Hard Tissue (Bone), Cartilage, Tendons/Ligaments, Nerves/Joints Flashcards
What makes up bone tissue?
Collagen, ground substance, and minerals
Is bone tissue vascular?
Highly vascular
Why is it important for bone to be highly vascular?
Excellent capacity for self-repair
What kind of bone is tougher: cortical or trabecular?
Trabecular
What is the term referring to how bone tissue exhibits distinct mechanical properties when loaded along various axes because its structure differs in the transverse and longitudinal directions?
Anisotropic
Which can cortical bone tolerate more: longitudinal loads or transverse loads?
Longitudinal loads
What are the two general ways in which a bone fracture can occur?
Single load that exceeds the ultimate strength of the bone OR repeated applications of lower-magnitude loads
What type of stress is cortical bone BEST at withstanding: tension, shear, or compression?
Compression
What type of stress is cortical bone the WORST at withstanding: tension, shear, or compression?
Shear
What is the concept referring to how bone has the ability to remodel by altering its size, shape, and structure to meet the mechanical demands placed on it?
Wolff’s Law
What happens to bone that is not needed for reasons such as disuse or aging?
Resorbed
Is cartilage vascular?
No (semi-exception = articular cartilage with minimal blood supply)
What makes up cartilage?
Collagen, chondrocytes, and ground substance
What are the three types of cartilage?
Articular, hyaline, and fibrocartilage
What are the three main functions of cartilage?
Increase joint stability
Shock absorption
Protection of bone
What property of articular cartilage makes it more susceptible to creep and relaxation?
It is viscoelastic
What is the range of the forces present at the joint surface during joint articulation?
0-10X body weight
What allows cartilage to experience minimal wear under varied load?
Synovial lubrication
For what reason is cartilage considered to be unlike any man-made material?
Near frictionless properties
What is interfacial wear of articular cartilage?
Interaction of bearing surfaces
What causes interfacial wear of articular cartilage?
Adhesion or abrasion
What is fatigue wear of articular cartilage?
Bearing deformation under load
What causes fatigue wear of articular cartilage?
Repetition of high loads over short period OR repetition of low loads of extended period
Why does articular cartilage have a limited capacity for repair and regeneration?
Small blood supply
What two things determine the magnitude of the stress sustained by articular cartilage?
Total load on the joint AND how the load is distributed over the articular surface contact area
What is the term for the fibrous tissue that connects muscle to bone?
Tendon
What is the term for the fibrous tissue that connects bone to bone?
Ligament
What makes up tendons and ligaments?
Collagen and fibrocytes
What is the location where tendons join to skeletal muscle?
Musculotendinous junction
What are the three characteristics stages for the healing of strains and sprains?
1 Inflammation (Up to 72 hours) 2 Repair (28 hours to up to 6 weeks) 3 Remodeling (3 weeks to 12 months)
In what stage of sprain/strain healing do we see the collagen changing to increase function?
Remodeling stage
What is the definition of a strain?
Overexertion of stress on CONTRACTILE tissues
What kinds of muscles are most at risk for a strain?
Fusiform muscles crossing 2 joints (examples = hamstrings, rectus femoris, biceps brachii)
Are muscle strains more common in the upper or lower extremity?
Lower
In what grade of a strain or sprain are only a few fibers torn (less than 1/4) with only minor weakness and no palpable defect?
Grade One
In what kind of strain or sprain is about 1/4-1/2 of the muscle/tendon torn with moderate to major weakness and loss of function?
Grade Two
In what kind of strain or sprain are all fibers torn with minor to no pain and possible increased range of motion?
Grade Three
What is the term for overexertion or stress on NON-CONTRACTILE tissues?
Sprain
What two things can be sprained?
Ligament or capsule
What two types of damage to nerves can produce mechanical deformation on them?
Trauma or nerve entrapment
What are the two most common modes of nerve injury?
Stretching (tensile forces) and compression
What is the maximal elongation elastic limit of nerves?
About 20%
At what percentage of elastic limit does complete structural failure occur to a nerve?
Approximately 25% to 30%
What comes first: severe intraneural tissue damage of a nerve or nerve failure/rupture?
Severe tissue damage (long before)
What is usually the cause for tensile nerve injuries?
Result of accidents
What symptoms can result from nerve compression?
Numbness, pain, muscle weakness
At what level of local nerve compression can we see functional changes?
30 mmHg
At what level of local nerve compression can we see complete cessation of intraneural blood flow and complete ischemia?
80 mmHg
Can blood flow to neural tissue be restored even after over two hours of compression?
Yes
What is the term for the resting position of a joint when it has the most slack?
Loose pack position
What is the term for the position of a join when its surfaces are in the closest approximation and the capsule and ligaments are maximally stressed?
Close pack position
What is the clinical term for when a joint becomes excessively restricted due to adhesions in the capsule?
Adhesive capsulitis
What is unique about the limitation of range of motion in a joint?
Always found to be in a specific pattern
What kinds of abnormalities can cause non-capsular patterns of joints?
Joint mice
Impingements
Plica
Other internal derangements
