Joint
Articulation
-Not all are bone to bone
Joint Classification
Structural (anatomical feature) and also Functional (type and degree of movement)
Structural Classification
Two Criteria:
1) Presence/ absence of space between articulating bones (synovial Cavity)
2) Type of CT binding the bones together
Structural Classes of Joints
1) Fibrous JOints
2) Cartliaginous Joints
3) Synovial Joints
Fibrous Joints
bones held by Dense collagen fibers
Cartilaginous Joints
bones held by cartilage
Synovial Joints
bones held by ligaments
Functional Classification
relates type and degree of movement
Functional Classes
1) synarthrotic
2) amphiarthrotic
3) diarthortic
Synarthrotic
immovable (never synovial joints)
Amphiarthrotic
slightly moveable
Diarthrotic
freely movable
Types of fibrous joints
1) Sutures
2) syndesmosis
3) Gomphosis
Suture
-Held by very short, interconnected fibers (collagen) and bone edges interlock
-only in skull
-synarthrotic
-common in kids
syndesmosis
Joints held by ligament (also collagen fibers)
-fibrous tissue usually longer than sutures, varies in length
-Either synarthrotic OR amphi
-Tighter hold= less movement
Interoseous membrane
between two bones
Gomphosis
Peg in socket
-Teeth (periodontal ligament)
-synarthrotic, little collagen fiber
Which Joints have not cavities?
Cartilaginous and Fibrous Joints
Which fibrous Joints can move?
Certain Syndesmosis ones
Types of Cartilaginous Joints
1) Synchondroses
2) symphyses
Synchondroses
Bones connected via hyaline cartilage
Locations of Synchondroses
1)Epiphyseal Plate (temporary)
2) Connection of ribs to sternum (manubrium)
Which rib is immoveable?
1st Rib
Symphyses
Bone connected by fibrocartilage
Locations of symphyses
only midline body structures
1) Intervertebral disc
2) pubic symphysis
Synovial Joints characteristics
-ALWAYS Diarthrotic
-holds bones via ligaments
-has synovial cavity
-majority of joints
Synovial Joint Components
1)synovial Cavity
2) Synovial Capsule
3) Synovial Fluid
4) reinforcing ligaments
5)Nerves and blood supply
*6) Bursae and tendon sheaths
*7)articular disc
Synovial Cavity
space between articulating bones
What tissue is the superficial layer of the periosteum made of?
Dense Irregular
What tissue is the deep layer of periosteum made of?
Osteogenic material (osteoblast and clasts)
Synovial capsule
Sleeve-like capsule that encloses the synovial cavity.
Two Layers:
-Outer fibrous capsle
-Inner synovial membrane
Outer Fibrous Capsule (of synovial capsule)
continuous with periosteum
similar material to dense irregular
Inner synovial membrane
covers any bony surface inside the joint capsule that’s NOT covered by hyaline cartilage
-secrete synovial fluid
-replace osteogenic material
Synovial Fluid
viscous fluid (secreted by inner syn. membrane)
-like egg whites
-contains nutrients, derived from blood plasma (cartilage is avascular)
Synovial Fluid Functions
1) reduce friction between joined bones (lubricates)
2)supplies oxygen and nutrients to joint cartilages
Articular Cartilage
Hyaline cartilage at articulation sites
ALL synovial joints have this
Functions of Articular Cartilage
Absorb shock and decrease friction
Articular Discs
Fibrocratilage inside joint cavity
not all Syn. joints have this
Functions Articular Discs
extra shock absorption and improve fit of bones
(Example TMJ)
Reinforcing Ligaments
band like ligaments that strengthen joints
1)Capsular
2) Extra Capsular
3) Intracapsular
Capsular
thickened band in the joint CAPSULE itself
Extracapsular
outside the joint capsule
-medial and lateral collateral ligament of the knee joint
Intracapsular
Inside the joint capsule
-bathed in syn. fluid
ex. anterior and posterior cruciate ligament of knee joint
Nerves in Synovial Joints
only sensory information
-convey pain
-respond to degree of movement and stretch of joint
Blood supply of Synovial Joint
branches of nearby arteries/veins
-richly supplied
-chondrocytes in joints get nutrients from synovial fluid (derived from blood plasma)
-all other parts of syn joint directly supplied via vessels
Bursa
Sac-like structure filled with synvoial fluid
-btwn hard and soft things (ex. ligament and ligament)
-reduce friction
Tendon sheath
tube like bursa that wraps around tendons
Types of synovial joints
1) Planar
2) Hinge
3) Pivot
4) Condyloid
5) Saddle
6) Ball-and-socket
How are synovial joints classified?
By functionality and shape of the articulating bones (which determine the movement)
Planar Joints
Back and forth as well as side-to-side movements (aka GLIDING)
ex. carpal and tarsal bones and some intervertebral joints
Gliding
flat surface of bone move back and forth and/ or side to side over one another
Hinge Joints
cylindrical end fits with trough shaped surface of another
Movement: Flexion and Extension
Type of Hinge Joint Movement
Flexion and extension
Flexion
decrease angle between articulating bones
-move them closer together
Extension
increase angle between articulating bones
-Move further away from each other
Hyperextension
extension beyond anatomical position
(not usually natural without harm)
Movement Forward and Backwards
Sagitial Plane
Knee Joints
Femorotibial and Femoropatellar
Femur
medial and lateral condyles, patellar surface
Tibia
medial and lateral condyles
patella
medial and lateral articular facets
Knee Joint features
Modified hinge joint: mostly extension/flexion, some med/lat rotation
-Strong/ stable
Which bone doesn’t articulate with knee
Fibia
Which part of knee unlocks the knee for sitting?
popliteus
Intercapsular Knee Structures
1)anterior cruciate liagment
2) lateral and medial meniscus
3) posterior cruciate liagment
Meniscus
c shaped disc, shock absorption on condyles
-fibrocartilage
-poor regeneration capacity
Extracapsular ligaments of Knee
1)Lateral and medial patellar retinaculum
2) Tibial collateral ligament (medial collateral ligament MCL)
3) patellar liagment
4)fibular collateral ligament (lateral collateral ligament LCL)
Retinaculum (medial and lateral patellar)
similar to ligaments, form sheets with other ligaments to hold in fluid
Joint capsule of Knee Joint
1)tendon of adductor Magnus
2) medial & lateral head of gastrocnemius muscle
3)articular capsule
4) popliteus muscle
5) oblique popliteal ligament
6) arcuate popliteal ligament
7) tendon of semimembranosous muscle
Pivot Joints
Rounded end of one bone articulates with a ring formed by another bone +encircling ligament
-Ex. radial notch
How are notches named?
for the bone that fits within them
Supination
turning the palm anteriorly (no movement @ elbox, only at radial joints)
Pronation
turning the palm posteriorly
Condyloid Joints
Rounded end of one bone fits into oval shaped depression of another bone
ex. phalanges and metacarpals
What movements are condyloid joints possible of?
1)ab- and ad-duction
2) circumduction (not rotation)
3)extension and flexion
Abduction
movement of a bone away from midline
Adduction
movement of a bone toward the midline
circumduction
Movement of a body part in a circle (combination of ad- and ab-duction as well as flexion and extension?)
What is the abduction/adduction of the hands & feet?
in relation to midline of hands/ feet rather than the body
Saddle Joint
articular surface of one bone is saddle-shaped, and the articular surface of the other bone fits into the “saddle”
-Get slight circumduction
Saddle Joint Location
1)trapeizum and meta-carpal
2) sternum calvicular joint (very strong, only where entire upper limb attaches to axial body)
Sternoclavicular Joint
1)clavicle: sternal end
2) sternnum: sternoclavicular notch of the manubrium
Interclavicular ligament
dense fibrous band & holds from middle to both bones
Parts of Sternoclavicular Joint
1 &2) anterior and posterior sternoclavicular ligaments and joint capsule
3) interclavicular ligament
4)costoclavicular ligament
Ball and Socket Joints
Spherical head of one bone fitting into a cuplike depression of another bone
-in Hip and shoulder joints
-greatest possible movement
Movements of ball and socket joints
1)flexion and extension on medial/lateral axis
2) ad- and abduction
3) rotation
Glenohumeral Joint
aka shoulder joint
1) humerus: head
2) scapula: glenoid fossa
Glenohumeral joint characteristics
diarthrotic joint
-thin and loose capsule
-lots of flexibility, but weak (additional support from rotator cuff)
Coracohumeral ligament
corocoid porcess to lateral humerus
Joint capsule + 3 glenohumeral ligaments
attach glenoid fossa to head of humerus (half of it)
Femorocoxal Joint
Femur: head
Os Coxa: acetabulum
(ball and socket joint, more stable less flexible)
Ligamentum Teres
intracapsular ligament that attaches the fovea capitus to the acetabular fossa
capsular ligaments of the hip
illiofemoral, pubofemoral, and ischiofemoral ligament
Rotation
anterior aspect move toward or away from midline
-often joint and not bones that are rotating (medial/ lateral rotation)
External (lateral) rotation
anterior surface of bone is turned away from midline
Internal (medial) rotation
anterior surface of bone is turned toward midline
Range of motion
refers to range, measured in degrees of a circle through which bones of a joint can be moved
More ligaments
more stability (especially capsular joints)
-tighter= less room for motion
Muscle TOne
reinforces the restraint placed on a joint by its ligaments, restricts ROM
-stretch muscle, increase flexibility
How are sprains caused?
over-stretched dense irregular CT joint (less stable), collagen doesn’t stretch
Contact of soft parts
limits ROM, point at which one body surface contacts another
relaxin
in pregnant women, relaxes muscles before birth
Disuse
movement restricted if joint not used for while (shortens ligament)
Symphyses and synchondroses ______.
Cartilagenous joint
During middle age, fibrous tissue within sutures ossifies, leaving closed sutures called ______.
synostoses
articular capsule
aka Joint capsule
All of the following structures are common to all synovial joints EXCEPT ______.
articular discs
Which of the following movements CANNOT occur at the metacarpophalangeal joints?
rotation
________ is the special movement that allows humans to grasp objects by touching the thumb to the tips of other fingers.
Opposition
What structural type of joint is illustrated here joining the shaft of the radius to the ulna?
syndesmoses —- its a fibrous
Visceral muscle refers to
smooth and cardiac muscles
Sarcoplasmic reticulum lies
between myofibrils but in the fibers
x

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