Midterm Flashcards
1
Q
What is a primary injury?
A
• Results directly from the initial, immediate trauma associated with a particular mechanism of insult
2
Q
What are the types of primary injury (3)?
A
- Direct or Extrinsic. Trauma occurs at point of impact where the force meets the body. Ex: contusion from a direct force
- Indirect or intrinsic. A force meets the body in such a way that energy is transmitted to another part of the body where the trauma is concentrated and the injury occurs. Ex: dislocated shoulder from falling on an outstretched hand
- Overuse injury. Acute repetitive friction, Chronic repetitive microtrauma
3
Q
What is a secondary injury?
A
• Additional injury that occurs as a result of the primary injury.
4
Q
What are the types of secondary injury?
A
- Short-term. Results from the sequelae of injury, if not managed properly. Affects injured ells on periphery of the primary lesion
- Long-term. Over time may lead to degenerative conditions. Increases total quantity of tissue damage. Potentially increases healing time
5
Q
What is a secondary enzymatic injury?
A
• Lysosomes release enzymes (not specifically identified, perhaps phospholipases and acid hydrolases), which damage surrounding cells (cleave hydrocarbon chains from membrane phospholipids), and cell membrane loses integrity and polarity (swelling, cell death)
6
Q
What is secondary hypoxic/ischemic injury?
A
• Thought by some to be more important than enzymatic injury. Failure of vasculature to supply enough blood (=ischemia). Vascular and inflammatory changes cause a period of hypoxia, causing a shift to anaerobic metabolism. Eventually there is inability to produce adequate ATP, failure of membrane ion pumps, swelling, cell death
7
Q
Why does ischemia arise in secondary injury?
A
• Damaged blood vessels; hemostasis/clotting; inflammation induced hemoconcentration; thicker blood does not flow as well; increased extravascular pressure from expanding hematoma; pain induced muscle spasm; swelling of injured cells
8
Q
What physiological problems does ischemia cause?
A
• 3 things. Hypoxia. Inadequate supply of nutrients(glucose, etc); inadequate removal of waste
9
Q
What is tension?
A
• A force that pulls tissues (e.g muscle-tendon injuries); results in strain, cramp
10
Q
What is compression?
A
• A forceful blow to tissues; results in contusion , fracture
11
Q
What is shearing?
A
• A force that moves parallel to the tissues; Ex: vertebral disc injuries
12
Q
What is torsion?
A
• A twisting or turning force; an end of an object is twisted in one direction and the other end is stabilized or twisted in the opposite direction
13
Q
What is bending?
A
• A horizontal force causing the tissue to bend or strain; Ex: a spiral fracture or greenstick fracture
14
Q
What is stretching?
A
• The elongation of tissue (e.g ligaments); Ex: strain, sprain
15
Q
What do tendons resist?
A
• Tensile force
16
Q
What do bones resist?
A
• Compressive force
17
Q
What do ligaments resist?
A
• Tensile force
18
Q
What do discs resist?
A
• Tension, compressive, shear and torsion forces
19
Q
What is a bruise?
A
• Compression that causes bleeding under the skin
20
Q
What is a contusion?
A
• An acute compression causing hemorrhage of a muscle tissue
21
Q
What are muscle cramps?
A
• Acute painful involuntary muscle contraction caused by dehydration or an electrolyte imbalance
22
Q
What is a muscle spasm?
A
• A reflex muscle contraction caused by acute trauma; serves to protect or guard an area
23
Q
What is muscle hypertonicity?
A
• Increased activity of an otherwise normal muscle; no nerve or muscle pathology is present, but the resting tone of the muscle is greater than normal; may cause muscle imbalance with an inhibited/weak antagonist muscle
24
Q
What is muscle spasticity?
A
• Increase in muscle tone at rest; characterized by increased resistance to passive stretch, exaggerated deep tendon reflexes and possibly clonus; the result of an Upper Motor Neuron Lesion (UMNL)
25
What is a sprain?
• Stretching or tearing damage to a ligament; if ligamentous fibers are torn, it is reasonable to assume that the other tissue fibers are likely to have been torn (muscle, joint capsule, disc annulus)
26
What are the grades of sprains?
* Grade 1 (0-20%): minimal pain and loss of function, mild point tenderness, little or no swelling, and no abdominal motion when tested; stability of the joint in intact
* Grade 2 (20-75%): moderate pain, loss of function and swelling, moderate joint instability present
* Grade 3 (>75%): extremely painful with a major loss of function, tenderness, swelling and severe instability; surgical repair is probably indicated
27
What causes a sprain? Examples?
• End range loading. Sudden load (whiplash); a direct blow (lateral force to knee causing MCL sprain); repetitive overload (keyboard, typing); sustained postural overload (long hours at a workstation of studying)
28
How does a sprain present clinically?
* Decreased active range of motion with pain, especially in the direction that stretches the ligament or capsule
* Decrease passive range of motion with pain, especially in the direction that stretches the ligament or capsule
* Isometric muscle contraction causes no pain
* Local tenderness and occasionally edema or bruising
* May have pain on weight bearing (especially grade 1 and 2)
* Palpatory defect may be present in more severe sprains
* May produce joint instability
29
What are the residual or late effects of sprains?
• Fibrosis; subluxation; instability; proprioceptive and coordination/control problems; atrophy of related muscle (e.g. vastus medialis obliquus in knee injuries)
30
What is a strain?
• Acute stretch, tear, or rip in the muscle or tendon
31
What are the grades of strains?
• Grade 1 (50%): severe tearing with pain, loss of muscle function and a palpable deformity; surgical repair is probably indicated
32
What are causes of strains?
• Sudden contraction (most likely); sudden stretch; repetitive contraction (especially eccentric); sustained postural load; blow to a muscle (likely to be classified as a contusion or deep bruise)
33
How does a strain present clinically?
* Isometric muscle contraction is most provocative for pain and weakness
* decreased active range of motion with pain, either concentrically or eccentrically
* normal passive ROM without pain until end range in the direction that stretches the muscle or tendon
* local tenderness and occasionally edema or bruising
* palpatory defect may be present in more severe tears
34
What are the residual or late effects of strains?
• Fibrosis; subluxation; MFTPs; proprioceptive and coordination/control problems; atrophy; myositis ossificans
35
What are 4 types of synovial joint injuries?
* Acute synovitis: inflammation of the synovial membrane
* Dislocation: a complete separation between two articulating bones
* Subluxation: incomplete separation between two articulating bones
* Separation: increase in joint space between articulating surfaces
36
What are the types of intra-articular injury (4)?
* Osteochondrosis: degenerative changes of bone epiphysis or apophysis
* Osteochondritis dissecans: avascular degeneration of articular cartilage
* Apophysitis: inflammation of the tendon-bone junctions
* Traumatic arthritis: inflammation causing thickness of the synovium of a joint and resulting in crepitus and grating
37
What are the types of extra-articular injury (4)?
* Bursitis: inflammation of a bursa
* Capsulitis: inflammation of a joint capsule
* Paratendonitis: inflammation of the outside of a tendon or its sheath
* Tendinosis: degeneration of the collagen matrix of a tendon
38
What are the types of peripheral nerve injuries (5)?
* Burner: irritation and pain from nerve traction or stretching
* Neuritis: inflammation of nerve cells
* Sciatica: stretch of the sciatic nerve
* Carpal Tunnel Syndrome: compression primarily of the median nerve
* Morton’s Neuroma: tumor of a neuron in the foot
39
What are the stages of nerve injury?
• Neuropraxia, axonotmesis, neurotmesis
40
What is neuropraxia? Signs and symptoms
* Transient physiological block is caused by ischemia from pressure or stretch of the nerve with no wallerian degeneration
* Pain; none/minimal muscle wasting; muscle weakness; numbness; proprioception affected; recovery time: minutes to days
41
What is axonotmesis? Signs and symptoms?
* Internal architecture of the nerve is preserved, but axons are so badly damaged that wallerian degeneration occurs
* Pain; muscle wasting evident; complete motor, sensory and sympathetic functions lost; sensation is restored before motor function; recovery time: months (axons regenerate at a rate of 1 inch/month or 1 mm/day)
42
What is neurotmesis? Signs and symptoms?
* Structure of the nerve is destroyed by cutting, severe scarring, or prolonged severe compression
* No pain (anesthesia); muscle wasting; complete motor, sensory, and sympathetic functions lost; recovery time: months and only with surgery
43
What is the definition of inflammation?
• A fundamental reaction of the body tissues to protect, localize, and fight either an acute or chronic irritant or injury, as well as prepare the area for healing and repair
44
What is the purpose of inflammation?
• A protective mechanism to rid the body of the irritant and to promote repair and healing of the damaged tissues
45
What are some causes of inflammation?
• Trauma (sprain, strain, contusion); chemical agents (poisons, stings); pathogenic agents (infections); foreign bodies (splinters, sutures); hypoxia and ischemia; irradiation; autoimmune responses; immune reaction (hypersensitivity); thermal extremes of heat or cold (burns)
46
What is the inflammatory response?
• Either acute or chronic. Local reactions: 5 cardinal signs and symptoms; heat (calor); redness (rubor); swelling (tumor); pain (dolor); loss of function (function laesa, loss of motion or use)
47
What accompanies every injury? What determines the seriousness?
• Some degree of tissue damage; type of tissue involved and the extent of the tissue damage
48
How are the three phases of repair used to describe tissue injury?
* Each phase is discussed separately
* There is a large degree of overlap between the timing of the phases
* Sometimes repair of an injury involves: regeneration of the native cells; more often it involves the formation of scar tissue
49
What are the three phases of tissue injury and repair?
* Phase 1: acute inflammatory phase
* Phase 2: repair phase
* Phase 3: remodeling phase
50
What is phase 1? Purpose?
• Primarily involves the inflammatory process (cardinal signs). Purpose is to defend against foreign substances and infection, dispose of dead and dying tissue, immobilize injured area, compartmentalize area of damage
51
What are the physiological events in acute inflammation? Time frame?
* Neurologic; hemodynamic (changes in vascular flow, permeability); cellular
* A few hours to 2-3 days
52
What determines the physiological events of acute inflammation? Magnitude?
* Same regardless of the cause of inflammation
| * Depends on severity of injury, immune status
53
What are neurologic (vascular) events of acute inflammmation?
* Initial vasoconstriction: transitory and reflexive; usually lasts up to 30 seconds
* Gradual vasodilation: relaxation of reflexive spasm; causes “bleeding” to start
54
What are hemodynamic events of acute inflammation (5)?
* Vasoconstriction: from chemical mediators: NE (blood vessels), 5-HT (platelets)
* Vasodilation (hyperemia): relaxation of reflex vasospasm; chemical mediators: Histamine and PGs
* Slowing of blood flow (stasis): blood pooling (clotting)
* Margination of leukocytes: neutrophilic migration
* Permeability changes: mostly from chemical mediators (histamines, leukotrienes); occurs in capillaries and small venules (widening of endothelial cells); fluids leak (transudate and exudate cause edema); plasma exudate coagulates into a network of fibrin to start tissue repair
55
What are cellular events of acute inflammation (3)?
* Mast cells: already present in connective tissue; damage to connective tissue leads to activation and degranulation; release histamine (increased vasodilation and permeability); release heparin (anticoagulant)
* Circulating leukocytes: basophils (release anti-coagulants); neutrophils (phagocytosis)-release chemical mediators, primary job is phagocytosis of bacteria, magnifies inflammation greater than required in musculoskeletal injury
* Monocytes and macrophages: arrive approximately 5 hours post-injury; remove dead tissue debris (clean up tissue)
56
What are chemical events of acute inflammation (5)?
* Over 180 different chemicals involved in acute inflammation
* Sources include damaged cells, inflammatory cells, platelets, plasma, etc
* 5-HT: powerful vasoconstrictor
* Heparin: temporarily prevents blood coagulation
* Histamine: first chemical, strong vasodilator and increases permeability
* Bradykinins: increase permeability and pain, especially with PGs
* PGs: from released phospholipids (arachidonic acid cascade)
57
What is Phase 2 of injury, the repair phase?
• Purpose is to regenerate or repair lost and damaged tissue; some tissues regenerate native cells (skin, bone, lymph, liver, or kidney); musculoskeletal tissue repairs with connective tissue and scar formation (usually efficient, sometimes results in hypertrophic scarring or keloid formation)
58
What do the physiological events of the repair phase involve? What’s the time frame of phase 2?
* Granulation tissue formation, fibroplasia, scar formation and contraction
* Begins within 24 hours, may last from 48 hours to 6 weeks
59
What are the physiological events of the repair phase? Hallmark?
• Hallmark is synthesis and deposition of collagen
• Macrophages: remove cell debris, erythrocytes, and fibrin clot
• Granulation tissue: forms “gel-like” matrix of collagen, hyaluronic acid, and fibronectin
o Highly vascular and contains lymphatic cells to prevent edema formation
o Forms mesh-like framework for scar formation
• Fibroplasia (begins within hours after injury)
o Fibroblasts synthesize collagen and GAG (glycoaminoglycans)
o Initiates collagen synthesis and deposit
The integrity of the wound depends on this
The collagen is laid down haphazardly (at random)
The collagen is not fully oriented in the direction of tensile strength
Initially the quality of the collagen is an inferior type III collagen that is later replaced by the stronger, more appropriate type I collagen
o Myofibroblasts proliferate and migrate into the wound
60
What are the physiological events or repair phase?
• Wound contraction: begins once a scar has formed via myofibroblasts (4 days after injury, can take 6 months to 1 year to complete); contraction reduces wound size 5-10% over 6 weeks
61
What is the interstitial matrix of scarring made of?
• Fibrillar collagens, elastin, proteoglycan and hyaluronan
62
What is phase 3, the remodeling phase?
• Purpose is reorganization of the collagen fibers laid down during phase 2 (repair); collagen is remodeled to increase ability of damaged tissue to withstand stress
63
What are the physiological events of remodeling phase?
• During phase 2 collagen is laid down at random, haphazard
o Collagen with this type of arrangement cannot effectively resist tensile forces
o Tensile strength of tissue depends on the alignment of the collagen fibers
o Tensile strength of collagen is greatest in direction of the forces acting on it
o Remodeling involves the re-orientation of the collagen fibers
o Collagen fibers become arranged in line with the forces acting on the tissue
o Forces that remodel collagen fibers include: exercise, stretching, muscle contraction, manipulation, mobilization, transverse friction massage
• Collagen has a window of 8-10 weeks in which it can be re-oriented
• The collagen scar formation that results is only 80% as strong as the original tissue, which leaves the repair tissue vulnerable to re-injury
64
What is the time frame of phase 3?
• Repair and matrix formation begins in 2-4 weeks; may last from 3 weeks to 12 months or more
65
How does a tendon remodel?
• When the collagen fibers orient in the direction of the tensile forces acting on the tendon
66
What are the factors that delay healing?
* Intrinsic: age, chronic diseases, blood supply (circulatory disease); nutrition, neuropathy, nature of injured tissue, degree of damage
* Extrinsic: degree of immobilization, immune suppression, infection, irradiation, psychophysiologic stress
* Iatrogenic: medications, ischemia
67
What is the potential healing of soft tissues (4)?
* Cartilage: limited potential; primarily because of its poor vascular supply
* Ligaments: slower to heal because of less vascular supply; gradually form scar; may take as long as 1 year
* Skeletal muscle: muscle tissue heals with a collagen scar at the same rate as other vascular tissues
* Nerve: peripheral nerves have fair potential, depending on degree of damage; CNS nerves heal poorly
68
What are some points on tissue healing?
* Healing is unique to each patient
* Different types of tissue heal differently
* Age, motivation and compliance play a role
* Organic disorders can complicate and delay healing (diabetes)
* Heredity (genetic constitution) can be a factor in healing
* Psychosocial factor can complicate and delay healing
69
What are the 7 stages of the therapeutic order?
* 1. Establish the conditions for health
* 2. Stimulate the healing power of nature (VMN): the self-healing process
* 3. Address weakened or damaged systems or organs
* 4. Correct structural integrity (first and second order)
* 5. Address pathology (natural substances and modalities)
* 6. Address pathology (pharmacological or synthetic substances)
* 7. Suppress or surgically remove pathology
70
How would you address weakened or damages systems?
• Strengthen the immune system; normalize inflammatory function; balance regulatory systems; harmonize with your life force; decrease toxicity; optimize metabolic function; enhance regeneration
71
What are the first and second order interventions to correct structural integrity?
* First: manipulation, therapeutic exercise, massage or surgery for microtrauma, macrotrauma, repetitive stress, postural syndromes, congenital conditions
* Second: same, for structural problems that are the result of stress upon internal systems, eg digestive disorders
72
Where is the sympathetic innervation in the spinal cord? Parasympathetic?
* T1-L2
| * Cranial III, VII, IX, X; S2-4
73
Where do somato-visceral and viscera-somatic influences come from?
• Via central, peripheral, autonomic nervous systems
74
What are viscero-visceral reflexes?
• Local (influencing the structure which generated the impulses) or systemic (influencing other structures in response to a given stimuli)
75
What are psycho-somato-visceral reflexes?
• The mind influences the body and vice versa via complex interconnections and interactions
76
What does kinesiology provide knowledge for?
* Evaluation and diagnosis of structural involvement affecting health (congenital or acquired neuro-musculoskeletal disorders, immune disorders, systems/organ functional problems)
* Treatment for correction of resolution of structural deficits (NMT, therapeutic exercise to improve strength, control, coordination and balance)
77
What does kinesiology mean?
• “to move” and “to study”; study of motion or human movement
78
What is biomechanics?
• Applies the principles of physics to human motion; involves neurological, skeletal and musculotendinous structure
79
What is kinematics?
• The branch of biomechanics that describes the motion of the body, w/o regard to the forces or torque that may produce the motion
80
What are the two branches of kinematics?
* Osteokinematics: gross motion of joints in the cardinal planes (movement of the bone)
* Arthrokinematics: fine bone on bone motion within joints (mov’t of the joint surface)
81
What are the two types of kinematic motion?
• Translation: linear motion in which all parts of a body move in the same direction
o Rectilinear: gliding in a straight line
o Curvilinear: gliding in a curved line
• Rotation: motion in which body parts move in a circular path around a pivot point (axis of motion)
82
What are two ways to describe movement?
* Active: mov’t caused by muscle action
| * Passive: mov't caused by sources outside the body (push, or pull of gravity)
83
What is the anatomical position?
• Most widely used reference position; accurate for all aspects of the body; standing in an upright posture, facing straight ahead, feet parallel and close, palms facing forward
84
What is the fundamental position?
• Essential the same as anatomical except arms are at the sides and palms facing body (natural)
85
What are the planes of motion?
• Imaginary two-dimensional surface through which a limb or body segment is moved: sagittal (divides body into left and right), frontal (coronal, front and back), transverse (axial, upper and lower)
86
What is the axis of motion?
• Imaginary line perpendicular to the plane of motion and passing through the center of rotation
87
How do bones rotate within a joint?
• In a plane that is perpendicular (90) to the axis of rotation
88
How do the axes correlate to planes?
• X=frontal; Y=longitudinal (vertical); Z=sagittal
89
Where do flexion and extension occur?
• In sagittal plane, on frontal axis (runs anterior-posterior)
90
Where do abduction and adduction occur?
• In frontal plane, on sagittal axis (runs medial-lateral)
91
Where does rotation occur?
• In transverse plane, on longitudinal axis (runs superior-inferior)
92
What is the diagonal plane of motion?
• Axis of rotation is a combination of frontal and sagittal
93
What is osteokinematics?
• Describes the motion of bones relative to the three cardinal planes of the body (sagittal, frontal, transverse)
94
What is linear motion (gliding)
• Motion of one flat or nearly flat bone surface glides or slips over another without appreciable angulation or rotation (little motion): MC and MT joints, vertebral facet joints
95
What is angular motion (rotation)?
• Motion causing either an increase or decrease in the angle between two bones; may occur in any body plane; include flexion, extension, hyperextension; abduction; adduction; circumduction
96
What is the angular motion of flexion, extension, and hyperextension?
• Angular motion in the A-P plane; flexion reduces angle b/w elements; extension increases angle b/w elements; hyperextension passes the anatomical position
97
What is the angular motion of abduction and adduction?
• In the frontal plane; abduction moves away from the vertical axis; adduction moves toward vertical axis
98
What is the angular motion of circumduction?
• Circular motion without rotation; a combination of flexion, abduction, extension, and adduction performed in succession
99
What are supination and pronation (special mov’ts)?
* Supination: rotation of forearm so palm faces forward (upward)
* Pronation: so palm faces rear (downward)
100
What are inversion and eversion (special mov’ts)?
* Inversion: turning sole of foot inward or medially; standing with weight on outer edge of foot
* Eversion: sole of foot outward or laterally; stand with weight on inner edge of foot
101
What are plantar flexion and dorsiflexion?
* Plantar flexion: extension at ankle from neutral 90 (pointing toes)
* Dorsiflexion: flexion at the ankle from 90 (lifting toes)
102
What are elevation and depression?
* Elevation: motion in the superior direction (upward)
| * Depression: in inferior direction (downward)
103
What are protraction and retraction?
* Applies to thrusting the jaw, shoulders, or pelvis forward or backward
* Protraction: motion anteriorly in the horizontal plane (pushing forward)
* Retraction: posteriorly (pulling back)
104
What is thumb opposition and reposition?
• Important hand function that enables the hand to grasp objects; opposition is thumb mov't towards fingers or palm (grasping); reposition is mov’t back to the anatomical position
105
What are special mov’ts of the hand and digits?
• Radial and ulnar deviation (both flexion); abduction of fingers and thumb
106
What are special mov’ts of the trunk?
• Flexion, extension, lateral flexion
107
Where is rotation commonly seen?
• Head and trunk
108
What is a kinematic chain?
• A series of articulated segments linked together, for example, the connection b/w pelvis, thigh, leg, and foot
109
What do “open” and “closed” mean in reference to a kinematic chain?
* Use to indicate which end of the extremity is fixed (anchored) to the earth or an immovable object
* Open (OKC): distal segment of chain is NOT FIXED to earth or immovable object, therefore DISTAL segment is free to move (Ex: tibia moves on femur)
* Closed (CKC): distal segment IS FIXED to earth, therefore PROXIMAL segment is free to move (Ex: femur moves on tibia)
110
What are the functional classifications of joints?
• Synarthrosis (immovable); amphiarthrosis (slightly movable); diarthrosis (freely movable)
111
What are the structural classifications of joints?
• Fibrous (generally movable); cartilaginous (some immovable, some slightly movable); synovial (generally freely movable)
112
What is the classification of suture and gomphosis?
• Synarthrodial fibrous
113
Classification of Symphysis and synchondrosis?
• Amphiarthrodial cartilaginous
114
Classification of Syndesmosis?
• Amphiarthrodial fibrous
115
Classification of Arthrodial, ginglymus, trochoid, condyloid, sellar, enarthrodial?
• Diarthrodial synovial
116
What are fibrous joints?
• Bones joined by dense fibrous tissue; no joint cavity present; most are synarthrodial, some amphiarthodial (dependent on length of CT fibers connecting bones); suture, gomphosis, and syndesmosis
117
What are sutures?
* Synarthrodial fibrous; Occur only b/w bones of the skull; wavy bone edges interlock; joint filled with very short connective tissue fibers; continuous with periosteum
* Function: hold bones tightly together; allows bone growth during youth; ossified later in life (synostosis)
118
What is a gomphosis?
• Synarthrodial fibrous; Peg-in-socket fibrous joint; articulation of tooth into alveolar socket; fibrous connection is short periodontal ligament
119
What is a syndesmosis?
• Amphiarthrodial fibrous; bones connected by a ligament; cord or band of fibrous tissue; long collagen fibers, amount of mov’t depends on length of fibers
120
What are cartilaginous joints?
• Bones connected by some form of cartilage; no joint cavity; depending on length of collagen fibers, may be synarthrodial or amphiarthrodial; synchondrosis and symphysis
121
What is a synchondrosis?
• Synarthrodial cartilaginous; Bones connected by hyaline cartilage; Ex: epiphyseal plate joining diaphysis to epiphysis (temporary joint); costosternal joint
122
What is a symphysis?
• Amphiarthrodial cartilaginous; articular surfaces of bones are covered with hyaline cartilage; cartilage is fused to shock-absorbing pad of fibrocartilage; Ex: intervertebral joints, pubic symphysis
123
What are synovial joints?
• Bones separated by a fluid-filled joint cavity connected by ligaments of dense CT (permits freedom of mov’t); articular cartilage on ends of bones; articular capsule (fibrous capsule w/ inner synovial membrane); joint cavity (synovial cavity, small amount of synovial fluid); synovial fluid (produced by synovial membrane); reinforcing ligaments (outside of and blending into the capsule); most are diarthrodial, some are amphiarthrodial
124
What is synovial fluid?
• Occupies all free space within capsule and within cartilage; viscous fluid (large amount of hyaluronic acid); reduces friction b/w cartilages; nourishes articular cartilage
125
What are some additional features of some synovial joints?
* Fat pads b/w the capsule and synovial membrane or bone (hip or knee, provides cushion, adds stability, decreases friction)
* Fibrocartilage disc or meniscus separating articular surfaces (knee and TMJ, improves fir b/w articulating bones, stabilizes the joint, reduces wear and tear)
* Bursae (flattened sacs, bags): lines with synovial membrane, filled with synovial fluid, reduces friction b/w ligaments, muscles, tendons, bones
* Tendon sheath: elongated bursa wrapping around a tendon; lubricates moving tendons
126
What are some factors affecting synovial joint stability?
* Shape of the articular surfaces: deep ball-and-socket joint (hip_; determine possible mov’ts
* Number and position of ligs: more ligs create stronger joint; ligs are sufficient alone, require muscle and tendon
* Muscle tone: tendons crossing a joint are an important stabilizing factor; muscle tone keeps the tendons taut; significantly important in shoulder, knee, arch of foot
127
What are the 6 types of synovial joints (based on structure and type of motion)?
• Gliding, hinge, pivot, condyloid, saddle, ball-and-socket
128
What are gliding joints?
• Amphiarthrodial synovial; gliding motion along a flat articular surface; non-axial joints; Ex: facet joints of vertebrae, inter-carpal joints, inter-tarsal joints
129
What are hinge joints?
• Diarthrodial synovial; motion around an axis perpendicular to the long axis of a bone; convex surface of a bone fits into concave surface of another; motion in a single plane (uniaxial); permits flexion and extension only; Ex: ulna and humerus at elbow; femur and tibia at knee; finger and toe joints
130
What are pivot joints?
• Diarthrodial synovial; motion around a single axis parallel to the long axis of a bone; one bone has a projection that fits into the ligamentous ring of another bone; the projecting bone rotates on its longitudinal axis (uniaxial); Ex: atlantoaxial jt (axis and dens); proximal radioulnar jt
131
What are condyloid (ellipsoid) joints?
• Diarthrodial synovial; motion around two axes (biaxial); oval articular surface of one bone fits into a complementary oval depression in another; permits all angular motions; Ex: radiocarpal jt (wrist), MCP jts
132
What are saddle jts?
• Diarthrodial synovial; biaxial motion; articular surface of each bone is shaped like a saddle (concave one direction, and convex in other); unique jt allows several motions of thumb (flexion-extension, adduction-abduction, slight rotation, circumduction); thumb is only example: 1st carpometacarpal jt, allows for opposable thumb
133
What are ball-and-socket jts?
• Diarthrodial synovial; triaxial motion; a spherical or hemispherical head of one bone fits into a cuplike depression of another; permits most freely moving synovial jts (flexion-extension, adduction-abduction, rotation, diagonal mov’ts, circumduction); Ex: head of humerus into glenoid cavity, head of femur into acetabulum
134
What is skeletal muscle?
• Always attached to bone; responsible for mov’t of body and all joints; aids fluid and blood mov’t; contraction produces force (torque) to cause jt mov’t; provide protection, posture and support; over 600 of them, !40-50% body weight; pairs of SM (215) cooperate to perform opposite actions at the jts they cross
135
What is aggregate muscle action?
• Muscles work in groups rather than independently to achieve a given joint motion
136
What is the effect of different shapes and fiber arrangements of SM?
• Affect a muscles ability to exert force; affect the range through which a muscle can effectively exert force onto a bone
137
What effect does cross section diameter have on SM?
• Affects muscle’s ability to exert force: greater cross section diameter yields greater force exertion
138
What is the effect of a muscle ability to shorten?
• Longer muscles can shorten through a greater range and are more effective in moving jts through large ranges of motion
139
What are the 5 different fiber arrangements of SM?
• Parallel, fusiform, pennate, convergent, circular
140
What are parallel muscles?
• Fibers arranged parallel to the length of the muscle; produce a greater range of mov’t than similar sized muscles with pennate arrangement; Ex: Sartorius
141
What are fusiform muscles?
• Spindle shaped; fibers arranged parallel and with large cross section diameter; produce a greater range of mov’t that similar sized muscles with pennate arrangement; Ex: biceps brachii
142
What are pennate muscles?
• Feather-like; uni- bi- and multi- pennate; have shorter fibers; arranged obliquely to their tendons in a manner similar to a feather; arrangement increases the cross sectional area of the muscle, thereby increasing the power (tension); uni (extensor digitorum), bi (rectus femoris), multi (deltoid)
143
What are convergent muscles?
• Broad origin, pointed insertion; direction of pull can be varied (versatile); ex: pectoralis major
144
What are circular muscles?
• Concentric fibers adjust opening; sphincter, orbicularis oris; relaxed is open, contracted is closed
145
What is muscle strength?
• The maximal force a muscle can generate for a single maximal effort; the amount of tension a muscle produces
146
What is muscle power?
• Work done over a given period of time (P= w/t); a muscle contracting in a very brief amount of time
147
What is muscle torque?
• Muscle force causing rotary mov’t of a body around an axis; a turning or twisting force
148
What is muscle contraction?
• Tension developed in a muscle as a result of a stimulus; can be used to cause, control, or prevent jt mov’t (initiate or accelerate mov’t of a body segment, slow down or decelerate mov’t, prevent mov’t by external forces); all muscle contractions are with isometric or isotonic
149
What is isometric contraction?
• Tension in a muscle w/o motion of a jt (static contractions); occurs when tension is the same as the force applied to that muscle; used to stabilize jts
150
What is isotonic contraction?
• Contraction without much change in force (maintains tension under a constant load); tension develops for either initiating or controlling mov’t (dynamic contractions);
151
What are the two types of isotonic contraction?
• Concentric (shortening); eccentric (lengthening)
152
What is a concentric contraction?
• “coming to the center”; Tension as the muscle shortens; occurs when a muscle develops enough tension to overcome resistance being applied to it; used to initiate mov’t against gravity or resistance
153
What is an eccentric contraction?
• “away from the center”; muscle lengthens under tension; muscle tension is less than the resistance applied to it; results in controlled jt motion; used to decelerate body segment mov’t
154
What is the line of pull?
• The direction of mov’t produced by the contracting muscle; the pull of a muscle from its origin to insertion; may change during joint motion
155
What is the line of pull a function of?
• The muscles attachment; the plane of joint motion; the muscle’s distance from the joint’s axis of rotation
156
What happens if the line of pull is altered from its optimal position?
• (due to muscle weakness or poor posture); the muscle will be inefficient, work harder and have more strain put upon it; can lead to muscle and/or jt injury; can lead to muscle weakness, hypertonicity or trigger pts and to aberrant sensory input which may result in muscle imbalance and joint dysfunction
157
What are two examples of the concept of line of pull?
* Pec major is primarily a flexor of the humerus, but also adducts humerus b/c of its line of pull in certain arm positions; when the arm is abducted, the line of pull moves and the pec major contributes to abduction of the humerus
* Ideal posture vs. chronic forward head posture, strain taken off SCM, and put on levator scapulae and semispinalis capitis
158
What is the angle of pull?
• Angle b/t the line of pull of the muscle and the bone on which it inserts; changes with every degree of joint motion; vertical component is always perpendicular to the lever (attachment) and causes rotational mov’t at the jt axis (at 90, the force is 100% rotational); horizontal component is always parallel to the lever and causes non-rotational mov’t (at 90, rotational and stabilizing forces are equal)
159
What is the summary of muscle action?
• A muscle produces a contraction (tension) which causes rotational mov’t at a jt (torque) by pulling on its insertion (line of pull) at a constantly changing angle (angle of pull) which affects the force applied to that body segment (jt)
160
What is muscle action dependent on?
• Number of motor units activated; type of motor unit activated; size of the muscle; initial muscle length (max 20% stretch; angle of the muscle and joint; speed of muscle contraction
161
What is reverse-action of concentric muscle contractions?
• When a muscle contracts it pulls both ends toward the center of the muscle; if neither of the bone’s attachments are stabilized, the muscle contraction pulls both bones toward each other; usually the less stable bone moves toward the other; in some mov’ts this can be reversed
162
What are two examples of reverse-action of concentric muscle contractions?
* Reverse-action: biceps curl exercise (open chain); biceps brachii has its origin (least movable bone) on scapula and its insertion (most movable bone) on radius
* Reversed process: a chin up (closed chain), radius (least movable bone) is relatively stable and scapula moves
163
What is the range of motion?
• Depends upon length of muscle fibers; long fibers have large range of motion (parallel and fusiform muscles)
164
What is power?
• Depends on total number of muscle fibers; many fibers have greater power (convergent, unipennate, bipennate, multipennate)
165
What are the properties of muscle force production and mov’t?
• Irritability or excitability; contractility; extensibility; elasticity
166
What is irritability (excitability)?
• Property of muscle being sensitive or responsive to chemical, electrical or mechanical stimuli
167
What is contractility?
• Ability of muscle to contract and develop tension (internal force) against resistance when stimulated
168
What is extensibility?
• Ability of muscle to be passively stretched beyond its normal resting length
169
What is elasticity?
• Ability of muscle to return to its original length following stretching
170
How do muscles function?
• Work in groups to cause mov’t at a joint; any muscle can contribute, or multiple may be involved in an injury; one muscle may cause more than one action (same or different jt); may be innervated by multiple nerves, or one nerve for multiple muscles (interdigitation); muscles may have common tendon (Achilles, triceps)
171
What are the roles that muscles work in?
• Prime mover (agonist); antagonist; synergist; stabilizer (fixator)
172
What are prime movers (agonists)?
• Assume the major responsibility for producing a specific mov’t
173
What are antagonists?
• Oppose or reverse the mov’t by a prime mover; relaxed when prime mover is active (allowing mov’t at jt); regulate that mov’t by partially contracting to provide some resistance or to slow or stop the action; Ex: running, knee extends, hamstring relaxes or slowly releases to control momentum
174
What is a synergist?
• Performs or assists the same jt motion as the agonist; two muscles are call synergists if their contraction causes mov’t in the same direction
175
What are stabilizers (fixators)?
• Synergists that act to control motion of the prime mover; immobilize the origin of the PM so that the PM can act more efficiently; tends to be continuous low-level muscle activity with either isometric or eccentric pull
176
What is an example of a stabilizer?
Deltoid is PM of arm abduction; originates on scapula, which is moveable; when it contracts to move shoulder, pec minor, rhomboids, and trap muscle hold (stabilize) the scapula
177
What is a lever?
• A rigid bar that moves on a fixed point; ex: bones of the skeleton; function is to convert force into torque, the work of a contracting muscle to the force of a rotating bone; forces are muscles, gravity, and external physical contacts
178
What is a fulcrum?
• A fixed point of leverage; ex: joints of the body
179
What is effort?
• The force applied to move a resistance; tension (torque) of the muscles
180
What is load?
• The resistance to be moved; bone, tissue mass and objects to be moved
181
What is mechanical advantage (power lever)?
• Load is close to the fulcrum; effort is applied far from the fulcrum; a small effort applied over a relatively long distance can be used to move a large load over a small distance; such a lever operates at a mechanical advantage and is commonly called a power lever because it can lift heavy loads
182
What is mechanical disadvantage (speed lever)?
• Load is far from the fulcrum; effort is applied near the fulcrum; the force exerted must be greater than the load moved; these levers are useful because they allow the load to move rapidly through a larger range of motion and are called speed levers
183
What is the point of levers?
• Allows a muscle to move a heavier load or to move a load farther or faster than it otherwise could
184
What happens if there is a small difference in the site of a muscle’s insertion?
• Can translate into large differences in the amount of force needed to move a given load
185
What are the classes of levers?
• First, second, and third class
186
What is a first class lever?
• Fulcrum lies b/w the effort and the load (resistance); effort is applied at one end of lever and load lies on other end with fulcrum b/w; atlanto-occipital jt lies b/w posterior cervical muscles and the weight of the forehead and face
187
What is a second class lever?
• Load is b/w fulcrum and effort; great strength, less speed and range of motion; plantar flexion of foot; rare in the body, but they work at mechanical advantage
188
What is a third class lever?
• Effort at pt b/w load and fulcrum; most levers in body are third class; great speed with mechanical disadvantage; allow rapid mov’t with little shortening of the muscle; fast large mov’ts with little effort; biceps effort is applied to forearm b/w elbow and weight of hand and forearm
189
How is muscle activity modified with differences in positioning of effort, load, and fulcrum?
• With respect to Speed of contraction; range of motion; weight of the load that can be moved
190
What is difference between mechanical disadvantage and advantage levers?
* Disadvantage=speed levers; effort closer to load than fulcrum; force is lost (not strong); speed, range of motion if gained
* Advantage=power levers; effort farther than load from fulcrum; force is gained (strong); speed, ROM is lost, but stability is gained
191
What is the structure/ functional organization of skeletal muscles?
* Skeletal muscle surrounded by epimysium; contains muscle fascicles
* Muscle fascicle surrounded by perimysium; contains muscle fibers
* Muscle fiber surrounded by endomysium; contains myofibrils
* Myofibril surrounded by sarcoplasmic reticulum; consists of sarcomeres
* Sarcomere contains thick and thin filaments
192
What is a neuromuscular junction?
• Site where axon and muscle fiber communicate
193
What are the five basic components of the NMJ?
• Motor neuron; motor end plate; synaptic cleft; synaptic vesicles; neurotransmitters
194
What is happens in muscle contraction?
• Motor nerve impulses cause release of ACh from synaptic vesicles which bind to receptors on the motor end plate and generate muscle contraction
195
What happens in muscle relaxation?
• Acetylcholinesterase breaks down ACh; motor neuron impulses stop; Ca moves back into sarcoplasmic reticulum; myosin and actin binding prevented
196
What is a motor unit?
• A single motor neuron and all the muscle fibers it controls; the functional connection b/w the nervous system and the muscular system; when a motor unit fires, all the muscle fibers contract together
197
What creates both large and small motor units, and what is each useful for?
* Small: one muscle fiber innervated by several motor neurons; fine control; extraocular muscles (20 fibers); one muscle fiber may act with several motor units depending on demand
* Large: one neuron may innervate several muscle fibers; strength control; gastroc (1000 fibers)
198
What is a muscle twitch?
• A single brief stimulus to a muscle that produces a quick cycle of contraction and relaxation lasting less than 1/10 second; a single twitch contraction is not strong enough to do any useful work; normal activities require more tension than is produced by as single fiber twitch, they involve sustained muscle contraction of the hole muscle
199
What is a treppe?
• Relaxation is complete before next stimulus occurs, each contraction is a little stronger than previous
200
What is wave summation (temporal summation)?
• Is a second stimulus is applied before relaxation is complete, the second contraction is greater
201
What is tetanus?
• With higher frequency of stimulation, muscle relaxation between contractions is reduced
202
What is incomplete tetanus?
• Produces peak tension during rapidly alternating cycle s of contraction and partial relaxation
203
What is complete tetanus?
• Sustained maximal contraction at peak tension, typical of normal muscle contraction
204
What happens during a twitch?
• Three phases (latent, very short, contraction, longer, relaxation, longest); occurs with low frequency stimuli (up to 10 stimuli/sec); each stimulus produces an identical twitch response
205
What happens in treppe?
• Gradually increases contraction intensity during sequential stimulation; occurs with moderate frequency stimuli (b/w 10-20 stimuli/sec); each subsequent contraction is stronger than previous one until, after a few stimuli, all contraction are equal (plateau)
206
What happens in wave summation (temporal summation)?
• A rapid sequence of stimuli cause the muscle twitches to fuse together, each contraction being stronger than the one before, gradually generates more strength of contraction; occurs with higher frequency stimulation (20-40 stimuli/sec); each stimulus arrives before the previous twitch is over; as the frequency of stimulus increases, the frequency of contraction increases
207
What happens during incomplete tetanus?
• Very rapid sequence of stimuli (20-40 stimuli/sec); sustained fluttering contractions; muscle fibers partially relax b/w contraction
208
What happens in complete tetanus?
• Very rapid sequence of stimuli (40-50 or > stimuli/sec); no relaxation b/w contractions; twitches fuse into smooth, prolonged contraction
209
What are the three functional classifications of neurons?
* Sensory: afferent neurons; transmit impulses from receptors to the brain or spinal cord
* Motor: efferent neurons; transmit impulses from brain or spinal cord to effector sites such as muscles, glands or organs
* Interneuron: association neurons; transmit impulses from one neuron to another
210
What are the three types of nerve fibers?
* “A” fibers: myelinated; Subtypes: A alpha (100 ms), fastest conducting and largest diameter, motor efferents, muscle spindle afferents; A beta (50 ms), touch and pressure afferents (mechanoreceptors); A gamma (20 ms), motor efferent to muscle spindle; A delta (15 ms), skin temperature and pain (noxious stimuli)
* “B” fibers: (7 ms) myelinated, slower, slower preganglionic
* “C” fibers: (1 ms) unmyelinated; slower conducting than A fibers and smallest diameter; pain (burning, aching); sympathetic postganglionic
211
What is the spinal cord reflex arc?
• Basic functional unit of nervous system; automatic response to stimulus without conscious thought
212
What are the 5 basic components of the spinal cord reflex arc?
* Sensory receptor: transmits action potentials stimulated by sensation
* Sensory neuron: transmits impulses to spinal cord
* Interneuron: connects or switches impulses to other neurons
* Motor neuron: transmits motor impulses
* Effector organ: responds with reflex contraction of muscle or gland
213
What is the loop of the functional spinal cord reflex arc?
* Controlled condition: a stimulus or stress (pain, injury, inflammation, etc) disrupts membrane homeostasis by altering the current controlled condition
* Receptor: the receptors are sensory neurons which relay nerve impulses to a central control center (spinal cord)
* Control center: the control center (spinal cord) is an integrating center of neurons in the CNS. It relays the information to motor neurons
* Effectors: the motor neurons initiate some response by an effector organ (muscle or gland) to counteract the stimulus that originally disrupted homeostasis
* Return to homeostasis: the action of the effector organ returns the body process to within its normal homeostatic range
214
What is proprioception?
• The sense of position and mov’t of one’s own limbs and body without using vision (somatosensory); sense of body and limb position; sense of speed and direction of limb joint mov’t; sense of muscle length and tension
215
What are the 3 types of mechanoreceptors that detect proprioception?
• Muscle spindle receptors; golgi tendon organs; joint kinesthetic receptors
216
What are muscle spindle receptors?
• Located within fleshy part of a muscle; consist of intrafusal muscle (ends are contractile, attach to extrafusal) enclosed in extrafusal muscle fibers (voluntary); detects rate of muscle fiber stretch and length; change in length helps coordination and efficiency of contraction
217
What are the 2 types of intrafusal fibers?
• Nuclear bag fibers and nuclear chain fibers?
218
What are nuclear bag fibers?
• Nuclei concentrated in central “bag” part of fiber; ends are striated and contractile; contractile fibers attached to extrafusal; contractile ends receive input from gamma motor neurons; sensitive to sudden rate of change in muscle length (phasic)
219
What are nuclear chain fibers?
• Nuclei in “chain-like” order in center of fiber; ends are striated and contractile; contractile fibers are attached to ends of nuclear bag muscle fibers; sensitive to steady changes of length of muscle (tonic)
220
What is the central non-contractile region of bah and chain wrapped in?
• Sensory nerve endings that send input about length of spindle to CNS
221
What are the 2 types of sensory nerve endings?
* Primary, type 1a fiber: annulospiral sensory ending; larger diameter; conduct impulses faster (100ms); respond to rate of change in muscle fiber length
* Secondary, type 2 fiber: flower spray sensory endings; smaller diameter; conduct more slowly; respond to overall length of muscle fiber
222
How are muscles stretched?
• By contraction of antagonist muscles and by movements that occur when we lose our balance
223
What do muscle spindles sense and what do they do?
• Sense changes in muscle tension and compensate for stretch; sense changes in muscle length b/c spindle stretches as muscle stretches
224
What does stretching activate?
• Sensory neurons of spindle causing them to signal the spinal cord and brain; CNS then activates alpha motor neurons that cause the muscle (extrafusal ) to contract and resist further stretching
225
What are the two ways of responding to stretch?
* Monosynaptic spinal reflex: makes a rapid adjustment to prevent fall
* Controlled by cerebellum: regulates muscle tone; ie the steady force of a non-contracting muscle to resist stretching
226
What do gamma motor neurons do?
• Let the brain preset the sensitivity of spindle to stretch
227
What happens when the brain signals gamma motor neurons to fire?
• The intrafusal muscle fibers contract and become tense so that very little stretch is needed to stimulate the sensory endings
228
Why is making spindles highly sensitive advantageous?
• b/c balance reflexes have little margin of error
229
What are Golgi tendon organs?
• Encapsulated nerve endings located at the junction of tendon and muscle; ends have many terminal branches associated with bundles of collagen fibers in tendon; produces sudden relaxation of muscles; plays a role in muscle tone imbalance, muscle spasm and tender points
230
What do Golgi tendon organs detect?
• Force of muscle contraction; tension applied to the tendon; prevents contracting muscles from applying excessive tension to tendons
231
What is the mechanism of how Golgi tendon organs work?
• Tendons stretch as the muscle contracts, causing increased tension at tendon, which stimulates Ib sensory neurons of Golgi (only sensitive to intense stretch); sensory neurons enter spinal cord and synapse with inhibitory interneurons, which synapse with alpha motor neurons (inhibitory neurotransmitter released, inhibits alpha motor neurons which innervate the extrafusal muscle); muscle relaxes and reduces tension to tendon, protects tendon and muscle from damage
232
What are the dynamic and static responses of Golgi tendon organs?
* Dynamic: sudden increase in muscle tension causes decrease in muscle tone via involuntary muscular relaxation
* Static: a sustained or gradual increase in muscle tension causes a decrease in muscle tone
233
What is the clinical application of the Golgi tendon organ?
• Arranged in a series, respond to slow stretch by resetting a muscles’ length and inhibiting its synergistic stabilizers while facilitating its agonist
May serve a protective function by reflexively inhibiting its agonist at the end range of joint motion
234
What are the other key points to know about muscle spindles?
• Nuclear bag fibers (primary afferent only, fast stretch, dynamic); chain fibers (primary and secondary afferents, slow stretch, static);
235
What are the other key points to know about Golgi tendon organs?
• Dynamic response (quick stretch); static response (postural tone)
236
What are joint kinesthetic receptors?
• Located in and around synovial joint capsules; encapsulated and free nerve endings; stretch receptors
237
What do joint kinesthetic stretch receptors detect?
• Direction of mov’t of jt; acceleration/deceleration of jt; pressure in jt; excessive jt strain; postural changes (along with input from skin receptors; Ruffini and Merkel’s discs)
238
What are the three types of joint kinesthetic receptors?
• Pacinian corpuscles; Ruffini corpuscles; free nerve endings
239
What are Pacinian corpuscles?
• Located in CT and synovial jt capsules; respond to rapid pressure changes, stretch, and acceleration and deceleration of jt mov’t
240
What are Ruffini corpuscles?
• Located in synovial capsules and ligaments; respond to deep rapid and sustained pressure; especially responsive to lateral stretch; detect changes in joint angles; ligament receptors adjust muscle tone
241
What are free nerve endings?
• Located in most body tissues (jt capsules, ligaments, tendons, fat pads, menisci, periosteum); respond to rapid and sustained pressure
242
What are common locations of small Ruffini?
• Capsule (fibrous capsule and part of synovial membrane); capsular and cruciate ligaments; knee menisci
243
What are common locations of pacinian corpuscles?
• Fibrous capsule; adipose tissue; ligaments; knee menisci; annulus fibrosis cervical discs
244
Where are large Ruffini (Golgi tendon organ) found?
• Ligaments, capsular, intracapsular, extracapsular); capsular, b/w fibrous and synovial layers; menisci; cervical discs
245
Where are free nerve endings found?
• Capsule (fibrous and intima); fat pads; ligaments; menisci
246
What is the proprioceptors’ effect on muscle tone?
• A simple reflex arc: automatic response w/o conscious though; affect tone via three reflexes: quick stretch reflex, reciprocal inhibition, autogenic inhibition
247
What is the quick stretch reflex?
• Reflex response from muscle spindles; produces contraction of the muscle being stretched
248
What are the functions of the quick stretch reflex?
• Monitors status of muscle activity; guards against potential injury; respond to rapid and sustained pressure
249
What is the sequence of events in the quick stretch reflex?
* Stretching (via muscle contraction) stimulates the muscle spindle (intrafusal); within the spinal cord the sensory neuron activates the alpha motor neuron (monosynaptic); the alpha motor neuron stimulates the muscle (extrafusal) to contract and to resist the stretch
* 1) muscle is stretched 2) muscle spindle afferent to spinal cord 3) monosynaptic 4) alpha motor neuron stimulates agonist
250
What is reciprocal inhibition (reciprocal innervation)?
• Reflex response from muscle spindles; inhibits the muscle opposite the contracted muscle; function is to induce inhibition (relaxation) of an antagonist so that the agonist can contract and cause jt mov’t
251
What is the sequence of events of reciprocal inhibition?
* Stretching (via muscle contraction) stimulates the muscle spindle (intrafusal); w/in spinal cord sensory neuron activates an inhibitory interneuron which sends inhibitory signals to the antagonist of the muscle that was stretched; the antagonist is inhibited (relaxed) to allow the agonist to contract and cause jt mov’t
* 1) muscle is stretched 2) muscle spindle afferent to spinal cord 3) inhibitory interneuron relaxes antagonist
252
What is autogenic inhibition?
• Reflex response from Golgi tendon organs; an inhibitory response to a muscle that develops too musche tension (eithr via shortening or lengthening); fuctions to guard against potential injury to a muscle’s fibers, muscle relaxation reduces tension applied to the muscle and tendons and protects them from damage
253
What is the sequence of events in autogenic inhibition?
* Stretching the tendon (via muscle contraction or passive stretch) increases the tension in the tendon and activates the afferent Golgi tendon organ neurons (Ib); the Golgi tendon organ neurons synapse in the spinal cord with inhibitory interneurons; the interneuron inhibits the contracting muscle (agonist) and activates the antagonist; the contracting muscle relaxes and the antagonist cotracts
* 1) GTO stretched 2) Ib afferent 3) inhibitory interneuron relaxes agonist 4) excitatory interneuron contracts antagonist
254
What are the clinical applications of these reflexes?
• Severalclinical tenchinqies use thes reflexes; NMT reflexes used are post-isometric relaxation, muscle energy technique, strain-counterstrain
255
What are depp tendon reflexes?
• Part of a routine orthopedic and neurological examl test the integrity of the componentent of the simple reflex arc and contributes to determining if there is a lower motor neuron lesion or an upper motor neuron lesion
256
What is Arthrokinematics?
• Describes the motion that occurs b/w the articular surface of jts; most jt surfaces are curved, with one convex and one concave
257
What is important about the convex-concave relationship of jts?
• Increases contact surface area of the jt; contributes to increased jt stability; increases dissipation of contact forces; helps guide motion b/w the bones
258
What are the five movements that occur b/w jt surfaces?
* Roll: a tire rotatinf (rolling) across the pavemtn
* Slide: (glide) a stationary tire sliding ona stretch of icy pavement
* Spin: a spinning top on one spot on the floor
* Distraction and longitudinal traction: jt surfaces are pulled apart
* Compression: decrease in the space b/w two jt surfaces
259
What happens in rolling motion of jts?
• Multiple pts along one rotatinf articular surface contact multiple pts on another; analogous to a tire rotating on road; Ex: femoral condyles rolling on a tibial plateau; roll occurs in the direction of mov’t; occurs on incongruent (unequal) surfaces; usually occurs in combo w/ sliding or spinning
260
What happens in sliding motion of jts?
• A single pt on one articular surface contacts multiple pts on another; when a mobilization technique is applies to produce a slide in the jt it is referred to as a glide; analogous to a stationary tire sliding on ice road; Ex: carpal bones sliding along their facet surfaces; the more congruent the surface aream, the more sliding there is
261
What happens in spinning motion of jts?
• A single pt on one articular surface rotates on a single pt on another (rotates around a stationary longitudinal mechanical axis); analogous to a spinning top on floor; Ex: head of radius at humeroradial jt during pronation and supination (spin does not occur by itself during normal jt motion)
262
What is distraction and longitudinal traction?
• Jt surfaces are pulled apart; used to stretch a jt capsule and mobilize a jt; distraction is perpendiculat to body (pull hip or shouler out to side), traction is parallel (pull hip down, or lengthening of vertebrae)
263
What is comnpression?
• Decrease in the space b/w two jt surfaces; adds stability to a jt; normal response to muscle contraction; Ex: pushing hip inwards
264
What is the convex-on-concave and concave-on-convex rule?
* Describes the relationship of rolling and sliding motion within a jt when one jt surface is convex and the other concave
* Convex-on-concave: when the concave side is stabilized (anchored) the convex slides (glides) in the opposite direction as it rolls
* Concave-on-convex: when convex side is anchored the concave slides in the same direction as it rolls
265
What is the clinical significance of the convex-concave rule?
* Basis for jt mobilization techniques: clinician must aaply external force to restore natural arthrokinematic motions of jt
* Physiological mov’ts: done voluntarily, osteokinematics
* Accessory mov’ts: meaning the mov’ts of jt and tissues that are needed for normal ROM, but can’t be done voluntarily; ligament and jt capsule limitations (tightness) cause mov’t restrictins or aberrant jt motion
* Jt play: occur only as response to outside force; determined by jt capsule’s laxity; can be demonstrated passively, but not performed actively
* End-feel: a way to interpret and measure joint play mov’ts
266
How is the convex-concave rule used in treatment?
* Often combines facilitation of physiological mobilization (osteokinematics) and accessory mov’ts (arthrokinematic) to restore a particular jt mov’t
* Follow the rule to restore normal jt play which will increase pain-free jt ROM
267
What are the mov’ts of the glenohumeral jt?
* Roll, slide and spin: glenohumeral abduction roll, spin roll, slide, spin
* Roll and spin w/o slide: glenohumeral abduction roll w/o slide
268
What are the motions of the knee?
* convex on concave : Knee extension: roll and slide spin
| * concave on convex: knee flexion: slide and roll (w/o spin)
269
what is a plane?
• A flat surface determined by the position of three points in space: sagittal; frontal (coronal); transverse (axial)
270
What is plane motion?
• Motion in which all points of a rigid body move parallel to a fixed plane (2-D)
271
What motion occurs in the sagittal, frontal, and transverse planes?
* Sagittal: flexion, extensions
* Frontal: right lateral flexion, left lateral flexion
* Transverse: rotation
272
What is out of plane motion?
• All points of a rigid body do not move in a single plane (3-D)
273
What is an axis?
• A line; rotation or translation occur around /along it
274
What is the x-axis?
• Line passes horizontally from side to side; frontal or coronal axis; mov’t around it is in sagittal plane
275
What is the y-axis?
• Longitudinal or vertical axis; perpendicular to ground; axis of the transverse plane
276
What is the z-axis?
• Sagittal axis; lie from back to front; axis of the frontal plane
277
What are degrees of freedom?
• Number of ways a body can move; one degree is translation or rotation about one axis; spinal segments have 6 degrees (3 translations and 3 rotations)
278
What is the instantaneous axis of rotation (IAR)?
• An axis perpendicular to the plane of motion that passes through a point that is instantaneously not moving; used to describe any vertebral motion in a 2-D plane; can shift with different force vectors applied to a vertebra; differs under changing loads, and is different for cervical, thoracic, and lumbar spinal segments
279
What is a motion segment?
• The functional unit of the spine; smallest spinal segment with biomechanical characteristics similar to those of entire spine; 2 adjacent vertebrae and their interconnecting disc, joints, capsule, and ligaments; 6 degrees of freedom
280
What is coupled motion?
• Consistent association of one motion (translation or rotation) about one axis with another motion about a second axis; one motion cannot be produced without the other; two motions occurring at the same time along two different axes
281
What is an example of coupled motion?
• Bending neck to left or right, to the left involves right couples axial rotation of the upper cervical spine, and left coupled AR of the subaxial cervical spine; and vice versa
282
What is loose-packed joint position?
• Joint capsule and ligaments are most relaxed; maximum joint play is possible; articulating surfaces are maximally separated; position used for traction or joint mobilization; Ex: when facet joints are half-way between flexion and extension
283
What is closed-packed joint position?
Capsule and ligaments are maximally tightened; there is no joint play; there is maximal contact b/w the articular surfaces; Ex: when facet joints are in full flexion or extension
