Muscle System 1

Includes all skeletal muscle tissue that can be controlled voluntarily Muscular system 2

Classification of Skeletal Muscles 3

Muscles can be classified by action  Agonist (prime mover) Primary responsible for the movement  Antagonist Opposes the agonists  Synergist Aids the action of agonists Fixator Types of Muscles 4

Muscles can be identified by origin, insertion and action  Origin = stationary end  Insertion = movable end Origins and Insertions 5

Names give clues to muscle characteristics  Location of muscle’s origin and insertion Sternohyoid  Direction of fibers Tranverse, oblique, rectus  Number of origins Biceps, triceps Names of skeletal muscles 6

 Size of the muscle Maximus, minimus  Shape Deltoid, trapezius  Action Adductor, flexor  Location of the muscle Frontalis, orbicularis 7

Organization of skeletal muscle fibers Parallel muscle Convergent muscle Pennate muscle  Unipennate  Bipennate  Multipennate Circular muscle (sphincter) 8

Organization of skeletal muscle fibers 9

Muscles of the Head and Neck 10

Head 11

Muscles of the head and neck  Epicranius muscles Occipital O: occipital bone I: galea aponeurotic A: pulls the scalp posteriorly Frontal O: galea aponeurotic I: skin of the eyebrow A: raise the eyebrow 12

Muscles of the head and neck Orbicularis oculi  O: frontal and maxillary bones  I: eyelid  A: closes eyes Corrugator supercilli  O: frontal bone  I: skin of eyebrow  A: draws eyebrow inferiorly and medially 13

Muscles of the head and neck Levator labii superioris  O: zigomatic and maxilla bones  I: upper lip  A: raises upper lips Depressor labii inferioris  O: mandible  I: lower lip  A: pulls lower lip inferiorly 14

Muscles of the head and neck Depressor anguli oris  O: mandible  I: angle of mouth  A: pulls corner of mouth down and laterally Mentalis  O: mandible  I: skin of chin  A: protudes lower lip 15

Muscles of the head and neck Zigomatics  O: zigomatic bone  I: corner the mouth  A: smiling muscle Risorius  O: masseter  I: angle of the mouth  A: pulls corner of lips laterally 16

 Orbicularis oris O: maxilla and mandible I: lips A: compresses lips  Buccinator O: maxilla and mandible I: orbicularis oris A: compresses the cheek (whistling) Muscles of the head and neck 17

Muscles of Mastication 18

Masseter muscles  O: zigomatic and maxilla bones  I: mandible  A: closes the jaw Temporalis muscles  O: temporal fossa  I: mandible  A: closes the jaw Muscles of mastication 19

Muscles of mastication Pterygoids  O: sphenoid, palatine and maxillary bones  I: mandible  A: elevates mandible, grinding the teeth Buccinator 20

Muscles of the head and neck  Platysma O: fascia of chest and deltoid I: mandible, skin, corner of the mouth A: depresses mandible, pulls lip back and down  Sternocleidomastoid O: manubrium and clavicle I: temporal and occipital bones A: flexion forward of the neck 21

Neck 22

Neck 23

Muscles of the head and neck Scalenes – anterior, middle, posterior  O: cervical vertebrae  I: first 2 ribs  A: elevates first 2 ribs Digastric  O: mandible and mastoid process  I: hyoid  A: elevates hyoid bone 24

Muscles of the head and neck Mylohyoid  O: mandible  I: hyoid bone  A: elevates hyoid bone Sternohyoid  O: manubrium and clavicle  I: hyoid bone  A: depresses hyoid bone 25

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Inferior and superior rectus muscles Lateral and medial rectus muscles Inferior oblique muscles  Elevates the eye and turns it laterally Superior oblique muscles  Depresses the eye and turns it laterally Extrinsic eye muscles 27

Chapter 25 Muscles of the Trunk 28

Muscles of the trunk and shoulder  Serratus anterior muscles O:ribs I: scapula (anterior surface) A: fixates, protracts the scapula  Pectoralis minor muscles O: ribs I: scapula A: ribs fixed: moves scapula forward and inferiorly and with scapula fixed it moves up the rib cage 29

Muscles of the trunk and shoulder Deltoid muscles  O: clavicle and scapula  I: humerus  A: abduction of the shoulder Pectoralis Major  O: clavicle, sternum, ribs  I: humerus  A: agonist for shoulder flexion 30

Muscles of the thorax (front) 31

Muscles of Respiration External intercostal  O: rib above  I: rib below  A: elevates rib cage Internal intercostal  O: rib below  I: rib above  A: depresses rib cage 32

Muscles of Respiration 33

Muscles of Respiration Diaphragm  O: ribs and its cartilage, sternum, vertebrae  I: central tendon of the diaphragm  A: prime action in inspiration 34

Diaphragm 35

Muscles of the Trunk (back) 36

Muscles of the trunk (back) and shoulder Supraspinatus muscles  O: scapula  I: humerus  A: synergist for arm abduction Infraspinatus muscles  O: scapula  I: humerus  A: helps to hold the head of the humerus in the glenoid cavity, lateral rotation of humerus 37

Muscles of the trunk (back) and shoulder Teres major  O: scapula  I: humerus  A: adducts humerus, medial rotation of humerus Teres minor muscles  O: scapula  I: humerus  A: helps to hold the head of the humerus in glenoid cavity, lateral rotation of the humerus 38

Trapezius muscles  O: occipital bone, vertebrae  I: scapula, clavicle  A: extend head, elevate scapula Rhomboids  O: vertebrae  I: scapula  A: adduct and stabilize scapula Muscles of the trunk (back) and shoulder 39

Muscles of the trunk (back) and shoulder Levator scapulae  O: vertebrae  I: scapula  A: elevates scapula Latissimus dorsi muscles  O: vertebrae, ribs, ilium  I: humerus  A: agonist for shoulder extension 40

Muscles of Abdominal Wall 41

Rectus abdominis  O: pubis  I: xiphoid process, ribs  A: flexes vertebral column,increase abdominal pressure External oblique,  O: ribs  I: linea alba, pubis, ilium  A: see above, helps trunk rotation and lateral flexion Muscles of Abdominal Wall 42

Muscles of Abdominal Wall Internal oblique  O: lumbar fascia, ilium, inguinal ligament  I: linea alba, pubis, ribs  A: same as external oblique Transversus abdominis  O: ribs, inguinal ligament, ilium, lumbar fascia  I: linea alba, pubis  A: compresses abdominal content 43

Posterior muscles of the back 44

Chapter 25 Muscles of the Arm 45

Biceps brachii muscle  O: scapula, shoulder joint  I: radius  A: agonist for flexion of the elbow Muscles of the arm 46

Muscles of the arm 47

Muscles of the arm Brachialis  O: humerus  I: ulna  A: flex the elbow Brachioradialis  O: humerus  I: radius  A: synergist for flexion of the elbow 48

Muscles of the arm 49

Muscles of the arm Triceps brachii muscle  O: scapula, humerus  I: ulna  A: agonist for extension of the elbow 50

Muscles of the arm 51

Muscles of the arm 52

Rotator Cuff Muscles Supraspinatus, infraspinatus, teres minor, and subscapularis  Function mainly to reinforce the capsule of the shoulder 53

54 Rotator Cuff Muscles

Flexion of the wrist (O: humerus)  Flexor carpi ulnaris I: metacarpus and carpus  Flexor carpi radialis I: metacarpus  Palmaris longus I: palm of the hand A: also extends the palm of the hand Muscles of the forearm 55

Muscles of the arm and forearm 56

Muscles that affect the wrist Extension of the wrist (O: humerus)  Extensor carpi radialis I: metacarpus  Extensor carpi ulnaris I: metacarpus Pronation of the forearm (I: radius)  Pronator teres muscle O: humerus 57

Muscles of the forearm 58

Muscles of the forearm 59

Muscles of the forearm Extensors of the digitus  Extensor digitorum O: humerus I: phalanges 60

Chapter 25 Muscles of the Leg 61

Gluteus maximus  O: ilium, sacrum, coccyx  I: femur  A: extension of thigh (climbing stairs) Gluteus medius and minimus  O:ilium  I: femur  A: abducts thigh, steadies pelvis Muscles of the pelvis and lower limbs 62

Muscles of the leg Tensor fascia latae  O: ilium  I: fascia latae  A: flexes, abducts the thigh; tenses the fascia latae 63

Muscles of the leg 64

Formed from the merging of the psoas major and the iliacus muscles O: ilium, vertebrae I: femur Flexes trunk on thigh, flexes thigh Iliopsoas muscle 65

Muscles of the Leg 66

Sartorios  O: ilium  I: tibia  A: flexes the thigh and helps in crossing the leg Adductors of the leg  O: pubis  I: femur Muscles of the leg 67

Muscles of the pelvis and lower limbs Gracilis  O: pubis  I: tibia  A: adducts, flexes and medially rotates the thigh 68

Muscles of the leg Quadriceps (I: tibia; A: extends the knee)  Rectus femoris O: ilium  Vastus medialis, intermedius, lateralis O: femur 69

Leg 70

Leg 71

Muscles of the leg The hamstrings (O: ischium; I: tibia; A: extend thigh, flexes knee)  Biceps femoris muscles  Semimembranosus muscles  Semitendinosis muscles 72

Plantar flexion (I: calcaneal tendon)  Gastrocnemius muscle O: femur  Soleus muscle O: fibula and tibia Eversion and plantar flexion  Fibularis muscle O: fibula I: metatarsal bones (lateral side) Muscles of the lower leg 73

Muscles of the lower leg 74

Popliteus  O: femur  I: tibia  A: unlocks the knee joint Muscles of the lower leg 75

Muscles of the leg 76

Muscles of the lower leg Tibialis anterior  O: tibia  I: metatarsus and cuneiforme  A: dorsiflexion of the foot Tibialis posterior  O: tibia  I: tarsal and metatarsal bones  A: foot inversion 77

Muscles of the lower leg Extensor digitorum  O: Tibia and fibula  I: Digitus  A: Extends the digits 78

Chapter 25 Cat Dissection 79

Skinning the Cat Leave the skin of the back attached. Do not skin paws, tail, genital area, or head. Remove fat if possible. When you are done, use the skin to wrap the cat in. Use the pencil and tape to label the bag. 80

Skinning the Cat Cut the bag from the top to allow you to store the cat in it. Keep as much embalming fluid as possible in the cat for it’s preservation. Use several rubber bands; if one breaks, the bag will remain closed. Clean and dry tray, tools and lab bench before leaving. 81

Cat Dissection – Neck Muscles Mylohyoid Digastric Sternohyoid Sternothyroid Thyrohyoid 82

Cat Dissection – Thoracic Muscles Anterior muscles  Pectoralis Major and Minor  Serratus anterior  Intercostals Internal External 83

Cat Dissection – Thoracic Muscles Posterior muscles  Trapezius  Latissimus dorsi  Rhomboids  Supraspinatus  Infraspinatus 84

Cat Dissection – Abdominal Muscles External oblique Internal oblique Rectus abdominis Transversus abdominis 85

Cat Dissection – Arm Muscles Brachial muscles  Biceps brachii  Triceps brachii Long head Lateral head 86

Cat Dissection – Arm Muscles Antebrachial muscles  Pronator teres  Flexor carpi ulnaris  Palmaris longus  Flexor carpi radialis  Extensor carpi ulnaris  Extensor digitorum  Extensor carpi radialis 87

Cat Dissection – Leg Muscles Upper leg  Sartorius  Gracilis  Rectus femoris  Vastus lateralis  Vastus medialis  Adductors 88

Cat Dissection – Leg Muscles  Semimembranosus  Semitendinosus  Biceps femoris Lower leg  Gastrocnemius  Soleus  Tibialis anterior  Extensor digitorum  Fibularis 89