In the examination, diagnosis, and treatment of diseases, muscles are often an overlooked organ. However, muscles constitute a large organ with extensive and three-dimensional distribution, complex yet orderly movements, which are both beautiful and harmonious.

Muscles are not independent; they are often intertwined with other organs, manifested in two aspects: on the one hand, blood vessels with muscle tissue as part of their walls extend into every organ; on the other hand, there are a large number of arteries, veins, nerves, lymphatics, etc., inside and outside the muscles. The arteries, veins, nerves, lymphatics, and other structures are extremely complex, and Figure 11-0-1 shows a part of them. When considering the interrelationships between muscles and arteries, veins, nerves, lymphatics, etc., one will find the human body is truly exquisite and fascinating. Muscles, especially the respiratory muscles of the trunk, alternate between relaxation and contraction naturally and orderly, exerting a benign interactive effect on arteries, veins, nerves, lymphatics, etc.: muscle contraction accelerates blood flow in arteries and veins, ensuring adequate blood circulation and sufficient blood supply to nerves.

Therefore, any activity of muscles can affect these arteries, veins, nerves, lymphatics, etc., especially arteries—since large arteries are often closely attached to muscles, and medium and small arteries often pass through them. Muscles can affect these structures both under physiological and pathological conditions; under pathological conditions, a series of clinical symptoms will occur.

Tightened muscles, due to decreased muscle strength and impacts on links such as blood supply, cause changes in the function and state of organs innervated by relevant blood vessels, thereby leading to conditions such as dowager's hump, accessory breasts, cold disorders, age-related macular degeneration, tinnitus, and sudden deafness. These conditions caused by lesions in non-muscular organs due to tightened muscles are referred to as post-muscular disorders, analogous to secondary disasters in natural disasters.