50 Muscle Atlas (Origin, Insertion, Action) Flashcards
Orbicularis Oris
Origin: muscle fibers surrounding opening of mouth
Insertion: skin at corner of mouth
Action: close lips, compress lips against teeth, protrude lips, shape lips during speech
Orbicularis Oculi
Origin: medial orbital wall
Insertion: circular path around orbit
Action: close eyes
Masseter
i) origin: maxilla and zygomatic arch
ii) insertion: angle and ramus of mandible
iii) action: elevates mandible as in closing mouth, assists in side-to-side movement of mandible, and protracts (protrudes) mandible
Temporalis
i) origin: parietal bone
ii) insertion: coronoid process and ramus of mandible
iii) action: elevates and retracts mandible and assists in side-to-side movement of mandible
Sternocleidomastoid
i) origin: sternum and clavicle
ii) insertion: mastoid process of temporal bone
iii) action: contraction of both muscles flexes the cervical part of the vertebral column and draws the head forward; contraction of one muscle rotates face toward side opposite of the contracting muscle
Rectus Abdominus
i) origin: pubic crest and pubic symphysis
ii) insertion: cartilage of fifth to seventh ribs and xiphoid process
iii) action: flexes vertebral column and compresses abdomen to aid in defecation, urination, forced expiration, and childbirth
Obliquus Externus Abdominis (External Oblique)
i) origin: inferior eight ribs
ii) insertion: iliac crest and linea alba
iii) action: contraction of both compresses abdomen and flexes vertebral column; contraction of one side alone bends vertebral column laterally; rotates vertebral column
internal oblique
i) origin: iliac crest, inguinal ligament, and thoracolumbar fascia
ii) insertion: cartilage of ribs 7-10 and linea alba
iii) action: compresses abdomen
transverse abdominis
i) origin: iliac crest, inguinal ligament, lumbar fascia, and cartilages of ribs 5-10
ii) insertion: xiphoid process, linea alba, and pubis
iii) action: compresses abdomen
diaphragm
i) origin: xiphoid process of sternum, costal cartilages and adjacent portions of ribs 7-12, lumbar vertebrae and their intervertebral discs
ii) insertion: central tendon
iii) action: contraction [inspiration] elevates ribs and increases anteroposterior and lateral dimension of thoracic cavity (relaxation [expiration] does the opposite)
trapezius
i) origin: occipital bone, ligamentum nuchae, and spines of seventh cervical and all thoracic vertebrae
ii) insertion: clavicle and acromion and spine of scapula
iii) action: elevates clavicle, adducts scapula, rotates scapula superiorly, elevates or depresses scapula, and extends head
serratus anterior
i) origin: ribs 1-8 or 1-9
ii) insertion: vertebral border and inferior angle of scapula
iii) action: abducts scapula and rotates it upwards
pectoralis major
i) origin: clavicle, sternum, and cartilages of second to sixth ribs
ii) insertion: greater tubercle and intertubercular sulcus of humerus
iii) action: flexes, adducts, and rotates arm medially
Subscapularis
i) origin: subscapular fossa of scapula
ii) insertion: lesser tubercle of humerus
iii) action: medially rotates arm at shoulder joint
Teres Major
i) origin: inferior angle of scapula
ii) insertion: lesser tubercle of humerus
iii) action: extends arm at shoulder joint, and assists in adduction and medial rotation of arm at shoulder joint
Teres Minor
i) origin: inferior lateral border of scapula
ii) insertion: greater tubercle of humerus
iii) action: laterally rotates and extends arm at shoulder joint
Deltoid
i) origin: acromial extremity of clavicle and acromion and spine of scapula
ii) insertion: deltoid tuberosity of humerus
iii) action: abducts, flexes, extends, and may alternately medially or laterally rotate arm
Infraspinatus
Origin: infraspinous fossa of scapula
Insertion: greater tubercle of humerus (posterior)
Actions: extends arm; adducts and laterally rotates humerus
Latissimus dorsi
i) origin: spines of inferior six thoracic vertebrae, lumbar vertebrae, crest of sacrum and ilium, inferior four ribs
ii) insertion: intertubercular sulcus of humerus (to anteromedial to humerus)
iii) action: extends, adducts, and rotates arm medially; draws arm inferiorly and posteriorly
Biceps brachii
Flexor
Origins: 2 - long head from tubercle superior to glenoid cavity
short head from coracoid process of scapula
Insertion: radial tuberosity
Action: flexes and supinates forearm; flexes arm
Brachioradialis
FLEXOR
i) origin: lateral border of distal end of humerus
ii) insertion: superior to styloid process of radius
iii) action: flexes forearm
Brachialis
FLEXOR
Origin: distal, anterior surface of humerus
Insertion: ulnar tuberosity and coronoid process of ulna
Action: flexes forearm