Muscular System

PART II

Muscular System PART II

OBJECTIVES

Muscle Movements, Types and Names (pp. 198 – 206)• Define prime mover, antagonist, synergist, and fixator as they relate to muscles.• Identify these types of body movements (from images): flexion/extension,

supination/pronation, adduction/abduction, and inversion/eversion• List some criteria used in naming muscles.Gross Anatomy of Skeletal Muscle (pp. 206 – 219)• Name and locate the major muscles of the human body.Developmental Aspects (p. 221)• Explain the importance of a nerve supply and exercise in keeping muscles healthy.• Describe the changes that occur in aging muscles.Systems in Sync (p. 222)• Describe the homeostatic relationship between the muscular system and any one

other system.

Anterior and Posterior Diagrams*See Text p. 216 and 218

What’s in a name?

MUSCLES ARE NAMED ACCORDING TO:

1. Muscle size - Examples: Gluteus maximus vs. Gluteus medius (Incidentally, there is also a Gluteus minimus…)

2. Muscle shape – Examples: Trapezius and Rhomboideus

3. Associated bones – Examples: Zygomaticus

4. Action of the muscle – Example: Masseter and Flexor carpi ulnaris

More about names……

•Orbicularis - orbit, circular muscleMajor/Minor - large/small or sometimes upper and lowerVastus - largeDorsi or Dorsal - backsideInfra / Supra - lower and upperLongis / Brevis - long/ short (brief) Medialis / Lateralus - medial (toward the inside), lateral (toward the outside)

Major Muscles of the Face and Neck

A. Frontalis

B. Occipitalis

C. Masseter

D. Sternocleidomastoid

F. TemporalisG. Obicularis oculi

H. ZygomaticusI. Obicularis orisJ. BuccinatorK. Platysma

A Human Body Dissected

Major Muscles of the Anterior TrunkA. Sternocleidomastoid

B. Pectoralis minor

C. Intercostals

D. Serratus anteriorE. Rectus abdominus

G. Transversus abdominus

H. Zygomaticus

I. Deltoid J. Pectoralis major

K. External obliqueF. Internal oblique

Major Muscles of the Posterior Trunk

A. TrapeziusB. Deltoid

C. Latissimus dorsi

D. Levator scapulae

H. Teres major

I. Rhomboideus

F. Infraspinatus

Two areas used for intramuscular injections•Deltoid•Gluteus medius

Major Muscles of the Lower Arm (Pronated – radius rotated over ulna)

A. Triceps brachii

(C. and E.) Extensors

B. Flexor carpi ulnaris D. Extensor carpi radialis

Major Muscles of the Lower Arm (Supinated – radius and ulna are parallel)

A. Biceps brachii

E. Flexor carpi radialis D. Brachioradialis

F.-G. various flexors

*Define prime mover, antagonist, synergist, and fixator as they relate to muscles.

Synergists – reinforce the same movement as the prime mover. If it stabilizes the movement it may be called a fixator.

Antagonists – oppose or reverse a movement.

A prime mover is the muscle that has the major responsibility for causing a movement.

Major Muscles of the Anterior Upper Leg

B. Sartorius

C. Rectus femoris

D. Vastus lateralis F. Gracilis

G. Vastus medialis

E. Adductors

Major Muscles of the Posterior Upper Leg

A. Gluteus medius

B. Gluteus maximusC. Iliotibial tract D. Gracilis

G. Gastrocnemius

E-F. Semitendinosus* H. Biceps femoris*

*E. F. and H. are commonly known as the Hamstrings.

Major Muscles of the Lateral Upper Leg

A. Gluteus medius

B. Gluteus maximus

C. Biceps femoris

E. Sartorius

G. Vastus lateralis F. Rectus femoris

Major Muscles of the Lateral Lower Leg

A. Biceps femoris B. Vastus lateralis

C. GastrocnemiusE. Tibialis D. Soleus

Muscle Movements

Developmental Aspects1. Embryonic Development• laid down in segments and then nervous tissue developsMaturation of Muscle Control• cephalic to caudal direction (head to tail)• Babies raise their head, then sit up, and then stand

• proximal to distal direction- gross motor skills first, fine motor skills last

Aging Effects

•atrophy- decrease in muscle tissue, increase in connective tissue over time•muscles become stringier, more sinewy•decreased muscle strength•aging can be delayed (and to a degree reversed) with regular exercise