1' Embryology and tissues

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Muscle system
Functioning with skeletal sytem is
Muscles are all of mesodermal origin.
Muscles are made up of contractile fibers. They
can only generate force by shortening.
Muscle fibers are made up of fibrils.
Fibrils are made up of sarcomeres.
Sarcomeres are the functional unit, the place
where contractions are generated.
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Muscle types
innervation
location
fiber type
fiber arrangement
Smooth muscle
Smooth
parallel
autonomic
viscera
Skeletal muscle
parallel
voluntary
Striated
Striated muscle
Inter- connected
autonomic
heart
Striated
Cardiac muscle
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Muscles
Muscles are made up of fibers.
Fibers are made up of fibrils (these are the
cells).
Fibrils are made up of sarcomeres.
Z lines between sarcomeres produce
striations in striated muscle.
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Each sarcomere is made up of
BLUE
RED
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Simplified model.
One sarcomere.
Actin filaments.
Mysoin filaments.
During contraction, mysoin filaments latch on to
adjacent actin filaments via myosin heads. The
heads change shape pulling the actin filaments
towards one another.
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actin
myosine
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3
4
2
1
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Skeletal Muscles
Contractile fibers make up belly of muscle
Synovial joint
Only work by getting shorter, by contracting
Belly of muscle
Force of contraction transmitted by tendons (in
yellow)
Tendons do not contract
tendon
Force results in movement, usually of bones at
joints
Synovial joint
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Skeletal Muscles
All have an origin.
Synovial joint
Site of attachment closer to the midline
All have an insertion
Belly of muscle
Site of attachment away from the midline
These are standard descriptors of any muscle.
tendon
They are often used in a muscle name.
Synovial joint
e.g. coracomandiularis
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Because muscles can only work by contraction
they must work in antagonistic pairs.
Antagonistic pairs have opposite actions.
In this case Flexion (biceps) Extension (triceps)
The names of muscles frequently use the name of
the action of the muscle.
e.g. Flexor digitorum profundus
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Learning the names of muscles.
The names always describe properties of the
muscle, such as
1) origin and insertion.
coracomandiularis
xiphihumeralis
sternomastoid
cleidomastoid
2) number of heads or origins
biceps
triceps
2) depth of the muscle
pectoralis profundus
flexor digitorum superficialis
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Learning the names of muscles.
The names always describe properties of the
muscle, such as
4) relative position of the muscle.
flexor carpi ulnaris
flexor carpi radialis
lateral or medial head of triceps
5) length of a tendon
Adductor pollicus longus
Adductor pollicus brevis
6) action of the muscle
Flexor digitorum profundus
Extensor digitorum communis
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6) The actions of skeletal muscles
Always occur in pairs
Actions will be oppsite of each other
extensor carpi ulnaris
Extension -- make an angle larger
flexor carpi ulnaris
Flexion -- make an angle smaller
adduction -- pull towards midline
fin adductor
abduction -- pull away from midline
fin abductor
protraction -- reach forward from midline
tibialis cranialis
gastrocnemis
retraction -- pull back towards midline
pronation -- rotate thumb away from midline
pronator
supinator
supination -- rotate thumb towards midline
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Muscles function in lever systems
Fi x Li Fo x Lo
There is more to the system than mechanical
advantage
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But there is more than mechanical advantage
Distal end of arm (hand) moves much faster and
much farther than proximal end.
L
Allows for acceleration and wider range of
movement.
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Arthroscopic Knee Surgery

• Major parts of the knee
• Patella
• Femur
• Articular Facet for Patella
• Tibia Fibula
• Meniscus
• ACL (anterior cruciate ligament)

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The Procedure

• Knee arthroscopic surgery is a procedure
  performed through small incisions in the skin to
  repair injuries to tissues such as ligaments,
  cartilage, or bone within the knee joint area.
  The surgery is conducted with the aid of an
  arthroscope, which is a very small instrument
  guided by a lighted scope attached to a
  television monitor. Other instruments are
  inserted through three incisions around the knee.

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Repair Methods
Whenever possible, surgeons prefer to repair a
torn meniscus, rather than remove even a small
piece. Young people who have recently torn their
meniscus are generally good candidates for
repair. To repair the torn meniscus, the surgeon
inserts the arthroscope and views the torn
meniscus. sutures are used to sew the torn edges
of the meniscus together.
The femur has the articular facet for patella to
slide over. Sometimes the groove is not deep
enough, and bone must be operated on in order to
deepen this groove. This procedure is called
shaving
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Post-Surgery

• Arthroscopic surgery has a much shorter recovery
  time than more invasive surgeries. Aside from
  3-4 small holes around the knee, and a full
  leg-brace for 4-6 weeks, patients leave with
  minimal evidence of a surgery. Along with
  no-weight bearing instructions, physicians often
  prescribe painkillers and advise patients to
  refrain from flexing leg muscles as much as
  possible.
• After the brace is taken off, the leg muscles
  will be almost completely atrophied, physical
  therapy is essential to regain mobility.