When a COPD patient leans forward braced in a tripod position, this lends particular advantage to which accessory muscles of inspiration?

a. External intercostals
b. Pectoralis
c. Scalenes
d. Sternocleidomastoids

ANS: B
The major and minor pectoralis muscles are broad fan-shaped muscles of the upper anterior chest (Figure 9-25). The pectoralis major originates on the humerus and inserts onto the clavicle and sternum. The pectoralis minor originates on the scapula and inserts on the anterior portions of ribs 3 through 5. When these muscles receive impulses from the pectoral nerves, they normally func-tion to adduct the arms in a hugging motion. They are also capable of generating some anterior thoracic lift when the arms are braced on a surface in front of a subject. Those individuals who suffer with chronic shortness of breath often utilize these muscles by sitting in a "tripod" posi-tion. This is performed by sitting upright and leaning forward with both arms braced on a table.