Origins and Insertions
Trapezius O/I?
Origin- occipital protuberance down the ligamentum nuchae, spinous process of C7 through T12
Insertion: Lateral aspect of the clavicle, the acromion process, and along the scapular spine (attachment is just proximal to origin of deltoid muscle along the entire length
Trapezius Action and Innervation
Action: Upper trap- retraction* (scapular elevation), adduction, upward rotation ( neck extension in reverse)
Middle Trap- Scapular adduction*
Lower Trap- scapular depression*, adduction, and upward rotation
Innervation: Cranial Nerve XI (Spinal Accessory) and C3 & C4
What muscle action is to do Scapular Elevation?
Upper Trapezius, Rhomboids, Levator Scapulae
What muscles action is to do abduction/Protraction?
Pectoralis Minor, Serratus Anterior
Rhomboids (major&minor) O/I?
Origin: Spinous Process of C7 through T5
Insertion: Vertebral border of scapula from the spine to the inferior angle
Rhomboids Minor&Major
Action: Scapular elevation*, adduction, and downward rotation
Innervation: Dorsal scapular nerve C4 & C5
What Muscle action does depression?
Lower Trapezius, Pectoralis Minor
What mucles action is Forward Tilt?
Pectoralis Minor
Levator Scapulae O/I?
Origin: Transverse process of C1-C4
Insertion: Vertebral border of the scapula superior to the scapular spine
Levator Scapulae
Action: Scapular elevation*, Adduction, and downward rotation
Innervation: Dorsal Scapular nerve C4 & C5
What Muscle does upward rotation?
Upper Trapezius, Lower Trapezius, Serratus Anterior
Pectoralis Minor O/I?
Origin: Anterior Surface of ribs 3,4, and 5
Insertion: Coracoid process of scapula
Action: Forward tilt*, depression, abduction, and downward rotation. It helps to raise ribs in forced inhalation.
Innervation: Medical Pectoral Nerve C8 & T1
What muscles action is to do downward rotation?
Rhomboids, Levator Scapulae, Pectoralis Minor
Serratus Anterior O/I?
Origin: Anterolateral aspect of upper 9 ribs
Insertion: Anterior aspect of the vertebral border of the scapula (underside) with a concentration of fiber at the inferior angle end of the vertebral border
Serratus Anterior
Action: Scapular Protraction (abduction)*, upward rotation. The inferior fibers also depress the scapula and prevent winging. Hold the vertebral border to the thorax.
Innervation: Long Thoracic Nerve C5 & C6 & C7
What Muscle action does Adduction/Retraction?
Entire Muscle of trapezius, Rhomboids, Levator Scapulae