How many muscles are there in the human body

Muscle tissue is one of the most important tissues in the body and plays a core supporting role in the body's mobility. Therefore, the importance of muscle is self-evident. Muscles do not exist alone in a certain part of the body, but are a system composed of multiple muscles working together to provide powerful power for the body. So, how many muscles does the human body consist of? Let’s take a look at the explanation below.

There are 639 muscles in the human body. It is composed of about 6 billion muscle fibers, the longest of which is 60 cm long and the shortest is only about 1 mm. Large muscles weigh about two kilograms, while small muscles weigh only a few grams. The average person's muscles make up about 35 to 45 percent of their body weight.

The most important muscles of the human body are: the gastrocnemius of the calf, the quadriceps femoris of the thigh, the gluteus maximus, the rectus abdominis, the pectoralis major, the latissimus dorsi, the deltoid muscle, the biceps and triceps of the upper limbs, etc.

Muscles are mainly composed of muscle tissue. Muscle cells are slender and fibrous in shape, so they are usually called muscle fibers. In traditional Chinese medicine theory, muscle refers to the general term for the body's muscle tissue and subcutaneous fat tissue. The spleen controls the muscles, and the muscles obtain nutrition from the spleen's ability to transport and transform the essence of water and grain. Muscle: Name of anatomical structure. Therefore, whether the muscles are plump or not is closely related to the strength of the spleen.

According to the structure and function, it can be divided into three types: smooth muscle, cardiac muscle and skeletal muscle. According to the morphology, it can be divided into long muscle, short muscle, broad muscle and orbicularis muscle. Smooth muscle mainly constitutes the internal organs and blood vessels, and has the characteristics of slow contraction, durability, and low fatigue. Myocardial muscle constitutes the heart wall. Neither of them contracts according to human will, so they are called involuntary muscles. Skeletal muscle is distributed in the head, neck, trunk and limbs and is usually attached to bones. Skeletal muscle contracts quickly and forcefully, fatigues easily, and can expand and contract at will, so it is called voluntary muscle. Skeletal muscle appears striated when observed under a microscope, so it is also called striated muscle.

Muscle contraction pulls on bones to produce joint movement, acting like a lever device, and has three basic forms (Figure 3-4). ① Balanced lever movement, with the fulcrum between the focus and the force point, such as the head tilting and lowering movements performed by the atlanto-occipital joint. ② Force-saving lever movement, the focus of which is between the fulcrum and the force point, such as the movement of the ankle joint when lifting the heel to start. ③ Speed ​​lever movement, in which the force point is located between the focus and the fulcrum, such as the movement of the elbow joint when lifting a heavy object.