Introduction Of Myology

Myology(Ⅰ)

Section 1 Introduction Muscles can be divided into the following according to structure ： smooth muscle cardiac muscle skeletal muscle Skeletal muscle can make contractions, it is one part of locomotor system. The contraction is under the voluntary control, so it is also called voluntary muscles.

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More than 600 skeletal muscles make up the muscular system

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Collectively, the skeletal muscles account for approximately 40% of the body weight .

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Each skeletal muscle possesses a definite shape, structure, location and accessory apparatus, and is supplied by abundant blood vessels, lymphatics and nerves, so it can be regarded as an organ.

Ⅰ. Shape and structure of the muscle 1. Classification According to the shape, the muscles may be divided into: long m. short m . flat m. orbicular m.

According to the position, the muscles may be divided into: M.of head M.of neck M.of trunk M. of limbs M. of back M. of thorax M. of abdomen diaphragm

2. Structure muscle belly

muscle belly tendon

tendon

aponeurosis

aponeurosis

Ⅱ. Origin, insertion and action of skeletal muscles The muscular origin ( starting point or fixed point) refers to the position which approaches to the median plane of body or the four limbs part approaches to the proximate attachment point, while the other extremity is insertion or moving point. •antagonist •synergist •agonist •fixator •Balance lever movement •Labor-saving movement •Velocity lever movement

Ⅲ. Name of muscles Shape ： trapezius ， triceps Location ： pectoralis ， intercostals Attachment ： sternocleidomastoid, temporalis Size ： maximum ， minimus ， longus ， brevis Orientation of fibers ： rectus ， transverse ， oblique Relative position ： lateral ， medial ， internal and external Function ： adductor, flexor, extensor, pronator, and levator

Ⅳ. Accessory structure Ⅰ) fascia A. superficial fascia is found immediately under the skin and covering almost the entire body. containing fat. provides for increased mobility of skin, and contributes to thermal insulation and store energy.

B. deep fascia : form the dense inelastic and arranged to regular fiber membrane. may form a strong separate sheath to muscles or the vessels and nerves.

Ⅱ ）  synovial bursa: is found between a tendon and a bone or ligament, or between two tendons. lubricate surface of joint.

Ⅲ ） Tendinous sheath : is thought of as a synovial bursa that entends around the tendon to envelop it. has two layers. fibrous layer visceral layer (synovial sheath of tendon)

Ⅲ ） sesamoid bones: often developed in the tendon and afford for a great amount of pressure. e.g. patella.