Skeletal Muscle Origins, Insertions, and Actions

• Skeletal muscle origins, insertions and actions

LATISSIMUS DORSI

• Originates at the Inferior angle of Scapula, Spinous Process T6-T12, Thoracolumbar Aponeurosis, Iliac Crest of Ilium, Lower 3 Ribs (9-12)
• Inserts at the Bicipital Groove of Humerus
• Actions include Extend, Adduct, Internally Rotate, Horizontal Abduction of Shoulder

ANTERIOR DELT

• Originates at the Anterior Lateral 1/3 of the Clavicle
• Inserts at the Deltoid Tuberosity of Humerus
• Actions include Abduction, Flexion, Internal Rotation and Horizontal Adduction of the Shoulder

MIDDLE DELT

• Originates at the Acromion Process of Scapula and Spine of Scapula
• Inserts at the Deltoid Tuberosity of Humerus
• Actions include Abduction of the Shoulder

TERES MAJOR

• Originates at the Inferior angle of Scapula and Lower 1/3 of the lateral boarder of Scapula
• Inserts on the Lesser Tubercle of Humerus
• Actions include Extension, Adduction, and Internal Rotation of the Shoulder

POSTERIOR DELT

• Originates at the Spine of Scapula
• Inserts at the Deltoid Tuberosity of Humerus
• Actions include Abduction, Extension, Externally rotate and Horizontally Abduct the Shoulder

TRAPEZIUS

• Originates at the External Occipital Protuberance of Occipital Bone, C7-T12
• Inserts at the Lateral 1/3 of Clavicle, Acromion of Scapula, Spine of Scapula
• Actions include Upper-Extend/Laterally Flex Head, Rotate Head, Elevate/Upward Rotate Scapula, Middle-Scapular Adduction, Lower-Depression, and Downward Rotation of Scapula

SUPRASPINATUS

• Originates at the Supraspinatus Fossa of Scapula
• Inserts at the Greater Tubercle of Humerus
• Actions include Abduction of the Shoulder and Stabilizes head of humerus

RHOMBOID MAJOR

• Originates at the Spinous Processes of T2 to T5
• Inserts at the Medial border of scapula (between spine and inferior border)
• Actions include Adduction, Elevates Scapula and Downward rotation of Scapula

LEVATOR SCAPULAE

• Originates at the Transverse processes C1 to C4
• Inserts at the Medial border of scapula (superior angle)
• Actions include Elevates Scapula, Downwardly rotates scapula, Laterally flexes/rotates neck/extends neck

SERRATUS ANTERIOR

• Originates at the Upper 8-9 ribs
• Inserts at the Medial border of scapula (anterior surface)
• Actions include Abduct Scapula, Upward rotation of scapula, Depress scapula and Holds medial border of scapula to rib cage

BICEPS BRACHII

• Originates at the Coracoid Process (Short Head), Supraglenoid tubercle (long head)
• Inserts at the Radial Tuberosity
• Actions include Flexes the elbow, Supinates Forearm and Flexes the shoulder

INFRASPINATUS

• Originates at the Infraspinatus Fossa of Scapula
• Inserts at the Greater Tubercle of Humerus
• Actions include External Rotation, Horizontal Abduction, Extension and Stabilizes head of humerus

TERES MINOR

• Originates at the Lateral Border of Scapula
• Inserts at the Greater Tubercle of Humerus
• Actions include Extend, Adduct, Internally Rotate Shoulder

SUBSCAPULARIS

• Originates at the Subscapular Fossa of Scapula
• Inserts at the Lesser Tubercle of Humerus
• Actions include Internal Rotation, Stabilize head of humerus

CORACOBRACHIALIS

• Originates at the Coracoid process
• Inserts at the Medial surface, mid shaft of Humerus
• Actions include Flex the Shoulder and Adduct Shoulder

RHOMBOID MINOR

• Originates at the Spinous Processes of C7 to T1
• Inserts at the Medial border of scapula (across from spine)
• Actions include Adduct Scapula, Elevate Scapula and Downward rotation of Scapula

PECTORALIS MAJOR

• Originates at the Clavicle (medial ½), sternum, and cartilage of ribs 1-6
• Inserts at the Greater tubercle (humerus)
• Actions include Adduct shoulder, Internal rotation, Elevate thorax during inhalation, Flex shoulder (upper fibers), Horizontally adduct (upper fibers), Extend shoulder (lower fibers)

PECTORALIS MINOR

• Originates at the Ribs 3-5
• Inserts at the Coracoid Process (medial surface)
• Actions include Depress Scapula, Abduct Scapula, Downward Rotation of Scapula

SUBCLAVIUS

• Originates at the 1st rib
• Inserts at the Clavicle (inferior surface, middle 1/3)
• Actions include Depress Clavicle, Elevate 1st rib and Stabilize SC Joint

TRICEPS BRACHII

• Originates at the Infraglenoid Tubercle (Long Head), Posterior, proximal ½ of Humerus (lateral head) and Posterior, distal ½ of Humerus(medial head)
• Inserts at the Olecranon Process
• Actions include Extend elbow