Muscle Practical

Masseter origin

zygomatic arch

Masseter insertion

Angle and ramus of mandible

Masseter actions

elevates and protrudes mandible

Splenius origin

Spinous process of cervical and thoracic vertebrae

Splenius insertion

Mastoid process of temporal bone and occipital bone

Splenius actions

Extension/hyperextension of neck, R/L rotation of head at neck, lateral flexion of head at neck

Sternocleidomastoid origin

Sternal end of clavicle and manubrium of sternum

Sternocleidomastoid insertion

Mastoid process of temporal bone

Sternocleidomastoid actions

Laterally flexes head at neck, R/L rotation of head at neck

Pectoralis minor origin

Ribs

Pectoralis minor insertion

Coracoid process of scapula

Pectoralis minor actions

Protracts scapula at shoulder and downward rotation of scapula

Trapezius origins

Occipital bones and spinous processes of thoracic vertebrae

Trapezius insertions

Clavicle, acromion of scapula, spine of scapula

Trapezius actions

Shrug, retract, depress scapula at shoulder and extend/hyperextends head at neck

Rhomboids origins

Spinous processes of thoracic and cervical vertebra

Rhomboids insertion

Medial border of scapula

Rhomboids actions

Retracts scapula at shoulder (adducts, shifts scapula towards midline)

Serratus anterior origin

anterior and superior margin of ribs

Serratus anterior insertion

anterior surface of scapula

Serratus anterior actions

Protracts scapula at shoulder and upward rotation of scapula (raising arms above head)

Deltoid origins

Clavicle and acromion and spine of scapula

Deltoid insertion

Deltoid tuberosity of humerus

Deltoid actions

Abduction of arm at shoulder, flexion of arm at shoulder, extension of arm at shoulder, lateral/medial rotation of arm at shoulder

Supraspinatus origins

Supraspinous fossa of scapula

Supraspinatus insertion

greater tubercle of humerus

Supraspinatus action

Abduction of arm at shoulder