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 facial Expression

frontalis Epicranial Aponeurosis • Frontal belly • Action: Elevates eyebrows and wrinkles skin of forehead • Origin: Epicranial aponeurosis • Insertion: skin of eyebrow and bridge of nose 4

Occipitalis • Occipital belly • Action: Pulls scalp posteriorly; wrinkles skin on posterior surface of neck • Origin: Superior nuchal line on occipital bone • Insertion: Epicranial aponeurosis (Galea aponeurotica) 5

Nasalis • Action: Compresses nostrils, dilates nostrils • Origin: Maxillary bone and cartilage of nose • Insertion: Bridge of nose 6

Orbicularis Oculi • Action: Closes eyelids; acts during squinting and blinking • Origin: Medial aspect of bony orbit • Insertion: skin around eyelids 7

Orbicularis Oris • Action: Closes and purses lips as in speaking, kissing and whistling • Origin: Maxillary bone; mandible • Insertion: lips 8

Zygomaticus Major • Action: Elevates corner of mouth • Origin: Zygomatic bone • Insertion: Angle of mouth 9

Zygomaticus minor • Action: Raises upper lip. • Origin: Zygomatic bone • Insertion: Upper lip 10

Mentalis • Action: Protrudes lower lip; wrinkles skin on chin • Origin: Anterior surface of mandible • Insertion: skin of chin 11

Risorius • Action: Draws corner of mouth laterally • Origin: fascia of masseter • Insertion: corner of mouth 12

Muscles of Mastication

Masseter • Action: Elevates mandible to close jaw; protrudes mandible • Origin: Zygomatic arch • Insertion: lateral surface of the mandibular ramus 14

Temporalis • Action: Elevates and retracts mandible to close jaw • Origin: Temporal bone • Insertion: coronoid process of mandible 15

SUPERFICIAL MUSCULATURE OF THE NECK

Sternocleidomastoid • Action: Flexion and lateral flexion of neck; rotates head so that face is turned superiorly and to the opposite side. • Origin: Manubrium; medial third of clavicle • Insertion: Mastoid process 17

Omohyoid • Action: Depresses and retracts hyoid bone • Superior belly • Origin: Clavicle and first rib • Insertion: hyoid bone • Inferior belly • Origin: superior margin of scapula • Insertion: clavicle and 18

Thyrohyoid • Action: Depresses hyoid bone; elevates larynx • Origin: thyroid cartilage of larynx • Insertion: hyoid bone 19

Sternohyoid • Action: Depresses larynx and hyoid bone during swallowing. • Origin: Manubrium • Insertion: Hyoid bone 20

Stylohyoid • Action: Elevates and retracts hyoid bone during swallowing and speaking • Origin: Styloid process of temporal bone • Insertion: hyoid bone 21

Mylohyoid • Action: Elevates hyoid bone and floor of mouth during swallowing and speaking • Origin: Inferior margin of mandible • Insertion: Hyoid bone 22

Digastric Anterior Belly • Action: Elevates hyoid bone and base of tongue, depresses mandible • Origin: inferior margin of mandible • Insertion: Hyoid bone 23

Digastric Posterior Belly • Action: Moves hyoid bone back • Origin: mastoid process • Insertion: Hyoid bone 24

MUSCLES OF THE NECK & BACK

Scalenes Anterior • Action: Laterally flexes of neck • Elevates rib 1 during forced inspiration • Origin: transverse processes of cervical vertebrae. • Insertion: 1 st rib 26

Scalenes Middle • Action: Lateral flexion of neck • Elevates rib 1 during forced inspiration • Origin: transverse processes of cervical vertebrae. • Insertion: 1 st rib 27

Scalenes Posterior • Action: Elevates 2 nd rib, • Elevates rib 2 during forced inspiration • Origin: transverse processes of cervical vertebrae. • Insertion: 2 nd rib 28

Levator Scapula • Action: Elevates scapula and inferior rotation of scapula • Origin: Transverse processes of superior four cervical vertebrae • Insertion: medial border of scapula near superior angle 29

Rhomboid Minor • Action: Adducts scapula and performs downward rotation • Origin: Ligamentum nuchae; spinous processes of vertebrae C 7 and T 1 • Insertion: Medial border of scapula 30

Rhomboid Major • Action: Adducts scapula and performs downward rotation • Origin: Spinous processes of vertebrae T 2 -T 5. • Insertion: Medial border of scapula 31

Trapezius • Action: Elevate, retracts and depresses scapula. • Origin: Posterior surface of occipital bone; ligamentu nuchae; spinous processes of thoracic vertebrae. • Insertion: Lateral third of clavicle; acromion; spine of scapula 32

Latissimus Dorsi • Action: Extension, adduction and medial rotation of arm • Origin: Spinous processes of vertebrae T 6 -T 12; thoracolubar fascia; iliac crest; inferior three ribs • Insertion: Intertubercular groove of humerus 33

Erector Spinae • Action: Extension of vertebral column • Iliocostalis • Spinalis • Longissimus • Origin: Thoracolumbar fascia; posterior surface of lacrum; iliac crest; spinous processes of T 11 -T 12 and L 1 -L 5. 34

Erector spinae • Insertion: • Iliocostalis: angles of ribs and transvers processes of C 4 -C 6 • Longissimus: transverse processes of thoracic and cervical vertebrae, etc. • Spinalis: spinous processes of thoracic and cervical vertebrae 35

Inferior Serratus Posterior • Aka: serratus posterior inferior • Action: Pulls ribs down, resisting pull of the diaphragm • Origin: spinous processes of the lower two thoracic and upper two or three lumbar vertebrae • Insertion: lower borders of the bottom four ribs 36

Splenius • Action: Extension of head and neck; lateral flexion and rotation of the head and neck • Origin: Spinous processes of inferior cervical and superior thoracic vertebrae • Insertion: mastoid process, occipital bone, and transverse processes of superior cervical vertebrae 37

Internal Intercostal • Action: Depresses rib cage during forced expiration • Origin: Superior border of inferior rib • Insertion: Inferior border of superior rib 38

External Intercostal • Action: Elevates rib cage during inspiration • Origin: Inferior border of superior rib • Insertion: Superior border of inferior rib 39

Serratus Anterior • Action: Holds scapula to chest wall, • Protraction and superior rotation of scapula • Origin: External surfaces of ribs 1 -8 • Insertion: Medial border of scapula 40

Pectoralis Minor • Action: Draws scapula down and forward and elevates ribs • Origin: External surfaces of ribs 3 -5 • Insertion: Coracoid process of scapula 41

Pectoralis Major • Action: Flexes, adducts, and medially rotates humerus, draws body upward in climbing • Origin: Medial half of clavicle; sternum; costal cartilages of ribs 1 -6 • Insertion: lateral lip of intertubercular groove on humerus 42

Subscapularis • Action: Adduction and medial rotation of arm. • Origin: Subscapular fossa of scapula • Insertion: lesser tubercle of humerus 43

Supraspinatus • Action: Abduction of arm • Origin: supraspinous fossa of scapula • Insertion: Greater tubercle of humerus 44

Infraspinatus • Action: Lateral rotation of arm • Origin: Infraspinous fossa of scapula • Insertion: Greater tubercle of humerus 45

Teres minor • Action: Lateral rotation of the arm • Origin: Lateral border of scapula • Insertion: Greater tubercle of humerus 46

Teres major • Action: Extension, adduction and medial rotation of arm • Origin: Scapula, near inferior angle • Insertion: medial lip of intertubercular groove of the humerus 47

Deltoid • Action: • Anterior fibers: medial rotation and flexion of arm • Middle fibers: abduction of arm • Posterior fibers: lateral rotation and extension of arm 48

Deltoid • Origin: Lateral third of clavicle; acromion process; spine of scapula • Insertion: Deltoid tuberosity of humerus 49

Diaphragm • Action: Increases volume of thoracic cavity by pulling central tendon inferiorly • Origin: Xiphoid process and inferior six ribs • Insertion: central tendon of diaphragm 50

MUSCLES OF THE ANTERIOR ABDOMINAL WALL

Rectus Abdominis • Action: Tenses abdominal wall and flexes vertebral column • Origin: Pubic crest; pubic symphysis • Insertion: Xiphoid process, costal cartilages of ribs 5 -7 52

External Abdominal Oblique • Action: Compresses abdomen, contralaterally rotates and flexes vertebral column • Origin: External surfaces of inferior 8 ribs. • Insertion: Linea alba; pubic crest; pubic tubercle; iliac crest 53

Internal Abdominal Oblique • Action: Compresses abdomen, ipsilaterally rotates and flexes vertebral column • Origin: Thoracolumbar fascia; iliac crest; inguinal ligament • Insertion: Linea alba; pubic crest; inferior three or four ribs 54

Transverse Abdominis • Action: Compresses abdomen • Origin: Thoracolumbar fascia; inguinal ligament; costal cartilages of inferior six ribs; iliac crest • Insertion: linea alba; pubic crest 55

Biceps brachii • Action: Flexion and supination of forearm; flexion of arm • Origin: Long head: superior margin of glenoid fossa of scapula • Short head: coracoid process of scapula • Insertion: radial tuberosity of radius 56

Brachialis • Action: Flexion of forearm • Origin: Anterior surface of humerus • Insertion: Coronoid process of ulna 57

Coracobrachialis • Action: Flexion and adduction of arm • Origin: Coracoid process of scapula • Insertion: Medial surface of humerus 58

Triceps brachii • Action: Extension of forearm; long head extends and adducts arm • Origin: Long head: inferior margin of glenoid fossa • Lateral head: posterior surface of humerus • Medial head: posterior surface inferior to lateral head • Insertion: Olecranon process of ulna Long Head Lateral Head 59

The End 60