Name | Origin | Insertion | Action | Innervation |
Diaphragm | Xiphoid process. Ribs 6-12. L1-L3 | Central Tendon | Inspiration (increases length of thorax) | Phrenic nerve |
External intercostals | Inferior border of rib above | Superior border of rib below | Elevates ribs with inspiration | T2 - T12 |
Internal intercostals | Superior border of rib below | Inferior border of rib above | Draws ribs together with forced expiration | T2 - T12 |
Levator ani: Pubococcygenus | Pubis | Coccyx | Maintain pelvic viscera & expulsion of matter | S2 - S4 |
Levator ani: iliococcygeus | Ischial spine | Coccyx | Maintain pelvic viscera & expulsion of matter | S2 - S4 |
Pectoralis minor | Ribs 2- 5 | Coracoid process of scapula | Abducts scapula (rowing). Elevates ribs | Medial pectoral. |
Serratus anterior | Ribs 1 - 9 | Inferior angle of scapula | Abducts scapula. Elevates ribs | Long thoracic. |
Trapezius | Superior nuchal line of occipital bone. Ligamentum nuchae. Spine of C7 - T12 | Clavicle acromion. Spine of scapula. | Elevates clavicle & Scapula. Depresses & adducts scapula. Extends head. | Accessory XI (11). C3 - C5 |
Levator scapulae | C1 - C5 | Superior vertebral border of scapula | Extends scapula | Dorsal scapular. C3 - C5 |
Rhomboideus minor | C7 - T1 | Superior vertebral border of scapula | Elevates & adducts scapula | Dorsal scapula |
Pectoralis major | Ribs 1 - 6. Clavicle. Sternum. | Greater tibercle & intertubercular sulcus. | ADducts, extends, medially rotates humerus. Draws arm down and back | Thoracodorsal |
Deltoid | Ribs 8 - 12. Clavicle. Acromion. Spine of scapula | Deltoid tuberosity. | Abducts, extends, flexes humerus | Axillary |