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The study of movement & the active & passive structures involved
Biomechanics – evaluates the motion of a living organism and the effects of force, internal or external, on the organism
Kinetics – Describes the effect of forces
Kinematics – describes motion without respect to forces
What are the Applications of Kinesiology to PT
- Manual muscle testing
- Evaluation of mechanics of injury
- Therapeutic exercise prescription
- Joint mobilization
- Assessment of gait and posture
Name and define the Two pure types of Kinematics motion?
- Translatory - Movement along a straight pathway (unconstrained segment)
- Each point on the segment moves through the same distance at the same time
- Doesn’t occur in a pure sense in the body
- Rotary Motion - occurs around a fixed axis.
- Each point moves through the same angle at the same time.
- The human body rarely has a fixed axis and so an instantaneous axis of rotation is used to determine where the axis is during the range of motion of a joint
What is the name for the type of kinematic motion which includes both rotation & translation
Name, and describe the two positions commonly used in anatomy texts?
Anatomic position - serves as our reference position
Fundamental - Same as Anatomic but hands face medially
What is Osteokinematics?
Osteokinematics describes the motion of bones; typically around an axis or along an axis.
These motions occur in one of 3 Planes of motion
Axes of rotation with regard to planes of motion
Name all 3 planes of motion in Osteokinematics and list the axes of rotation for each plane?
- Mediolateral axis – Sagittal plane
- Anteroposterior axis – Frontal plane
- Vertical Axis – Horizontal plane
Name the Factors influencing Osteokinematics?
- Joint surface
- Tissue bulk
- Connective tissue
- Bony limitation
Name some of the most common Osteokinematic Movements?
Name the Osteokinematics: for the Scapula?
- Protraction /Retraction of scapula
- Elevation /Depression of scapula
- Upward rotation / Downward rotation of scapula
Name the Typical Osteokinematic motions that occur in Multiplanes?
- Pronation / Supination (at ankle and subtalar joint)
Name and define the 3 Types of Arthrokinematic Motions?
- Roll - Movement in which points, at equal intervals, on a moving joint surface contact points on the opposing surface.
- Example: Ball rolling on the ground
- Glide - Movement in which a single contact point on the moving surface contacts numerous points on the opposing surface
- Example:Tires sliding on an icy road
- Spin - Rotation around a stationary mechanical axis
- Example:A top spinning or the stationary axel of a car
In what Atherokinematic motions does spin occur?
- Where spin occurs
- Forearm pronation/supination
- Shoulder flexion/extension
- Hip flexion/extension
- SC joint rotation
T/F - Glide can occur alone but Roll and glide occur together?
Because if only roll took placethe moving bone wouldtend to dislocate, and If only glide took place, the moving bone would tend to impinge and prevent full ROM.
What are the Two Rules to Determine Arthrokinematic Motions for a Particular Osteokinematic?
- 1. Decide which direction the shaft of the bone is traveling
- -Roll is always in the direction of bone movement (distal aspect of shaft -
Example: If the tibia moves anterior then roll will also be anterior
2. Determine which joint surface is relatively fixed (stable) -
If the convex segment is fixed and the concave segment is movingRoll and Glide occur in SAME direction
-If the concave segment is fixed and the convex segment is movingRoll and Glide occur in the OPPOSITE direction
Shoulder Abduction What direction is the upper arm traveling?
What bone is relatively fixed?
The fixed bone has what type of joint surface?
- Shoulder Abduction What direction is the upper arm traveling?
- What bone is relatively fixed?
The fixed bone has what type of joint surface?
ConcaveWhat are the resulting arthrokinematics?Superior Roll and Inferior Glide (Roll / Glide Opposite)
Elbow Flexion What direction is the forearm traveling?
What bone is relatively fixed?
The fixed bone has what type of joint surface?
What are the resulting arthrokinematics?
Elbow Flexion What direction is the forearm traveling? Anterior
- What bone is relatively fixed? HumerusThe fixed bone has what type of joint surface?
- What are the resulting arthrokinematics?
Anterior Roll and Anterior Glide (Roll / Glide Same)
What is Joint Congruency, name the two types of it?
The fit of the joint Can be
What happens to a joint in a close-packed postion?
- Joints become maximally congruent
- Most ligaments and capsule are pulled taught
- Provides stability
- Arthrokinematic motions are very limited
What happens to a joint in a open-packed postion?
- All other positions from close-packed position
- Ligaments and capsule
- slacken Allows for mobility
Force – a push or pull exerted by one object or substance on another
Name the two types of forces?
Internal and external
What is COM or COG?
Point of application – Center of Mass (COM) or gravity (COG)
in the overall human body this point occurs around (COM) at S2 (2nd sacral vertebra)
T/F Does every body have it's own COM?
What is LOG and how is it magnitude determined?
Direction – line of gravity (LOG) is the direction of the force of gravity
Magnitude – determined by the distance from the center of the earth
Base of support (BOS) is the contact that the body has with the ground
What determines the stabilit of the over all human body?
Stability is determined by where the LOG falls in relationship to the BOS
hence a wider base of support or a lower center of gravity makes you more stable.
Name 4 external forces and two internal forces?
- Air resistance
- Muscle contraction
What is newtons law of inertia?
Inertia is the property of an object that resists both initiation and change in motion
Is proportional to its mass
Application – Walkers
What is Newton’s Law of Acceleration?
Acceleration is proportional to the net unbalanced forces and inversely proportional to its mass
Acceleration is in the direction of the unbalanced force
Is related to the Law of Inertia based on mass
What is newtons law of reactions?
All forces come in pairs that are applied to contacting objects, are equal in magnitude and opposite in direction
Impact on PT is in things like Ground reaction force
Explain what a linear forces system is?
When two or more forces act:on the joint of interest in the same plane and in the same line (if tails were extended would overlap)
What types of force are created on joints do to a linaer force system?
Results of linear force systems
Traction/Distraction: net force moves a bony segment away from its adjacent bony segment
Compression: two segments are pushed together
Shear: a force that moves or attempts to move one object on another
What is a Concurrent force system?
Concurrent Force System
When two forces are applied to the same object are not collinear but intersect
Most forces acting on the body are concurrent
Graphically you can understand how forces interact with each other by using the parallelogram method
What is the parallelogram method?
It is a graphical way to determine a resultant force vecotor. From two other forces.
Muscle contractions create internal force vectors. Since most muscles attach at an angle the force vector created can be resolved into components. These components have different effects on the joint depending on their direction, what are these effects?
Normal force – forces perpendicular to the bone shaft where the muscle attaches
May cause translation or rotation
Tangential force – forces acting parallel to the bone shaft where the muscle attaches
May occur as a compression or distraction within the joint
Force through the COM will cause what type of effect on a joint?
Force through the COM will cause translation
Force away from the COM with a fixed axis will cause what type of motion?
Force away from the COM with a fixed axis will cause rotation
Strength of rotation is known as? What is the equation for this force?
Torque = Force x moment arm
Explain what Musculoskeletal Levers are and what componets make them up?
Definition – A rigid segment that rotates around an axis, which produces torque
What’s NeededTwo forces – Load (L) and Effort (acts to move the lever in the opposite direction of the Load)
Two moment arms are associated with levers, may have different lengths
Explaine: Type 1 lever?
1st Class levers: Axis is in between the effort and load forces
Common Example: teeter totter
Uncommon in the human bodyExample – Atlanto-Occipital jt
Explain a second class lever?
Second Class Levers: load force is between the axis and the effort force
Common Example: Wheel barrow
Unusual in human bodyExample – Raising heels off of ground
Explain: what a 3rd class lever is?
Third class levers: effort force is between the axis and the load force
- Most musculoskeletal levers in body are 3rd class
- Example – bicep curls
Define the two types of kinamatic chains?
Open Chain – distal segment is free to move while the proximal segment is fixed
Closed Chain – proximal segment is free to move while the distal segment is fixed
Whenever the foot or hand is contacting an object, certain joints may NOT be in closed chain position
What are the three classifications of Joints by anatomical structure?
- Three types:
What Ct makes up a Synarthrosis joint, how much motion is it capable off and list an example?
Joint Material – Dense, irregular connective tissue
Available Motion – negligible
Examples – Interosseous membrane
What CT makes up a Amphiarthrosis joint, how much motion is it capable off and list an example?
Joint Material – hyaline cartilage or fibrocartilage
Available Motion – minimal
Examples – Intervertebral disk, pubic symphysis
What CT makes up a Diarthrosis joint, how much motion is it capable off and list an example?
Joint Material – true joint space filled with synovial fluid, surrounded by a capsule
Available Motion – extensive
Examples – will be listed on a different slide
Name the Elements of Diarthrodial Joints? Specify which are required and which aren't required?
RequiredSynovial fluid – provides nutrition to articular surface
Articular cartilage – allows for near frictionless movement
Articular capsuleCapsular ligaments
Not RequiredMenisci & Labra – increase stability (increase congruence), provide shock absorption, & facilitate motion
Classify of synovial joints based on planes of motion?
- Uniaxial – movement in one plane
- Biaxial – movement in two planes
- Triaxial – movement in three planes Ball and socket
- Random - Plane
Give an example of each type of Synovial joint?
- Hinge: Humeroulnar joint
- Pivot: Proximal radioulnar
- Condyloid: Metacarpophalangeal
- Saddle: 1st Carpometacarpal joint
- Ball and socket: Glenohumeral
- Plane: Intercarpal joints
Name some of the CT marterials that make up joints?
Name the cells that form CT?
- Chondroblast - Found in cartilage
- Creates mostly Type II collagen
- Fibroblast - Found in tendon, ligament, and bone
- Creates mostly Type I collagen
- Osteoblast - Found in bone
- Creates mostly Type I collagen and hydroxyappatite
What is the EMC and what two layers make it up?
Extracellular Matrix (ECM) – Function of connective tissue is primarily determined by the ECM
- Two parts
list and define the cells that make up the ECM – specificly the Interfibrillar part?
Glycoprotein – carbohydrate covalently bound to protein. They Fasten various components of the ECM together
Proteoglycans – similar to glycoproteins; differ in the number of carbohydrates attached. Distinguished by their protein core and their attached Glycosaminoglycans (GAG)
- Glycosaminoglycans (GAG) - Attract water through their GAGs.
- Proportion of GAGs determine how much water is contained in connective tissue
Regulate collagen fibril size
Are increased in tissues subjected to alternating cycles of compression
Name and define the fibers that make up the Fibrillar part of the ECM?
Type I Collagen - Most common, it has a high tensile strength. Found in ligaments, tendons, fascia, and fibrous capsules.
Type II Collagen - Possess less tensile strength as type I. Helps maintain the general shape and consistency of structures. Found mainly hyaline cartilage and center of intervertebral disk
- ElastinHave more give when stretched. Readily return to their original shape after being deformed.
- Found in small quantities in load bearing tissues
Define: Load and deformation?
Load: external force(s) applied to a structure
Deformation: caused by a force that acts upon a structure
Name and define the types of load?
- Tensile – pull apart
- Compressive – push together
- Torsional – twisting
- Shear – surfaces try to slide past each other
- Combination – bending; tensile and compression on opposite sides
Define stress and strain?
Stress is a measure of load that is in an object
Equal to force / cross sectional area
Strain is a relative deformation (change in length, width, or shape) of a structure
What is the stress strain curve?
Plotting the stress against the strain – gives information about the properties of the material.
There are five regions or points/regions on the stress-strain curve define them?
Toe region - Slack of tissues is taken up
Elastic region - Slope of elastic region is referred to as Young’s Modulus or Modulus of Elasticity. Is a measure of the material’s stiffness. In the elastic region - Fibers are elongated and resist the force – influenced by the type of collagen, fibril size, and cross-linking between fibrils
Yield point - Marks the end of the elastic region and the start of the plastic region.
Plastic region - Permanent deformation after load is removed. Progressive failure as stress continues
Ultimate failure point
Where on the stress-strain curve will you find a grade I ligament sprain? (injury to a few ligament fibers)
Early part of plastic range
Where on the stress-strain curve will you find a grade III ligament sprain? (complete rupture of lig)
At failure point
Materials where the stress-strain curve changes as a function of time
T/F Rate of loading - Slope is greater if load is applied quickly. Slope is less if same load is applied slowly.
This Helps protect underlying structures.
Define Creep and explain how CT tissue demonstrate creep?
Creep - is a progressive strain of a material under a constant load over time.
Tendons or ligaments demonstrate creep through tensile loads.
Bone or cartilage demonstrate creep through compressive loads.
What is Viscoelasticity –Stress Relaxation?
If the strain is held constant, the stress decreases with time.
Name the different names for the two Types of Bone.
Compact, Cortical or Lamellar
Trabecular, Spongy or Cancellous
Explaine the microstructure of compact bone?
Central Canal- runs parallel to bone, and contain nerves, veins, and arteries, around this is are the Lamella- Concentric layers of bone that surround central canal, each layer contains collagen fibers at a 45 degree angle and each layer runs opposite to the one beneath.
Within this is the Lacunae- small cavities between adjacent lamella. They are connected by canaliculi, which allow nutrients to pass through them.
Explain the Microstructure of Trabecular Bone?
Lamellae not arranged in concentric layers. Arranged in lines corresponding to where max stress is applied in the body
What are the implications if compact bone is stiffer than trabecular bone?
Can have more force applied before failure
What are the implications if trabecular bone can withstand greater strain than compact bone?
Can elongate further before failure
What cause microfractures in Trabecular bone?
- Compressive loading will cause hyptertrophy in trabecular bone
- Dependent on rate, frequency, duration, and magnitude microfractures can occur do to
- High repetitions with a low load
- Low repetitions with a high load
What are the properties of tendons?
Collagen fibers are nearly parallel; when straightened not all fibers will be affected the same due to the nearly parallel arrangement.
Cross-sectional area, composition of the tendon, and the length of the tendon determine the amount of force that can be resisted.
Transition regions (muscle to tendon; tendon to bone) render tendons more susceptible to injury due to changes in composition.
In response to a tensile force, tendons have a moderate ↑ in thickness & strength
What are the properties of ligaments?
Are similar to tendons mechanically. The more variable collagen orientation make ligaments more able to function in a range of load directions without being damaged.
Handle tensile forces from multiple directions
Intermittent tension will cause an increase in thickness and strength to ligaments
What are the properties of Cartilage?
In order for cartilage to withstand compressive forces it must have an intact collagen network and proteoglycan/GAG matrix.
The compressive load is supported by both the fluid components and solid components of cartilage Upon being loaded in compression, fluid will be “squeezed” out of the solid component region and with the removal of the load the fluid will enter via an osmotic gradient
Behavior to tensile stresses is similar to tendons and ligaments.
Resistance to shear stresses is dependent on the collagen present
Is loading excercise good for cartilage?
Some level of loading or exercise is appears to be beneficial for cartilage – The magnitude or frequency is yet to be determined
What are the General Changes that occur do to Immobilization?
Immobilization can be due to a inflammation, cast, bed rest, weightlessness, or denervation If immobilization is due to inflammation, a loose pack joint position will be assumed. Capsule, ligaments, tendon, and muscle will adapt to this position in as short as just a few weeks. Muscles develop contractures; ligaments and capsules will have one side lengthen and one side shorten
Effects of immobilization on ligaments and tendons?
Effects on Ligaments and Tendon
Have a decrease in their collagen content and cross-linking, i.e. weaken
Can loose 50% of tensile strength in 8 weeks
Recovery may take over a year to regain strength
Graded reloading is necessary to restore tendon and ligament strength
Effects of immobilization on Articular Surfaces and Bone?
Effects on Articular Surfaces and Bone
Cartilage will atrophy
Proteoglycan synthesis is decreased
Greater deformation when subjected to compressive loads
Bone can have a regional osteoporosis
Due to less collagen formed and an increase in bone resorption
Effects of agingon CT tissues?
- Decreased number and size of GAG molecules
- Fibers don’t align themselves as readily to imposed tensile forces
- Adhesions are more likely to form between connective tissue
name the gernal components of a muscle fiber/cell?
- Sarcolemma: cell membrane
- Sarcoplasm: – contains myofilaments, which are composed of actin and myosin
- Non-contractile proteins:
- Contractile proteins: - Myosin, Actin
What are the characteristics of myosin?
- Contractile proteins
- Contains a rod-like tail and two globular heads
- Hinge joints occur between the myosin head and tail
- ATPase activity: found on Myosin – referred to as the thick filament myosin heads
What are the componets of the myofilament , actin?
- The actin filament is made up of three separate protein molecules:
- Actin molecules (G-actin) form a twisted pearl strand, referred to as F-actin
- Tropomyosin hides the actin-myosin binding site Troponin has 3 isoforms
What are the structural proteins inside a muscle cell and what do they do?
Structural proteinsC-protein – holds the myosin tails in correct spatial arrangement
Titin – links myosin (M-line) to Z-line
α-Actinin – attaches actin to Z-line
Name and define the lines and bands that make up a sarcomere?
Z-line to Z-line; composed of two bands
BandsA-band: composed of myosin filaments and areas of overlap with actin fibers; lies at the center of the sarcomere
H-zone: lies in the middle of the A-band; contains only myosin tails
I-band: composed of actin filaments; part of two adjacent sarcomeres, bisected by Z-line
Explain the interaction of the actin/myosin cross bridges?
Action potential (AP) enters cell
Ca+2 is released in response to AP, which binds to troponin
Troponin moves tropomyosin to uncover the binding site for myosin
Binding of myosin to actin is referred to as a cross-bridge and is what is required for tension to develop in muscles
Name the layers of CT that suround each structutral level of a muscle?
Endomysium – surrounds the muscle fiber
Perimysium – surrounds bundles of muscle fibers called a fascicle
Epimysium – surrounds the whole muscle
What Factors Influence a Muscle’s Ability to Produce Movement?
Length of the muscle fibers
Size of the muscle’s moment arm
What determines joint ROM?
Joint range of motion (ROM) is determined by two properties.
- Sarcomeres in series.
- Muscle architecture
Discuss muscle shortening?
Muscle shortening is proportional to the length of the muscle fibers
Typically muscles can shorten to ~50% of its length
- There is a wide variety of muscle lengths in the human body
- Sartorius vs. Bicep brachii
Length of the muscle fibers is a function of the muscle architecture
Name and define the two classification of fiber architecture?
- Fiber architecture can be divided into two main classifications
Parallel – muscle fibers are approximately parallel to the length of the whole muscle
Pennate – muscle fibers are oriented obliquely to the long axis of the muscle
What effect does the moment arm have on ROM?
Muscles with greater moment arms have to shorten more than muscles with smaller moment arms to achieve the same ROM for the same joint angle
What factors effect muscle strenght?
- Muscle size
- Muscle moment arm
- Contraction velocity
- Muscle recruitment
- Fiber types
What two methods are used to determine muscle size?
Anatomic cross-sectional area is a cross-section of the muscle at the widest part
Physiologic Cross- Sectional Area (PCSA) is the cross-sectional area of the muscle that is perpendicular to the orientation of the muscle fibers
How does a muscles moment arm effects it ability to generate torque?
A muscle with a greater moment arm will be able to produce greater torque around a joint than a muscle with a smaller moment arm if they contract with the same force
After 90 degrees what effect does the tangential componet of muscle force have on a joint?
After 90°, the tangential component of the total muscle force produces a distraction force
What is resting length of a muscle?
There is a sarcomere length at which actin and myosin are optimally overlapped for cross-bridge formation, this is the resting length of the muscle
What effect does changing a muscles length from it optimal length to a greater or lesser length have on cross bridge formation?
Changing the sarcomere width beyond the optimal length decreases the number of cross-bridges Active tension may still be developed, however, it is less due to fewer cross-bridges between actin and myosin
Tension in a muscle is also developed in a muscle when it is lengthened (i.e. put on stretch), the resistance is due to?
- CE = contractile elements
- PE = parallel elements
- SE = series elements
Define passive and active tensions?
Passive Tension – tension developed in the parallel & series elastic components
Active Tension – the tension developed by cross-bridge formation
What is passive insuficancy?
Passive Insufficiency - A muscle can’t stretch enough to achieve full range of motion at all joints it crosses
Occurs with multiarticulate muscles
Muscle is being moved by someone (i.e. therapist) or something else (i.e. antagonist muscle) – it takes a passive role in being lengthened
What is active insuficancy?
Active insufficiency – a muscle can’t develop full force due to the actin-myosin overlap, which decreases ROM for the distal joints the muscle crosses
Occurs with multiarticulate muscles
Muscle is causing the change in length or change in ROM – taking an active role
- Decrease in cross-bridge formation
- Change in moment arm at different joints
- Passive tension of antagonist muscle
Name and define the three types of muscle contractions?
Types of Muscle Contraction
Isometric – tension is generated by myosin and actin binding but no movement occurs
Concentric – tension is generated; actin is pulled into the H-zone; shortening of the muscle occurs
Eccentric – tension is generated; actin is pulled away from the H-zone; lengthening of the muscle occurs
Explain the Force velocity relationship?
This is the relationship between velocity of contraction and force produced
When shortening contraction speed increases, force that can be produced decreases
When lengthening contraction speed increases, force that can be developed is able to increase to a certain point
In a dynamic contraction you have to consider both the velocity and the length of the muscle in order to determine force production
We don’t move with constant velocity so force changes with a change in velocity & change in length
Explain alpha motor units?
A motor unit consists of an alpha motor neuron and all of the muscle fibers associated with that neuron
Size of a motor unit can vary from a few muscle fibers to 1000s of fibers
Fine control is provided by small motor units
Gross movement is provided by large motor units
Smaller motor units are recruited first
If additional force is required, larger motor units will be recruited
Partly due to energy conservationWhat does that mean?
More energy is expended when a large motor unit is recruited since is activates 1000s of muscle fibers
Name the 3 types of muscle fibers and there characteristics?
Type I - Don’t fatigue easily; often referred to as stability or postural muscles; force production is limited
Type IIa - Characteristics are between those of Type I and Type IIb
Type IIb - Fatigue easily; can generate tremendous amounts of force
List the roles a muscle can play in movements?
Prime mover (agonist) – the muscle whose role is to produce a desired motion
Antagonist – opposes the movement of the agonist
Co-Contraction: provides stability
Synergist – assist the agonist to perform the desired motion. Can help produce the desired motionor. Can stabilize a segment to allow the agonist to produce the motion
Name the syngerists involved in wrist flexion?
- Flexor carpi radialis and ulnaris are agonists for wrist flexion;
- extensor digitorum is the antagonist;
- flexor digitorum is a synergist by helping produce wrist flexion
Name the syngerists for Finger flexion?
- Flexor digitorum profundus will cause wrist flexion
- so the extensor digitorum will act as a synergist and eliminate wrist flexion
- so the profundus can produce finger flexion
Name and explain the role of the seonsroy receptors involved with muscles?
Muscle Spindle – within muscles; is sensitive to stretch and will contract the muscle in order to avoid injury
Golgi Tendon Organ – within tendons, is sensitive to tension, will cause relaxation of muscle in order to prevent injury
What are the effect of immobilization on Muscles?
In shortened position -
- Decrease in number of sarcomeres
- Increase in connective tissue
- Muscle atrophy
- Prevention of the above effects need only ~30 minutes of daily ROM activities
In lengthened position
- Increase in the number of sarcomeres
- May have a decrease in strength
Effects of aging on muscles?
- Fiber number and fiber type changes
- Loss of muscle fibers
- Decrease in type II fibers Increase in type I fibers
- Connective tissue changes
- Increased connective tissue
What are the arthrokinematics of closed-chain knee flexion from standing to sitting?
A. Roll Posterior, Glide Posterior
B. Roll Posterior, Glide Anterior
C. Roll Anterior, Glide Posterior
D. Roll Anterior, Glide Anterior
Which of the following answers is an aspect of Newton’s 2nd law and defines shear force?
A. Is proportional to its mass; net forces move a bony segment away from its adjacent bony segment
B. All forces come in pairs that are applied to contacting objects; a force that moves one object on another
C. Is inversely proportional to its force; net forces moves a bony segment away from its adjacent bony segment
D. Is in the direction of the unbalanced forces; a force that moves one object on another
What are the four articulations for the shoulder complex?
- Sternoclavicular joint (SC jt)
- Acromioclavicular joint (AC jt)
- Scapulothoracic joint not a true physiologic joint
- Glenohumeral joint (GH jt)
What are the charcteristics of the SC joint?
- The SC joint has incongruent joint surfaces
- Joint Type: Saddle (2 physiologic DOF; 1 non-physiologic: rotation)
- Joint DiskShock Absorber
- Improves joint surface contact
What are the motions of the SC joint and what are the arthokinematics for each of these motions?
- Arthrokinematics: Roll/Glide opposite
- Arthrokinematics: Roll/Glide same
- Arthrokinematics: Spin
Name and define all of the stabilizing tissues of the SC joint?
- Articular disc
- Anterior SC ligament Restricts retraction
- Posterior SC ligament Restricts protraction
- Interclavicular ligament Restricts depression
- Costoclavicular ligament
- Restricts: ElevationProtraction, Retraction
Muscle: Sternocleidomastoid, sternohyoid, sternothyroid – stretched in depression
Depression can cause a pinching of nerves & arteries
What type of joint is the AC joint? What does it do?
Joint Type: Plane: has 3 DOF
Joint Disk: May only be partial disk
Degeneration is common
Motion: Helps fine tune the position of the scapula after motions have occurred at the SC joint
Motions of the AC joint and what planes do they occur in?
- Motion: Upward Rotation/Downward Rotation
- Plane: Frontal
Winging - Plane: Horizontal
Tipping - Plane: Sagittal
What are the stabilizing tissues of the AC joint?
Superior AC ligament - Restricts downward rotation
Inferior AC ligament - Restricts upward rotation
Coracoclavicular ligament - Restricts upward rotation
Muscles: Deltoid & Trapezius – surround the joint
What is the Scapulothoracic Joint, and explain were it is?
Interface between scapula and thorax
- Superior angle = rib 2, inferior angle = rib 7
Medial border = ~2 inches from spinous processes
Bony connections: SC and AC joints
Which of the following is correct for the SC joint?
A. A tight posterior SC ligament would restrict protraction while anterior glides would help restore protraction
B. A tight costoclavicular ligament would restrict retraction while anterior glides would help restore retraction
C. A tight anterior SC ligament would restrict elevation while superior glides would help restore elevation
D. A tight interclavicular ligament would restrict depression while inferior glides would help restore depression
What are the motions of the scapulothoracic joint?
- Upward / Downward Rotation
What is the type anf position of the GH joint?
- Joint type – Ball and Socket
- Glenoid fossa: Lateral
- Slightly anteriorSuperior
- Humeral head:
What is the stabilizing tissues of the GH joint?
Glenoid labrum – increases the joint congruency
Rotator cuff muscles – dynamic stabilizers, attach to the capsule
Biceps brachii – long head – blends with the superior capsule
Adduction, External rotation
external rotation horizontal abduction
- Inferior – has three bands
- Anterior restricts: Abduction, External rotation
- Axillary pouch restricts: abduction
- Posterior restricts: Abduction, Internal rotation
Name the factors that effect GH joint stability?
- Adequate size of the glenoid fossa
- Humeral head retroversion
- Intact capsule and labrum
- Shoulder girdle muscle control
What what causes Static Stability of the GH?
- Superior capsule
- Coracohumeral ligament
- Passive tension of supraspinatus
Resultant force pulls the head of the humerus into the glenoid fossa
Deltoid contracts creates rotation and superior translation
Supraspinatus Produces a compressive force
Infraspinatus, Teres Minor, Subscapularis - Produce an inferior translation to counteract the superior translation of the deltoid contraction
What are the GH joint motions?
- Flexion / Extension
- Arthrokinematics: Spin (both open & closed chain)
- Inferior / Posterior glide
- Abduction / Adduction
- Arthrokinematics: Roll / Glide Opposite (open chain)
- External / Internal rotation
- Arthrokinematics: Roll / Glide Opposite (open chain)
- Horizontal Adduction / Horizontal Abduction
- Arthrokinematics: Roll / Glide Opposite (open chain)
Explain Scapulohumeral rhythme?
Combination of GH and STJ for abduction and flexion
Is a 2:1 ratio of movement between GH and STJ
Scapula has 60° upward rotation
GH contributes 120° of elevation, even if scapula is fixed
Total ROM is 180°
What is the purpose of the scapulohumeral rythme?
Assists in maintaining proper length tension relationships
Distributes motion between two joints
Maintains glenoid fossa in an optimal position
Explain the phases of the scapulohumeral rythme?
- 0 – 90° arm elevation
- 60° GH abduction
30° upward rotation
- SC joint 20-25° elevation
- AC joint 5-10° upward rotation
- 90 – 180° arm elevation
- 60° GH abduction
- GH external rotation 30° STJ upward rotation
- SC joint 5° elevation
- AC joint 20 - 25° upward rotation
- Posterior clavicular rotation
Name the muscles and division of muscles that make up the Axioscapular & Axioclavicular?
- Upper - Elevation, Retraction, Upward rotation
Tightness – elevation of shoulder girdle or asymmetrical head position
- Middle - Retraction
- Lower - Depression, Retraction
Weakness – due to chronic scapular elevation or reciprocal inhibition
Serratus Anterior- Protraction, Upward rotation
Weakness – winging
- Levator Scapula & Rhomboids
- Downward rotation
Tightness: in the levator scapula may cause headaches
- Pectoralis Minor
- Downward rotation
- Anterior Tilt (Tip)
- Deltoid - Anterior
- Internal rotation
- Horizontal adduction
- External rotation
- Horizontal abduction
- Pectoralis Major
- Sternal head - Flexion, Extension (from 180 flexed position), Adduction, Internal rotation, Horizontal adduction
Clavicular head - Flexion, Internal rotation
Latissimus Dorsi - Extension, Adduction, Internal rotation, Shoulder depression
Teres Major - Internal rotation, Extension, Adduction
Coracobrachialis - Flexion, Adduction
Biceps Brachii – Long head - Flexion
Triceps Brachii – Long head - Extension, Adduction
Supraspinatus - Abduction
Weakness – significant abduction weakness and loss of endurance with abduction
Teres Minor - External rotation
Infraspinatus - External rotation
Subscapularis - Internal rotation, Flexion, Adduction, Horizontal adduction
Weakness – may contribute to anterior instability of the shoulder
Explain the Synergy of Trapezius and Serratus Anterior?
Trapezius and Serratus Anterior form a force couple for upward rotation - Serratus pulls from the bottom while the upper trapezius pulls from the topIf one of the muscles becomes paralyzed but the other muscle is intact; ROM is affected
Flexion - With serratus anterior paralysis (trapezius intact): result is weak, partial ROM. Only 130°. With trapezius paralysis (serratus anterior intact): result is weak, full ROM. Unopposed retraction of trapezius only allows the scapula to upwardly rotate 1/3 of the normal motion.
Abduction - With serratus anterior paralysis (trapezius intact): result is weak, full ROMWith trapezius paralysis (serratus anterior intact): result is weak, partial ROM. Only 75°. Without the trapezius the scapula rests in a downward rotated position
What type of joint is the Humeroulnar Joint?
What is the carrying angle and what two terms describe it?
Carrying Angle - is the angle of the forearm in relation to the body.
- Valgus = distal part is abducted
- Varus = distal part is adducted
If the elbow does Flexion / Extension, what are the Arthrokinematics of this motion? (open chain)
What changes with the arthrokinematics when the elbow is performing a closed-chain movement?
– Roll / Glide Same (open chain)
Roll / glide opposite (closed chain)
What are the stabilizing tissues of the elbow?
Articular capsule covers humeroulnar, humeroradial, and proximal radioulnar joints
Posterior-lateral = Varus force
Anterior-medial = Valgus force
- Annular ligament – surrounds radial head and
- Prevents dislocation of radial head (Nursemaid’s elbow)
Radiohumeral joint – will resist valgus forces
- Medial collateral ligament
- Anterior fibers
- Resists Valgus
- Resists Extension
- Posterior fibers
- Resists Valgus
- Resists Flexion
- Lateral collateral ligament
- Ulnar component - resists -Varus and Flexion
Radial component - resists - Varus