BioMech4 Test 1 Flashcards
What is the most common joint in the extremities?
Synovial Joint.
What is the biomechanical triad?
muscles, skeleton, joints.
What makes up scar tissue and why is it different than regular tissue?
Fibroblasts make up the scar tissue and it is different from regular tissue because they orient themselves according to stress placed on them.
What cell will make scar tissue?
Fibroblasts.
How will fibroblasts lay scar tissue?
They orient themselves according to stress placed on them.
What is the diaphysis?
Diaphysis- shaft or body of the long bone.
What is the metaphysis?
Metaphysis- Between diaphysis and the epihyseal plate.
What is the epiphyseal plates?
Epipyseal plate- growing lines.
What is the epiphysis?
Epiphysis- Top part of the long bone.
What is the name for a secondary growth center on a long bone (ie: for tubercles or other muscle/ligament attachments?
Apophysis.
Epiphyseal plate is aka?
Physis.
What is a closed physis?
Where the epiphyseal plate was but the cartilage is gone and growth has stoped, but a line is still there.
Perisoteium is continous with what?
Fibrous capsule.
What is the bone called that is deep to the articular cartilage in a synovial joint?
Subchondral bone.
What is articular cartilage like in synovial joints?
Blue, slippery caps of adjacent bone ends and lines the bone
Where is intra-articular cartilage found at? What type of cartilage is it?
Discs and menisci and it is fibrous cartilage between bones.
What inner lining part of the synovial joint that lines the synovial cavity?
Synovial membrane.
What is the synovial cavity?
Joint Cavity
What does the synovial cavity contain?
Synovial fluid
What is synovial fluid?
Viscous fluid in joint cavity
What is the periosteum?
Membrane lining outer bone
Will synovial joints have a perichondrium?
No.
Where is synovial fluid secreted from?
The innermost layer (intima) of the synovial membrane.
How much synovial fluid is there in synovial joints?
Just enough to form a film.
What is synovial fluid like?
Transparent high viscosity rich in glycosaminoglycans (GAG’s).
What is the major GAG in synovial fluid?
Hyaluronic acid.
Hyaluronic acid injections are used to treat what in synovial joints?
Osteoarthritis.
What are the functions of synovial fluid? (4)
Shock absorber, lubrication, supplies nutrients to cartilage, removes waste from cartilage.
How many layers are there for synovial membranes?
two, Intima and sub-intima.
What layer of the synovial membrane is closest to the synovial fluid and which layer is closest to the bone?
Intima- closest to the fluid. Sub-intima- closest to the bone.
What is the intima like?
Epithelioid layer (like epithelium), but not epithelium.
What is the sub-intima like?
Connective tissue that is a thicker outer layer.
What are the 3 different types of sub-intima?
Areolar, fibrous, adipose.
Is the synovial membrane innervated and vascularized?
Yes, but only the subintima not the intima.
What are the functions of the synovial membrane?
Produce and resorbe synovial fluid and provide immunity to the joint cavity.
What is found in the transition zones of cartilage?
Villi and fibrocartilage.
Name the cells found in synovial membranes?
macrophages, secretory, fibroblast, lipocytes.
What are synovial membrane capillaries like and why?
Fenestrated to increase the fluid exchange.
Will Synovial membranes have lymphatic vessels?
Yes even the intima has lymphatic vessels as it needs to extract fluid from the synovial joint
What is the function of the fibrous capsule of synovial joints?
Support, guide/ limit movement, absorb shock.
What are the different cell types of the synovial membrane cells?
macrophages, secretory, fibroblast, lipocytes.
What are fenestrated capillaries and what is the significance of them in the synovial joint?
Increase fluid exchange
Other than synovial joints, where else are fenestrated capillaries also found?
Kidneys for fluid exchange
With joint support what is the difference between dynamic and static?
Dynamic- muscles. Static- inter-locking bones and joint capsules.
What happens when the fibrous capsule has scar tissue?
It will have abnormal wear and tear.
What are extracapsular ligaments?
Those that are independent of the joint capsule. (don’t develop in the capsule)
What are sharpey’s ligaments?
Ligaments that go into bone.
What is Wolff’s law?
Bones grow from tension, the more tensile force on bone the more growth of bone occurs
What is the innervation like for fibrous capsules?
well innervated with lots of proprioception.
What is the vascularization like for fibrous capsules?
Not well vascularized, but is vascularized.
If a joint has lots of bleeding or brusing involved what should be thought of?
Blood might come from a fracture, or muscle injury since bones and muscles are well vascularized.
What is Bursae?
Synovial membrane lined extra-capsular pockets or pouches.
Bursae communicate with what?
Synovial cavity, Thru passages/defects in the capsule. Others are separate.
What are the 2 functions of bursae?
Lubricate and pad.
What is another synovial membrane lined structure besides bursae that lines extra-capsular pockets or pouches?
Gastrocnemius and popliteus bursae.
What is the purpose of gastrocnemius and popliteus bursae?
To help guide and lubricate tendons.
What is the fluid like with bursae?
Thin film or fluid.
What is the most common type of articular cartilage?
Hyaline cartilage.
What is the leaste common type of articular cartilage and where is it found at?
Fibro-cartilage only 3.5 joints; AC, TMJ, 1/2 SI.
What are the 3 things articular cartilage is made of?
water, collagen, GAG.
What is the main component of articular cartilage?
H2O.
What are the 2 parts of articular cartilage?
wet and dry parts.
H20 makes up what % of total weight of articular cartilage?
80%.
What makes up what % of the total dry weight of articular cartilage?
Collagen- 60-70%. GAG- 30-40%.
What is the function of collagen in articular cartilage?
Holds things together and resists shear.
What will give articular cartilage the rigid characteristics?
Strong water attraction from GAG’s.
What is needed to make Collagen?
Vitamin C and amino acids.
How are collagen fibers oriented at the articular surface?
Parallel.
How will articular cartilage receive nutrition?
Synovial fluid, deep layers receive from bone diffusion. NO NUTRITION FROM BLOOD VESSELS.
Name 2 important GAG’s in synovial joints?
chondroitin sulfate and glucosamine sulfate.
Name 2 other GAG’s in synovial joints?
Keratin sulfate, hyaluronic acid.
What is a dietary source of GAG’s?
Connective tissue, shellfish, cartilage.
How will GAG’s pull water inside the articular cartilage?
It will attract H2O with the negative charged Sulfate and Carboxyl groups. This is why the Chondroitin sulfate and glucosamine sulfate GAG’s are important in articular cartilage.
Synovial joint boundary lubrication is like what?
Teflon.
What are small compressive loads of synovial joints like?
Weak inoic bonding and GAGs lubricate the surface.
What are large compressive loads of synovial joints like?
Squeeze fluid film out of the cartilage.
Why are slow oscillations of synovial joints good?
Fluid exchange.
Why would rapid or no oscillations of synovial joints be bad?
Decreased fluid exchange.
What happens to synovial joints with DJD?
Decreased cell # which leads to decreased GAGs and increased serous fluid which leads to decreased lubrication, which leads to increased calcification.
subchondral or cancellous bone is aka?
Spongy bone.
subchondral / cancellous / spongy bone is tuff stuff that does what?
Shock absorption.
What happens with subchondral bone aka cancellous aka spongy bone with DJD?
Increases calcification which increases rigidity which increases thickness and impedes nutrient delivery, which decreases shock absorption.
What is cartilage innervation in general like?
It is not innervated, but intra-articular cartilage is in the outer 1/3.
What are the different types of intra-articular cartilage?
- Disc. 2. Meniscus.
Name 4 examples of disc intra-articular cartilage?
AC (in early 20s), SC, TMJ, Ulnocarpal (triangular fibrocartilage).
Name 2 joints made of meniscus intra-articular cartilage?
Knee, AC (late 20’s to early 30’s).
Intra-articular cartilage is made of what?
Fibrocartilage.
What is the function of intra-articular cartilage?
Increases shock absorption, increases congruency(fits better), increases stability, decreases friction, increases motion.
What type of innervation will intra-articular cartilage have?
Outer 1/3 transition with capsule, but has proprioception, nociception.
What is the vascularizatino of intra-articular cartilage like?
Outer 1/3 is and inner 2/3 is avasular.
In which part of the intra-articular carilage is it the furthest away from the nutrient source?
Middle of the intra-articular cartilage
What happens to intra-articular cartilage with age?
Meniscus tear easier as we get older.
How does intra-articular cartilage age?
Similar to IVD, increase vascularization, decrease chondrocytes, decrease GAGS, decrease collagen, increase collagen fiber size (more brittle_, decrease shock absorption, decrease flexibility
Chiropractors are human ______.
Joint experts.
Name the parts of synovial joints?
synovial membrane, fibrous capsule, articular cartilage, intra-articular cartilage, subchondral bone.
What is the Number 1 disability encountered by the medical profession?
Joint disease.
Synovial joint extends from where to where?
Metaphysis to metaphysis.
Forces exerted on synovial joints and the tissues that provide support are generated how?
Partly by body weight, and mainly by muscle contraction across the joint.
Synovial joints originate from what?
Mesenchymal “articular discs” between the primoridla bones.
What happens to the mesenchyme in the zones where the joint will later appear?
It is replaced by cartilage.
After the mesenchyme is replaced by cartilage what happens?
The cartilage plate then cavitates.
Synovial fluid is secreted by what?
Cells of the synovial membrane.
What are the 2 functions of the synovial membrane?
secrete and remove synovial fluid.
What are the 2 groups of cells in the synovial membrane and what do they do?
A or F- Rich in hyalurionic acid. B or M- immune cells.
What is the fibrous capsule of synovial joints like?
A barrel shaped sleeve around the joint that is reinforced by thickenings called capsular ligaments.
From what will the fibrous capsuel develop?
Perichondrium of the embryonic cartilaginous model and remains attached to the periosteum.
What is the main cellular component of articular cartilage?
Chondrocytes.
What are chondrocytes responsible for?
Maintenance and repair of the cartilage matrix.
What are chondrocyte life cycles like?
They are long lived in normal adult cartilage there is no further mitosis and growth subsides. Repair and regeneration of articular cartilage will predictably diminish with age.
What happens when 2 cartilage surfaces are rubbed together?
An interposed film of synovial fluid that is 40 times more slippery than teflon occurs.
What are the 2 types of lubrication and what are they used for?
Boundary- small loads. Hydrostatic- high loads.
What is subchondral bones stiffness like?
100 times less stiff than cortical bone.
What is the purpose of subchondral bone being less stiff?
It forms an intermediate zone that protects both articular cartilage and the diaphysis.
Why would it be better for subchondral bone to be injured vs. articular cartilage?
Bone can heal better.
Intra-articular cartilage developed from what?
Mesenchyme.
What happens when intra-articular cartilage is torn?
It is rarely abosorbed and becomes a foreign body that can accelerate wear and tear on articular cartilage surface and should be removed.
When intra-articular cartilage is removed what happens?
It is replaced by a dense fibrous connective tissue.
What is the vascularization like for synovial joints?
They are highly vascularized around each joint there is a plexus called a rete or periarticular plexus.
What are the 3 groups of arteries or veins that reach the joint area?
- Epiphysis/metaphysis. 2. Fibrous joint capsule. 3. Synovial membrane.
Why will the articular, intra-articular cartilage and synovial cavity be avascular?
They contain a substance that specifically inhibits the incursion of blood vessels and only in diseased and dying cartilage will blood vessels invade.
Will synovial joints have lymphatics?
Yes and they help with the removal of synovial fluid.
What is the innervation of large joints like?
They receive pain fibers from several spinal levels and the pain may be poorly localized or even deceptive.
Active protection of a synovial joint is done by muscle contraction and joint motion and this active protection is called what?
Negative work.
Negative work is the most important factor in what?
Sparing synovial joints from excessive loading.
80% of cases of idiopathic osteoarthritis at the hip joint are due to what?
Defects that produce joint incongruity and uneven or increased impact loading.
What happens to Proteoglycan with lack of compression in synovial joints?
This will result in decreased proteoglycan synthesis and abnormal binding.
What will excersise do to ligaments?
Hypertrophy and increased strength.
Osteoarthritis is not associated with what?
Systemic phenomena that are features of primary inflammatory joint diseases like RA.
Deterioratin is most common in what joints?
Those that are subjected to abnormal loads.
What is the specific healing agent with osteoarthritis?
None aside from reducing the source of irritation which may allow healing to occur.
Most extremity synovial joints are what type of joint?
diarthroidal and highly mobile.
What are the 3 types of joints according to the # of articulations?
- Simple- 2 articular surfaces (1 articulation). 2. Compound- 2 or more articulations. 3. Complex- 1 or more articulation plus intra-articular disc/meniscus.
What is an example of a simple joint?
DIP joint
What is an example of a compound joint?
tibiofemoral, subtalar, patellofemoral joint
What is an example of a complex joint?
Knee, ulnocarpal, AC, SC, TMJ, knee joint & radiocarpal joint
What is a joint complex?
Several joints acting together as a functional group. Like the knee, shoulder, wrist, elbow.
What are the 6 types of joints based on anatomical/ morphological classifications?
- Spheroid- ball and socket. 2. Ellipsoid- condyloid. 3. Arthroid- planar(gliding). 4. Sellar- saddle. 5. Ginglymus- hinge. 6. Trochoid- pivot.
What is an example of a spheroid joint?
shoulders and hip (more moveable than ellipsoid
What is an example of an ellipsoid joint?
Knee and occipital axial joint (spheriod in shape but moves in pairs)
What is an example of a arthroid joint?
Planar = flat, radioulnar joint
What is an example of a sellar joint?
First carpal metacarpal joint
What is an example of a ginglymus joint?
knee, elbow, intercarpal joint
What is an example of a trochoid joint?
humeral-radius joint at the capitellum
What are the 4 joint motion classifications?
- angular. 2. Translational. 3. Rotational. 4. Circumduction.
What is angular motion?
Flexion, extension, abduction, adduction.
What is translational motion?
Primarily gliding non-angular.
What is rotational motion?
Non-angular (not spin).
What is circumduction motion?
A combinatino of all of the above 3 motions.
What are 4 motions based on axes of motion?
- Uniaxial. 2. Biaxial. 3. Polyaxial. 4. Nonaxial.
What is uniaxial motion?
Can only move in 1 plane. (ankle joint (plantar and dorsiflexion))
What is biaxial motion?
Can move in only 2 planes. (knee, most bicondylar joints)
What is polyaxial motion?
Can move in many planes. ( shoulder and hip)
What is nonaxial motion?
Gliding.
Why are joint surfaces irregular and ovoid in shape?
Non linear accessory motions.
What is the function of crooked or crank shaped bones?
actions differ from joint motion.
MacConail coined the term osteokinematics which is based on what?
Mechanical axis not axis of rotation.
What are the 2 types of mechanical axis aka osteokinematics?
Spin and swing.
What is spin?
Stationary mechanical axis (not always the same as rotation).
What is swing?
Mechanical axis moves.
With spin is the mechanical asix stationary or moving?
Stationary.
Spin may rotate when?
The mechanical axis is parallel to the long axis.
Why will spin usually not equal rotation?
Bones are crooked/ bent and the mechanical axis does not parallel the long axis.
How often will pure spin occur?
Not often.
What does spin usually accompany?
swing
Why don’t we use spin and rotation synonymously?
Spin can produce angular motion or rotation so they are not the same (for example: shoulder internal and external rotation is actually swinging because the humerus is swinging along the glenohumeral joint)
What are the motions of swing?
Straight line, chord, arc.
What is impure swing?
Spin + swing. (typical motion)
What is conjoint/conjunct rotation?
Relates to impure swing.
Screw home mechanism is what?
External rotation of the tibia with knee extension.
Screw home mechanism at the knee is a good example of what?
Conjoint rotation.
How rare is pure swing?
Rare.
Arthrokinematics is based on what?
Movement at articular surfaces.
What are the 3 types of movements with arthrokinematics?
Roll, slide/glide, spin.
What would the name be of the movement of all 3 arthrokinematic motions combined?
Accessory rotation.
Roll only results in what?
Progression. (ie: car lifting off ground with high acceleration
What are the 3 problems created with roll?
Progression, distraction, impingement.
What are the 3 problems created with slide?
Progression, distraction, impingement.
Can convex and concave surfaces both roll?
Yes
What is the arthrokinematic motion used with manipulations?
Slide.
What are the 2 rules used when combining roll and slide?
Convex and concave rule.
What is the convex rule?
Direction of slide is opposite the direction of angular, roll is in same direction of angular motion and slide and roll occur in opossite directions.
What is the concave rule?
Direction of slide and roll are in the same direction of angular movement. Slide and roll occur in same direction
What surface is longer the concave or convex?
Convex.
What is conjunct or conjoint rotation?
Accessory rotation that is combining the arthrokinematic movements.
What is the difference between closed and open positions in kinematics?
Closed aka tight packed position is when the joint is stabilized as the joint capsule is tense and this inhibits movement. Open aka loose packed position is necessary for movement.
What are the different types of open and closed positions?
Open there are an infinite amount of positions. Closed there is only 1 closed packed position.
What is the difference between resting and neutral position with kinematics?
Resting position- the loosest packed position or the most open position. Every joint has a resting position. Position patients get in when they have a problem. Resting position is just a part of the loose pack position they are not synonyms. Neutral position- This is a position that was decided upon by a group of people and is often the anatomical position. This position is known as zero which is between the different types of motion for the joint (like between flexion and extension).
What is the difference between end play and joint play?
end play- accessory movements that occur within motion that the person can create. Joint play- a movement in a direction that cant be normally produced.
Name 7 muscle functions?
shock absorption, dynamic joint stabilization, dynamic joint alignment, acceleration, deceleration, heat production, venous circulation.
Name the static joint stabilizers?
Hydrostatic, capsular, and bone fit.
What muscle functions will be concentric and what will be eccentric contractions?
Acceleration- concentric. Deceleration- eccentric.
What is an isometric muscle contraction?
No movement or length change.
What is an isotonic muscle contraction?
Produces joint motion, muscle length change, variable velocity.
What is an isokinetic muscle contraction?
Same as isotonic except velocity remains constant.
What is the line of progression?
A line that is in the middle of the legs when walking and is the line that shows the progression made.
What is step, step length?
one step with one limb.
What is stride?
One complete cycle of gait so it is 2 steps.
What is a normal amount of foot flare while walking?
5-7 degrees.
Increased foot flare leads to what?
Decreased efficiency.
Foot flare decreases with what?
Increased cadence (flow or rhythm. Running).
Too much toe out leads to what?
Increased stress on the lower extremity leading to injury. Also leads to inefficient so muscles need to work more and stride length is decreased.
What are the 2 phases of the gait cycle?
- Stance - support (foot in contact with ground). 2. Swing. - recovery (foot is not in contact with ground)
What is the kinetic chain like for the 2 phases of a gait cycle?
stance- closed. Swing- open.
Running and walking will each involve what parts of the gait phases?
Running- 40% stance, 60% swing. Walking- 60% stance, 40% swing.
Why will increased speed during gait cycles lead to more injury?
When speed is increased the following will also be increased; compression, distraction, torsion, shear, bending, inertia. Also Increased ground reaction forces and increased muscle activity.
Of the forces that are increased when speed is increased with gait which ones are the most damaging?
Torsion, shear.
The stance phase of the gait cycle is from when to when?
From footstrike to take off.
What is the difference between toe off and take off?
Toe off- is the very end of take-off. So toe off is just a part of take-off.
When will the swing phase of gait happen at?
From toe-off to heel strike.
What is a closed kinetic chain?
The distal end of limb is connected to a fixed object (ie: the ground) - foot strike to toe off
What is an open kinetic chain
The distal end of the limb is not connected/attached to a fixed object - from toe off to footstrike
What is double support and float and when will they happen?
Double support- one foot is in foot strike while the other is in take-off, this only happens during walking. Float- both limbs in swing, this only happens while running.
What are the 3 subdivisions of the stance phase of gait and what % of the stance phase will each take up?
- Contact aka foot strike- 25%. 2. Midstance or midsupport- 50%. 3. Take-off aka proplusive- 25%.
During the contact or foot strike phase the foot lands where?
Ahead of the center of gravity.
Name 2 important functions of the contact phase of gait?
- Abosrb shock. 2. adapt to ground uneveness.
Pronation of the foot is what?
Medial rotation of foot.
What is a pronated foot like?
more flexible and can absorbe more energy.
Name the 2 important joints involved in the contact phase of gait?
subtalar and midtarsal. (for pronation and supination)
What are the motions of the calcaneus and talus during the contact phase of gait?
Eversion in general. And some abduction of foot and calcaneus to talus and dorsiflexion of calcaneous relative to the talus (ie: talus plantar flexes)
What is heel rocker?
dorsiflexion of calcaneus and forefoot; talus at ankle plantar flexes (heel rocker) completed before pronation is complete.
During contact phase what is the motion of the forefoot in relation to the the rearfoot?
dorsiflexion.
When is the foot most pronated?
At the end of the contact period or at the beginning of the midstance period
What position is the foot in when it lands while we are walking?
it is 2 degrees supinated.
While walking after the foot lands 2 degrees supinated what happens?
The talus plantar flexes and then the foot begins pronating.
What is the ideal and clinical pronation range while walking?
Ideal- 6-10 degrees. Clinical- 5-15 degrees.
Why is it important that the tibia and femur internally rotate during the contact phase while walking?
This will reduce torque. (if the leg and foot rotate in opposite directions, torque is increased)
What 2 types of stress seem to be most deleterious to connective tissue?
Torsion and Shear
During the gait cycle what is the action of the foot relative to the leg?
Subtalar rotates with leg, but not at ankle. Calcaneus moves with the foot.
While walking the foot lands 2 degrees supinated and then what will happen before it pronates?
Plantar flexion.
When will people be rearfoot strikers or forefoot strikers?
Rearfoot- walking, slow running, jogging. Forefoot- fast running.
While walking what happens right after rearfoot strikers strike?
Foot/talus plantar flexes.
With rearfoot strikers how is the plantar flexion accomplished?
Tibialis anterior eccentrically controls plantar flexion at the subtalar and midtarsal joint and it also controls pronation of the foot and it also pulls the leg forward.
What large thigh muscle will the tibialis anterior assist?
Quadriceps.
How will the peroneus tertius aid the tibialis anterior?
in dorsiflexion and it will counteract the tibialis anterior induced inversion.
While running what muscle will be very active at lowering the ankle and what will this accomplish?
Gastrocosoleus and it will be a shock absorber.
While running after forefoot strikes what happens?
The foot dorsiflexes after the metatarsal heads strike the ground and the heel moves toward ground.
While running the forefoot strike is in what position?
2-4 degrees supinated.
While running will the foot pronate after it lands 2-4 degrees supinated?
yes at subtalar and midtarsal joints.
While running what muscle will control the pronation?
tibialis anterior and posterior.
What will more inertia that comes from running cause?
more eccentric muscle activity —> increased risk of injury.
When will midstance happen?
From foot flat to heel off.
During midstance where will the center of gravity be?
over the stance limb.
While in midstance with a single support what position is the other limb in?
Swing.
What position is the foot in during midstance?
pronated relative to neutral.
During midstance the foot is pronated and what motions will it undergo?
supination.
How is supination done while in the midstance?
ankle/talus dorsiflexes as center of gravity continues to move forward relative to stance foot. This is dorsiflexion of the foot “ankle rocker”.
What position will the leg and thigh be in during midstance? Why?
Leg and thigh extend and externally rotate and this will reduce torque.
When should heel lift occur during running, walking and what will this mean?
Running- after swing limb passes stance limb. Walking- at heel strike of opposite limb. The significance is overloading the gastrosoleus.
What should arm swing be like compared to the midstance?
counterbalancing arm swing (crawl mechanism right upper and left lower limb move back and forth together).
Where is the center of gravity during take off?
anterior to stance foot.
During take off what muscles lift the heel?
gastrocsoleus. (d/t stretch) but push off in running
What muscle will rapidly invert the calcaneusto complete rearfoot supination at take-off?
Tibialis posterior rapidly inverts the calcaneus.
What happens to the foot when supination is completed?
The foot is ridgid lever except toes.
What will allow roll on ball of foot during take off?
Passive toe extension.
The toe extension tenses what?
The plantar fasciae escpecially the hallux. (Hallux extends 60 degrees)
What muscles will eccentrically control the toe extension?
Toe flexors.
How will weight shift on the plantar surface during the take-off phase?
It shifts medially across metatarsal break.
What is the metatarsal break?
Oblique angle of metatrasal heads.
What motion happens at the end of take-off and why?
Slight pronation and this will increase the load bearing on the 1st and 2nd metatarsals.
What is the last part of the take-off phase?
Toe off.
What ray is most important to forefoot control just prior to toe off?
1st
What 5 muscles are important to 1st ray stabilization and control of pronation prior to toe off?
P. longus, Flexor Hallucis Longus, Flexor Hallucis Brevis, Adductor Hallucis, Abductor Hallucis (since they all attach to the first ray)
What are the tibia and femur doing during take off and why?
They are externally rotating to reduce torque.
What happens if there is too much late pronation in take-off?
Overwork of muscles and torque on osseous and fibrous tissues that may affect the foot, ankle or leg (may lead to stress fractures). Usually a first sign is posterior shin splints.
What is the peroneus longus doing during take-off?
Lifts cuboid and lateral foot (pronates), depresses and plantar flexes first ray which helps shift weight medially along metatarsal break. It also maintains contact between ground and 1st metatarsal head during take off.
What muscle will help the peroneus longus maintain contact between ground and 1st metatarsal head during takeoff?
Toe plantar flexors.
How will foot supination and foot pronation affect the leverage of the peroneus longus?
supinated foot- increases leverage. Pronated foot- decreases its leverage.
What will happen with a hypermobile dorsiflexed 1st metatarsal / hallux valgus?
It will lead to late pronation which will increase torque and therefore increase injury.
During the swing phase how is inertia produced?
acceleration and decelleration.
What are the 3 divisions of the swing phase and what will the limb be doing in these phases?
- Initial or follow through- limb moves back and stops. 2. Mid-swing or forwar/anterior swing- limb moves forward and stops. 3. Terminal swing or foot descent- limb moves back again.
What are the knee and tibia doing during the intial swing part of the swing phase?
Knee flexes and tibia internally rotates.
What is the hip doing during initial swing?
Hip extends and externally rotates. (increases internal tibial rotation)
What muscles eccentrically decelerate the hip and knee in the initial swing phase?
hip flexors.
What muscles will accelerate the hip and knee during the first part of mid-swing phase and how will they do this?
Hip flexors, concentrically.
Will there be more initial swing during walking or running?
Running.
Where is the opposite limb at during the initial swing while walking and running?
Walking- end of foot strike. Running- terminal swing.
The early part of mid-swing phase is like what?
The bowling ball effect- momentum pulls forward. (caused by hip flexors)
What hip flexor is the most vulnerable to injury?
Rectus Femoris
What muscles will slow the swinging limb during mid-swing and how?
Gluteal and hamstrings eccentriaclly slow the forward swinging limb and hip and knee.
What is the foots position during mid-swing and why?
Neutral to slightly dorsiflexed to prevent foot dragging.
What is happening to the hip during mid-swing and why?
The hip is being internally rotated by the adductors which brings the foot back to the line of progression.
What muscles will accelerate the limb backwards during terminal swing phase?
Hip extensors and knee flexors
What is determined during the swing phase?
foot flare and amount of rearfoot inverions and pronation during the next stance phase.
What is the tension like on the hamstrings during terminal swing?
The tension is highest.
Why would the foot rotate in the same direction as the leg and thigh during gait?
To reduce torque and injury.
What is the general trend during the contact phase?
Everything is medially rotating
What is the general trend during the mid stance phase?
Everything is laterally rotating
How many bones, muscles and joints are there in the foot and ankle
Bones- 28. Joints- 35 or more. 18 foot and 11 leg muscles.
Name the 6 important joints of the foot and ankle?
- Talocural. 2. Subtalar. 3. Choparts aka midtarsal. 4. Lisfranscs. 5. 1st tarsometatarsal. 6. first metatarsophalangeal.
Where is the subtalar joint at?
Talocalcaneal. (2 concave and 1 convex)
What is the lisfrancs joint?
1-5 TMT joint.
During gait, which two joints are important lisfranc joints?
First tarsometatarsal and first metatarsophalangeal
What is another name for the tarsometatarsal joint?
Cuneometatarsal joint.
What is the midline of the foot and why will this matter?
It is the 2nd metatarsal and it is a reference point for abduction and adduction of the toes.
What are the midtarsal and subtalar joint most important for?
Medial and lateral rotation of the foot
Name the three arches of the foot and the keystones that go with them?
Medial arch- talus. Lateral arch- cuboid. Transverse arch- second metatarsal.
What is the largest of the 3 arches of the foot?
Medial longitudinal arch.
What % of body weight is on which part of the foot while standing?
Heel-60%. Metatarsal head- 26%(of the 26% 50% is on the first and second metatarsal heads).
How will static weight distribution happen with heel inversion?
Inversion aka rearfoot varum will shift weight to the lateral side of the foot and can cause more ankle sprains.
How will static weight distribution happen with heel eversion
Eversion aka rearfoot valgum and shifts weight to medial side of heel and might affect the knee and helps bend big toe out.
How will static weight distribution happen with high heels or tight gastrocsoleus?
Causes shift in weight to forefoot (ball of foot) and shortens the gastrocnemius. (forefoot can’t usually handle constant weight)
How will static weight distribution happen with a dorsiflexed first ray and a plantar flexed first ray?
Dorsiflexed- collapsed medial longitudinal arch and pronation may be affected. Plantar- Changes arch with higher arch more supinated less pronation and shifts weight to outside foot.
How will static weight distribution happen with a fixed 1st Metatarsaophalangeal joint?
Prevents big toe from extending and shifts weight to lateral side of foot.
How will static weight distribution happen with a long 2nd ray? What is this also known as?
aka mortons foot and increases weight on 2nd metatarsal and may cause stress fractures and may interfere with first ray and take off.
How will static weight distribution happen with Forefoot varus and forefoot valgum?
Varus (rigid foot)- shifts weight to outside of foot. Valgum- shifts weight to inside of foot.
How will static weight distribution happen with splay foot?
Splay- loss of transverse arch causing metatarsals to spread apart. Increases weight bearing to middle 3 metatrsals and can cause stress fractures.
How will static weight distribution happen with pes planus?
Pes planus- Flat foot, causes a weight distribution evenly and this is not good.
How will static weight distribution happen with pes cavus?
Pes Cavus- increases tripod effect to the extreme and this is bad. Heel first metatarsal and not so much weight everywhere.
How will static weight distribution happen with rear foot valgus?
shifts weight to Medial side of foot
How will static weight distribution happen with rear foot varum?
shifts weight to Lateral side of foot
What are the 3 keystones in the foot for arch support?
Talu, Cuboid and 2nd metatarsal and cuneiform
Which bone is the keystone for the medial longitudinal arch?
Talus
Which bone is the keystone for the lateral longitudinal arch?
Cuboid
Which bone is the keystone for the transverse arch?
2nd metatarsal and 2nd cuneiform
What are the 4 ligaments that act as staples/ mortor for the foot and ankle?
Spring (plantarcalcanealnavicular), long plantar, short plantar, transversemetatarsal ligaments.
What ligament acts as the staple/mortor for the medial longitudinal arch?
Spring ligament
What ligament acts as the staple/mortor for the lateral longitudinal arch?
Long plantar and short plantar ligaments
What ligament acts as the staple/mortor for the transverse arch?
Transverse metatarsal ligament
For foot and ankle support what will act as tie beams (bowstrings)?
Foot intrinsics, Tibialis poster, Flexor Digitorum longus and Flexor Hallucis Longus (Tom, Dick and Harry), Peroneus longus, plantar fasciae.
What is the most important part of the plantar fasciae for foot and ankle support?
Medial part.
What are the 4 suspensors of foot and ankle support?
Tibialis Anterior, Tibialis posterior ,Peroneous Longus, Peroneus Brevis, Peroneus Teritius
What are the 2 stirrup muslces that support the foot and ankle?
Peroneus Longus, Tibialis Anterior.
OF the 4 tie beams which one will be dynamic?
Muscles are always the dynamic supports
What is the keystone of the medial longitudinal arch?
Talus
What is the staples of the medial longitudinal arch?
Spring ligament (plantarcalcanealnavicular)
What are the beams of the medial longitudinal arch?
Plntar fascia, intrinsics (hallicus), plantar aponeurosis, abductor hallucis and flexor digitorum brevis of first 2 toes, tibialis posterior (in hind foot)
What are the suspenders of the medial longitudinal arch?
Tibialis anterior and posterior
What is the keystone of the lateral longitudinal arch?
Cuboid
What is the staples of the lateral longitudinal arch?
Long and short plantar ligaments
What are the beams of the lateral longitudinal arch?
Lateral part of plantar fascia, long and short plantar ligaments and lateral foot intinsics
What are the suspenders of the lateral longitudinal arch?
Peroneals
What is the keystone of the transverse arch?
2nd metatarsal and 2nd cuneiform
What is the staples of the transverse arch?
Transverse metatarsal ligament
What are the beams of the transverse arch?
Peroneus Longus tendon, adductor hallicus (transverse head), plantar aponeurosis and plantar fascia
What are the suspenders of the transverse arch?
None
What do the intrinsics of the foot and ankle act like?
Spring like dynamic tie beams.
Fatigue of the plantar fascia from overuse leads to what?
Pronation syndrome and foot cramps.
Is the plantar fascia and elastic or inelastic tie beam?
Inelastic.
Is the plantar fascia static or dynamic?
Static.
The plantar fascia connects what two structures together?
Medial and lateral calcaneal tubercles to the bones and fasciae of the toes.
When the toes extend what toe attachment of the plantar fascia is most important?
first toe is important and it extends during takeoff
Why is there more stress on the medial tubercle?
When the big toe extends passively it leads to the forward pull on the calcaneus leading to a decrease of stress on muscles
During toe extension the plantar fascia allows the foot to do what?
Roll and act as a rigid lever.
What is the windlass effect of the plantar fascia?
maintains the arches and allows gastrocsoleus to act at the ball of foot like a pully.
Where does the plantar fascia or aponeurosis extend?
Extends the Achilles’ tendon to forefoot
What will the plantar fascia do for the arch of the foot?
Support it and functions as a pulley
What is another name for supinated foot and pronated foot (not eversion/ inversion)?
Supinated- pes cavus. Pronated- pes planus.
What happens to the arch of the foot with pes cavus and pes planus?
Pes cavus- high arch. Pes planus- low arch.
Which foot will be curved and which one is straigth pes cavus or pes planus?
Pes cavus- curved. Pes planus- straight.
What happens to shock absorption for pes cavus and pes planus?
They both decrease shock absorption.
What part of the shoe will break down faster with pes cavus and pes planus?
Pes cavus- lateral shoe. Pes planus- medial shoe.
What are the static listings of the calcaneus with a pronated foot and what happens with these?
everted calcaneus- decreases inversion joint play. Posterior calcaneus- decreases anterior slide at subtalar joint.
What are the static listings of the talus, navicular with a pronated foot and what happens with these?
Medial talus- talus swings medial with the leg plantar flexed head which leads to head swing medial with leg not at ankle joint. Inferior navicular (didn’t give rationale)
What happens to the metatarsals with a pronated foot in static weight bearing position?
Dorsiflexed- at Tarsometatarsal joints.
What happens to the proximal phalanges with a pronated foot in static weight bearing position?
Flexed- straight toe.
What type of shoe will be prefered by someone with a pronated foot?
Stiff supportive, straight last, medial post.
What foot will be longer and what foot will be shorter a pronated or supinated foot?
Pronation- functionally decreases leg length and supination increases leg length.
What are the static listings for the calcaneus for a supinated foot in static weight bearing position?
Inverted calcaneus. Anterior calcaneus- dorsiflexed to the ground, but plantar flexed relative to talus.
What are the static listings for the talus, and navicular for a supinated foot in static weight bearing positions?
Lateral talus- head swings lateral with head. Superior navicular.
What happens to the metatarsals and proximal phalanges with a supinated foot in static weight bearing position?
Plantar-flexed metatarsals. Extended proximal phalanges (claw toes).
What type of shoe will be prefered by someone with a supinated foot?
Slip last- no stiff board, curved last, shock absorbing innersole and mid-sole.
What is the torque converter between the leg and foot?
Subtalar joint.
What is the key that locks and unlocks the midtarsal joints?
Subtalar joint.
What foot will be more rigid and what foot will be more flexible a pronated or supinated foot?
Pronated- flexible. Supinated- rigid.
What can cause abnormal or excessive foot pronation?
Rearfoot varum, forefoot varum, forefoot valgum, leg length asymmetry, muscle imbalance, fatigue, weakness or injury.
What happens with a tibialis anterior and posterior fatigue or injury?
Shin splints.
