Human Anatomy - Muscles

Front 1

Functions of muscle tissue

Back 1

1. Motion

2. Maintain posture

3. Heat production

Front 2

Functional of skeletal muscle

Back 2

Action is a movement produced by a muscle

- Skeletal muscle rarely acts independently or alone. They act in groups.

Front 3

Functional groups of skeletal muscle

1. Agonist

Back 3

Prime movers; produce most of the work

 

Front 4

Functional groups of skeletal muscle

2. Antagonist

Back 4

Opposes, reverses, or steadies a movement

Front 5

Functional groups of skeletal muscle 

Back 5

Agonist and antagonist can switch.

Example: Biceps brachii and triceps brachii. Biceps are the agonist when flexing the arm but triceps are the agonist when doing a pull up.

Front 6

Functional groups of skeletal muscle 

3. Synergists

Back 6

Assist prime movers by:

- Adding extra force

-Stabilizing movement

-Modifying movement direction

 

Example: Brachioradialis to the biceps brachii

Front 7

Functional groups of skeletal muscle

4. Fixators

Back 7

Immobilize bone or muscle's origin

Example: The abdomen and back muscles act to stop you from falling off your bike

Front 8

Skeletal muscle terminology

1. Origin

Back 8

Area where muscle attaches to bone that does not move (remains stationary). Usually more proximal.

Front 9

Skeletal muscle terminology

2. Belly

Back 9

Thick region of the muscle

Front 10

Skeletal muscle terminology

3. Insertion

Back 10

Area where muscle attaches to bone that moves. Usually more distal.

Front 11

Origin and Insertion may switch

Back 11

Example: Biceps brachii. When picking something up, the insertion is in the radius, but when doing a pull up, the insertion is the shoulder.

Front 12

Facial muscles

Back 12

Muscle: Epicranius (frontalis)

Action: Elevates eyebrows & wrinkles forehead

Front 13

Facial muscles

 

Back 13

Muscle: Epicranius (occipitalis)

Action: Elevates eyebrows & wrinkles forehead

Front 14

Facial muscles 

Back 14

Muscle: Temporalis

Action: Elevates/retracts jaw

Front 15

Facial muscles

 

Back 15

Muscle: Orbicularis oculi

Action: Closes eyelids

Front 16

Facial muscles

 

Back 16

Muscle: Orbicularis oris

Action: Closes lips

Front 17

Facial muscles

 

Back 17

Muscle: Masseter

Action: Clenches jaw - mastication

Front 18

Facial muscles

 

Back 18

Muscle: Mentalis

Action: Lower lip pouts

Front 19

Facial muscles

 

Back 19

Muscle: Buccinator

Action: Compresses cheek, whistles, sucks, and blows air

Front 20

Facial muscles

 

Back 20

Muscle: Risorius

Action: Contract lips laterally for smiling or laughing

Front 21

Neck muscles

 

Back 21

Muscle: Platysma

Action: Tenses skin of neck, draws down lip and angle of mouth in surprise expression

Front 22

Neck muscles

 

Back 22

Muscle: Sternocleidomastoid

Unilateral action: Flexes and laterally rotates head to look over shoulder

Bilateral action: Draws the head forward and down for reading/eating

 

Origin: Manubrium and medial end of clavicle

Insertion: Mastoid process

 

Antagonist: Splenius capitis

Front 23

Neck muscles

 

Back 23

Muscle: Trapezius

Action: Extend & laterally flex neck; Elevates or Depresses scapula; Retracts and Rotates the scapula

 

From superior to inferior: Clavotrapezius, Acromiotrapezius, Spinotrapezius

 

Origin: Occipital bone, ligamentum nuchae & spinous processes of C7 to T12

Insertion: Acromion, spine of scapula and clavicle

Front 24

Neck muscles

 

Back 24

Muscle: Splenius

Unilateral action: Roates head to look over shoulder

Bilateral action: Extends head and neck

 

Origin: Ligamentum nuchae and spinous processes C7 to T6

Insertion: Mastoid process and occipital bone for Splenius capitis and transverse processes of C1-C3 for Splenius cervicus

 

Antagonist: Sternocleidomastoid

Front 25

Neck muscles

 

Back 25

Muscle: Splenius

Unilateral action: Roates head to look over shoulder

Bilateral action: Extends head and neck

 

Origin: Ligamentum nuchae and spinous processes C7 to T6

Insertion: Mastoid process and occipital bone for Splenius capitis and transverse processes of C1-C3 for Splenius cervicus

 

Antagonist: Sternocleidomastoid

Front 26

Torso muscles

 

Back 26

Anterior torso (chest, abdomen, back) muscles

In general are flexors

Front 27

Torso muscles

 

Back 27

Posterior torso (chest, abdomen, back)  muscles

In general are extensors

Front 28

Torso muscles

 

Back 28

Anterior. 

Muscle: Pectoralis minor

Action: Draws scapula anterior (forward) and inferior (down). 

 

Origin: Anterior surface of ribs 3-5

Insertion: Coracoid process of scapula

Front 29

Torso muscles

 

Back 29

Anterior

Muscle: Serratus anterior

Action: Rotates/protract scapula

 

Origin: Anteriorlateral surface of ribs 1-8

Insertion: Portion of the anterior surface of the scapula

Front 30

Torso muscles

 

Back 30

Anterior

Muscle: Internal intercostals

Action: Elevate ribs during inspiration, depresses the rib cage during forceful expiration

 

Origin: Superior border of below rib

Insertion: Inferior border of above rib

Front 31

Torso muscles

 

Back 31

Anterior

Muscle: External intercostals

Action: Elevate ribs during inspiration

 

Origin: Inferior border of above rib

Insertion: Superior border of below rib

Front 32

Torso muscles

 

Back 32

Anterior

Muscle: Diaphragm

Action: Prime mover of inspiration by increasing volume of thoracic cavity

 

Origin: Inferior-internal surface of sternum, costal cartilages and lumbar vertebrae

Insertion: Diaphragm central tendon (aponeurosis)