Unit V - MovementMuscle Movement

Biomechanics

Chapter 10

Urinary system 0.7%Respiratory system 1.7%

Nervous system 2%Digestive system 6%

Lymphatic system 0.3%Reproductive system 0.15%Endocrine system 0.15%Cardiovascular system 9%

Integumentarysystem16%

Skeletalsystem20%

Muscular system44%

Muscle Functions

• 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

• Perimysium

• Epimysium

• Fascia

Perimysium

Musclefascicle

EndomysiumEpimysium

NerveMuscle fibersBlood vessels

Epimysium

Muscle fiber

Perimysium

Endomysium

Blood vesselsand nerves

Tendon Capillary Myofibril Endomysium

Myosatellite cells

Axon of neuron

Perimysium

Epimysium

Endomysium

Tendon

Deep fascia

Deep and Superficial Fascia

Superficial Fascia

Deep Fascia

Fascicle

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

• Origin

– stationary attachment

• Insertion

– mobile attachment

• Belly

– thicker, middle region

Scapula

Bellies

Radius

Insertion

Humerus

UlnaInsertion

Origins Origins

Triceps brachii

Extensors:

Long head

Lateral head

Flexors:

Biceps brachii

Brachialis

4 Types of MusclesClassified 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 MusclesBased on orientation of fascicles:

GastrocnemiusSartorius

Masseter Orbicularis oris

Pennate

Sphincter

Temporalis (Quadriceps)

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, 10Lab: 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 questionsUnit 5 Lab: muscle tissue and manual questions

names of muscles and action produced (lab pgs 124-126)