Biomechanics and Kinesiology Final

Center-edge angle of acetabulum

Coverage of femoral head by acetabulum in frontal plane Average 35-40 degrees, range 22-42 degrees Smaller angle (vertical orientation of acetabulum) results in less coverage of head and increased risk of dislocation

Articular cartilage

Covers ends of bones Thickness varies depending on how much compression in a given area Primarily type II collagen fibers (stability) No perichondrium (poor ability to repair if damaged)

Distal intertarsal joints

Cuneonavicular joints Cuboideonavicular joint Intercuneiform and cuneocuboid joint complex

Articular cartilage function

Distributes & disperses compressive forces to bone Reduces friction between joint surfaces

Primary wrist extensors

ECRL, ECRB, ECU

Primary wrist flexors

FCR, FCU, PL

Newton's 3rd law

For every action there is an equal and opposite reaction

Fibrocartilage

High fiber content (interwoven type I collagen) Good for stabilizing joints, guiding complex arthrokinematics and dissipating forces

PCL mechanism of injury

High-energy trauma -MVA - "dashboard injury" -Football -Falling on a flexed knee

Inner layer of joint capsule

Highly vascular Poorly innervated Serves as medium for nutrient-waste exchange

Uniaxial synovial jionts

Hinge joint Pivot joint

Osteokinematics at talocrural joint

1 degree of freedom, axis through body of talus and tips of both malleoli, DF associated with slight abduction and eversion, PF associated with slight adduction and inversion

6 kinematic principles associated with full abduction of the shoulder

1. ABD = 180 degrees (120 GH joint, 60 ST joint) 2. 60 degrees scapular upward rotation = elevation of SC joint, upward rotation of AC joint 3. Clavicle retracts at SC joint 4. Slight post tilt and ER of scapula (brings more toward frontal plane) 5. Post rotation (spin) of clavicle 6. GH joint ER

Scapulothoracic upward rotation accounts for about ________ of 180 of shoulder elevation

1/3

The clavicle degrees how many degrees

10 degrees (bony block)

Palmar tilt a the wrist

10 degrees (flexion>extension)

Resting position of scapula

10 degrees of anterior tilt 5-10 degrees of upward rotation 35 degrees of internal rotation

Talocrural joint: As the lateral malleolus is inferior and posterior to medial malleolus, axis is not pure M-L axis. How many degrees in the horizontal plane? How many degrees in the frontal plane?

10 degrees superior to horizontal plane 6 degrees anterior to frontal plane

Resting position of distal radioulnar joint

10 degrees supination

Normal angle of inclination in the femur

125 degrees - angle in the frontal plane between femoral neck and medial side of femoral shaft (less than 125 is coxa vara, more than 125 is coxa valga)

Normal Q-angle

13-15 degrees

Angle of inclination of humeral head

135 degrees

Total flexion/extension ROM in craniocervical region

135 degrees Flexion = 50 degrees Extension = 85 degrees

The clavicle retracts how many degrees?

15-30 degrees

What TMT joint provides flexibility to the medial longitudinal arch?

1st

Degrees of freedom of 1st CMC joint

2 Abduction/ adduction in sagittal plane Flexion/ extension in frontal plane (opposition from motions in 2 main planes)

Normal genu valgum

5-10 degrees

Normal carrying angle of elbow

5-15 degrees

Total lung capacity

5.5 to 6.0 L

Functional forearm supination and pronation ROM

50 degrees supination and 50 degrees pronation

Resting position of HU joint

70 degrees elbow flexion, 10 degrees supination

ACL Mechanisms of Injury

70% of sporting ACL injuries are non-contact or minimal contact injuries -Landing from a jump -Quick and forceful deceleration -Cutting -Pivoting over a fixed LE Excessive hyperextension with planted foot

________ % of sagittal plane motion occurs at C2-C7

80 only 20-25% of sagittal plane motion occurs at OA and AA joints

1st toe hyperextends to ________ which is important for _________________

85 degrees terminal stance/push-off phase of gait

Closed packed position of HR joint

90 degrees elbow flexion, 5 degrees supination

Excessive genu valgum

<170 degrees (or more than 5-10 degrees) "knock-knee"

Genu varum

>180 degrees (or less than 5-10 degrees) "bow-leg"

Excessive cubitus valgus

>20-25 degrees (impact the ulnar nerve)

Acetabular Anteversion Angle

Acetabulum surrounds femoral head in horizontal plane Normal is ~20 degrees leaving part of head exposed anteriorly Increases in angle increase tendency for anterior dislocation

7 elements of a diarthrosis

Articular cartilage Joint capsule Synovial membrane Synovial fluid Ligaments (capsular and extracapsular) Blood vessels Sensory nerves (pain & proprioception)

Forearm pronation can be limited by tightness in:

Biceps Supinator

Diaphragm attachments

Costal part: upper margin of lower 6 ribs Sternal part: posterior side of xiphoid process Crural part: bodies of upper 3 lumbar vertebrae 3 parts connect to form central tendon

Valgus force: Primary restraint

MCL Superficial fibers with knee flexed 20-30 degrees Deep fibers with knee in full extension

Medial column of the foot (TNJ) =

Mobility

Motion at 1st TMT joint

PF and eversion DF and inversion

Clinical implications of lateral tracking of patella

PFP Subluxation Dislocation

Where is the human body COG located?

S2

Lateral column of the foot (CCJ) =

Stability

Secondary function of menisci

Stabilizing tibiofemoral joint during movement Lubricating the articular cartilage Providing proprioception Guiding the arthrokinematics

Major articulations of wrist

Radiocarpal joint Midcarpal joint (also includes intercarpal joints which allow for gliding and rotary movements)

Primary function of menisci

Reduce compressive stress across tibiofemoral joint

ACL details

Type I collagen 2 bundles (Ant-Med and Post-Lat) Fiber orientation changes as knee flexes and extends Taught in max extension (extension > 0 degrees = further elongation of ACL) Aides in limiting ant tibial translation (glide) during the last 50-60 degrees of knee extension (counteracts external force of quads in this ROM)

Periosteum

Touch fibrous layer: Has fibroblasts to repair damaged bone Vascular Innervated

Windlass mechanism

Tightening of the plantar fascia during dorsiflexion, thus shortening the longitudinal arch (shortening the distance between the calcaneus and metatarsals causing elevation of the medial longitudinal arch)

Carpal tunnel boundaries

Trapezium Scaphoid Pisiform Hook of hamate

Oblique axis of the transverse tarsal joint

allows motion through all planes of motion almost equally (allows adaptation to variety of surfaces (TTJ and STJ control most of pronation and supination of the entire foot)

Normal orientation of acetabulum

anterior and inferior tilt

ACL limits...

anterior tibial translation

Biceps tendon long head restricts...

anterior translation superior translation

Glenoid fossa faces...

anterior, lateral, and slightly superior (scapular plane)

Lumbar flexion

associated with transfer of forces away from apophyseal joints to the discs and posterior spinal ligaments (discs become compressed and ligaments tensed) -apophyseal joint capsule is an important resisting force to flexion of the lumbar spine

About half of axial rotation in craniocervical region occurs at ___________________ joints

atlanto-axial (also get flexion and extension)

Wolff's Law

bone is laid down in areas of high stress and reabsorbed in areas of low stress

Inner layer of bone

cancellous (spongy) bone has capacity for remodeling Important for distribution of forces

Outer layer of bone

compact (cortical) bone shaft has thick layer ends have thin layer

At the SC joint, the clavicle is __________________ transversely

concave

At the SC joint, the sternum is __________________ longitudinally

concave

Protraction/retraction of the clavicle follows what rule?

concave

1st CMC joint concave and convex partners (flexion/extension)

concave metacarpal convex trapezium

At the SC joint, the clavicle is ________________ longitudinally

convex

At the SC joint, the sternum is ____________________ transversely

convex

Elevation/depression of the clavicle follows what rule?

convex

DIP concave and convex joint partners

convex head of middle phalanges concave base of distal phalanges

PIP concave and convex joint partners

convex head of proximal phalanges concave base of middle phalanges (joint capsule reinforced by radial and ulnar collateral ligaments)

1st CMC joint concave and convex partners (abduction/adduction)

convex metacarpal concave trapezium

The clavicle elevates how many degrees

convex rule: 35-45 degrees

Slight _______________________ allows for greater ability to bear weight in femur

convexity anteriorly

Most mobile region of spine

craniocervical OA joints AA joints Joints of C2-C7

Kinematics

describes motion of a body without regard to forces or torques that may produce the motion

Kinetics

describes the effect of forces and torques on the body

Annular ligament resists...

distraction of the radius

Describe adduction at 1st CMC joint

dorsal roll, palmar glide

CMC joints 2-5 are strengthened by...

dorsal, palmar and interosseous ligaments

Movement at AC joint

due to movements at other joints (plane joint)

High EMG activity in the brachioradialis occurs when

during rapid flexion against high resistance

Closed packed position of HU joint

elbow extension and supination

Resting position of HR joint

elbow extension and supination

SC joint motions

elevation/depression, protraction/retraction, rotation (spinning in posterior direction)

Scapulothoracic joint motions

elevation/depression, upward/downward rotation, protraction/retraction

Inner 2/3 of menisci

essentially avascular

Subtalar joint pronation =

eversion and abduction

What thumb motions elongate the ligaments?

extension, abduction, and opposition

External torque =

external force (gravity) x external moment arm

FOOSH injury

fall on outstretched hand (Distal radius fx, MCL at elbow, TFCC, and more)

Fibular collateral ligament (LCL)

fibers have a vertical orientation from lateral epicondyle of femur to head of fibula

Manubriosternal joint

fibrocartilaginous joint (synarthrosis)

Triangular fibrocartilage complex (TFCC)

fills most of the ulnocarpal space (allows carpal bones to pronate and supinate with the radius) Articular disc attaches to triquetrum

OA joint movements

flexion and extension slight lateral flexion

Flexion/extension concave rule of MCP joints

flexion: palmar roll, palmar glide extension: dorsal roll, dorsal glide

Torque =

force x moment arm

Thoracic facet orientation

frontal plane, mild slope of 0-30 degrees from vertical

Mechanical advantage of a type 2 lever

greater than 1

Pes cavus

high arch

AC joint adjustments that occur with IR (winging)

horizontal adjustment

Toes passively hyperextend and flex to what degree?

hyperextend to 65 flex to 30-40

Cubitus varus

if forearm deviates toward midline (not common)

Femoral torsion

in transverse plane rotation between bone's shaft and neck view from superior to inferior Normal: 8-20 degrees of femoral anteversion (15 degrees is typical reference point) Creates optimal alignment and joint congruence

Anterior pelvic tilt with lumbar extension

increased lordosis spinous processes closer, post disc compressed (nucleus moves anteriorly) shorten hip flexors

Thoracolumbar spine from cranial-to-caudal permits...

increasing amounts of flexion and extension at expense of axial rotation

Bucket-handle mechanism

inspiratory muscles pull the ribs upward and outward

Pump-handle mechanism

inspiratory muscles pull the sternum upward and outward

Eccentric torque

internal < external

Concentric torque

internal > external

Internal torque =

internal force (muscle) x internal moment arm

Subtalar joint supination =

inversion and adduction

"Screw-Home" rotation of the knee: flexion

knee must 1st internally rotate to unlock (popliteus is primarily responsible for this)

C-spine permits...

large amounts of motion in all 3 planes

T-spine permits...

lateral flexion

The larger the Q-angle, the greater the....

lateral muscle pull on the patella

Describe extension at 1st CMC joint

lateral roll, lateral glide

Unipennate muscles are capable of __________ force production and contract through a ______________ ROM

less smaller

Mechanical advantage of a type 3 lever

less than 1

Fusiform muscles are generally capable of lifting _____________ loads through _____________ ROM

lighter greater

Pes planus

low/flattened arch

When is anterior longitudinal ligament strongest?

lumbar region

Pelvic tilting has a direct influence on...

lumbar spine

Articulations within the thorax

manubriosternal joint sternocostal joints interchondral joints costovertebral and costotransverse joints thoracic intervertebral joints

Newton's 2nd law

mass x acceleration

Vital capacity

max exhaled after a maximal inspiration 4.5 L

Closed packed position of DIPs and PIPs

maximal extension

Closed packed position of thumb

maximal extension

Closed packed position of wrist

maximal extension

Closed packed position of the hip

maximal extension, IR, abduction

Closed packed position of MCPs 2-5

maximal flexion

Closed packed position of knee

maximal knee extension

Closed packed position of proximal and distal radioulnar joints

maximal pronation or supination

Excessive femoral anteversion in children

may see toe-in gait Normal development (improves over time) CP (anteversion of 25-40 degrees common, up to 60-80 degrees is reported)

Describe flexion at 1st CMC joint

medial roll, medial glide

Femoral head projects what direction?

medially and slightly anterior to articulate with the acetabulum

Humeral head faces...

medially and superiorly posterior orientation due to natural retroversion

Most common injury at the knee

meniscal tears (medial > lateral)

Most common type of muscle

multipennate (produce high force)

Function of muscles of expiration

muscles that decrease intrathoracic volume decreased thorax space increased intrathoracic pressure forces air out

Function of muscles of inspiration

muscles that increase intrathoracic volume diaphragm contracts (moves down) increased thorax space decreased intrathoracic pressure (allows air to flow in)

Fibrocartilage has few __________________ and limited _______________________

neural receptors blood supply near the periphery

Forearm supination and pronation rotation ROM

neutral (0 degrees) to 75 degrees pronation and 85 degrees supination

Articular cartilage is nourished by...

nutrients in synovial fluid Nourishment is dependent on back-and-forth flow of fluid (more movement = more fluid)

Coupled motions: Extension in lumbar

opposite

Coupled motions: Extension in thoracic (T4-12)

opposite

Coupled motions: Extension in upper cervical

opposite

Coupled motions: Flexion in upper cervical

opposite

Posterior pelvic tilt lumbar flexion

opposite anterior tilt decreased lordosis shortens hip extensors

Facet surfaces of C2-C7

oriented like shingles on a sloped roof (45 degrees) -halfway between frontal and horizontal planes -freedom to move in all planes

Describe abduction at 1st CMC joint

palmar roll, dorsal glide

Scapular dyskinesis may be associated with...

pathology or injury not directly related to scapula (AC joint separation, fractured clavicle, adhesive capsulitis)

Fibrocartilage typically lacks...

perichondrium

Bone is covered by...

periosteum (except for ends of bone)

Most mobility at what TMT joint?

peripheral TMT joints

Prime pronator of the foot

peroneous longus

Diaphragm innervation

phrenic nerve (C3-C5)

Loose-packed position of the talocrural joint

plantarflexion Narrow posterior part of talus loosely sits between the malleoli Most collateral ligaments are slackened

Pronation and supination at the talocrural joint

primarily DF and PF

Lateral collateral ligament (LCL)

primary restraint to lateral gapping or varus force

Medial collateral ligament (MCL)

primary restraint to medial gapping or valgus force

Distal intertarsal joints assist midtarsal joint in...

pronation and supination at the midfoot

Primary function of distal intertarsal joints

provide stability across midfoot

Ventilation can be _____________ or ___________________

quiet; forced

Concave and convex joint partners at the proximal radioulnar joint

radius (convex) ulna (concave)

Mechanical advantage

ratio of internal moment arm to external moment arm (MA = internal moment arm/external moment arm)

External 1/3 of menisci

receives direct source of blood

Lumbopelvic rhythm

relationship between posture and movement of spine and pelvis Understanding of normal rhythm during trunk flexion and extension can help distinguish pathology in spine from that in hips

Nutation (nod)

relative anterior tilt of base (top) of sacrum relative to ilium

Counternutation

relative posterior tilt of base (top) of sacrum relative to ilium

Bone has a great potential for...

remodeling, repair and regeneration

Anterior cruciate ligament (ACL)

restrains anterior tibial translation on the femur and IR of the tibia on the femur

Posterior cruciate ligament (PCL)

restrains posterior tibial translation on the femur

Which side of diaphragm is slightly higher?

right side due to location of liver

Secondary motions at the AC joint

rotational adjustments in the horizontal and sagittal planes

Ligamentum teres

runs between transverse acetabular ligament and the head of the femur

AC joint adjustments that occur with anterior tilting

sagittal plane adjustment

Coupled motions: Extension in lower cervical (C2-T3)

same

Coupled motions: Flexion in lower cervical (C2-T3)

same

Coupled motions: Flexion in lumbar

same

Coupled motions: Flexion in thoracic (T4-12)

same

Excessive stiffness of 1st ray limits...

shock absorption ability of the arch

Max EMG activity in biceps brachii occurs in what position

simultaneous flexion and supination

Resting position of DIPs and PIPs

slight flexion

Resting position of MCPs 2-5

slight flexion

Resting position of thumb

slight flexion

Resting position of the wrist

slight palmar flexion and slight ulnar deviation

Femoral shaft courses...

slightly medially

Kinematics of SI joint

small rotation and translational motions (mainly in sagittal plane) motions are nutation and counternutation (sagittal plane about a mediolateral axis)

4 joints of the shoulder complex

sternoclavicular acromioclavicular scapulothoracic glenohumeral

Axis of rotation of the wrist passes through...

the head of the capitate

Prime supinator of the foot

tibialis posterior

What does the stress-strain curve not acknowledge?

time

Excessive anteversion (femoral torsion)

torsion greatly beyond 15 degrees

Retroversion (femoral torsion)

torsion significantly less than 15 degrees

Most common lever in musculoskeletal systems

type 3

Concave and convex joint partners at the distal radioulnar joint

ulnar notch of radius & proximal surface of articular disc (concave) Head of ulna (convex)

Primary motions at the AC joint

upward and downward rotation

Medial collateral ligament at elbow resists...

valgus (abduction) force

Lateral collateral ligament at elbow resists...

varus (adduction) force

Meniscal tears occur most commonly...

with a rotation about a flexed knee in WB

Tenodesis action

wrist is extended when fingers are passively flexed; wrist is flexed when fingers are passively extended

Optimizing length-tension to maximize grip force at the wrist

~35 degrees of extension and 5 degrees of ulnar deviation

Resting position of shoulder complex

~55 degrees abduction, 30 degrees horizontal adduction, and slight ER

Ulnar tilt at the wrist

25 degrees (limits radial deviation)

Resting position of the knee

25-40 degrees flexion

Scapulohumeral rhythm: after 30 degrees of abduction, _______ ratio of abduction to upward rotation

2:1

Least mobility at which TMT joint?

2nd

Scapulothoracic joint is located between which ribs?

2nd and 7th

Angle of retroversion of humeral head

30 degrees

The clavicle protracts how many degrees?

30 degrees

Resting position of the hip

30 degrees flexion, 30 degrees abduction, slight ER

Functional elbow ROM

30-130 degrees

Resting position of proximal radioulnar joint

35 degrees supination, 70 degrees elbow flexion

Normal lumbopelvic rhythm

40 degrees lumbar flexion 70 degrees hip flexion

Subtalar joint: Axis of rotation is a line that runs from the posterior-lateral heel in an anterior, medial, and superior direction. How many degrees in the horizontal plane? Sagittal plane?

42 degrees superior to the horizontal plane 16 degrees medial to the sagittal plane

Maximum ROM of elbow

5 degrees hyperextension to 145 degrees flexion

Pronation and supination at the subtalar joint

Abduction/eversion Adduction/inversion

Abduction/Adduction concave rule of MCP joints

Abduction: lateral roll, lateral glide Adduction: medial roll, medial glide

Triaxial synovial joints

Ball-and-socket joints Plane joint

Tibiofemoral joint

Condyloid joint Biaxial Modified-hinge 2 degrees of freedom

4 primary types of tissues in the human body

Connective tissue Epithelial tissue Muscle tissue Nervous tissue

MCP concave and convex joint partners

Convex metacarpal heads Concave proximal surfaces of proximal phalanges (2 planes of motion: flex/ext, ABD/ADD)

Alar ligament

Dens to medial aspect of occipital condyle, limits contralateral rotation

Periarticular connective tissues

Dense connective tissue (ligaments & tendons) Articular cartilage Fibrocartilage (labrum & menisci)

Muscles of quiet inspiration

Diaphragm scalenes intercostals

"Screw-Home Mechanism" of the knee

ER of knee that occurs during last 30 degrees of extension Maximizes overall contact area of knee = stability Locking the knee in full ext requires ~10 degrees of ER at the knee (ER not independent movement, but occurs in conjunction with the extension)

Elastin

Elastic properties Can deform under stress and return to original state after removal of force Found in ear cartilage, ligamentum flavum of the spine

Biaxial synovial joints

Ellipsoid/Condyloid joint Saddle joint

Outer layer of joint capsule

Encircles bony components Attaches to periosteum by Sharpey's fibers Reinforced by ligaments Poorly vascularized Highly innervated by joint receptors

Pronation involves what movements in the ankle?

Eversion Abduction Dorsiflexion

Contents of carpal tunnel

Flexor digitorum superficialis, flexor digitorum profundus, flexor pollicis longus, median nerve

Arthrokinematics of the subtalar joint

Gliding between the 3 sets of facets

Mechanical advantage of a type 1 lever

Greater than, equal to, or less than 1

Medial compartment of midcarpal joint (concave and convex partners)

Hamate (HA), Capitate (CA): convex Scaphoid (SC), Lunate (LU), Triquetrum (TQ): concave

Oblique axis of rotation of the midtarsal joints

Has strong vertical and M-L pitch (orientation) Motion occurs as ABD and DF; ADD and PF

Patellofemoral joint

Interface between patella and trochlear groove of femur Glides: superior/inferior, medial/lateral

Isometric torque

Internal = external

Limiters to forearm supination

Interosseous membrane Oblique cord Quadrate ligament

Fibrocartilage is found in:

Intervertebral disks Symphysis pubis TMJ disc Knee meniscus Labrum of acetabulum and glenoid fossa TFCC

Other potential elements of a diarthrosis

Intraarticular disks or menisci Peripheral labrum Fat pads Bursa Synovial plicae

Cruciate ligaments

Intracapsular Covered by an extensive synovial membrane Poorly vascularized Provide stability to the knee Resist extremes of ALL knee movements Guide arthrokinematics at the knee Proprioceptive feedback to the nervous system

Supination involves what movements in the ankle?

Inversion Adduction Plantarflexion

What components of pronation and supination are evident at the subtalar joint?

Inversion/eversion Abduction/adduction

Varus force: primary restraint

LCL

Hallux valgus

Lateral deviation of great toe

Closed-packed position of the talocrural joint

Max dorsiflexion Wider anterior part of talus wedges into the mortise Most collateral ligaments are taut

Closed packed position of shoulder complex

Maximal abduction and ER

Ventilation

Mechanical process by which air is moved in and out of the lungs

Collagen

Most abundant protein in the body Type I and II Very strong (integrity/strength to tissues) Nonelastic, but can deform

Collagen Type I

Most common (ligaments, fascia, fibrous joint capsule, tendon, bone, labrum) Thick fibers, stiff, not much elongation when under tension Important for strength of the tissue

Patellar tracking

Most important influencer in patellar biomechanics is magnitude and direction of force produced by quads Normal biomechanics: superior with slight lateral and posterior movement Quadriceps Angle (Q-Angle) is clinical measure of overall lateral line of pull of quadriceps relative to the patella

Skeletal muscle function is determined by:

Muscle mass Pennation angle Sarcomere length Muscle length

Longitudinal axis of rotation of the midtarsal joints

Nearly coincident with the straight A-P axis Primary motions are eversion and inversion

Synarthrosis

Negligible movement Binds bones together and transmit forces Fused for strength (Ex. sutures of skill, teeth in sockets, interosseous membrane of forearm)

Layers of the joint capsule

Outer layer = Stratum fibrosum (fibrous) Inner layer = Stratum synovium (synovial membrane)

Arthrokinematics of forearm pronation at PRU and DRU

PRU: anterior roll, posterior glide DRU: anterior roll, anterior glide

Arthrokinematics of forearm supination at PRU and DRU

PRU: posterior roll, anterior glide DRU: posterior roll, posterior glide

Arthrokinematics of patellofemoral joint

Patella glides proximally on femur during knee extension

Lateral compartment of the leg (eversion)

Peroneus longus Peroneus brevis

Clinical significance of Scapulothoracic joint upward rotation

Positions glenoid fossa in position to cradle the head of the humerus (increased stability) Maintains optimal length-tension relationship of muscles involved in UE elevation Preserves volume of subacromial space

"slouched posture"

Posterior pelvic tilt with flexed lumbar spine Hamstrings may shorten Increased compression on anterior disc margins protracted head (forward head posture) Thoracic and mid-to-lower C-spine (C3-7) go into excessive flexion Upper c-spine extends (adaptive shortening of posterior suboccipital muscles)

Varus force: secondary restraints

Posterior-lateral capsule IT band Biceps femoris tendon Joint contact medially Compression of the medial meniscus ACL and PCL Gastrocnemius (lateral head)

Valgus force: secondary restraints

Posterior-medial capsule ACL and PCL Joint contact laterally Compression of the lateral meniscus Medial retinacular ribers Pes anserinus Gastrocnemius (medial head)

Hallux limitus/rigidus

Primarily a posttraumatic condition Forceful hyperextension ("Turf toe") Gradual limited motion Articular degeneration Pain at 1st MTP

Movement at humeroradial joint

Pronation and supination = spin Direction of spin follows direction of bone

Forearm supination can be limited by tightness in:

Pronator teres Pronator quadratus

Primary forearm pronators

Pronator teres Pronator quadratus (stabilizes DRU - compressive force and guides joint through arthrokinematics)

MCL functions

Resists valgus (abduction) Resists extension Resists extremes of rotation

LCL functions

Resists varus (adduction) Resists extension Resists extremes of rotation

4 parts of a lever system

Rigid beam Pivot or fulcrum Effort force Resistance

Lateral compartment of midcarpal joint (concave and convex partners)

Scaphoid (SC): convex Trapezoid, trapezium: concave

"Screw-Home" rotation of the knee is driven by 3 factors

Shape of medial femoral condyle Passive tension in the ACL Slight lateral pull of quad muscle

Amphiarthrosis

Some (little) movement Cartilaginous Good shock absorption Exist in midline of body (Ex. Pubic symphysis)

Factors associated with non-contact ACL injury

Strong quad activation over moderately flexed or nearly extended knee Marked valgus collapse of knee Excessive ER of knee (femoral IR on fixed tibia)

Acetabular labrum

Strong, flexible fibrocartilage ring that encircles most of the rim of the acetabulum (transverse acetabular ligament) Poorly vascularized Good nerve supply (pain and proprioception)

Posterior compartment of the leg

Superficial (PF) -Gastrocnemius -Soleus -Plantaris Deep (inversion/PF) -Tibialis posterior -Flexor digitorum longus -Flexor hallucis longus

Tibial collateral ligament (MCL)

Superficial and deep portions -superficial fibers are parallel from medial epicondyle to medial/proximal tibia) -deep fibers are more oblique to joint capsule, medial meniscus, and tendon of semimembranosus

Ischiofemoral ligament

Superficial fibers taught in internal rotation (slightly taught in extension) Deep fibers taught at end range flexion

Primary forearm supinators

Supinator (active during all supination movements) Biceps brachii (high power supination, especially when elbow is flexed to 90 degrees)

Diarthrosis

Synovial joints Allow moderate to extensive motion

Articulations of the transverse tarsal (midtarsal) joint

Talonavicular joint Calcaneocuboid joint

Pubofemoral ligament

Taught in hip abduction and extension Primary function = stabilization of hip joint

Dense connective tissue

Tendons and ligaments Stability and mobility depend on: Collagen to elastin ratio and arrangement of collagen fibers

Collagen Type II

Thinner & not as strong as Type I Found in hyaline (articular) cartilage and nucleus pulposus Provides framework for maintaining shape of cartilage Provides internal strength to cartilage Fibers anchor cartilage to subchondral bone

Anterior compartment of the leg (DF)

Tibialis anterior Extensor digitorum longus Extensor hallucis longus Peroneus tertius

PCL details

Type I collagen 2 bundles (ant-lat and post-med) Tension increases as knee flexes; peaks between 90-120 degrees of knee flexion Aides in limiting post tibial translation (glide) during flexion (counteracts external force of hamstrings in this ROM) Aides in limiting ant translation of the femur during closed chain activities

Articular cartilage degenerative changes

When compression is increased and sustained for a prolonged period When immobilized (no compression) for a prolonged period

Iliofemoral ligament

Y-ligament Thick, strong, connective tissue Strongest and stiffest ligament of the hip Elongated with hip extension and ER Standing with hip extended, head of femur rests against iliofemoral ligament Individuals with paraplegia "lean" into ligament to assist with standing

STJ pronation brings the two axes to what position?

a more parallel "unlocked" position

STJ supination brings the two axes to what position?

a more perpendicular "locked" position

Scapular dyskinesis

abnormal position and pattern of motion of the scapula (decreased upward rotation, excessive downward rotation, anterior tilt)

Why is pain more common near the thoracolumbar junction?

abrupt transition from frontal to sagittal facet orientation

Respiration

action of breathing

Tidal volume

air moving in and out of lungs during each ventilation cycle 0.5 L (~10% VC)

Purpose of CMC joint

allows concave palm to firmly fit around objects