Muscles of the Spine

Latissimus Dorsi Origin: Insertion: Action: Spinous process of T6 through T12 and Lumbar vertebrae Insertion: Intertubercular groove of the Humerus Inferior portion of scapula Action: Lateral trunk flexion Anterior rotation of the pelvis

Trapezius

Trapezius Upper 1/3: Origin: Insertion: Action Occipital protuberance Spinous process of C7 Insertion: Distal/lateral 1/3 of Clavicle Acromion Process Action Elevation of Scapula Upward rotation of Scapula Rotation of Scapula to the opposite side

Trapezius Middle 1/3: Origin: Insertion: Action: Spinous processes of the 7th cervical vertebrae, & T1-T5 Insertion: Acromion Process Spine of the scapula (superior-lateral border) Action: Retraction of scapula Fixation of thoracic spine

Trapezius Lower 1/3: Origin: Insertion: Action: Spinous processes & Supraspinal ligaments of T8-T12 Insertion: Spine of Scapula (medial portion) Action: Depression of Scapula Retraction of Scapula Fixation of thoracic spine

Serratus Anterior

Serratus Anterior Origin: Insertion: Action: Anterior surface of the first 8-9 ribs Insertion: Anterior surface of medial border of scapula Action: Abducts (protracts) and upwardly rotates scapula; stabilizes scapula

Iliocostalis Origin: Insertion: Actions: Iliac Crest, Ribs 3-12 Ribs 1-12, Transvers processes of C4-C7 Actions: Laterally Flexes, extends the spine

Longissimus Origin: Insertion: Actions: Common erector spinae tendon, Transverse processes of T1-T5, Articular processes of C5-C6 Insertion: Transverse processes of T3-T12, Ribs 1-12, Transverse processes of C2-C6, Mastoid process of skull Actions: Extension & lateral bending of spine, extension of skull and cervical spine, rotation of the face toward same side

Rhomboids Major: Minor: Actions: Origin: Insertion: Spinous Processes of T2-T5 Insertion: Vertebral border of scapula (lower 2/3) Minor: Spinous Processes of C7-T1 Vertebral border of scapula (upper 1/3) Actions: Retraction, elevation, downward rotation of scapula; Fixation of thoracic spine