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

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.

MUSCLES OF THE HEAD

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

The End The End