) rhomboid major and the trapezius. Answer: 33) The pulling away of the trapezius muscle exposes the A) serratus anterior and subclavian muscles. B) infraspinatus and teres minor muscles. C) deltoid and supraspinatus muscles. D) rhomboid and levator scapulae muscles. E) gastrocnemius and tibialis anterior muscles