Biomechanics Exam2 SG - SquarespaceExam2+SG.pdf · Obt$Ext$ 6. Quad$Fem$ 7. Gemellus$Sup$ 8. GemellusInf$ ... OSTEO* ROM* MUSCLES* Extra$ FLEX$ 0R140°$ 1. Biceps$Femoris$ 2. Semitendinosus$

HIP JOINT: Ilium, ischium, pubic bone

Loose Pack Closed Pack ADL Hip 30 FLEX, 30 ABD, slight ER Full EXT, IR, ABD 120 FLEX, 20 ER, 20 ABD

Angles of the femoral neck to shaft angle in the frontal plane

Anterioposterior angles of the femoral neck to the shaft of the transverse plane Angle is formed by a line through the center of the long axis of the femoral head and neck and a line connecting the posterior end of the medial and lateral femoral condyles

STABILITY Iliofemoral Ligament Pubofemoral Ligament Ischiofemoral Ligament Anterior capsule All twist HyperEXT Superior ADD Inferior ABD, ER

Anterior capsule All twist Hyper EXT All ABD, ER

Posterior Capsule Spiral anteriorly and blend w/iliofemoral ligament, loose in FLEX All HyperEXT, ADD, IR

OSTEO ROM ARTHRO MUSCLES Extra FLEX 0-‐120/140° Posterior

Rotation in sagital plane

1. Iliopsoas 2. rectus femoris 3. pectineus (0-‐40°), 4. TFL

*Hip extended 5. Add longus 6. Add brevis 7. Add magnus

* Sitting – iliopsoas, rectus femoris

Sartorius (ER) cb TFL (IR) Iliopsoas is the main flexor >90°, stabilize lumbar spine, involved w/ sitting form supine w/ SLR, leaning back on chair Tight anterior pelvic tilt Weak posterior pelvic tilt Rectus Femoris – slackness poor hip flexor >90°, ↓ slackness by full flex knee

HypEXT 0-‐15/30° Anterior rotation in sagital plane

1. Glut Max 2. Biceps femoris 3. Semimembranosus 4. Semitendinosus

Glut Max conc control post pelv rot, and ecc control ant pelv rot. Hamstring tightness post pelv tilt during hip ext for lifting and bending, assist in SLR from prone

ABD 0-‐30/ 45° Medial rotation in frontal plane

1. Glut Med 2. Glut Min 3. TFL 4. Piriformis 5. Sartorius 6. Abductor

Weakness Trendelenburg sing standing on one leg, non-‐support side drops, lateral bending of trunk to non-‐support side, compensatory lateral bending of trunk to support weak glut med Cane should be used on strong side long force arm

ADD 0-‐25/ 30° Lateral rotation in frontal plane

1. Add Mag 2. Add Long 3. Add Brev 4. Gracillis 5. * Pectineus, Obt ext,

Quad fem, Glut max

Gracilis assist in EXT, when hip is FLEX, and assist in FLEX, when hips is extended

IR 0-‐30/ 45° Medial rotation in transverse plane

1. Glut Med 2. Glut Min 3. TFL 4. Piriformis (hip flex)

Piriformis When hip is in EXT, greater trochanter is anterior change position of line of action enables ER

ER 0-‐45/ 60° Lateral rotation in transverse plane

1. Glut Max 2. Glut Med 3. Sartorius 4. Obt Int 5. Obt Ext 6. Quad Fem 7. Gemellus Sup 8. Gemellus Inf 9. Piriformis (hip ext)

Piriformis When hip is in FLEX, greater trochanter is posterior change position of line of action enables IR

Femoral Angle Normal 125° Coxa Vara >125° Coxa Valga <125°

Torsion Angle Normal 12-‐15° Head Compensation If head secure Anteversion >20° IR ER lower

limb Move weight bearing surface of femoral head posteriorly

Retroversion <12° ER IR lower limb

Move weight bearing surface of femoral head anteriorly

PELVIS ON FIXED FEMORAL HEAD LUMBAR SPINE WITH PELVIS MOVEMENT Anterior Pelvic Tilt

ASIS ↓ & ant Sacrum ↑ Hip FLEX

M: head and trunk forward C: lumbar spine EXT

Posterior Pelvic Tilt

ASIS ↑ and post Sacrum ↓ Hip EXT

M: head and trunk backward C: lumbar spine FLEX

Lateral Pelvic Tilt w/ support side dropped

Support ≤ Non-‐Support Tilt Support Hip ABD

M: trunk lateral non-‐support/dropped C: Lat FLEX support

Lateral Pelvis Tilt w/ non-‐support side dropped

Support ≥ Non-‐Support Tilt Non-‐support Hip ADD

M: trunk lateral support/dropped C: Lat FLEX non-‐support

Forward Pelvic Rotation

Non-‐Support forward Hip IR, ADD Support/Pivot Hip

M: rotate lumbar and trunk support C: rotate non-‐support

Backward Pelvic Rotation

Non-‐Support backward Hip IR, ABD Support/Pivot Hip ER

M: rotate lumbar and trunk non-‐support C: rotate support

Contralateral Cane ↑ Moment Arm, ↓ torque, ↓ Joint Reaction Force Weight on contralateral ↑ Joint Reaction Force

WEIGHT BEARING STRUCTURES

Tensile strain lateral shaft and superior aspect Compression strain medial shaft and inferior aspect If stronger in compression than tension deform vulnerable to fracture Muscle contraction ↓ strain

o Vastus Lateralis compression force on lateral side ↓ tensile strain o Glut Med compression strain on superior neck main pelvic level during up and down stairs

Zone of weakness mergence of distal neck and greater trochanter FORCES DURING WALKING

Forces @ hip

↑ After heel strike ↓ At Midstance ↑ Peak @Heel Off ↓ @ Toe Off Least @ swing

Other force: 4x’s body weight, using elbow to elevate pelvis to use bed pan Using traps to use bedpan, ↓ 4x’s compared to when using elbow

8/24/2012

31

The Kinetics of Single Limb Stance

Weak L Hip Abductors,

Compensated with ipsilateral

trunk lean


Compensated with ipsilateral

cane


Compensated with contralateral cane

Functionally strong L Hip Abductors,

What if You Add a Cane?

ABDUCTION MOMENT ADDUCTION MOMENT

Notepack: page 20-21 Text page 382-384

15% of HAT

D3

CANE FORCE

(CF)

COUNTERCLOCKWISE TORQUE CLOCKWISE TORQUE

HAF X D BWF X DCF X D

Example: Abductor MA = 4.39 cmHAT MA = 8.64 cmCane MA = 35 cm

Body Weight = 171 lbs (760.6 N)HAT = 0.6666 x 760.6 N = 507 NWeight of LEFT Limb, (LL) = 760.6 N x 0.1666 = 126.8 NHAT+LL: 507N + 126.8 N = 633.8NCane Force (CF): 15% x 507 N = 76 N

External Torque: (633.8N x 0.0864m) – (76N x 0.35m) = 28 Nm

If Internal Torque= External Torque

then: Y x 0.439m = 28Nm

Y = 635.7N or 142.7 lbs

Calculating the Abductor Muscle Force Required to Stand on 1 Leg with a Level Pelvis + Contralateral

Cane

Notepack: page 20-21 Text page 382-384

0.35M

~50% REDUCTION

8/24/2012

21

PELVIC MOTION ACCOMPANYING HIP JOINT MOTION

COMPENSATORY LUMBAR SPINE MOTION

ANTERIOR PELVIC TILT HIP FLEXION LUMBAR EXTENSION

POSTERIOR PELVIC TILT HIP EXTENSION LUMBAR FLEXION

Examples Below: Standing and Weight Bearing Through the LEFT Limb (the right limb is the NON-support limb)

LATERAL PELVIC TILT ( RIGHT PELVIC DROP)

LEFT HIP ADDUCTIONLATERAL FLEX. TOWARDS

SUPPORT SIDE (L)

LATERAL PELVIC TILT ( RIGHT PELVIC HIKE)

LEFT HIP ABDUCTIONLATERAL FLEX TOWARDS NON-SUPPORT SIDE (R)

FORWARD ROTATION OF NON-SUPPORT SIDE

LEFT HIP MEDIAL ROTATION

LUMBAR RIGHT ROTATION

BACKWARD ROTATION OF NON-SUPPORT SIDE

LEFT HIP LATERAL ROTATION

LUMBAR LEFT ROTATION

Pelvis: Hip: Lumbar Spine

Notepack: pages 8-13, Text page 368-373

Structural Adaptations to Weight Bearing

Notepack: pages 14-15, Text page 366

Remember:

The Bone’s trabeculi will form and remodel

and tend to line up along lines of bone

stresses

GRF

Lateral Trabecular System

Medial Trabecular System

Bending Moment Across the Femoral Neck

Notepack: pages 14-15, Text page 366

23

FORCES AT HIP JOINT

• FORCES DURING WALKING

o Forces at the hip increase after heel strike but then decrease at midstance.

o Peak force occurs at heel off but then declines sharply by toe off.

o Forces at the hip are the least during the swing phase.

• OTHER FORCES

o Forces of 4 X BW occur at the hips when a patient lying supine uses their elbows to elevate their pelvis to use a bed pan.

o When a patient uses a trapeze to pull themselves up to use a bed pan, forces at the hip decrease by a factor of 4 compared to forces when the patient uses their elbows to use a bed pan.

KNEE JOINT Loose Pack Closed Pack ADL Knee 10-‐20° Flexion Full Extension 115-‐120° FLEX, good with -‐5/-‐10° EXT

STABILITY FLEX EXT Medial Collateral Lax Taut Lateral Collateral Lax Taut ACL – anteromedial

Taut Lax

ACL – posterolateral

Lax Taut

Antmed max taut @ 90° FLEX Injuries: Antmed FLEX w/ ER or IR, Postlat hyperEXT Limits medial tibial rotation during knee FLEX, becomes tense as it winds around PCL Limits lateral tibial rotation during knee FLEX, tense over lateral femoral condyle

PCL – anteriolateral

Taut Lax

PCL -‐ posteromedial

Lax Taut

Antlat max taut @ 90° FLEX Limits tibial rotation both directions, valgus, varus Tightness of postmed during EXT can lat rot tibia (screw home mech) Injuries: Antlat @ knee FLEX, Postmed @ EXT

OSTEO ROM MUSCLES Extra FLEX 0-‐140° 1. Biceps Femoris

2. Semitendinosus 3. Semimembranosus 4. Gastrocnemius 5. Plantaris 6. Popliteus

Rectus Femoris also flex hip Vastus lateralis forms part of patellar retinaclum w/ IT band Vastus Medialis (distal/oblique) forms medial patellar retinaculum Peak Quadriceps torque @ 50-‐80° FLEX Last 15° of knee EXT, Quads need 60% more force than at 90° or 45° FLEX Removal of patella ↓ force production of Quads by 30%

HypEXT 5-‐10° 1. Vastus Medialis 2. Vastus Latearlis 3. Vastus Medialis

IR 30° (90°flex)

1. Biceps femoris 2. TFL

ER 40° (90°flex)

1. Semitendinosus 2. Semimembranosus 3. Popliteus 4. Gracilis 5. Sartorius

During walking, 9-‐10° , FLEX > 90° ↓ due to soft tissue restriction

ABD/ ADD

11° Most movement @ 30° FLEX, > 30° ↓ due to soft tissue restriction

SCREW HOME MECHANISM -‐ During EXT, tibia translate anteriorly -‐ Last 20-‐30°, anterior tibial translation persist on medial condyle (longer) -‐ Prolonged anterior glide ER tibia relative to femur (open) or IR femur relative to tibia (closed) Screw Home UNLOCKING -‐ ER of femur relative to tibia (closed) or IR of tibia relative to femur (open) -‐ Popliteus unlocks knee (runs posterior medial tibia to lateral femoral epicondyle) by ER femur or IR tibia

HEFLET TEST: used to determine amount of ER of tibia relative to femur during extension Sit w/ hip 90° FLEX, knee FLEX so lower leg hanging free Mark medial and lateral borders of patella and midline of patella and tibial tuberosity EXT knee fully and observe movement of tibial tuberosity relative to midline of patella Normal: tibial tuberosity moves laterally during extension and realigns w/ midline of patella during flexion

FORCES ON TIBIOFEMORAL JOINT Genu Valgum Genu Varum Medial ligaments STRAINED, Lateral ligaments LAX Lateral femoral and tibial condyles compressed erosion of lateral meniscus & articular cartilage Medial knee pain: medial ligament, lateral articular structures

Medial ligaments LAX, Lateral ligaments STRAINED Medial femoral and tibial condyles compressed erosion of medial meniscus and articular cartilage Medial knee pain: medial articular, lateral ligament and capsule

KNEE FLEXION ARTHRO (closed) KNEE EXTENSION ARTHRO (closed) 0-‐25° Anterior Rotation 140-‐115° Posterior Rotation 25-‐140° Ant Rotation

Ant Glide due to ACL 115-‐0° Post Rotation

Post Glide due to PCL Menisci move Posteriorly Loss of menisci limit

Menisci move Anteriorly Ant movement of Post horn block femoral glide preventing hyperextension Loss of menisci limit

FEMUR ON TIBIA (Open)

FLEX Tibia rotate, glide Posteriorly PCL blocks posterior glide Tibia rotate medial relative to femur, Femur rotate lateral relative to tibia

EXT Tibia rotates, glides Anteriorly ACL blocks anterior glide Tibia rotate back laterally, screw home mechanism

FORCES DURING WALKING

Forces @ Knee ↑ @ Heel Strike (hamstring decelerate, ecc control ext, stab) ↑ @ Foot Flat (body weight, ecc control of quad, resist buckling) ↑ Peak @ Heel Off (body weight and contraction of gastroc PF of ankle to

raise heel) ↓ @ initial swing ↑ @ terminal swing (hamstrings ecc decelerate the extending knee)

Role of Menisci

↑ contact surface area ↑ force distribution ↑ stability ↓ unit force pressure on condyles NOT shock absorbers

PATELLOFEMORAL JOINT Q-‐ANGLE

The line representing resultant pull of quadriceps muscles, ASIS mid patella, Mid Patella tibial tuberosity MALES: 12°, FEMALES: 15° >20° is abnormal: Increase lateral pull on patella, Femoral anteversion, External tibial torsion, Lateral displacement of tibial

tuberosity

90-‐135 ° 70-‐90° 20-‐90° 0-‐20° Patella moves laterally and tilts medially into intercondylar groove, full flexion femoral condyle fully covered, medial condyle almost fully exposed

Quad tendon contacts region of intercondylar groove and becomes weight bearing structure ↓ compressive JRF

Patella moves into intercondylar grove

Tibia IR ↓ lateral pull Patella move into intercondylar groove and follows groove until 90°

90-‐130° Post femoral contact Compressive force max @ 90° , large area 130-‐135° Lat facet of patella full contact w/ Post femur, ↑ Force, ↑ SA Odd facet to Med femur, ↑ Force, ↓ SA

45-90° Med & lat facets of patella contact med & lat facets of femur Max surface contact area, but still only 30% Compressive force significant increase, but still low

0° No contact 20° Little inferior pole contact Compressive Force Low, near 0

FORCES ON PATELLOFEMORAL JOINT: flex quad tension ↑ patellar ligament tension ↑ compressive joint reaction force ↑

As quad force ↑, compressive force ↑ o Walking = 0.5 x BW o Stair = 3 – 4 x BW o Squat = 7 – 8 x BW

Normal Force o Tight Rectus patella cranial ↑ inferior patella compression ↑ anterior femoral compression, ↑ PatFem

compression Upward Downward Laterally Medially Rectus Femoris & Vastus Int Patella ligament Vastus Lat, IT band Vast Med

Shifts in location o Factors Affecting Tibial Rotation and Q Angle

IT band tightness Biceps femoris tightness Semimembranosus, semitendinosis weakness

o ↑ Q-‐angle ↑ lateral compression forces ↑ lateral patella facet and lateral femoral condyle wear o Angle

Femoral anteversion Excessive pronation of foot which internally rotates tibia and femur

Changes in length o Patella alta: Ligament 20% longer than patella, females, result from subluxation and dislocation o Patella baja: ligament 20% shorter, occur with ACLR when central patella ligament graft

41

o In genu varum * The strains are opposite those of genu valgum - the

medial ligaments and capsule would be lax and with time shorten and weaken and the medial articular surface compressed with increased erosion.

* The lateral ligaments and capsule would be strained in tension and vulnerable to tearing and elongation.

* Medial knee pain would likely involve articular structures and lateral knee pain involve the lateral ligaments and capsule.

• WALKING

o At heel strike, compression forces at the knee are high because of body weight and contraction of the hamstrings acting to decelerate and control knee extension and stabilize the knee for heel contact with the ground.

o At foot flat, compression forces are high because of body weight and eccentric contraction of the quadricep

controlling the degree of knee flexion to resist buckling of the knee.

8/24/2012

25

Left KneeLeft Knee

“SKYLINE VIEW”

Lateral

VIEW BETWEEN 20-900 OF FLEXION

VIEW BETWEEN 90-1300 OF FLEXION

Path of the sliding patella during active tibia-on-femoral extension: PATELLA MOVES PROXIMALLY

DURING EXTENSION

Arthrokinematics of the PFJ

Regions of Patellar Contact

90 – 600

maximum amount of surface contact

between femur and patella (but

only 30%)

Continued migration of patella contact

points distally towards the inferior

pole

At 1350 --- contact near the superior pole of the patella and the odd facet

Notepack page:s 43-49Text pages 422-429

200

Flexion

900

Flexion1350

Flexion

Full Extension

At full extension the patella rides ABOVE the

groove,

TALOCRURAL/ANKLE JOINT JOINTS

-‐ Distal Tibiofibular Joint: fibrous, superior to ankle joint

o Anterior tibiofibular ligament o Posterior tibiofibular ligament o Interosseus tibiofibular ligament

-‐ Fibulotalar joint: synovial o Anterior talofibular ligament o Posterior talofibular ligament o Calcaneofibular ligament

-‐ Tibiotalar joint o Medial Collateral Ligament

Anterior tibiotalar ligament Posterior tibiotalar ligament Tibionavicular ligament Tibiocalcaneal

-‐ Mortise: inverted “U” shaped curve

ANKLE MOVEMENTS: Up&Out, Down&In

-‐ 3 cardinal planes o Runs anterior posterior from lateral side of trochlea of talus in sagital plane and transverse planes o 10° from medial malleolus superiorly to lateral malleolus inferiorly

-‐ Angulation results in lateral malleolus of the fibula moving a greater distance in an anterior and posterior direction than the medial malleolus of tibia during sagital plane movement

-‐ Angulation also results in o sagittal plane dorsiflexion and plantar flexion being coupled o IR and ER in transverse plane o inversion and eversion in frontal plane

-‐ Results in TRIPLANAR movement -‐ PF: 50°, DF: 20°, IR/ER: 11°

Osteokinematic Arthrokinematic Open Chain (talus tib/fib) Convex Concave

Arthrokinematic Closed Chain (tib/fib talus) Concave Convex

Muscles (Controls eccentrically)

Pronation Dorsiflexion ER/ABD Eversion

Post Rot, Post glide, Ant Roll of talus ER of talus Medial glide of talus

Ant Rot, Glide, Roll of tib/fib IR of tib/fib Minimal lateral glide of tib/fib

Tibialis anterior * EDL, EHL

Supination Plantarflexion IR/ADD Inversion

Ant Rot, Ant glide, Post Roll of talus IR of talus Lateral glide of talus

Post Rot, Glide, Roll of tib/fib ER of tib/ fib Minimal medial glide of tib/fib

Gastrocnemius Soleus Tibialis Posterior * FDL, FHL, PL&B

STABILITY Movement Open Chain Closed Chain DF PF

Dependent on mortise’s ability to widen Tibiofibular joint integrity: fracture of fibula, tear of interosseous membrane, fibrosis, inflammation

Inversion 87% from LCL: calcaneofibular (1st), anterior talofibular (2nd), posterior talofibular (3rd)

Eversion 83% from deltoid ligament

Mainly by compression of articular surfaces

IR Anterior talofibular (LCL), posterior talofibular (MCL) Post talofib (LCL), calcaneofib (LCL), ant tibiotalar (MCL), tibionavicular (MCL)

ER Posterior talofibular (LCL), anterior tibiotalor (MCL) Ant talofib (LCL), Post tibiotalar (MCL), Tibiocalcaneal (MCL) Talar Tilt Medial movement of talus and calcaneous away from fibula

PF: talar tilt limited by anterior talofibular lig Neutral: talar tilt limited by ant/post talofibular lig DF: talar tilt limited by calcaneofibular & posterior talofibular lig

FORCES DURING WALKING

Forces @ Ankle ↑ gradually @ heel strike heel off Max Compression (4-‐5x’s) @ Heel off due to gastroc and soleus ↓ rapidly @ heel off toe off ↓ @ swing phase

With normal standing, compression force on talus is “V” shaped With slight shift of tibia, distribution force is 2 small areas high forces damage

64

• COMPRESSION FORCE DISTRIBUTION ON TALUS WITH WEIGHT BEARING

o With normal standing, compression forces on the trochlea of the talus are distributed in a “V” shaped pattern to decrease the unit forces on the articular cartilage. o With just a slight shift of the tibia, the distribution of compression forces changes and forces are now concentrated in two small areas. o This re-distribution of forces results in high unit forces in these two areas and increases the likelihood of articular cartilage damage.

FOOT: rearfoot/hindfoot (calcaneous, talus, subtalar), midfoot (navicular, cuboid, cuneiform, midtarsal), forefoot (metatarsal, phalange, metatarsophalangeal, interphalangeal joints) JOINTS Joint Type Articulations Movements Ligaments Subtalar Joint

Plane synovial joint

Post/Sup Calcaneous Ant/Mid/Post talus

inversion and Eversion

Medial/Lateral/Posterior talocalcaneal Calcaneofibular Tibiocalcaneal Interosseous calcaneal

Midtarsal Joint: Calcaneocuboid

Plane synovial

Post Cuboid Ant Calcaneous

Inversion and Eversion

Dorsal Calcaneocuboid Calcaneocuboid (bifurcate) Plantar calcaneocuboid (short plantar) Long plantar

Midtarsal Joint: Talonavicular

Ball and socket synovial

Convex Talar head Concave Post Navicular

DF, PF, ER, IR Dorsal talonavicular Tibionavicular Plantar calcaneonavicular (spring)

Tarsometatarsal Plane synovial

Cuneiform and Cuboids 1st-‐5th metatarsals

Flexion and Extension

Dorsal tarsometatarsal Plantar tarsometatarsal Interosseous tarsometatarsal Plantar and dorsal metatarsal ligaments

Metatarsophalangeal Condyloid synovial

Metatarsal head proximal phalanx

Flex, Ext, slight Abd, slight Add, slight circumduction

Medial collateral Lateral collateral Plantar ligament Deep transverse metatarsal ligaments

Interphalangeal Hinge synovial

Proximal phalanx distal phalanx

Flexion and Extension

Medial Collateral Lateral Collateral Plantar ligament

Rays of Forefoot Functional units of foot: 1-‐3: cuneiform metatarsal, 4-‐5: metatarsal 4&5 SUBTALAR JOINT

Eversion Inversion

MIDTARSAL JOINT: triplanar controlled by subtalar -‐ Two axis of motion -‐ Produce 1/3 – ½ as much supination/pronation as subtalar joint

o Longitudinal Axis: inversion, eversion with slight PF, DF, or IR/ER During gait, midtarsal inversion = medial arch of foot rises and eversion = medial arch of foot falls

o Obilque or transverse axis: DF, PF, ER, IR with slight Inversion/Eversion -‐ Hindfoot (subtalar) pronation long and obliq axis becoming parallel mobile/free.

o Heel strike or initial loading allows foot to contour to substrate -‐ Hindfoot (subtalar) supination long and obliq axis becoming corssed restricted

o Heel off and toe off Ray 1 Ray 2 Ray 3 Ray 4 Ray 5 Sup/Pron Twist Gait ↑ hindfoot Pronate: DF (main), Inv, slight adduction Supinate: PF, Ever, slight abduction

Mainly DF, slight inversion Mainly PF, slight eversion

DF PF

Mainly DF, slight eversion Mainly PF, slight inversion

Pronate: DF, Evert, slight abduction Supinate: PF, Inv, slight adduction

SupTwist: Ray1&2 DF, Ray 4&5 PF, forefoot inverts PronTwist: Ray1&2 PF, Ray4&5 DF, forefoot everts

Heel-‐strike toe-‐off ST & MT pron, forefoot sup Heel-‐off toe off ST & MT sup, forefoot pron

Pron: MT is mobile so C by sup, forefoot sup Sup: MT is restricted so can’t pron, forefoot pron

Closed Packed Loose Packed Neutral 5° Pronation Full supination

° Limiting Structures Evert 10 Calcaneofibular

Lateral talocalcaneal Interosseous talocalcaneal Tendon of PL&B Sustentaculum tali Medial talar tubercle

Invert 20 Tibiocalcaneal Medial talocalcaneal Interosseous talocacaneal Tendon of PT, FDL, FHL Lateral process of talus

Osteokinematic Open Chain Closed Chain Muscles Pronation Eversion

(main) Abduction/ER DF

Calcaneal Eversion Calcaneal ABD/ER Calcaneal DF

Calcaneal Eversion Talar ADD/IR Talar PF Tib/Fib IR

PL PB EDL (W)

Supination Inversion (main) Adduction/IR PF

Calcaneal Inversion Calcaneal ADD/IR Calcaneal PF

Calcaneal Inversion Talar ABD/ER Talar DF Tib/Fib ER

PT (ecc pron) Gastr Soleus ATib (W, ecc pron) EHL (W)

Neutral Position at which calcaneous inverts 2x’s # of degrees it everts

FORCES ON FOOT Standing Compression Force

-‐ 60.5% across heel -‐ 7.8% by midfoot -‐ 28.2% by forefoot -‐ 3.6% by toes

Forces at Foot Vertical forces highest at flat foot ↓ w/ slight midstance ↑ @ heel off ↓ rapidly after heel off low @ toe off and swing phase

Greastest load during gait from heel to forefoot transmitted across highest part of longitudinal arch (medial foot) force travels from heel talonavicular naviculocuneiform 1st metatarsal head

Least Loads transmitted along lateral foot forces travels through cuboid 5th metatarsal head

PLANTAR FASCIA

this fascia extends along longitudinal arch of foot form calcaneous to metatarsal heads acts like a tie-‐rod between two trusses When foot loaded, distal and prox ends to plantar fascia move apart which tense up fascia Function:

o shock absorber o distribution of forces o stabilize midfoot esp. during running, climbing types of activities

Plantar fasciits o Inflammation of plantar fascia o May be associated with bone spurs o Overuse o Arch supports may help

GAIT WALKING GENERAL TERMINOLOGY

o Stance time o Stride length: heel strike heel strike of same leg o Stride duration o Step length: heel strike of one leg heel strike of opposite leg o Step duration o Cadence: steps/min, male: 110steps/min, female: 116steps/min o Walking velocity o Width of support base: horizontal distance btwn middle heel of one foot middle heel of opposite foot

80

+ forefoot also compensates by supinating

* Excessive hindfoot supination + midtarsal movement is restricted and unable to

compensate by pronating. + forefoot compensates by pronating excessively

FORCES ON THE FOOT

STANDING

o Compression force distribution * 60.5% across heel * 7.8% by midfoot * 28.2% by forefoot * 3.6% by toes

• WALKING

o Vertical forces are highest at flat foot but then decrease

slight at midstance only to increase again at heel off

o Vertical forces decrease rapidly after heel off and are low at toe off and during the swing phase

84

BIOMECHANICS OF LOCOMOTION

WALKING

GENERAL TERMINOLOGY o Stance time: time of stance phase o Stride length: distance from heel strike of one leg to the

next heel strike of the same leg (heel strike to heel strike distance of the same leg

o Stride duration: time of one stride o Step length: distance from heel strike of one leg to the

successive heel strike of the opposite leg o Step duration: time of one step o Cadence: number of steps per minute

* males: 110 steps per minute * females: 116 steps per minute

o Walking velocity: distance walked per unit time o Width of support base: horizontal distance between

the middle heel of one foot and the middle heel of the opposite foot

PHASES OF GAIT Stance phase

TRADITIONAL TERMS

RANCHO LOS AMIGOS TERMS

HEEL STRIKE INITIAL CONTACT

FOOT FLAT LOADING RESPONSE

MIDSTANCE MIDSTANCE

HEEL OFF TERMINAL STANCE

TOE OFF PRESWING

85

Swing phase

TRADITIONAL TERMS

RANCHO LOS AMIGOS TERMS

ACCELERATION INITIAL SWING

MIDSWING MIDSWING

DECELERATION TERMINAL SWING

Right foot at heel strike (initial contact) and Left foot at toe off, (preswing)

91

• GROUND REACTION FORCES DURING GAIT

STANCE PHASE

SWING PHASE

91

• GROUND REACTION FORCES DURING GAIT

STANCE PHASE

SWING PHASE

GROUND REACTION FORCE – force transmitted up the lower extremity Lies posterior or anterior to hip, knee and ankle applying

flexion or extension moment to that joint The force of ground is trying to move the joint in a

particular direction o If GRF Ant to Hip Flex o If GFR Post to Hip Ext o If GRF Ant to Knee Ext o If GRF Post to Ankle PF

As LE changes position during gait, GRF does too During gait, forces on joint can be from GRF or concentric

muscle contraction By comparing GRF with joint movement, one can

determine if the muscles are producing movement or produced by GRF and controlled by eccentric activity of muscle

* If movement of joint is same as moment applied by GRF at joint, then concentric action is not needed but eccentric by antagonist is * If movement of joint is opposite the moment applied by GRF, concentric action is needed to overcome GRF and move joint

95

THE KNEE

PHASE OF GAIT

ROM MOVEMENT MOMENT MUSCLE CONTRACTION

Heel Strike to Foot Flat

0-5 deg to 15 deg flexion

extension

flexion quads eccentric (prevent knee bucke li ng)

Foot Flat to Midstance

15 deg to 5 deg

extension

extension

flexion

extension

quads

quads

concentric

no activity

Midstance to Heel Off

5 deg to 0 deg

extension extension no activity none

Heel Off to Toe Off

0 deg to 30 deg

flexion

flexion

extension

flexion

quads popliteus

quads

no activity concentric

eccentric

Acceleration to Midswing

30 deg to 60 deg

60 deg to 30 deg

flexion

extension

none

none

hamstrings sartorius graclis

quads

concentric

concentric

Midswing to Deceleration to Heel Strike

30 deg to 5 deg

extension none quads

hamstrings

concentric

eccentric

93

THE HIP (sagittal movements)

PHASE OF GAIT

ROM MOVEMENT MOMENT MUSCLE CONTRACTION CONTRACTION


30 deg. to 25 deg.

extension flexion add. mag. glut. max.

concentric concentric


25 deg. to 0 deg.

extension

extension

flexion

extension

glut. max.

glut. max.

concentric

no activity


0 deg. to 10-20 deg.

backward extension

extension hip flexors eccentric

Heel Off to Toe Off

10 – 20 deg. to 0 deg

flexion extension iliopsoas add. long. add. mag.

concentric concentric concentric


0-20 deg. to 30 deg.

flexion none iliopsoas gracilis sartorius

concentric concentric concentric


30 deg. flexion none glut. max hamstrings

eccentric eccentric

94

OTHER PELVIS, HIP, AND FEMUR MOVEMENTS

PHASE OF GAIT

PELVIS HIP JOINT FEMUR


forward internal rotation

adduction

external rotation

neutral to adduction


forward to neutral

internal rotation

adduction

external rotation

adduction


neutral to backward

internal to external rotation

adduction

external to internal rotation

adduction

Heel Off to Toe Off

backward external rotation

abduction

internal rotation

abduction


backward to neutral

external rotation

abduction

internal rotation

abduction


forward external to internal rotation

abduction to adduction

internal to external rotation

abduction to neutral

96

THE ANKLE

PHASE OF GAIT

ROM MOVEMENT MOMENT MUSCLE CONTRACTION


0 deg to 15 deg

plantar flexion plantar flexion ant. tib. ext. dig. long. ext. hal. long.

eccentric


15 deg to 5-10 deg

plantar flexion to dorsiflexion

plantar flexion to dorsiflexion

sole us gastroc. plantar flexors

eccentric


5 deg to 0 deg

dorsiflexion to plantar flexion

dorsiflexion sole us gastroc. post. tib. plantar flexors

eccentric to concentric

Heel Off to Toe Off

0 deg to 20 deg

toes

plantar flexion

extension

dorsiflexion

extension

sole us gastroc. post. tib. pero ne us long. and b rev.

FDL, AbH, interossei lumbricles FDB, FHL

concentric to no activity

eccentric


20 deg to neutral dorsiflexion none

ant. tib. ext. dig. long. ext. hal. long.

concentric


remains in neutral none none

ant. tib. ext. dig. long. ext. hal. long.

concentric

97

ANKLE AND FOOT MOVEMENTS

PHASE OF GAIT

ANKLE SUBTALAR MIDTARSAL FOREFOOT


supination (PF)

pronation (EVERT)

pronation (EVERT)

supination (INVERT)


supination (PF) to pronation (DF)

pronation (EVERT) to neutral


supination (INVERT) to neutral


pronation (DF) to supination (PF)

neutral to supination (INVERT)

neutral to supination (INVERT)

neutral to pronation (EVERT)

Heel Off to Toe Off

supination (PF)

supination (INVERT)

supination (INVERT)

pronation (EVERT)


supination (PF) to neutral




Midswing to Deceleration

neutral neutral neutral neutral

99

THE HIP

PHASE ROM MOVEMENT MUSCLE CONTRACTION

Weight acceptance to pull-up

60 deg flexion to 30 deg flexion

extension gluteus max. gluteus med.

concentric

Pull-up to forward continuance



concentric

Foot clearance to foot placement


flexion iliopsoas concentric

THE KNEE




extension rectus fem. vastus lat. (quads)

concentric




concentric


10 deg flexion to 90 –100 deg

90-100 deg flexion to 85 deg flexion

flexion

extension

hamstrings

rectus fem. vastus lat. (quads)

concentric

concentric

ASCENDING STAIRS

Stance Phase Weight Acceptance Weight Acceptance Pull Up Pull up forward continuance

Swing Phase Foot Clearance Foot Placement

DESCENDING STAIRS

98

ASCENDING STAIRS

• PHASES IN STAIR CLIMBING

o Stance phase * weight acceptance * weight acceptance to pull up * pull up to forward continuance

o Swing phase * foot clearance * foot placement

99

THE HIP





concentric




concentric



flexion iliopsoas concentric

THE KNEE





concentric




concentric


10 deg flexion to 90 –100 deg

90-100 deg flexion to 85 deg flexion

flexion

extension

hamstrings

rectus fem. vastus lat. (quads)

concentric

concentric

100

THE ANKLE



20-25 deg dorsiflexion to 15 deg dorsiflexion

plantar flexion

gastrocnemius soleus acting on tibia

concentric


15 deg dorsiflexion to 10-15 deg plantar flexion

plantar flexion

gastrocnemius soleus acting on tibia and then foot

concentric


10 deg plantar flexion to 20 deg dorsiflexion

dorsiflexion anterior tibialis concentric

DESCENDING STAIRS

100

THE ANKLE



20-25 deg dorsiflexion to 15 deg dorsiflexion

plantar flexion

gastrocnemius soleus acting on tibia

concentric


15 deg dorsiflexion to 10-15 deg plantar flexion

plantar flexion

gastrocnemius soleus acting on tibia and then foot

concentric


10 deg plantar flexion to 20 deg dorsiflexion

dorsiflexion anterior tibialis concentric

DESCENDING STAIRS

101

SUPPORT LIMB

JOINT MOVEMENT MUSCLE ACTION

Hip flexion gluteus max. eccentric to control hip flexion

Knee flexion quads eccentric to control knee flexion

Ankle dorsiflexion gastrocnemius soleus plantar flexors

eccentric to control ankle dorsiflexion

Toes extension FDL, FDB, FHL, FHB, AbH, interossei lumbricales

eccentric to control toe extension

NON-SUPPORT LIMB

JOINT MOVEMENT MUSCLE ACTION

Hip extenion gluteus max. concentric to extend flexed hip

Knee extenion quads concentric to extend knee to reach step below

Ankle plantar flexion to dorsiflexion

gastrocnemius soleus plantar flexors

concentric plantar flexion to reach step below then eccentric to control dorsiflexion for full foot loading

Toes Neutral to slight flexion

FDL, FDB, FHL, FHB, AbH, interossei lumbricales

no activity to concentric for toe to step contact

RUNNING

Stance Phase Foot strike Foot strike to midsupport Midsupport to toe off

Swing Phase Forward Swing Deceleration

Running Speed As Speed ↑, stance phase ↓, swing phase ↑ At high speeds, non-‐support is called FLOAT PHASE, where both feet is off the ground

Forces Vertical Forces

o Greater with running than walking o During walking, vertical forces reach 110-‐120% body weight o During running, 200%

Fore and Aft Shear o ↑ 50-‐100% during running as compared to walking

Medial and lateral shear o ↑ 150-‐200% during running as compared to walking

Movements @ Heel strike Walking & Foot Strike Running Calcaneous everts (passive subtalar pronation), midtarsal joint pronates,

midfoot mobile @ Midstance Walking & Midsupport Running Calcaneous inverts and passing through subtalar neutral (midtarsal joint

supinates, midfoot becoming rigid) During running from Foot Strike to Mid support Rapid DF During running from Foot Strike to Midsupport Rapid PF During stance phase of running hip adducts As running speed ↑ magnitude of hip adduction ↑

General Muscle Muscle actions associated w/walking are similar for running, but more overlap of muscle activity, especially btwn hamstring

and quads, as phases of movement are shorter in running In running, muscles are active >70-‐80% of the stance phase (stance phase ↓ w/ running, so muscles are active more) In walking, muscle groups are active <50% of stance phase (stance phase ↑ w/walking, so muscles are active less)

Repetitive Stress on Foot Walking

o 150lb male w/ step length of 2.5ft and walking at 2110 steps/mi shows average vertical force of 80% BW @ heel strike o For a 1 mile walk, the repetitive forces total 253,440lbs (127tons) = 63.5 tons/foot

Running o A 150lb male w/ step length of 3.5ft and rate of 1175 steps/mi shows average vertical forces of 250% BW @ foot strike o For a 1 mile run, the repetitive forces total 440,625lbs (220tons) =110 tons/foot

102

RUNNING

Stance phase o foot strike o foot strike to midsupport o midsupport to toe off

Swing phase o forward swing o deceleration

RUNNING SPEED

o As speed increases, the period of the stance phase decreases and the period of the swing phase increases.

o At high speeds, there is a period of non-support called the FLOAT PHASE in which both feet are off the ground.

FORCES

o Vertical forces * Greater during running than walking. * during walking, vertical forces are 110 - 120% body

weight. * During running the vertical forces reach 200% of body weight.

o Fore and aft shear * Increase of 50 - 100% during running as compared to

walking.

o Medial and lateral shear * Increase of 150 - 200% during running as compared

to walking.

Documents

Biomechanics Exam2 SG - SquarespaceExam2+SG.pdf · Obt$Ext$ 6. Quad$Fem$ 7. Gemellus$Sup$ 8. GemellusInf$ ... OSTEO* ROM* MUSCLES* Extra$ FLEX$ 0R140°$ 1. Biceps$Femoris$ 2. Semitendinosus$