Muscles

Muscles

1. A Interactive Apporach Of Muscles
(Complete Info ppt.)
By- Dr. Armaan SinghBy- Dr. Armaan Singh

2. Muscle Strains
Tend to occur at the
musculotendinous junction
At the muscle fibers
At the tendon or tenoperiosteal
junction
It is essential to know the origin and
insertion of a muscle, to assess it
correctly
Passively stretching the muscle
Testing its isometric, concentric and
eccentric contractions

3. Types of Muscle
Voluntary muscle
Striated: somatic nerves
Involuntary: smooth
Autonomic system
Cardiac muscle
Autonomic system

4. Voluntary Muscle
Consists of contractile element
Muscle fibers which develop tension
Non-contractile, connective tissue, of
which the tendon forms a major part
Connective tissue transmits the force of
the muscle to the bones
Helps protect the muscle tissue and
binds muscle fibers together
Muscle fibres are grouped into bundles
called fasciculi

5. Muscle Fibres
Are grouped into bundles called
fasciculi
The size of fasciculi varies
Muscles performing gross movements
have a larger number of fibres in each
fasciculus

6. Muscle Fibres
Muscles performing fine movements have smaller
fasciculi
Supplied by a greater number of nerve fibres

7. Fasciculi
Arrangement of the fasciculi
determines the shape of the
muscle
Amount of tension
Speed of contraction
Fasciculi contain fibres that are
either parallel or oblique

8. An individual muscle cell is called a
muscle fibre
Sarcoplasma is the cytoplasm of the
muscle fibre
It is enclosed by the sarcolemma, a
plasma membrane
Sarcoplasm contains
T- tubules which transport
substances
Sarcoplasmic reticulum stores
calcium
Muscle Fibres

9. Myofibrils
Myofibrils are made up of
sarcomeres
Smallest functional unit of a
muscle
Sarcomere is composed of
filaments of myosin and actin
responsible for contraction
Myosin is thick filament
Actin is thin filament
Tropomyosin and troponin are
attached to Z-disc

10. Muscle
Epimysium around muscle
Perimysium around fasciculi
Endomysium around muscle cell
Bundles of muscle cells or fibre
Myofibril consists of myofilament
actin myosin filament

11. Muscle belly with two tendons
Two heads: biceps
Three heads: triceps
Four heads: quadriceps
Muscle Types

12. Short muscle fibres are connected
together by tendinous intersections.
They develop from myotomes
Have a segmental nerve and blood
supply
Each segment has a short range of
contraction
The range of the muscle is the sum of
the segments
e.g. rectus abdominus muscle or
sternomastoid
Parallel Fibres

13. Long muscle fibres are found in strap
muscles
They can shorten a great deal
Producing a large range of movement,
e.g. the sartorius
Parallel Fibres

14. Oblique Fibres Pennate Muscles
Unipennate – muscle fibres are
confined to one side of the tendon,
e.g. unipennate lumbrical from
flexor pollicis longus
Bipennate – fibres on both sides of
the tendon, e.g. bipennate
lumbrical, rectus femoris
Multipennate – muscle fibres attach
and converge on several tendons
e.g. deltoid

15. Sphincter
Circular fibres, true sphincter has no bony
attachments
Deep portion of external anal sphincter

16. Muscle can only act on a joint, if it
crosses the joint
Muscles that have a common action on
the joint, tend to have same nerve
supply
Exception, flexors of the elbow, have
several different nerves
Nerve supplying the muscle, gives an
articular branch to joint
Muscles

17. Tendons, consist of type I collagen
Form a connection between the
muscle belly and its attachments
Tendon

18. Musculotendinous Junction
Junctional area between muscle
and tendon
Growth plate of muscle
Subjected to great mechanical
stress
Muscles tend to tear at
musculotendinous junction

19. Muscle Attachments
Muscles are attached to bone by
tendons
There is a gradual transition from
tendon to fibrocartilage to lamellar
bone via the periosteum
Benjamin & Ralphs, 1986; Benjamin et al., 1996

20. Osteotendinous Junction
Four zones
Pure fibrous tissue
Unmineralised fibro-cartilage
Mineralised fabricating
Bone
Benjamin et al., 1986

21. Force of Muscle
The force of a muscle depends
on its physiological cross-section
area
Strap muscles are weaker than
pennate muscles

22. Some muscles cross two joints
Hamstrings:
semi-membranosus,
semitendinosus, long head of
biceps femoris
Medial and lateral heads of
gastrocnemius, plantaris
Rectus femoris portion of
quadriceps
More likely to be injured
Muscles

23. Muscle Tears

24. Muscle Tears

25. Skeletal Muscle Action
No muscle acts alone
Muscles usually act in groups
The major muscle which initiates
movement, is called the agonist (prime
mover)
Antagonists have the opposite action
Synergist muscles act as stabilisers or
fixators

26. Synergists help to steady the
part being moved
Fixators stabilise the attachment
of the prime mover
Enable it to work more efficiently
Flexing the elbow, brachialis is
the prime mover
Biceps brachii and the brachioradialis are synergists
Fixators are muscles around the shoulder joint; the rotator cuff
muscles stabilise the head of the humerus
Muscle Action

27. Muscles
Muscles develop from mesoderm
Myotomes are a group of voluntary
muscles supplied by a specific nerve root
A dermatome is an area of skin supplied
by a specific nerve root
They generally tend to follow the
segmental supply of the underlying
muscles

28. Myotomes
Four consecutive spinal segments
Control each lower limb joint
Hip L2,3,4,5
Knee L3,4,5, S1
Ankle L4,5, S1,2

29. Myotomes
Flexion of hip
Iliopsoas L2,3
Extension of hip mainly gluteus
maximus and hamstrings, L4,5
Extension of knee
Quadriceps L3,4
Flexion of knee L5, S1

30. Myotomes
Dorsiflexion of ankle
tibialis anterior (TA) L4,5
Extensor hallucis longus
L5
Plantar flexion of ankle
Posterior muscles of calf
S1,2

31. Inversion and dorsiflexion
Tibialis anterior L4 inversion and
plantar flexion
Tibialis posterior L4
Inversion

32. Plantar flexor and evertor
Peroneus longus
Peroneus brevis L5,S1
Dorsiflexor and evertor
Peroneus tertius L5,S1
Evertors

33. Skin
Bones
Muscles / tendons
Nerves
Blood vessels
Dermatomes

34. Dermatomes Lower Limb

35. Types of Muscle Action

36. Voluntary Muscle Action
Three types
 Isometric
 Concentric
 Eccentric

37. Isometric Action
No change in the length of
the muscle fibres
Increase in tension
Least stress to the muscle
First phase in the
rehabilitation of a muscle tear
or strain

38. Isometric Action
Isometric produces an
increase in strength only at
the joint angle at which it is
performed
It should only be done for
short periods
Muscle fatigue due to
restriction of the blood supply

39. The origin and insertion move
towards each other
The muscle shortens as it
increases its tension
It is the traditional action in
books
Second phase of the rehabilitation
of a muscle
Pulling up on a bar
Elbow flexors work concentrically
Concentric Action

40. Muscle lengthens as it develops
tension
Elbow flexors when lowering
yourself from a bar
Eccentric action is the most
powerful action
It is the most stressful
The last phase in muscle
rehabilitation
Eccentric Action

41. Musculoskeletal Injuries
Extrinsic factors
Sport
Contact sports
Environment
Equipment
Protective
Overuse
Intrinsic factors
Physical
Physiological
Psychological
Previous Injury
Inadequate rehabilation

42. Muscle Injuries
Damage to muscle fibres heal relatively
quickly because of their rich blood
supply
If tendons are damaged, healing is
slower due to their relatively poor blood
supply
If the injury is close to the bone, e.g. a
blow to the vastus intermedius
May develop myositis ossificans
These injuries usually take
longer to heal

43. Muscle
Pre-stretching the muscle prior to a
concentric muscle action
Increases the force because of elastic
recoil
Long jumpers stretch the extensor
muscles in the downward sink on to the
board before take-off
Wind-up or cocking phase in bowling a
ball in cricket
If it is stretched more than 120% then
its force of contraction decreases