Cocaine normally stays in the system for approximately 48 hours. Although the method of administration and the dose administered affects how long it takes for the body to metabolize this drug. When coca leaves are chewed, absorption time is around 30 minutes.
The muscles that provide the movement for the shoulder and upper arm include the anterior muscles in the front, the posterior muscles in the back, and the shoulder muscles that are sort of in between. Pectoralis major: This muscle has two heads, or sections of muscle tissue, and covers much of the front of the thoracic cage.
The trapezius, along with the rhomboideus major and minor, and levator scapulae, work together to elevate the shoulder. Scapula adduction, or the act of moving your arm and shoulder backwards, involves the trapezius and the rhomboids. The trapezius also acts in head/neck extension, or the act of tilting your head back.