Skeletal Muscles Flashcards
Splenius Capitis
Origin: Fascia & spinous process c7-t4
Insertion: mastoid process of temporal bone
Action: Bilaterally: extend head & neck unilaterally: rotate head & neck from same side & laterally flex head & neck
Splenius Cervicis
Origin: Spinous processes of t3-t6
Insertion: Posterior tubercles of transverse processes c1-c3
Action: Bilaterally extend head & neck unilaterally: rotate head & neck from same side & laterally flex head & neck
Sternocleidomastoid SCM
Origin: Sternal head manubrium of sternum Clavicular head: medial clavicle
Insertion: Mastoid process of temporal bone
Action: Bilaterally: flexion of neck Unilaterally: rotation of the head & neck to the opposite side of the body lateral flexion of head/neck
Trapezius
Origin: Occiput to c7-t12
Insertion: Upper: acromion process of scapula Middle: spine of scapula lateral 1/3 of clavicle. Lower: root of spine of scapula
Action: Upper: elevation of scapula Middle: retraction of scapula Lower: depression of scapula
Levator Scapula
Origin: C1-c4 transverse process
Insertion: Superior angle of scapula
Action: Elevation of the scapula
Supraspinatus
Origin: Supraspinous fossa of scapula
Insertion: Greater tubercle of humerus more lateral than lesser tubercle
Action: Initiates 1st 15 degrees of abduction of humerus stabilizes Glenohumeral Joint
Infraspinatus
Origin: Infraspinous fossa of scapula
Insertion: Greater tubercle of humerus
Action: Lateral rotation extension of humerus
Teres Minor
Origin: upper auxillary border of scapula
Insertion: Greater tubercle of humerus
Action: lateral rotation extension of humerus
Subscapularis
Origin: Subscapular fossa of scapula
Insertion: Lesser tubercle of humerus
Action: Medial rotation of humerus
Teres Major “The Lats little helper”
Origin: Inferior angle of scapula
Insertion: Greater tubercle of humerus
Action: Bicipital groove of humerus Action:
Rhomboids
Origin: Minor: c7-t1 Major: t2-t5
Insertion: Vertebral border of scapula
Action: Retraction & elevation of scapula
