Tendons, Ligaments, and Bones

Ligaments, Tendons, and Bones

• Tendons are connective tissue composed of collagen.
• Fascia connects muscle to muscle.
• Tendons connect muscle to bone.

How Tendons Work

• When a bone is moved, the tendon pulls on the bone.
• Tendons possess elastic and strong properties.
• Bundles of collagen fibrils make up tendons with the last one being a collagen fibril.

Tendon Injuries: Tendonitis

• Injured tendons are referred to as tendinopathies.
• Tendons resist repetitive loading, though excessive loading results in stress and micro-tears that can usually repair easily.
• If the rate of degeneration exceeds regeneration, repetitive strain occurs.
• Injuries commonly occur near joints like the shoulder, elbow, hip, knee, and ankle.
• Tendonitis is acute tendon injuries leading to inflammation.

Healing of Tendinopathies

• Healing requires a degree of rest to reduce stress on the tendon.
• Eccentric exercises, stretching, massages, and directing collagen fibers appropriately are elements of rehab.

Ligaments

• Ligaments connect bone to bone.
• They stabilize and limit bone movement.
• Long, stringy collagen fibers make up ligaments, creating bands of tough, elastic tissue to increase flexibility.
• If stretched beyond their limit, ligaments may compromise joint stabilization.

Bones

• Bones serve as predictors of bone healing.
• Muscles attach to bones for movement.
• They provide protection for organs like the brain, lungs, spinal cord, and heart.

Peak Bone Mass

• The greatest amount of bone mass one will have reduces the likelihood of fractures and osteoporosis.
• Throughout life, bone is both lost and created.
• Bones become denser between the ages of 18-25 because kids form bone faster than they lose it.

Bone Structure

• Cortical bone, the outside layer, is solid.
• Trabecular bone, inside the bone, has a honeycomb structure with spaces between fluid bone marrow cells.

Broken Bone Healing

• Inflammation starts the process with bleeding that results in blood clotting, offering stability and producing new bone.
• Fibrous tissue and cartilage will replace the blood clot.
• The bone starts to harden as it heals.
• The bone becomes compact and returns to its original form after a couple of months.

Weight Bearing

• Weight-bearing is possible when sufficiently healed.
• Stronger bones result from increased stress.

Tissue Loading and Deformation Principles

• Springs snap back when stretched and released due to the force trying to return them to their original position.
• Rubber bands snap back, restoring force.
• Thicker rubber bands that are stretched to the same extent need more force to stretch due to increased area and thickness, resulting in a higher restoration force.
• Stress indicates how hard a material will snap back, as influenced by internal restoration force.
• Strain is change in length from lifting something very heavy causing muscles to be pulled.

Graphs

• Material snaps back within elastic limits, but goes beyond this results in some permanent deformation.
• Material elongates which results in restoration force.
• The hooked law limit and elastic limit (yield point) have a linear relationship to the point where it can handle the most stress within limits, then it snaps back.
• The ultimate tensile strength is the maximum stress a material can endure before permanent damage.
• Strain increases up to the material's breaking point, which involves pinching in the center, narrowing, and then snapping beyond ultimate tensile strength (rubber band).

Femur Bone Example

• Force from the top of the bone and restoration force from the bottom are equal.
• The bone is able to handle the limit of 5000 kg.

Muscle Microscopic Anatomy

Muscle Fiber

• A collection of muscle fibers consists of myofibrils.
• The deepest CT sheath is the endomysium.
• Sarcolemma refers to muscle fiber plasma membrane (underneath the endomysium).
• Multiple nuclei are directly below the sarcolemma with many embryonic cells
• These fuse to form skeletal muscle fiber.

Within Muscle Cell

• Sarcoplasm is a soup-like solution where all intracells float.
• Glycosomes are used in energy conversion and glycogen storage.
• tightly packed myofibrils that make up 80% of cell volume store myoglobin- O2 binding protein- 02 storage.
• (such as mitochondria are squished between (red)
• Intracellular tubules surround fibril- sarcoplasmic reticulum
• They regulate intracellular calcium.
• T-tubules are continuous with the sarcolemma, increases surface area, help contractions, and allows action potential to rush down the muscle fiber to allow for complete contraction. (pink)
• Sarcomeres run along myofibrils (length-tension relationship).

Muscle Inactivity and Immobilization

Type I Fibers

• The greatest muscle atrophy tends to occur here.
• This is due to a loss of actin-myosin protein content that changes the Ca+ sensitivity.
• Decreases the ability of muscle fibers to generate force by decreasing facile length pennation angle.

Immobilization in a Lengthened or Neutral Position

• Might result in less muscle atrophy when compared to a shortened position, which is due to: electrical stimulation or resistance training and Neuromuscular electrical stimulation 40min a day.

Reducing Atrophy

• Achieved by dynamically contracting muscles and moving adjacent joints, and protein-based diet interventions can be used as potential countermeasures for disuse-related alternations in protein turnover as well as increasing quantity.

Effects of Muscle Atrophy (QUADS and Achilles tendon)

• VMO = Quads can contract when squeezed when active extension is not possible.
• Loss of cartilage may occur
• VMO raise = pushing knee down into towel, then trying to raise the heel.
• Achilles rupture = calf stretched reduced, base of tendon becomes so much thicker, calf atrophy; leads to struggling in calf raises.

General Inflammation Response

• Redness, swelling, heat, and pain form the field of battle.

Immunology: Filed of Battle

• Skin, mast, and dendric (near external area) cells participate with dendrites. They phagocytose particles to help activate T-cells
• Interstitial fluid
• Capillary Endothelial cells - within blood, white blood cells flowing
• Example – picked with nail and cow manure
• Bacteria damages the skin and interstitial fluid.
• Skin signals (chemokines- small molecules that signal), mast cells activate, releasing histamine
• Antihistamine meds counteract histamine, going to endothelial cells separating and expanding capillaries (vasodilation) while fluid fills them.
• White blood cells (neutrophil) role capillaries emigrate through the wall to phagocytose. Specific actors = B-cells, T-cells also go.
• Non-specific complement system comprise proteins, becomes when inflammatory response activated to help clean invading pathogens.
• Blood, fluid going in and out, exudate - where swelling and redness

Soft Tissue Injuries

Muscle Guarding

• Response to pain.
• Involuntary preventing further injury.

Muscle Spasms

• Reflex reaction trauma leads to tendon injuries. -Alternating involuntary rhythmic movement/ jerking
• Or tonic rigidity for sustained period of time

Muscle Contracture

• ROM stifness/constriction, followed injury/inactivity.

Muscle Strains

• Stretch, tear, or rip to muscles/ligaments range Minute separation.

Grade (definition)

• I: some tissue stretched or actually torn, hurts active range of motion full range
• II: tissue torn and active contraction hurts, usually palpable divots swelling discolor
• III: Complete rupture muscle/tendon junction impairs/pain diminishes due to nerve.

Rupture/Tear

• Pain resumes contractions under resistance or while stretching.
• Complete tear –no pain during contraction stretch.

Tendinopathy

• General swelling, pain or crepitus.

Tendinosis

• Degenerative visible movement more common.

Tendonitis

• Gradual tenderness inflame and crack.

Tenosynovitis

• Acutely crepitus/swelling chronically induces pain/ thickening.
• Enthesopathy results fibrosis that's calcifying with inflammation.

Avulsion Fracture

• Tendon/ligament detachment tear fragment bone tissue.

Bursitis

• Inflammation repetitive movement fluid, shoulder, elbow hip irritates friction.

Bone Skin/ Muscle

• Pain to indicate swell stiff.

Bone Healing

Fracture

• Integrity bone mechanical trauma.
• Hematoma blood clot for first 48h
  • Leaks filling providing mesh cleanse.
• Soft Callus stage –two platelet provide growth for osteo/chondrocytes
  • Osteoblasts bone organic.
• Bony Callus – 2–12w mineralization
• Remodeling –Weight begin osteoclasts physically rest structures area, then bony structure rest.

Acute / Inflame Reaction

• Vessel Constrict/dilate 24h to endothelium leukocyte
• Chemicals – cyt/leukot/ prostaglandins to area foreign particles plasma.
• Form blockage proteins to area of irritation.
• Consume debris response four days from occurance.

Therapy Goals

• Fluid/spasm impedes movement.
• Inflammation select manage to symptoms.
• Contemporary loading rest.

Subacute

• Proliferating to revascular oxygen nutrient. breaks down
• collagen fibrous filler. Collagen tissue.
• Fragile until then, signal injury.

Chronic Maturation

• Decrease Collagen tissue increases breakdown remodelling and tensile formed.
• Non-tissue and function. If contraction.
• Integrity to guide it.
• Exercise: progress swell progress fast.

Chronic Stage

• Individuals functioning tasks to improve skills further.
• You observe needs to find movements task.

Precautions Moving

• Reduce inflamed, discom discomfort four hours, progression signs.
• Progression needs participation limitation of strength.