Lab Activity 11 Group I Muscles Martini Chapter

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. 2

MUSCLES OF THE HEAD

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

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

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

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

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

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

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

Risorius • • • Origin: Fascia of masseter Insertion: Corner of mouth Action: Draws corner of mouth laterally 11

SUPERFICIAL MUSCULATURE OF THE NECK

Omohyoid • Origin: Medial tip of suprascapular notch • Insertion: Body of hyoid bone • Action: Depresses hyoid bone 13

Sternohyoid • • • Origin: Posterior surface of manubrium, and medial clavicle Insertion: Hyoid bone Action: Depresses hyoid bone 14

Mylohyoid • • • Origin: Mylohyoid line of mandible Insertion: Hyoid bone Action: Elevates hyoid bone and floor of mouth, depresses mandible 15

Digastric Anterior Belly • • • Origin: Lower border of mandible near midline Insertion: Intermediate tendon on the hyoid bone Action: Elevates hyoid bone and base of tongue, depresses mandible 16

Digastric Posterior Belly • • • Origin: Mastoid notch of temporal bone Insertion: Intermediate tendon on the hyoid bone Action: Moves hyoid bone back 17

MUSCLES OF THE NECK & BACK

Sternocleidomastoid • • • Origin: Manubrium and medial third of clavicle Insertion: Mastoid process Action: Rotates head to opposite side, extends head, and flexes vertebral column 19

Trapezius • • • Origin: External occipital protuberance, superior nuchal line and spinous process of C 7 -T 12 Insertion: Anterior border of scapular spine, acromion process, lateral third of clavicle Action: Elevates, adducts, and depresses scapula 20

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 21

Levator Scapula • Origin: Transverse processes of C 1 -4 • Insertion: Superior angle spine of scapula • Action: Elevates scapula 22

Rhomboid Major • • • Origin: Spinous process of T 1 -5 and supraspinous ligament Insertion: Medial border below spine of scapula Action: Adducts scapula and performs downward rotation 23

Rhomboid Minor • • • Origin: Spinous process of C 7 -T 1 Insertion: Medial border of scapula at base of spine Action: Adducts scapula and performs downward rotation 24

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 25

Erector Spinae • • • Origin: Sacrum, iliac crest, spinous processes of lumbar vertebrae and T 11, 12 Insertion: Angles of the ribs. Spinous & Transverse processes of vertebrae Action: Extension of vertebral column 26

MUSCLES OF THE THORACIC WALL

External Intercostal • • • Origin: Inferior border of rib above Insertion: Superior border of rib below Action: Elevates rib cage during inspiration 28

Internal Intercostal • • • Origin: Superior border of rib below Insertion: Inferior border of rib above Action: Depresses rib cage during expiration 29

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 30

Pectoralis Minor • • • Origin: Anterior surface of ribs 3 to 5 Insertion: Coracoid process of scapula Action: Draws scapula down and forward and elevates ribs 31

MUSCLES OF THE ANTERIOR ABDOMINAL WALL

Rectus Abdominus • • • Origin: Pubic symphysis and crest of pubis Insertion: Xiphoid process and cartilages of ribs 5 to 7 Action: Tenses abdominal wall and flexes vertebral column 33

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 34

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 35

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 36

Deltoid • • • Origin: Anterior surface, lateral clavicle, acromion process and spine of scapula Insertion: Deltoid tubercle of humerus Action: Abducts humerus; aids in flexion, extension, and internal and external rotation 37

Supraspinatus • • • Origin: Supraspinous fossa Insertion: Greater tubercle of humerus Action: Abducts humerus 38

Infraspinatus • • • Origin: Infraspinous fossa Insertion: Greater tubercle of humerus Action: Rotates humerus laterally 39

Teres Minor • • • Origin: Axillary border of scapula Insertion: Greater tubercle of humerus Action: Rotates humerus laterally 40

Teres Major • • • Origin: Axillary border at inferior angle of scapula Insertion: Intertubular groove of humerus Action: Extends, adduction and medial rotates humerus. 41

Subscapularis • • • Origin: Subscapular fossa Insertion: Lesser tubercle of humerus Action: Rotates humerus medially 42

Biceps Brachii • • • Origin: Long head, supraglenoid tubercle; Short head, coracoid process scapula Insertion: Radial tuberosity of the radius Action: Flexes radius and humerus, and supinates forearm Short Head Long Head 43

Coracobrachialis • • • Origin: Coracoid process of scapula Insertion: Middle third of humerus Action: Flexes and adducts humerus 44

Triceps Brachii • • • Long Head Lateral Head Origin: Long head, infraglenoid tubercle; Lateral head, proximal portion of posterior humerus; Medial head, distal half of posterior humerus Insertion: Olecranon process of ulna Action: Extends humerus and ulna 45

Brachialis • • • Origin: Anterior distal two-thirds of humerus Insertion: Coronoid process of ulna Action: Flexes ulna 46