A seven-year old boy breaks his tibia and requires immobilization by a hard cast for 6 weeks until the break heals. A potential consequience of this therapy is atrophy of the pectoralis major?
No, immobilization of a broken tibia in a hard cast for six weeks would not directly cause atrophy of the pectoralis major muscle, which is located in the chest. The pectoralis major is primarily involved in movements of the shoulder and arm, such as flexion and adduction.
In this case, the tibia fracture would not directly affect the function or usage of the pectoralis major muscle. Atrophy, or muscle wasting, usually occurs when a muscle is not used or stimulated for a prolonged period of time. If the immobilization of the leg causes the child to refrain from using the arm and shoulder on the same side, there might be a decrease in muscle tone due to disuse.
However, it's important to note that atrophy of the pectoralis major would be an indirect consequence of the immobilization. It is advisable for the child to maintain an active lifestyle and perform appropriate exercises for the unaffected muscles during the immobilization period to minimize muscle loss and prevent overall deconditioning.