LAB 11

Muscle Mechanics

Leverage

Fascicle arrangement

Lever Systems: bone-muscle relationships

Lever allows effort to move a heavier load
Lever allows effort to move a load faster/further

Parts of Lever System (4)

Lever

Fulcrum

Applied Force

Resistence

Parts of Lever System: Lever

rigid bar that moves on a fixed point (fulcrum)

bones

Parts of Lever System: Fulcrum

fixed point

joints

Parts of Lever System: Applied Force

effort (force)

muscle contraction applied at muscle insertion

Parts of Lever System: Resistence

bone + tissue is moved

Types of Levers

classification depends on position of 3 elements: lever, fulcrum, load

First - Third class

First Class Levers

effort applied at 1 end of lever
load is at the other end of lever
fulcrum in between the two

seesaws, scissors, lifting head from chest

Second Class Levers

effort applied at 1 end
fulcrum is at the other end of lever
load is in between the two

wheelbarrow, standing on toes

Third Class Levers

effort applied at point between load and fulcrum

most skeletal muscles of body, lifting barbell by forearm

Arrangement of Fascicles (4)

determine muscle range of motion and power

1. Parallel

2. Pennate

3. Convergent

4. Circular

Arrangement of Fascicles: Parallel

long axis of fascicle run parallel with long axis of muscle

sartorius, biceps brachii

Arrangement of Fascicles: Pennate

fascicles are short and attach obliquely to central tendon running length of muscle

unipennate - extensor digitorum longus
bipennate - rectus femoris
multipennate - tendon is branched with fascicles obliquely attached

Arrangement of Fascicles: Convergent

broad origin and fascicles converge toward single tendon
muscle is triangular or fan shaped

pectoralis major

Arrangement of Fascicles: Circular

fascicles arranged in concentric rings
act as sphincters

muscles surrounding body openings (orbicularis and oculi)

Interactions of Skeletal Muscles in Body

muscles ONLY pull

muscle contraction ONLY causes shortening

muscle can be any ONE of the following:

1. Prime mover (agonist)

2. Antagonist

3. Synergist

Prime Mover

agonist

muscle which provides major force for producing specific movement

Antagonist

muscles that oppose a movement

when agonist is active, antagonist is being stretched (relaxed)

located on opposite side of joint from agonist

Synergist

aid agonist by promoting same movement or reducing undesirable movements during agonist contraction

Naming of Skeletal Muscles (7)

1. Location

2. Shape

3. Size

4. Direction

5. Number of origins

6. Location of origins or insertion

7. Action

Naming: Location

temporalis muscle overlies temporal bone

Naming: Shape

deltoid (triangular)

trapezius (form trapezoid altogether)

Naming: Size

maximus = large

minimus = smallest

longus = long

brevis = short

Naming: Direction

direction of muscle fibers

rectus = straight/parallel to axis

transverse/oblique = fibers run at right angles and obliquely to line

Naming: Number of Origins

biceps = 2 origins

triceps = 3 origins

quadriceps = 4 origins

Naming: Location of Origins/Insertion

named according to attachment point
origin named prior to insertion

sternocleidomastoid = origin at sternum and clavicle and insertion at mastoid process

Naming: Action

flexor, extensor, adductor, abductor

Head Muscles (11)

1. Frontalis

2. Occipitalis

3. Temporalis

4. Orbicularis Oculi

5. Buccinator

6. Orbicularis Oris

7. Platysma

8. Masseter

9. Sternocleidomastoid

10. Trapezius

11. Zygomaticus Minor and Major

Neck Muscles (6)

1. External and Internal Intercostal

2. Diaphragm (right under ribs!)

3. Pectoralis Minor

4. Serratus Anterior

5. Trapezius

6. Rhomboid Minor and Major

Abdominal Wall Muscles (5)

1. Transverse Abdominis

2. Internal Oblique

3. External Oblique

4. Linea Alba

5. Rectus Abdominis

Shoulder Muscles (6)

1. Deltoid

2. Pectoralis Major

3. Latissimus Dorsi

4. Teres Major and Minor

5. Infraspinatus

6. Supraspinatus

Arm Muscles (5)

1. Triceps Brachialis

2. Brachioradialis

3. Biceps Brachii

4. Flexor Carpi Radialis

5. Pronator Teres

Hip Leg and Knee Muscles Anterior View (7)

1. Iliopsoas
   - psoas major + iliacus

2. Pectineus

3. Sartorius

4. Quadriceps Femoris
   - rectus femoris + vastus lateralis + vastus medialis + vastus intermedius

5. Adductor Longus

6. Gracilis

7. Adductor Magnus

Hip Leg and Knee Muscles Posterior View (7)

1. Gluteus Medius

2. Gluteus Maximus

3. Gluteus Minimus

4. Biceps Femoris

5. Semitendinosus

6. Semimembranosus

7. Gastrocnemius

Leg and Foot (3)

1. Tibialis Anterior

2. Soleus (anterior to tibialis anterior)

3. Popliteus