Unit V - Movement
Muscle Movement
Biomechanics
Chapter 10
Muscle Functions
Lymphatic system 0.3%
Reproductive system 0.15%
Endocrine system 0.15%
Cardiovascular system 9%
Urinary system 0.7%
Respiratory system 1.7%
Nervous system 2%
Digestive system 6%
Integumentary
system
16%
Skeletal
system
20%
Muscular system
44%
•
•
Movement
Stability
− Center of gravity is low and centered
− Lower lumbar area
•
•
Control of openings and passageways
Heat production
Connective Tissues of Muscle
• Endomysium
– Fascicles
Muscle
fascicle
Perimysium
Endomysium
Epimysium
Nerve
Muscle fibers
Blood vessels
• Perimysium
• Epimysium
Muscle fiber
Perimysium
• Fascia
Epimysium
Blood vessels
and nerves
Endomysium
Tendon
Capillary Myofibril
Endomysium
Myosatellite cells
Axon of neuron
Deep and Superficial Fascia
Tendon
Deep fascia
Epimysium
Perimysium
Superficial Fascia
Fascicle
Endomysium
Deep Fascia
Attachment to Bone
Two forms:
1. Direct (fleshy) attachment
– Ex. intercostal muscles
2. Indirect attachment
– E.x. biceps brachii
• Aponeurosis
– E.x. scalp, abdominal, lumbar, hand and foot muscles
• Retinaceum
– E.x. wrist
General Anatomy of Muscles
Origins
• Origin
Scapula
– stationary attachment
• Insertion
– mobile attachment Extensors:
Triceps brachii
• Belly
Long head
– thicker, middle region Lateral head
Origins
Humerus
Bellies
Flexors:
Biceps brachii
Brachialis
Insertion
Radius
Insertion
Ulna
4 Types of Muscles
Classified according to their actions:
• Prime mover or agonist
– E.x. biceps brachii when elbow is flexed
• Synergist
– E.x. brachioradialis in flexing the elbow
• Antagonist
– E.x. triceps brachii in flexing the elbow
• Fixator
– E.x. muscles attached to scapula prevent its movement
when biceps brachii contracts
MUSCLES CANNOT PUSH – ONLY PULL!
5 Types of Muscles
Based on orientation of fascicles:
Pennate
Sphincter
Temporalis
(Quadriceps)
Sartorius
Gastrocnemius
Masseter
Orbicularis oris
Intrinsic and Extrinsic Muscles
• Intrinsic muscles (hand)
• Extrinsic muscles
• Seen in tongue, larynx, back, hands, and feet
Names of Muscles
• Terms used to name muscles
– levator = elevates a body part
– Inferior = bottom
– quadriceps = having 4 heads
– sternocleidomastoid = bones attached to
Biomechanics
Lever – an elongated, rigid object that rotates around a fixed point called
the fulcrum. Rotation occurs when an effort applied to one point on the
lever overcomes a resistance at some other point.
fulcrum – joint
effort – applied by a muscle
resistance – an object the body is working against
Mechanical Advantage (MA) – ratio of its output force to its input force
MA = LE/ LR
LE = the length of the effort arm
LR = the length of the resistance arm
If MA > 1.0 the lever produces more force but has less speed or distance
If MA < 1.0 the lever produces more speed or distance but less force
Types of Levers
First Class
• Fulcrum is in the middle
• Atlanto-occipital joint
Types of Levers
Second Class
• The resistance is in the middle
• Mandible
Types of Levers
Third Class
• The effort is applied in the middle
• The forearm when flexing the elbow
Range of Motion
• Degrees through which a joint can move
• Determined by:
– structure of the articular surfaces
– strength and tautness of ligaments, tendons and joint capsule
– action of the muscles and tendons
Resting muscle maintains a state of tension – muscle tone
Final Exam!
Unit V:
Chapters: 4, 9, 10
Lab: muscle tissue and manual questions
names of muscles and action produced (lab pgs 124-126)
OR:
Cumulative: (same amount of points)
First 4 units tests, quizzes, in class review questions
Unit 5 Lab: muscle tissue and manual questions
names of muscles and action produced (lab pgs 124-126)