Muscle Head model #on little #on big Origin Insertion Action torso torso model model 34 1 Occipital bone, ligamentum Clavicle, spine of scapula and Adducts scapula, hyperextends Trapezius nuchae, spinous processes of acromion process of scapula head C7 and all thoracic vertebrae Levator scapulae 36 1st to 4th cervical vertebrae Superior angle of scapula Extends head backward and flexes laterally, elevates scapula Splenius group 35 Ligamentum nuchae, 7th Occipital bone and mastoid Extension and rotation of head process cervical & 1st three thoracic vertebrae TRUNK AND SHOULDER (Anterior) Muscle # on little torso # on big Origin Insertion Action model torso model 51 21 Clavicle, sternum, costal cartilage Between greater & lesser tubercles Adduction, flexion, and medial Pectoralis major of humerus rotation of humerus 52 24 Ribs 3, 4, & 5 Coracoid process of scapula Depresses shoulder by drawing Pectoralis minor scapula downward 50 Clavicle, acromion process and Deltoid tuberosity of humerus Whole muscle abducts humerus; In Deltoid (anterior, spine of scapula part, may flex, rotate, extend middle, posterior) humerus Serratus anterior 54 1st to 9th ribs Anterior medial border of scapula Pulls scapula downward, forward, inward External intercostals 26 Inferior borders of ribs Superior borders of ribs Elevates ribs (aids in inspiration) (11 pairs) Internal intercostals 53 27 Superior borders of ribs Inferior borders of ribs Depresses ribs (aids in expiration) (11 pairs) Diaphragm 44 Inferior border of rib and sternum, Central tendon Inspiration, increases vertical costal cartilages of last six ribs and dimensions of thorax, increases lumbar vertebrae intra-abdominal pressure
Muscle Head model #on little torso model #on big torso model Origin Insertion Action Trapezius 34 1 Occipital bone, ligamentum nuchae, spinous processes of C7 and all thoracic vertebrae Clavicle, spine of scapula and acromion process of scapula Adducts scapula, hyperextends head Levator scapulae 36 1st to 4th cervical vertebrae Superior angle of scapula Extends head backward and flexes laterally, elevates scapula Splenius group 35 Ligamentum nuchae, 7th cervical & 1st three thoracic vertebrae Occipital bone and mastoid process Extension and rotation of head TRUNK AND SHOULDER (Anterior) Muscle # on little torso model # on big torso model Origin Insertion Action Pectoralis major 51 21 Clavicle, sternum, costal cartilage Between greater & lesser tubercles of humerus Adduction, flexion, and medial rotation of humerus Pectoralis minor 52 24 Ribs 3, 4, & 5 Coracoid process of scapula Depresses shoulder by drawing scapula downward Deltoid (anterior, middle, posterior) 50 Clavicle, acromion process and spine of scapula Deltoid tuberosity of humerus Whole muscle abducts humerus; In part, may flex, rotate, extend humerus Serratus anterior 54 1st to 9th ribs Anterior medial border of scapula Pulls scapula downward, forward, inward External intercostals (11 pairs) 26 Inferior borders of ribs Superior borders of ribs Elevates ribs (aids in inspiration) Internal intercostals (11 pairs) 53 27 Superior borders of ribs Inferior borders of ribs Depresses ribs (aids in expiration) Diaphragm 44 Inferior border of rib and sternum, costal cartilages of last six ribs and lumbar vertebrae Central tendon Inspiration, increases vertical dimensions of thorax, increases intra-abdominal pressure