Functional Anatomy Lecture Test One
In relation to a joint, explain the general functions of cartilage such as menisci, disks, plates, and labra.
provide passive joint stability by deepening articular surfaces and increasing joint congruence.
Explain the term end-feel.
the difference between how different bones feel when they are fully extended. Elbow joint: comes to immediate stop. Bones hit fit snugly together with little wiggle room. Knee joint: slight give when fully extended. Slightly looser fit.
The general structure of connective tissue
the general structure of connective tissue is comprised of cells (such as fibroblasts, mast cells, neutrophils, macrophages, etc) and extracellular matrix (ECM) (of which collagen is a component)
Elastic Region
deformation is not permanent; structure will return to original dimensions immediately after load is removed
Plastic Region
deformation will be permanent when load is removed, but structure is intact. Structure is intact but will never return to its original form.
lateral flexion
Used when the moving segment IS part of midline (trunk/head)
Describe the physiological response of ligaments to intermittent tension; discuss the affects of immobilization on ligaments.
- Intermittent (tensile) causes an increase in thickness and strength - Immobilization = RAPID weakening - Can take over 12 months to recover original properties
Identify the functions of the synovial fluid; Identify which component can be injected into the joint cavity to help reduce s/s of OA.
- Keeps joint surfaces lubricated to reduce friction - Provides nourishment for the hyaline cart In particular it is the hyaluronate component that is responsible for the viscosity and lubrication of the synovium: this is sometimes injected into OA joints
Discuss the hyaline cartilage's ability to repair after injury. Considering it has no blood or nerve supply (adults), discuss how hyaline cartilage receives its nutrition; read the Case Application 2-4 to understand how immobilization affects joint integrity.
- Once damaged, has limited and imperfect mechanism for repair. Its best bet for repair is when subchondral bone is damaged. - During motion or when cartilage is compressed, fluid exudes through pores, fluid flows back into cartilage via osmotic pressure when load is removed - Devoid of blood vessels and nerves (in adult), thus nutrients are carried solely by this fluid flow
Explain the concept of an anatomical pulley. Using the example provided, identify what part is considered the anatomical pulley and describe how it affects muscle pull. *essay question*
- When the direction of muscle pull is altered (such as when a muscle "wraps" around a bone or are deflected by a bony prominence) the bone or prominence causing the deflection forms an anatomic pulley. - The direction of force changes but does not affect the magnitude of the applied force. This direction change can affect the ability to produce torque. - Fig 1-59 shows how the bony pulley (the patella) deflects the line of pull away from the axis...thus increasing the MA. - When MA is increased, torque is increased which allows the quad to work less in order to cause the same movement (compared to if the patella was missing)
Use the concept cornerstone 1-1 to learn 3 primary rules of force
1. All forces on a segment must come from something that is contacting the segment 2. Anything that contacts a segment must create a force on that segment (although the magnitude may be small enough to disregard) 3. Gravity can be considered to be "touching" all objects
Identify the two types of tendon attachments to bone; discuss the two categories of a fibrous entheses.
1. Fibrocartilaginous enthesis 2. Fibrous enthesis Divided into two categories: a. Periosteal (tendon fibers attach to periosteum = indirect connection to bone) - With age, sometimes convert to bony attachment b. Bony (tendon fibers attach to directly to bone)
Identify the three main classifications of joints and give an example of each type; describe the amount of movement allowed for each main class of joints and identify the type of tissue used to connect the bony components; (handout and text)
1. Fibrous Joints: The plates of the skull. Little to no movement. Sutures (skull), gomphoses (in between each tooth and the mandible), and syndesmoses (between the distal tibia and fibula). 2. Cartilaginous: Pubic symphysis. Bone growth and a very small amount of movement. Symphysis joints: directly joined by fibrocartilage in the form of discs or pads. Synchondrosis joints: hyaline cartilage connects (articulation of the first seven ribs). 3. Synovial Joints: Elbow and knee joints. Bony components are free to move in relation to each other because no connective tissue directly connects them. Indirectly connected to one another by means of a fibrous synovium-lined joint capsule that encloses the joint.
What are the 3 rules related to the stability of the human body?
1. The larger the base of an object, the greater the stability of that object 2. The closer the object's center of mass is to the base of support, the more stable the object 3. An object cannot be stable unless its line of gravity is located within its base of support
Identify the five kinematic variables that describe motion and give an example of each.
1. Type of displacement: translatory motion, rotatory motion, general motion 2. Location in space of the displacement: axis of motion and planes of motion 3. Direction of segment displacement: flexion/extension, internal/external rotation, abduction/adduction, lateral flexion 4. Magnitude of displacement: range of motion 5. Rate of displacement (velocity) or rate of change (acceleration): speed, velocity, and acceleration
Explain the concept of torque as related to force couple. Give an alternate name for torque. Explain the term moment arm (MA). Explain the relationship between the magnitude of forces and the distance between the forces when referring to torque.
A force couple will always produce a moment of force (torque). Torque is the product of the magnitude of one of the forces in a force couple and the shortest perpendicular distance between the forces, referred to as the moment arm. The greater the magnitude of the force couple, the greater the strength of rotation; the farther apart the forces of a force couple (the greater the MA), the greater the strength of the rotation.
Identify the minimum number of force vectors that are created when a muscle contracts.
A minimum of 2 force vectors are created and are, as previously stated, directed toward the center of the muscle.
Discuss the purpose for the varied arrangement of collagen fibers.
Arrangement of collagen fibers are such that they can resist forces from more than one direction Contrast to a tendon where forces are from a muscle and tend to be in one direction
Abduction/adduction
ABDuction - movement away from median plane ADDuction - movement toward median plane
Explain how active insufficiency of a muscle affects muscle performance; Use figure 3-25 to visualize and understand this concept.
Active Insufficiency: muscles contracted Decrease in torque often seen in two-joint muscles one end of muscle is put on "slack" = decreased ability to produce enough torque to move segment through full ROM Ex: Hamstrings in standing (two-joint muscle) Ex: Triceps (two-joint muscle) Ex: Fig 3-15 (one-joint wrist flexors versus extensors with passive insufficiency)
Give your thoughts on using leg weights with patients. Are there any alternative tools that can be used to reduce the tension at the capsule but still strengthen knee muscles? Determine whether the force of gravity works equally throughout the entire range of knee extension. Give your thoughts on positioning patients who have knee pain with their legs unsupported.
An alternative way to reduce tension at the capsule while still strengthening the knee is to position the PT/PTAs hand at the bottom of the foot to support it and reduce the pull of gravity while they do knee extensions. Wherever the moment arm is the longest, gravity will be strongest. Therefore, the force of gravity is the strongest when the knee is fully extended. Positioning patients with knee pain with their legs unsupported is a bad idea because it causes passive tension on the knee. It is better to do exercises where the knee will be supported (ie heel sides on table top surface etc)
Use Example 2-4 on page 89 to give a general principle of how to increase the length of tissue with little risk of injury.
Apply a manual SLOW stretch to the muscle that is just short of producing pain, hold this position for up to 2 minutes to induce creep deformation (elongation) of the muscle. Take a brief rest and repeat. Use an ice pack after to reduce inflammation.
Identify the purpose of ligaments.
Arrangement of collagen fibers are such that they can resist forces from more than one direction
Relate CoM to the axes of movement.
As your body moves in different planes (sagittal, frontal, etc), your CoM moves in order to keep you balanced. I.e. Leaning forward (moving into the sagittal plane) your CoM moves as well.
Describe the changes in fiber number and fiber type that occurs with aging; Relate this change to being able to perform activities of daily living (ADLs).
At 60+, loss of muscle fiber occurs - In some areas up to 50% loss! - Gradual decrease in number and size of type II fibers...leaving a relative increase in type I fibers: (Type I are "slow to contract to stimulus" remember (go back to Table 3-1) Decrease in the amount of motor units. This affects ADLs by making joints more stiff and motions take longer to complete
Identify the term used for the attachment site of tendon to muscle; Considering the structure of the MTJ, discuss the danger of fast, heavy loading post immobilization.
Attachment of tendon to muscle called myotendinous junction (MTJ) Very sensitive to situations where no loads are applied and weakens the junction making it more susceptible to injury THUS, loading muscles post immobilization should be progressed gradually to prevent injury
Determine which lever provides balance, power, and speed/ROM Determine what type of lever is found most often in the body and explain the advantage and disadvantages of it.
Balance: 1st class lever: head nodding Power: 2nd class: standing on tip toes Speed/ROM: 3rd class: bicep curl The most common lever in the human body is a 3rd class lever. It is advantageous because it provides mobility and ROM but disadvantageous because it is mechanically inefficient and lacks leverage and strength.
Explain why CoR is the actual point of rotation of a segment rather than at the joint itself for most body segments
Because most body segments follow a curvilinear path, the true center of rotation is the point around which true rotary motion would occur and is generally quite distant from the joint.
Explain how tension is created in a passive structure
By pulling that structure in opposite directions
In relation to a joint, explain the general functions of capsules, ligaments, and tendons.
Capsules: Provide an enclosure for the joint cavity and enhance joint stability through its passive restraints Ligaments: passive stabilizers of the joint that can blend in with the capsule or appear as individual structures. Tendons: Tendons transmit forces developed by muscles to the bones and allow joint movement and joint stability
Compare the concepts of close-packed and loose-packed positions of joints; Determine which position causes: 1) the greatest stability and is resistant to tensile forces and 2) the maximum amount of joint play; Determine which position a therapist would place a joint prior to manual mobilization of that joint and explain how a patient could be injured by choosing the wrong position.
Close-packed position - Position in which joint surfaces are maximally congruent and the ligaments and capsule are maximally taut - Thus, there is little joint play or distraction - Usually at the extreme end of ROM - Has greatest stability and resistance to tensile forces in this position Loose-packed position - Position in which joint surfaces are relatively free to move in relation to one another - Thus, the joint has a maximum amount of joint play - Some refer to this as the "position of comfort" for a patient who has an injured joint due to the relief of pain felt by this positioning Loose-packed is best for manipulation because it gives the most movement possible at the joint. A patient could be injured doing manipulations with a close-packed position because the joint surfaces could rub/pinch each other more easily during the manipulation.
Explain how weight-bearing and NWB movements of joints are related to the concepts of open chain and closed chain; Use the principles of open/closed kinematic chains to explain why the hip can be affected when the ankle is injured.
Closed chain is often during weightbearing conditions. Under weightbearing conditions, motion at one joint is generally accompanied by motion at one or more joints for the body to remain stable. Foot/ankle limitations will affect the entire lower extremity chain when the body is bearing weight. If ROM at knee were limited (due to bracing, joint stiffness, pain...), the hip and/or ankle joints would have to compensate for that missing ROM in order for the foot to clear the floor when walking.
Describe the typical location of the CoM in people; determine whether the CoM is the same in all people.
CoM is found at a point approximately just anterior to S2 when in anatomical position. The CoM at atomical position changes slightly for each person depending on the proportions (weight distribution) of that person. CoM changes when you move out of anatomical position.
Give the term used to identify the site where the ligament (or tendon) inserts at the bone; explain why this area is "stiffer" than the rest of the ligament.
Collagen fibers "cement" into bone during growth & development this forms Sharpey fibers (perforations of fibrous tissue into bone) -The ligamentous bony insertion site is called the enthesis -This stiffening reduces chance of ligament giving way from bone but is a common site for degenerative changes in the underlying bone
Describe the term curvilinear motion. Determine what kind of motion swinging a bat would be (the segment moving being the bat)
Combination of translation and rotation of a segment. The axis of rotation is not fixed but shifts so that the segment travels in a curvilinear path. Most body segments move this way. Swinging a bat would be rotary motion.
Explain the term "resultant force"
Combining two or more forces will result in a new vector, the resultant vector or force. Has the same effect (in force) on the segment as the original two vectors, however, the direction of the vector is different
Explain the convex-concave rule
Convex joint surfaces roll and glide in opposite directions, whereas concave joint surfaces roll and slide in the same direction.
Describe the terms effort force (EF), axis (A), resistance (RF), effort arm (EA), and resistance arm (RA).
Effort Force (EF) - Force acting in the direction of the rotation - Muscle contracting concentrically against a force - Is usually the "winner" in the torque game against the RF Resistance Force (RF) - The opposing force - Muscle contracting eccentrically against a force Effort Arm (EA) - The MA for the EF Resistance Arm (RA) - The MA for the RF Axis/fulcrum - Point around which a segment rotates (such as a joint) - The position of the axis in relationship to the EF and RF will determine the class of lever.
Define the term elasticity and relate back to another term, elastic region.
Elasticity = the ability to return to the original state after deformation when the force or deforming load is removed This occurs in the elastic region: Elastic Region = deformation is not permanent; structure will return to original dimensions immediately after load is removed
Describe translatory motion and give two examples of this kind of motion in human movement and another example in non-human movement
Each point on a segment moves the same distance, at the same time, and in parallel paths. Example: picking up a cup; doing a leg press Non-human example: a bus driving
Describe rotary motion and give an example of this type of motion in human movement. Determine why perfect rotary movement does not really occur in joints.
Each point on segment moves through same angle, at the same time, at a constant distance from the CoR Example: shaking someone's hand Not perfectly accomplished in human movement as translation is difficult to prevent; however, this term IS used to describe motion
Identify the three main categories of cartilage.
Fibrocartilage (white) - Forms bonding cement in joints that permit little motion - found in intervertebral disks, labra, SI joint surface - Also contains Type I Elastic cartilage (yellow) - Higher ration of elastin to collagen fibers - Found in ears, epiglottis Hyaline cartilage (articular) - Forms a relatively thin (1-7 mm) covering on ends of bones in synovial joints - Provides smooth, resilient, low-friction surface for smooth articulation
Explain the function of bursae; Describe the various types of bursae found in the body
Flat sacs of synovial membrane separated by fluid film Located where moving structures are in tight approximation Between tendon and bone: Subtendinous bursae Bone and skin: Subcutaneous bursae Muscle and bone: Submuscular bursae Ligament and bone
flexion/extension
Flex = Brings ventral surfaces of adjacent segments closer together Ext = Brings dorsal surfaces of adjacent segments closer together
Describe the relationship between angle of application and the MA of the force; describe the relationship of MA and torque
For all forces (internal and external): - The moment arm of a force is greatest when force is applied at, or as close as it will get to, 90 degrees (perpendicular) to the segment it is acting on. - The moment arm of a force is at least when the force is applied at, or as close as it will get to, 0 or 180 degrees (parallel) to the segment. - the angle of application (and moment arm) of a muscle force will vary with the angle of the joint it is crossing because the segment moves in space. - The angle of application (and moment arm) of gravity will vary with the orientation of the segment in space, regardless of the joint angle. - Most muscles are aligned fairly parallel to the bony segments to which they attach; consequently, muscles that have an angle of application that comes close to 90 degrees are the exception rather than the rule.
Determine the direction toward which the force of gravity is always acting
Force of gravity is ALWAYS vertically downward
Define, in simple terms, the word force; identify the term used in the US for a unit of force; determine whether gravity is considered a force.
Force: a push or pull exerted by one object or substance on another. The term used in the US for a unit of force: the newton Gravity is considered the most consistent external force
Name the plane and axis in which adduction and abduction is typically seen in:
Frontal Plane and z axis (sagittal axis/anterior-posterior axis)
Discuss the two sensory receptors that affect muscle performance; Determine how they help protect the muscles from injury during day-to-day activities; Discuss how initiation of the stretch reflex during therapy can be an unwanted event; Know the various names for the response to a quick stretch: DTR, MSR, and stretch reflex.
Golgi tendon organ - Located in tendon at MTJ - Sensitive to tension - Activated by active muscle contraction or excessive passive stretch - When excited, sends a message to nervous system to inhibit the muscle - When you're stretching slowly, it gives a little bit more give in the muscle in order to protect the muscle. Together, these help protect the muscle from injury Muscle spindles - Intrafusal fibers interspersed throughout the muscle - Sensitive to the length and velocity of lengthening of the extrafusal muscle fibers - Send messages to brain about the state of stretch of the muscle - When stretching rapidly, tells muscles to tighten and contract in order to protect the muscle. Opposite of Golgi tendon organ. - Responsible for sending message to muscle to contract when the tendon of a muscle is tapped with a hammer DEEP TENDON REFLEX or stretch reflex Initiation of the stretch reflex can be an unwanted event because
Compare/contrast the structure of tendons to ligaments
Has approx same composition and structure as ligament: Contains slightly more type I and less type III Suggests that they adapt to larger tensile forces
Explain the terms creep and recovery.
If a load is applied and maintained to a structure, deformation will increase over time (this is called creep): (though this sounds like a bad thing, it is actually very good when we're referring to a patient who is handicapped because of how tight their muscles have become) - Muscles, tendons and ligaments face constant tensile loading, thus creep occurs - Bones face constant compressive loading, thus creep occurs here as well - When loading is removed and the structure returns to its original length (if possible), recovery occurs
Determine where the LoG lies in relation to BoS when a person stands in anatomical position.
In order to have stability, the line of gravity must fall between the base of stability. In anatomical position, the line of gravity is directly in the middle of the base of stability.
Describe synovial fluid and discuss how its viscosity is affected by temperature.
Is sensitive to change in temp High temps = decreased viscosity (resistance to flow) Low temps = increased viscosity
Compare concentric and eccentric contractions for 1) tension-creating capability, 2) muscle shortening/lengthening, 3) which causes positive versus negative work; Know that some therapist refer to negative work as negative reps.
Isometric (muscle activated but maintains constant length) Concentric (shortening under load) Tension increases as the speed of active shortening (concentric) decreases A muscle contracting concentrically produces more tension when the "speed of the movement" decreases as compared to a "faster concentric movement" AKA positive work Eccentric (lengthening under load) Tension increases as the speed of active lengthening (eccentric) increases A muscle contracting eccentrically produces more tension when the "speed of the movement" increases as compared to a "slower eccentric movement" AKA negative work
Discuss the five features that are common to all synovial joints.
Joint capsule Joint cavity Synovial tissue Synovial fluid Hyaline cartilage
Compare the terms kinematics, arthrokinematics and osteokinematics
Kinematics: biomechanical concepts used to describe motion (aka displacement) Arthrokinematics: refers to the movement of joint surfaces Osteokinematics: describes the clear movement of bones which is visible outside of the body
Give a simple definition of a lever; Describe first, second, and third class levers.
Lever: any ridged segment that rotates around a fulcrum (or axis) 1st: EAR-the axis is between the effort and the resistance. Ex: see-saw Example in human body: nodding your head 2nd: ARE: Resistance is between the axis and effort. Ex: Wheelbarrow Example in human body: Standing on tip toes 3rd: AER: effort is between the axis and the resistance. Ex: baseball bat Example in the human body: elbow flexion/ bicep curl TIP: Class of Levers can be remembered as FRE: 1 class: F (force/axis is in the middle) 2 class: R (Resistance is in the middle) 3 class: E (Effort is in the middle)
Identify the many forms of connective tissue that make up the components of joints
Ligaments, tendons, bursae, and cartilage.
Determine which, tendons or ligaments, are able to withstand all three types of forces (shear, compressive, and tensile)
Ligaments: Slightly less resistant to tensile stress than tendons but are more able to function within a range of load directions (compressive and shear) without being damaged
Define mechanical advantage (MA) and give the formula used to determine MA of a lever. Relate MA to the musculoskeletal system.
M Ad is a measure of the mechanical efficiency of a lever system Formula: M Ad=EA/RA Levers can be used so that a small force can move a much bigger force. In our bodies, bones act as lever arms, joints act as pivots, and muscles provide the effort forces to move loads.
Discuss the important function that collagen plays in connective tissue.
Main substance of connective tissue Most abundant protein in body Has the tensile strength near steel Is responsible for the functional integrity of connective tissue structures and their resistance to tensile forces
Define the term translatory motion and give an alternate name
Movement of a segment in a straight line. Also known as, linear displacement.
Define the term rotatory motion and give an alternate name.
Movement of segment around a fixed axis (center of rotation CoR) in a curved path AKA angular displacement
Define what normal range of motion (ROM) is considered to be.
Normal ROM = amount of motion available to a joint (w/in anatomic limits)
opposition/reposition
Opposition - movement of thumb and little finger toward each other Reposition - return to anatomical position
Explain how passive insufficiency of a muscle affects muscle performance; Use figure 3-25 to visualize and understand this concept.
Passive Insufficiency: muscles relaxed Term applied to situation where muscle length is insufficient to allow full or "functional" ROM at the joints Typically seen with two-joint muscles Ex: hamstring stretching
Compare active and passive tension; determine which contributes to the total tension developed during a muscle contraction.
Passive Tension: Tension developed in the muscle by lengthening the muscle beyond the slack length of the tissue (noncontractile) Active Tension: Tension developed in the muscle by the contractile elements in the muscle Passive tension + Active Tension = Total Tension
Define/explain these terms used to describe muscles and their movements: prime mover, agonist, antagonist, co-contraction, synergist, neutralizer; Apply these terms to muscles and movements.
Prime Mover: Muscle that can produce full range for a given motion (in anatomic position) Assistor: Muscle that assists a Prime Mover but is not a Prime Mover of that motion MANY muscles function as Prime Movers of one action and are Assistors of other actions. EX: Adductor longus: prime mover of hip adduction but can assist in hip flexion in certain circumstances Agonist/Antagonist: Co-contraction Synergist: Muscle(s) that work together to perform a motion Can be prime movers or assistors Neutralizer: Muscle(s) that prevents a motion from occurring EX: Supination of forearm using biceps brachii and pronator teres agonists can be prime movers and antagonists can be neutralizers but the terms are not interchangeable; it's just possible for a muscle to fit both categories.
Define the term range of motion, identify the instrument used in PT to measure ROM
Range of Motion: is the magnitude of motion describing the degrees of movement at a joint. In rehab, the goniometer is used to measure joint ROM An inclinometer is used to measure joint ROM of neck and spine
Distinguish between these terms used to describe what occurs after the elastic range has been exceeded: failure/microfailure, rupture, and avulsion.
Rupture = ligament or tendon failure that occurs in the middle of the structure via tearing and disruption of connective tissue fibers Typically created with fast loading rates Avulsion = failure via tearing off at the bony attachment Typically created with low loading rates Microfailure: overt failure of the tissue
Name the plane and axis in which flexion and extension is usually seen in
Sagittal plane and x axis (coronal axis/frontal axis)
Discuss how ligament structure can differ (for example, between a GH ligament and ACL).
Some are blended with the joint capsule.
Identify the physiological makeup of the majority of ligaments; identify how the ligamentum flavum differs from most others.
Some blend with joint capsule - Referred to as "capsular ligaments" Seen as dense, white bands or cords of connective tissue Contains large amount of ECM (80-90%) as compared to cells Composed mainly of type I collagen (except lig flavum = 75% elastin) Arrangement of collagen fibers are such that they can resist forces from more than one direction Contrast to a tendon where forces are from a muscle and tend to be in one direction
Define and relate the following terms: speed, velocity, and acceleration
Speed: displacement per unit of time regardless of direction Velocity: displacement per unit of time in a given direction Acceleration: Velocity that changes over time (velocity per unit of time)
For each joint capsule layer, determine degree of vascularization; discuss the innervation of the capsule layers; Use Table 2-7 to understand the type of stimulation that joint receptors in the capsule are sensitive.
Stratum fibrosum (outer) -Poorly vascularized but contains many joint receptors Stratum synovium (inner) Intima layer -rich with capillary vessels, lymphatic vessels, and nerve fibers Subsynovial layer - Well vascularized and innervated
Considering joint capsules, explain the relationship of structure to stability and mobility; explain the purpose for having capsular ligaments at a joint.
Structure vs function: Some are thin and loose (allowing more movement), others are thick and dense (providing stability) Purpose for capsular ligament: These passive tissues provide additional joint stability or restraint to movement based on their orientation, which is influenced by typical stresses on the joint.
Describe and give the purpose for following types of connective tissue: superficial fascia, deep fascia, tracts, retinacula, and aponeuroses.
Superficial fasciae - loose tissue found directly under skin Deep fasciae - compacted collagen fibers found attached to muscles and bones; may form tracts, bands, or retinacula - Sometimes indistinguishable from aponeuroses - a sheet of dense white compacted collagen fibers attached to muscles, fasciae, bones, cartilage
Compare the various types of loading a tissue can encounter: tensile, compression, and shear
Tensile loading = equal forces pulling in opposite directions in the same "line of pull" Compressive loading = equal forces acting toward each other in the same line Shear loading = equal, parallel forces working in opposite directions but not in same line of pull
Relate degrees of freedom to axes of movement and to planes of the body.
Term used to describe how many axes and planes a segment moves through
Describe the physiological response of tendons to intermittent tension; determine where the tendon is the most vulnerable to forces and discuss situations where tendons are at more risk for injury.
Tendons thickness and strength increases (moderately) with the application of intermittent tensile force. - Tendons can withstand large tensile forces, and the ends of tendons are more vulnerable to injury rather than midsubstance - When weakened, are at risk for injury - IMMOBILIZATION atrophies the MTJ and - Corticosteroid use, nutritional deficiencies, hormonal imbalance, dialysis, chronic loading in the high linear range without adequate recovery, and sudden large loads predispose the tendon to injury
Discuss the functions of tendons.
Tendons transmit forces developed by muscles to the bones, this results in: joint movement and joint stability
Essay for the Patella as an anatomical pulley
The classic example of an anatomical pulley is the patella. The patella is embedded in the quadriceps tendon and pushes the tendon away from the femur, changing the angle that the patellar tendon makes with the tibia and changing the line of pull of the quadriceps muscle away from the knee joint axis. This results in an increased moment arm, which means that the same magnitude of the quadricep's muscle force will produce greater torque. Key words: moment arm, torque, and muscle force.
Describe the direction of pull that always occurs with a muscle contraction
The direction of pull for any muscle is always toward the center of that muscle.
Give several examples of synovial joints that contain other types of cartilage besides only hyaline cartilage.
The knee joint contains fibrous cartilage within the meniscus (rubbery shock absorber of the knee) The knee also contains articular cartilage that pads the ends of the bones.
Name the plane and axis in which lateral rotation and medial rotation is usually seen in
Transverse plane and y axis (vertical axis/longitudinal axis)
Explain the term "force couple"; describe the movement elicited by a true force couple; give an example of a modified force couple in the human body
Two forces equal in magnitude, opposite in direction, parallel, and applied to the same object at different points are known as a force couple. Example:
Identify the two layers of a joint capsule and determine which is the outer/inner layer; For the stratum synovium, discuss the important functions of the specialized fibroblasts called synoviocytes.
Two layers Stratum fibrosum (outer) - Poorly vascularized but contains many joint receptors Stratum synovium (inner) - Intima layer - Contains synoviocytes that remove debris from joint cavity and maintain structural repair
Identify whether each subclassification of synovial joints is considered uniaxial, biaxial, or triaxial (multiaxial) Relate the degrees of freedom to each subclassification of synovial joints.
Uniaxial - One plane around one axis = 1 deg of freedom - Hinge (DIP) and Pivot (C1/C2) (knee, elbow) Biaxial (carpometacarpal joint) - Two planes around two axes = 2 deg of freedom - Condyloid (MCP) and saddle (CMC) Triaxial (hip and shoulder) - Three planes around three axes = 3 deg of freedom - Plane (carpal joints) and Ball/socket (hip)
Describe how segments move in relation to the planes of the body; describe the three planes of the body; determine what makes a cardinal plane special.
When a segment moves in a plane, it moves directly along that plane. The axis is the hinge by which its rotates. - Rotation of a segment around the frontal (coronal, x) axis occurs in the sagittal plane. Ex: Knee flex/ext - Rotation of a segment around the vertical (y) axis occurs in the transverse plane. Ex: GH rotation - Rotation of a segment around the sagittal (z) axis occurs in the frontal plane. Ex: GH add/abduction What makes a cardinal plane special? A cardinal plane divides the body into perfect halves and they all intersect at the CoM at the L2
Internal (medial)/external (lateral) rotation
When applied to a segment that IS part of midline (trunk, neck), then use simply rotation
Examine the use of arrows to graphically represent force vectors: explain the term "point of application" when referring to vectors
When illustrated, is represented by an arrow that points in the direction of the force being exerted. For muscle vectors, the arrow originates at either the origin or insertion, depending on what the picture is depicting. The point of application is where the force is exerted on the segment The force vector that represents gravity will always originate at the CoM of that segment
Use Example 2-19 to understand why sliding and gliding are crucial to joint function; Explain why a therapist should understand this rule when performing joint mobilization.
When you have convex moving on a concave, the rolling and sliding happens in opposite directions. When you have a concave moving on a convex move in the same directions. It is important for a therapist to know this so that they can instruct the patient to exercise this function in their joint to regain full mobility.
a. Refer back to the definition or arthrokinematics and describe these joint movements: slide, spin, and roll and give an example of each b. Discuss what determines which type of movement (one or more) is seen at any particular joint.
a. slide: Linear motion like car wheels skidding-MCP joints Spin: Rotation of the components like a spinning top-Radius spinning on capitulum during supination/pronation Roll: Rolling of one surface on another like a tire rolling on road-Knee Joint Flex b. The mechanics of the joint surface movement is controlled by the shape of the articulating surfaces
Explain the term tensile force
always equal in magnitude, always in OPPOSITE directions, always applied parallel along a single line
dorsiflexion/plantarflexion
dorsiflexion is a movement where angle between foot and leg decreases; angle between foot and leg increases during plantarflexion
Load
external force(s) applied to a structure
Describe anatomic position; explain the purpose for understanding this body position
feet shoulder-width apart and toes facing forward; arms to side with palms facing forward; head facing forward. This is important because it helps us correctly identify joint movements.
radial/ulnar deviation
from anatomical position of the wrist toward radial side or ulnar
scaption
movement of the humerus away from the body in the scapular plane
inversion/eversion
movements of the sole of the foot medially or laterally
Deformation
occurs when a force is applied to an object Example: a tensile load will produce elongation (a type of deformation)
Ultimate Failure Point
point that is reached when loading continues into the plastic range where the material continues to deform and finally fails (due to the failure load). Rupture, need surgery to repair.
spinal rotation (left and right)
rotary movement of spine in horizontal plane; chin rotates from neutral toward shoulder & thorax rotates to one side
Yield Point
signals the end of the elastic region; after this point, the material will no longer immediately return to its original state when the load is removed...but may recover in time.
Explain the concept of open and closed kinematic chains as it relates the body;
system of joints linked together in such a way that motion at one joint can produce motion at the other joints Open kinematic chain - One joint can move independently of others in the chain - We tend to move UE (upper extremities) this way - Ex: hand weights, cuff weights, pulleys, swimming Extremity is moving relative to the body Closed kinematic chain - Movement of one joint automatically creates movement in the other joints in the chain (one end of the chain is fixed) - We tend to move LE (lower extremities) this way - Ex: walking, bicycle, push-ups, squats, weight machines that fixate hand/foot Body is moving relatively to the extremity
circumduction
the circular movement at the far end of a limb
