Muscles Flashcards
Zygomaticus
Origin: Zygomatic
Insertion: Angle of mouth; upper lip
Action: draws corners of mouth back and up
Buccinator*
Origin: Maxillary bone and mandible
Insertion: blends into fibers of orbicularis oris
Action: compresses cheek
Masseter
Origin: Zygomatic arch
Insertion: lateral surface of mandible
Action: elevates mandible
Temporalis*
Origin: along temporal lines of skull
Insertion: coronoid process
Action: elevates mandible
Platysma
Origin: cartilage of second rib to scapula
Insertion: mandible and skin of cheek
Action: tenses skin of neck, depresses mandible
Sternocleisomastoid
Origin: superior margins of sternum and clavicle
Insertion: mastoid region of skull
Action: both flex neck, alone bends head toward shoulder and turns face
Splenius capitus
Origin: Spinous process of lower cervical and upper thoracic vertebrae
Insertion: mastoid process, skull base, upper cervical vertebrae
Action: both extend neck, alone rotates and flexes head
External Intercostals
Origin: inferior border of each rib
Insertion: superior border of next rib
Action: elevate ribs
External obliques
Origin: lower eight ribs
Insertion: linea alba and iliac crest
Action: compresses abdomen, depresses ribs, flexes or laterally flexes vertebral column
Rectus abdominis
Origin: superior surface of pubis around symphysis
Insertion:binferior surfac of costal cartilages 5-7 and xiphoid process
Action: depresses ribs, flexes vertebral column
Trapezius
Origin: occipital bone and thoracic vertebrae
Insertion: clavicle and scapula
Action: elevate, adduct, depress rotate scapula, elevate clavicle, extend or hyperextend the neck
Pectoralis minor*
Chest; ribs/ coracoid process
Deltoid
Origin: clavicle and scapula
Insertion: deltoid tuberosity of humerus
Action: abduction at shoulder
Latissimus dorsi
Origin: lower thoracic and lumbar vertebrae
Insertion: intertubercular groove of humerus
Action: extension, adduct and medial rotation at shoulder
Pectoralis major
Origin: cartilages of ribs 2-6, body of sternum, clavicle
Insertion: greater tubercle of humerus
Action: flexion, adduction, and medial rotation at shoulder