Muscles and Joints 1 1

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. 2 2

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 http://www.springerimages.com/Images/Biomedicine/1-10.1007_s00424-006-0069-2-1 ATP is hydrolyzed to move myosin head back to the starting position. 3 3

But muscles do not produce systemic motion by themselves! Muscles and Movement On a systemic level: Most muscles work in muscle pairs: Contracting  Agonist “Relaxing”  Antagonist Contraction Relaxation http://www.springerimages.com/Images/Biomedicine/1-10.1007_s00424-006-0069-2-1 But muscles do not produce systemic motion by themselves! 4 4

Joints Consist of: Bone* Cartilage* Muscle* Ligaments* Tendons* Synovium* Nerves Glands Blood Vessels http://www.springerimages.com/Images/Biomedicine/1-10.1007_s00424-006-0069-2-1 5 5

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 http://www.springerimages.com/Images/Biomedicine/1-10.1007_s00424-006-0069-2-1 6 6

Joints Motion Classification: Hinge Ball and Socket Pivot Ellipsoidal And many more Each joint has a certain Range of Motion (ROM) associated with it. http://www.springerimages.com/Images/Biomedicine/1-10.1007_s00424-006-0069-2-1 7 7

Knee http://www.springerimages.com/Images/Biomedicine/1-10.1007_s00424-006-0069-2-1 8 8

Extension and Flexion: 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 http://www.springerimages.com/Images/Biomedicine/1-10.1007_s00424-006-0069-2-1 9 9

Lateral Collateral Ligament (LCL) Knee Ligaments Lateral Collateral Ligament (LCL) Located: Outer (or Lateral) side of the knee. Function: Mediolateral Stability http://www.springerimages.com/Images/Biomedicine/1-10.1007_s00424-006-0069-2-1 10 10

Medial Collateral Ligament (MCL) 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 http://www.springerimages.com/Images/Biomedicine/1-10.1007_s00424-006-0069-2-1 11 11

Anterior Cruciate Ligament (ACL) 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 http://www.springerimages.com/Images/Biomedicine/1-10.1007_s00424-006-0069-2-1 12 12

Posterior Cruciate Ligament (PCL) 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 http://www.springerimages.com/Images/Biomedicine/1-10.1007_s00424-006-0069-2-1 13 13

Chicken Leg http://www.springerimages.com/Images/Biomedicine/1-10.1007_s00424-006-0069-2-1 The chicken’s knee is analogous to the human knee!! Let’s look for those ligaments! 14 14

Measuring the Effects of Injury and Illness 15 15

Injury and Illness Stress/Strain related: Fracture: Arthritis: http://www.springerimages.com/Images/Biomedicine/1-10.1007_s00424-006-0069-2-1 16 16

Current treatment Drug Therapy Reattachment Partial Joint Replacement Total Joint Replacement http://www.springerimages.com/Images/Biomedicine/1-10.1007_s00424-006-0069-2-1 17 17

Ability to Align Growing Fibrils Hopes for the Future Stem Cell Therapy Ability to Align Growing Fibrils Degradable Metal Scaffolding http://www.springerimages.com/Images/Biomedicine/1-10.1007_s00424-006-0069-2-1 18 18

Knee http://www.springerimages.com/Images/Biomedicine/1-10.1007_s00424-006-0069-2-1 19 19

Extension and Flexion: 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 http://www.springerimages.com/Images/Biomedicine/1-10.1007_s00424-006-0069-2-1 A loss of anything more than 3 degrees of motion can lead to serious problems and pain. 20 20

The Screw Home Mechanism Why??? The Screw Home Mechanism http://www.springerimages.com/Images/Biomedicine/1-10.1007_s00424-006-0069-2-1 21 21

Any questions?