1. Muscles Martini Chapter 11
Lab Activity 11: Group I
Muscles
Martini Chapter 11
Portland Community College
BI 231

2. Origin and Insertion
Origin: The place where the fixed end attaches to a bone, cartilage, or connective tissue.
Insertion: The site where the movable end attaches to another structure.

3. MUSCLES OF THE HEAD

4. Frontalis Origin: Epicranial aponeurosis Insertion: Skin over forehead
Action: Elevates eyebrows and wrinkles skin of forehead

5. Occipitalis Origin: Occipital and temporal bones
Insertion: Epicranial aponeurosis
Action: Fixes epicranial aponeurosis and pulls scalp posteriorly

6. Orbicularis Oculi Origin: Medial orbital margin and zygomatic bone
Insertion: Skin surrounding eye
Action: Closes eyelids and depresses skin of forehead

7. Temporalis Origin: Temporal fossa
Insertion: Coronoid process of mandible
Action: Elevates and retracts mandible

8. Masseter Origin: Zygomatic process and arch
Insertion: Angle and ramus of mandible
Action: Elevates mandible

9. Orbicularis Oris Origin: By muscular skips to surround muscles
Insertion: Muscles interlace to surround mouth
Action: Closes and purses lips

10. Zygomaticus Major Origin: Zygomatic arch Insertion: Corner of mouth
Action: Elevates corner of mouth

11. Sternohyoid
Origin: Posterior surface of manubrium, and medial clavicle
Insertion: Hyoid bone
Action: Depresses hyoid bone

12. Sternocleidomastoid Origin: Manubrium and medial third of clavicle
Insertion: Mastoid process
Action: Rotates head to opposite side, extends head, and flexes vertebral column

13. Trapezius
Origin: External occipital protuberance, superior nuchal line and spinous process of C7-T12
Insertion: Anterior border of scapular spine, acromion process, lateral third of clavicle
Action: Elevates, adducts, and depresses scapula

14. Latissimus Dorsi
Origin: Spinous processes of lower 6 thoracic vertebrae, thoracolumbar fascia, crest of ilium
Insertion: Intertubercular groove of humerus
Action: Extends, rotates humerus medially, draws shoulder down and backward

15. Levator Scapula Origin: Transverse processes of C1-4
Insertion: Superior angle spine of scapula
Action: Elevates scapula

16. Rhomboid Major
Origin: Spinous process of T1-5 and supraspinous ligament
Insertion: Medial border below spine of scapula
Action: Adducts scapula and performs downward rotation

17. Rhomboid Minor Origin: Spinous process of C7-T1
Insertion: Medial border of scapula at base of spine
Action: Adducts scapula and performs downward rotation

18. Serratus Anterior Origin: Lateral surface of upper 8 ribs
Insertion: Anterior lip of medial border of scapula
Action: Holds scapula to chest wall, medially rotates scapula in abducting or extending humerus

19. Erector Spinae
Origin: Sacrum, iliac crest, spinous processes of lumbar vertebrae and T11,12
Insertion: Angles of the ribs. Spinous & Transverse processes of vertebrae
Action: Extension of vertebral column

20. Scalenes Anterior Origin: Transverse processes of C3-C6
Insertion: 1st rib
Action: Elevates 1st rib, flexes neck forward and laterally, rotates neck

21. Scalenes Middle Origin: Transverse processes of C2-C7
Insertion: 1st rib
Action: Elevates 1st rib, flexes neck forward and laterally, rotates neck

22. Scalenes Posterior Origin: Transverse processes of C4-C6
Insertion: 2nd rib
Action: Elevates 2nd rib, flexes neck laterally, slightly rotates neck

23. External Intercostal Origin: Inferior border of rib above
Insertion: Superior border of rib below
Action: Elevates rib cage during inspiration

24. Internal Intercostal Origin: Superior border of rib below
Insertion: Inferior border of rib above
Action: Depresses rib cage during expiration

25. Pectoralis Major
Origin: Medial half of clavicle, sternum, costal cartilages, aponeurosis of external abdominal oblique
Insertion: Intertubular groove of humerus
Action: Flexes, adducts, and medially rotates humerus, draws body upward in climbing

26. Pectoralis Minor Origin: Anterior surface of ribs 3 to 5
Insertion: Coracoid process of scapula
Action: Draws scapula down and forward and elevates ribs

27. Rectus Abdominus Origin: Pubis symphysis and crest of pubis
Insertion: Xiphoid process and cartilages of ribs 5 to 7
Action: Tenses abdominal wall and flexes vertebral column

28. External Abdominal Oblique
Origin: External surface of lower 8 ribs
Insertion: Anterior half of iliac crest and linea alba
Action: Compresses abdomen, contralaterally rotates and flexes vertebral column

29. Internal Abdominal Oblique
Origin: Lateral half of inguinal ligament, anterior iliac crest and thoracolumbar fascia
Insertion: Lower four ribs, linea alba and by conjoined tendon to pubis
Action: Compresses abdomen, ipsilaterally rotates and flexes vertebral column

30. Transverse Abdominis
Origin: Lateral third of inguinal ligament, anterior iliac crest, and thoracolumbar fascia
Insertion: Linea alba, and by conjoined tendon to pubis
Action: Compresses abdomen

31. The End
The End