14（二） masticatory muscles masseter ：Origin－inferior border and medial surface of zygomatic archInsertion－lateral surface of ramus of mandible and angle of mandibletemporalis ：Origin－temporal fossaInsertion－coronoid process of mandibleaction： masseter, temporalis--- elevates mandible—close the mouth
15（二） masticatory muscles medial pterygoid ：lateral pterygoid ：action：medial pterygoid elevates mandible—close the mouthlateral pterygoid ：pull the head of mandible forwards--- open the mouth
17PlatysmaSternocleidomastoidOrigins: manubrium and medial1/3 of clavicleInsertion: mastoid process of temporal bone;Actions: acting alone, the head is inclined ipsilateral and the face is rotated to opposite side; acting together, they extend the head.
18elevate (raise) hyoid bone and depress mandible. 1、suprahyoid musclesAnterior bellyPosterior bellydigastricMylohyoidStylohyoidGeniohyoidAction:elevate (raise) hyoid bone and depress mandible.
20scalene fissure ： （三）The deep cervical m. 1、lateral goup scalenus anteriorscalenus mediusscalenus posteriorscalene fissure ：it is bounded by the scalenus anterior and medius and first rib ，it contains the subclavian a and brachial plexus.2、medial group：longus collilongus capitis
231、superficial group （ 1）Trapezius a large, triangular m. lying on the back of the neck and thorax;Origin: external occipital protuberance, superior nuchal line, ligamentum nuchae, the spinous processes of 7th cervical vertebrae and all thoracic vertebrae;Insertion: lateral 1/3 of clavicle, acromion and spine of scapula.
241、superficial group （ 1）Trapezius Action： raises, descends, and rotates the scapula and extends the head.
251、superficial group （2）Latissimus Dorsi It is a largest and triangular m. lying the back and lateral wall of thorax;Origins: the spinous processes of lower 6 thoracic vertebrae and all lumbar vertebrae;Insertion: inserted into the floor of the intertubercular sulcusAction:Extend, adduct， and rotate the shoulder joint mediallyLatissimus dorsi
261、superficial group （3）levator scapulae origin：the transverse processes of the upper 4 cervical vertebrae;insertion：superior angle of scapula.Action：raise the scapula.Levator scapulaeRhomboideus（4）rhomboideusLies deep to the trapezius，
272、The deep group Erector Spinae Splenius position： It lies in the vertebral groove on each side of vertebral spines;Action：extend the spinal column and headSpleniusposition：Action：
30Pectoralis majorOrigin: medial half of clavicle,sternum,1th-6th costal cartilages.Insertion: crest of greater tubercle of humerus.Action: flexes, adducts and rotates arm medially; arm fixed, elevates trunk; elevates ribs 1-6,aidding in forced inspiration.
31Pectoralis minor Origin: 3rd-5th ribs Deep to the pectoralis majorOrigin: 3rd-5th ribsInsertion: coracoid process of scapulaAction:Draw the scapula forwards and downwards,when the scapula is fixed it helps the inspiration(by elevation the ribs)
32Serratus anterior It overlies the laeral wall of thorax Origin: external surfaces of the upper 8~9 ribsInsertion: medial border of scapulaAction: holds the scapula against the chest wall；Pulls the scapula forwards in throwing and pushing.
33Intercostales externi 2. Intrinsic musclesIntercostales externiOrigin: lower border of ribInsertion: upper border of rib below originexternal intercostals membrane .Action: elevate ribs adding in forced inspiration
34Intercostales interni Origin: upper border of rib；Insertion: lower border of rib above originReplaced posteriorly by internal intercostals membrane.Action: depress ribs for forced expiration
35Ⅲ. Diaphragm (1) Position and division: Sternal part: Costal part: dome-shaped between thorax and abdomen, consists ofCentral tendonmuscular partSternal part:Costal part:Lumbar part: arises by left and right crus from upper 2-3 lumbar vertebraeInsertion: central tendon
36③ Vena caval foramen ① Aortic hiatus ② Esophageal hiatus (2) Openings of diaphragm① Aortic hiatusat the level of 12th thoracic vertebra, the thoracic aorta and thoracic duct pass through itinferior vena cavaT8② Esophageal hiatusat the level of 10th thoracic vertebra, the esophagus and vagus n. pass throught itT10esophagusthoracic aortaT12③ Vena caval foramenat the level of 8th thoracic vertebra, inferior vena cava through it
37(3) ActionContraction: the dome moving downward, increases the volume of thoracic cavity which results in inspiration.Relaxation: the dome returns to the former position, reduces the volume of the thoracic cavity, resulting in expiration.
38(2) Weak areas: triangular spaces without muscular tissue Lumbocostal trianglebetween costal and lumbar parts.Sternocostal trianglebetween costal and sternal parts.
39Muscles of abdomen Anterolateral group Obliquus externus abdominis Obliquus internus abdominis Transversus abdominisRectus abdominis
40Obliquus externus abdominis Origin:Arises from the lower 8 ribs,and the muscular fibers runobliquely from the superolatealto the inferomedial, theanterior part of the m. changegradually into aponeurosis,which pass over the rectusAbdominis;insertion: Linea alba.
41Obliquus externus absominis Structures formed by aponeurosis of this m. include：Inguinal ligamentSuperficial inguinal ringSuperficial inguinal ring triangular-shaped hiatus above pubic tubercleLacunar ligamentLacunar ligament
42Obliquus internus abdominis Origin: thoracolumbar fascia , iliac crest and the lateral half of the ingunal lig.Insertion: Linea albaThe muscular fibers run upwards and forwards, and become the aponeurosis close the lateral border of the rectus abdominis. Its aponeurosis divided into two layers to inclose the rectus abdominis.
43Transversels abdominis is the deepest one of the three flat abdominal m.Origin: it arises from the costal cartilages of the lower 6 ribs，the thoracolumbar fascia , the iliac crest and the lateral 1/3 of the ingunal lig. ,Insertion: Linea albaThe muscular fibers run transversly ,and pass deep to rectus abdominis.
44Transversels abdominis Inguinal falx(conjoined tendon) or is a common aponeurosis joined by obliquus internus abdominis and transverse abdomini, it turns downwards to insert the pubic crest and pecten pubis.Cremaster : around the spermatic cord and testis
45The Sheath of rectus abdominis Anterior layer－ formed by theaponeurosis of obliquusexternus abdominis ；anterior leaf of aponeurosisof obliquus internus abdominisPosterior layer：formed byposterion leaf of aponeurosisof obliquus internus abdominis ；aponeurosis of transversesabdominis
46The Sheath of rectus abdominis arcuate line semicircular lineat about 4-5cm below the umbilicus, the lower free border of the posterior layer of the sheth present arcuated.Below this line the rectus abdominis in contact with transverse fascia directly.
47Linea alba－tendinous raphe between right and left rectus abdominis from xiphoid process to pubic symphysis.
48The functions of the four pairs of muscles Support and protect the abdominal visceraMaintain and increase intra-abdominal pressure, aid in vomiting, coughing, sneezing, defecation, urination and childbirth.Flex, lateral flex, and rotate vertebral column
50Inguinal canalPosition: oblique passage about 4cm long, and passes downwards and medially, it lies parallel to, and immediately above medial half of inguinal lig. It has two openings and four walls.
51Four walls Anterior wall Aponeurosis of obliquus externus abdominis Obliquus internus abdominis (lateral third of wall)
52Roof－ lower fibers of obliquus internus and transversus abdominis Post wall —Transverse fascia ；Inguinal flax mediallyRoof－ lower fibers of obliquus internus and transversus abdominisFloor－inguinal ligament．
53Two openings Superficial inguinal ring Deep inguinal ring defect in transverse fascia，lies at about 1.5cm above midpoint of inguinal ligament
54Structures passing through the inguinal canal Male: Spermatic cordfemale: Round ligament of uterus