Transcript Joint for tomorrowx

Muscles and Joints
What are Muscles?
Muscle  Fascicle
Muscle fiber 
Myofibril
Units are bundled
together with
various connective
tissues
Myofibril consists
of bands of actin
and myosin
filaments.
Muscles and Movement
On a cellular level:
ACh released by the
axon ending signals a
release of Ca2+
Ca2+ removes complex
over the actin fibril.
Myosin head attaches to
actin groove and
contracts
ATP is hydrolyzed to
move myosin head back
to the starting position.
Muscles and Movement
Most muscles work in
muscle pairs:
On a systemic level:
Contracting  Agonist
“Relaxing”  Antagonist Contraction
Relaxation
But muscles do not
produce systemic
motion by themselves!
Joints
Consist of:
Bone*
Cartilage*
Muscle*
Ligaments*
Tendons*
Synovium*
Nerves
Glands
Blood Vessels
Joints
Synovial Joints:
Majority of the joints in
your body
Contain a synovial cavity
or sheath between the
contact points
Synovial cavity with fluid
allows joints to glide
across each other
Joints
Motion Classification:
Hinge
Ball and Socket
Pivot
Ellipsoidal
And many more
Each joint has a certain
Range of Motion (ROM)
associated with it.
Knee
Knee
Hinge Joint
Synovial Joint
ROM:
Extension and Flexion:
-5 to 143 degrees (women)
-6 to 140 degrees (men)
Studies of the range of knee motion show that • 93 degrees is required for rising from a seated position
• 106 degrees is required for shoelace tying
• 135 degrees is required to take a bath
Knee Ligaments
Lateral Collateral Ligament (LCL)
Located:
Outer (or Lateral) side of
the knee.
Function:
Mediolateral Stability
Knee Ligaments
Medial Collateral Ligament (MCL)
Located:
Inner (or Medial) side of
the knee.
Function:
Mediolateral Stability
Covers major glands and
nerves of the knee
Knee Ligaments
Anterior Cruciate Ligament (ACL)
Located:
Inside the knee joint,
under the patella, near
the front (anterior)
Function:
Resists anterior
translation and medial
rotation of the tibia
Knee Ligaments
Posterior Cruciate Ligament (PCL)
Located:
Inside the knee joint,
under the patella, near
the back (posterior)
Function:
Prevent the femur from
sliding anterior to the
tibia and tibia from
displacing posterior to
the femur
Chicken Leg
The chicken’s knee is analogous to the
human knee!! Let’s look for those ligaments!
Measuring the Effects of Injury
and Illness
Injury and Illness
Stress/Strain related:
Arthritis:
Fracture:
Current treatment
Drug Therapy
Partial Joint
Replacement
Reattachment
Total Joint
Replacement
Hopes for the Future
Stem Cell Therapy
Degradable Metal
Scaffolding
Ability to Align Growing
Fibrils
Knee
Knee (Revisited)
Hinge Joint
Synovial Joint
ROM:
Extension and Flexion:
-5 to 143 degrees (women)
-6 to 140 degrees (men)
Studies of the range of knee motion show that • 93 degrees is required for rising from a seated position
• 106 degrees is required for shoelace tying
• 135 degrees is required to take a bath
A loss of anything more than 3 degrees of
motion can lead to serious problems and pain.
Why???
The Screw Home Mechanism
Any questions?
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