Skeletal muscles - intro

Question 1

Muscle shapes

Answer 1

• muscles have many shapes, depending upon the size and actions of a specific muscle
• wide (latus), toothed (serratus), triangular (deltoid)

Question 2

Muscle location

Answer 2

• skeletal muscles are attached to the bones

- each end of a muscle is attached to a different bone (contraction of the muscle causes bones to move their joints)

Question 3

Muscle location

Origin and Insertion

Answer 3

-the specific anchoring ends of a muscle

Question 4

Origin

Answer 4

• the beginning (proximal) attachment of a muscle
• this is the end that is attached to a site or bone that moves very little
• the bone may be fixed or immobile

Question 5

Insertion

Answer 5

• this is the distal end of a muscle

- this end attaches to a bone with the most movement during contraction

Question 6

Biceps brachii

Answer 6

Origin: scapula
Insertion: tuberosity of the radius
Action: flexion (bending) of the forearm

Question 7

Single muscle actions

Answer 7

each muscle causes movement of a body part during contraction

Question 8

Sternocleidomastoid

Answer 8

Origin: manubrium of sternum and medial clavicle
Insertion: mastoid proces and superior nuchal line
Action: one contraction alone: laterally flexes head and neck to same side and rotates head and neck to opposite side both contracting together
Innervation: spinal accessory (CN XI)

Question 9

Pectoralis major

Answer 9

Origin: clavicle, sternum, superior six costal cartilages and abdominal aponeurosis
Insertion: lateral crest of intertubercular groove of the humerus
Action: flexes shoulder; adducts and medially rotates arm; extends shoulder from flexed position
Innervation: medial and lateral pectoral nerves

Question 10

Muscle group actions

Answer 10

-groups with similar actions and groups with opposite actions

Question 11

Groups with similar actions

Answer 11

• for most actions there are usually several muscles involoved
• one muscle has most of the responsibility for the action and is called the PRIME MOVER
• others muscles that aid the action are called SYNERGISTS

Question 12

Bending (flexing) the forearm

Answer 12

Prime mover: biceps brachii

Synergists: brachialis and brachiordialis

Question 13

Groups with opposite actions

Answer 13

• for each body movement there is an opposite action which returns the body to anatomical position
• muscles with opposite actions are called AGONISTS and ANTAGONISTS

Question 14

Agonist muscle

Answer 14

a muscle that accomplishes a certain movement

-ie. biceps brachii

Question 15

Antagonist muscle

Answer 15

• a muscle that works in opposition to another muscle

- ie. tricep

Question 16

Types of actions

Answer 16

know all of the following…

Question 17

Flexion

Answer 17

movement of a body part anterior to the coronal plane

Question 18

Extension

Answer 18

movement of a body part posterior to the coronal plane

Question 19

Abduction

Answer 19

movement away from the midline

Question 20

Adduction

Answer 20

movement toward the midline

Question 21

Rotation

Answer 21

the turning of a structure around its long axis, as in rotating the head or humerus

Question 22

Pronation

Answer 22

rotation of forearm towards facedown

Question 23

Supination

Answer 23

rotation of forearm faceup

Question 24

Circumduction

Answer 24

combination of flexion, extension, abduction, and adduction

Question 25

Elevation

Answer 25

moves structure superiorly

Question 26

Depression

Answer 26

moves structure inferiorly

Question 27

Protraction

Answer 27

gliding motion that moves a structure in an anterior direction

Question 28

Retraction

Answer 28

moves the structure back to the anatomical position

Question 29

Lateral excursion

Answer 29

moving the mandible to either the right or the left of the midline

Question 30

Medial excursion

Answer 30

returns that mandible to that midline position

Question 31

Opposition

Answer 31

movement of the thumb and little finger towards each other

Question 32

Reposition

Answer 32

returns the thumb and little finger to the neutral position

Question 33

Inversion

Answer 33

turns the ankle so that the plantar surface of the foot faces medially

Question 34

Eversion

Answer 34

turns the ankle so that the plantar surface faces laterally

Question 35

Head | Frontalis (1)-epicranius

Answer 35

raises scalp and eyebrows

Question 36

Head | Occipitalis (1)-epicranius

Answer 36

draws scalp backwards

Question 37

Head | Orbicularis oculi-(2)

Answer 37

closes eyelid

Question 38

``` Head Orbicularis oris (9) ```

Answer 38

closes, compresses lips

Question 39

Head | Buccinator (14)

Answer 39

compresses cheek, sucking

Question 40

Head | Temporalis (22)

Answer 40

elavates and retracts mandible (chewing) Origin: temporal fossa Insertion: coroniod process, mandibular ramus

Question 41

Head | Masseter (15)

Answer 41

elevates, protracts mandible (chewing)

Question 42

Neck | Digastic (17,19)

Answer 42

elevates hyoid Origin: mastoid process of temporal Insertion: mandible near midline

Question 43

Neck | Mylohyoid (16)

Answer 43

elevates hyoid

Question 44

Neck | Sternohyoid (218)

Answer 44

depresses hyoid

Question 45

``` Neck Sternocleidomastoid (21) ```

Answer 45

flexes, rotates head and neck

Question 46

``` Torso Pectoralis Major (262) ```

Answer 46

flexes, adducts, and medially rotates arm Origin: clavicle, strenum, superior six costal cartilages Insertion: lateral crest of intertubercular groove of the humerus

Question 47

``` Torso Serratus anterior (542) ```

Answer 47

abducts and rotates scapula

Question 48

Torso | Diaphragm

Answer 48

depresses thorax floor

Question 49

``` Torso External intercostals (255) ```

Answer 49

elevates ribs

Question 50

``` Torso Internal intercostals (256) ```

Answer 50

depresses ribs

Question 51

Torso | Trapezius (226)

Answer 51

extends head Origin: occipital protuberance, nuchal ligament spinous processes of C7-T12 Insertion: clavicle, acromoin process and spine of scapula

Question 52

Torso | Rhomboidius major

Answer 52

adducts and rotates scapula

Question 53

``` Torso Latissimus dorsi (541) ```

Answer 53

adducts and medially rotates arm