Structural & Functional Classification of Joints
angular movements
increase or decrease the angle between two bones -movement may occur in any plane of the body -These movements called: -flexion -extension -abduction -adduction -circumduction
The edges of sutures
the edges of joining bones are wavy and interlocking -knit bones together -allow for growth during childhood -In adulthood, fibrous tissue ossifies and skull bones fuse (closed sutures called synostoses)
lateral rotation
the opposite direction of the limb's anterior surface turning toward the medial plane of the body
arthrology
the scientific study of joints
Rotation
the turning movement of a bone around the longitudinal axis
Movement of the TMJ
two surfaces of the disc allow movement 1. concave inferior surface receives the mandibular head and allows the familiar hingelike movement of depressing and elvationg the mandible while opening and closing the mouth 2. superior surface of the disc glides anteriorly with the mandibular head whenever the mouth is opened wide. This anterior movement braces the mandibular head against the dense bone of the articular tubercle, so that the mandible is not forced superiorly through the thin roof of the mandibular fossa when one bites hard foods such as nuts
Structural and Functional Characteristics of Body joints: skull
1. Articulating bones -cranial and facial bones 2. Structural type - Fibrous; suture 3. functional type; movement -synarthrotic; no movement
Special movements of the synovial joint
1. Elevation and depression 2. Protaction and retraction 3. protraction and retraction 4. supination and pronation 5. Opposition 6. Inversion and eversion 7. dorsiflexion and plantar flexion
Examples of synchondrosis
Cartilaginous joints - epiphyseal plates (classified immovable) -immovable joint between the first rib's costal cartilage and the manubrium of the sternum
Synchondrosis
Cartilaginous joints -a joint where hyaline cartilage unites the bones -"junction of cartilage"
Examples of sympheses
Cartilaginous joints -intervertebral discs -pubic symphysis of the pelvis
Symphyses
Cartilaginous joints -joint where fibrocartilage unites the bones -slightly movable joints (amphiarthroses) that provide strength with flexibility
Synovial joints classified by shape
Shapes of the articulating bone surfaces determine the movements allowed at a joint plane hinge pivot condyloid saddle ball-and-socket joints
Reinforcing ligaments - intracapsular
are internal to the capsule (articular capsule) -example: *anterior and posterior cruciate ligaments on the knee -they are covered with a synovial membrane that separates them from the joint cavity through which they run
Reinforcing ligaments - extracapsular
are located just outside the capsule -example: *fibular and tibial collateral ligaments of the knee
Shape of synovial joint: plane joint
articular surfaces are essentially flat plane -only short gliding and -translational movements allowed
joints are also called
articulations
structural classification of joints
based on the material that binds the bones together and the presence or absence of a joint cavity -fibrous joints -cartilaginous joints -synovial joints
hypertension
bending back a joint back beyond its normal range of motion
lateral flexion
bending the trunk away from the body midline to the right or left (instead of abduction)
lateral flexion
bending the trunk away from the body midline to thre right or left
Two important function of bones
!. support 2. movement
Shape of synovial joint: condyloid joint
"knuckle-like" -egg shapped articular surface of one bone fits into an oval concavity in another -allow 2 types of movement -back and forth (flexion-extension) -side to side (abduction-adduction) bone cannot rotate around its long axis -biaxial (movement occurs around two axes)
Syndesmosis
*Fibrous joint -bones connected by ligaments -fibrous tissue longer than in a suture -movement depends on length of connecting fibers -the longer more movement, shorter less movement
General Structure of Synovial Joints: Articular cartilage
- -keep bone ends from being crushed
circumduction
- Latin "moving in a circle" - moving a limb or finger so that it describes a cone in space - combines flexion, abduction, extension, and adduction in succession.
adduction
- Latin "moving toward" - the opposite of abduction - movement of a limb toward the body midline
temporomandibular joint
- also called jaw joint -modified hinge joint, lies anterior to the ear -head of mandible articulates with the inferior surface of the squamous temporal bone
lateral excursion
- as the posterior teeth are drawn into occlusion during grinding, the mandible moves with a side-to-side motion -this movement is unique to the masticatory apparatus of mammals
synovial joints
- called "joint eggs" most movable joint each joint contains fluid filled joint cavity
Shape of synovial joint: saddle joint
- each articular surface has both convex and concave areas -these biaxial joints allow the same movement as condyloid joints -example:first carpometacarpal joint in the ball of the thumb - the structure of this joint allows for opposition of the thumb
example of rotation
- entire column rotates - twisting the whole trunk to the right or left -Roatation occurs at the hip and shoulder joint
ligaments
- hold together the bones together -prevent excessive motion -medial or inferior side joint resist excessive abduction - lateral and superiorly located igaments resist adduction -anterior ligaments resist excessive extension and lateral rotation
Elbow joint
- humeroulnar joint -is a hinge that allows only extension and flexion -formed by the ulna's trochlear notch that forms the hinge and stabilizes joint
muscle tone
- important factor in joint stabilization -constant, low level of contractile force generated by a muscle even when it is not causing movement
Examples of adduction
- in the case of digits, toward the midline
angular movements
- increase or decrease the angle btwn 2 bones -movement in any plane of the body - includes flexion, extension, abduction, adduction and circumduction
abduction
- latin "moving away" - movement of a limb away from the body midline
example of adduction
- moving the digits toward the midline of the hand or foot
supination
- occurs when the forearm roatates laterally so that the palm faces anteriorly (the hand is lying on its "back" spine
TMJ mandibular fossa
- posteriorly it forms this in a concave shape
examples of abduction
- raising trhe arm or thigh laterally -fingers and toes spreading apart, midline the middle finger - bending the trunk away from the body midline to the right or the left....called lateral flexion instead of abduction
sternoclavicular joint
- saddle joint - found in only two locations in the body -allows for multiple complex movement -critical for mobility of the upper extremity
Shape of synovial joint: ball-and-socket joints
- spherical head of one joint fits into a round socket in another - multiaxial joints that allow movement in all axes -found in the shoulder and the hip
extension
- the reverse of flexion and occurs at the same joints - increases the angle between the joining bones and is a straightening action -straightening the fingers after making a fist is an example - at the shoulder and the hip, extension moves the limb posteriorly - bendgind a joint back beyond its normal range of motion
eversion
- turn the foot sole laterally
Rotation
- turning movement of a bone around the longitudinal axis - only movement allowed btwn the first two cervical vertebrae
Shape of synovial joint: hinge joint
-Angular movement is allowed only in one plane -like a door on a hinge -cylindrical end of one bone fits into a trough-shaped surface on another bone -classified as uniaxial,movement around one axis only
synostoses
-When fibrous tissue of sutures ossifies and skull bones fuse together -means "bony junction" -otherwise movement of cranial bones would damage the brain -this is a protective adaptation
TMJ articular tubercle
-anteriorly it forms a dense knob called this
tendon sheath
-associated with synovial joints -contain synovial fluid -closed bags of lubricant -act like "ball bearing" to reduce friction btwn body elements that move over one another -an elongated bursa that wraps around a tendon like a bun around a hot dog -occur only on tendons that are subjected to friction example - those that travel through joint cavities or are crowded together within narrow canals (carpal tunnel of wrist)
bursa
-associated with synovial joints -contain synovial fluid -closed bags of lubricant -act like "ball bearing" to reduce friction btwn body elements that move over one another -means "purse" - flattened fibrous sac lined by a synovial membrane -occur where ligaments, muscles, skin, tendons, or bones overlie each other and rub together
articular disc or meniscus
-contained in synovial joints -disc of fibrocartilage -occur in the temporomandibular (jaw) joint, stenoclavicular joint, knee joint, more -occurs in joints where articulating bone ends have different shapes -allow two different movements at the same time
plantar flexion
-depressing the foot or elevating the heal ( point the toes)
Examples of hinge joints
-elbow joint -ankle joint -joints between the phalanges of the fingers
articular capsule of shoulder joint
-is thin and loose -extends from the margin of the glenoid cavity to the anatomical neck of the humerus -strong superior part of capsule called corachohumeral ligament, helps support the weight of the upper limb -the anterior part of capsule thickens slightly into three weak glenohumeral ligaments
Examples of condyloid joints
-knuckle or metacarpophalangeal joint (you can spread your fingers apart and together -also flex and extend your fingers -wrist joints (abduction/adduction and flexion/extension are possible)
dorsiflexion
-lifting the foot so that its superior surface approaches the shin
General Function of Synovial Joints
-lubricating devices -allow joining bones to move across one another with minimum friction -subject to compressive forces -when articular cartilages touch synovial fluid is squeezed out -weeping lubrication
types of rotation
-medial rotation -lateral rotation
gliding
-nearly flat surfaces of 2 bones slip across each other -occurs at the joints btwn the carpals and tarsals -occurs btwn the flat articular processes of the vertebrae
pronation
-occurs when the forearm rotates medially so lthat the palm foaces posteriorly (hand lying "belly" side down, as in a prone float) - brings the radius across the ulna so that the tow bones form an X.
Examples of rotation
-only movement allowed between two cervical vertebrae -entire vertebral column also rotates to the right or left -occurs at hip and shoulder joints
coracohumeral ligament
-originates at the base of the coracoid process andinserts on the head of the humerus -Strengthens the superior part of the articular capsule and helps support the weight of the upper limb
Example of pivot point
-proximial radioulnar joint (where the head of the radius rotates within a ringlike ligament secured to the ulna) -joint between the atlas and the dens of the axis
Examples of abduction
-raising the arm or thigh laterally -finger and toes means spreading them apart (midline longest digit the third finger or the second toe)
General Structure of Synovial Joints: Reinforcing ligaments
-reinforced and strengthened by bandlike ligaments -ligaments are intrinsic or capsular (thickened parts of fibrous capsule) -ligaments are extracapsular or intracapsular
Shape of synovial joint: pivot joint
-rounded end of one bone fits into a ring that is formed by another bone plus encircling ligament -uniaxial (because the rotating bone can turn only around its long axis)
shoulder joint
-stability is sacrificed to provide freely moving joint of the body -ball and socket joint
General Structure of Synovial Joints: Nerves and vessels
-synovial joints have many sensory nerve fibers -nerve fibers innervate the articular capsule--monitor how much capsule is being stretched -fibers detect pain -functional redundancy of nerve and blood vessels
General Structure of Synovial Joints:Articular capsule
-the joint cavity is enclosed by a two-layered articular capsule or joint capsule *outer layer of capsule called fibrous capsule *inner layer of capsule called synovial membrane
inversion
-turn the foot sole medially
General Structure of Synovial Joints: Synovial fluid
-viscous liquid resembles raw egg white -primarily a filtrate of blood arising from capillaries in the synovial membrane -contains special glycoprotein molecules
weeping lubrication
-when opposing articular cartilages touch synovial fluid is squeezed out of them producing a film of lubricant between the cartilages surfaces -when the pressure on the joint stops the synovial fluid rushes back into the articular cartilages like water into a sponge -it is stored and ready for use again
Function of joint capsules
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Structural and Functional Characteristics of Body joints: Atlanto-occipital
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Structural and Functional Characteristics of Body joints: Atlantoaxial
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Structural and Functional Characteristics of Body joints: Knuckle (metacarpophalangeal)
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Structural and Functional Characteristics of Body joints: Temporomandibular
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Structural and Functional Characteristics of Body joints: acromioclavicular
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Structural and Functional Characteristics of Body joints: ankle
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Structural and Functional Characteristics of Body joints: carpometacarpal of digit 1 (thumb)
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Structural and Functional Characteristics of Body joints: carpometacarpal of digits 2-5
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Structural and Functional Characteristics of Body joints: elbow
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Structural and Functional Characteristics of Body joints: finger (interphalangeal)
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Structural and Functional Characteristics of Body joints: hip (coxal)
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Structural and Functional Characteristics of Body joints: intercarpal
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Structural and Functional Characteristics of Body joints: intertarsal
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Structural and Functional Characteristics of Body joints: intervertebral
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Structural and Functional Characteristics of Body joints: knee (femoropatellar)
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Structural and Functional Characteristics of Body joints: knee (tibiofemoral)
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Structural and Functional Characteristics of Body joints: metatarsophalangeal
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Structural and Functional Characteristics of Body joints: pubic symphysis
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Structural and Functional Characteristics of Body joints: radioulnar (distal)
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Structural and Functional Characteristics of Body joints: radioulnar (proximal)
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Structural and Functional Characteristics of Body joints: sacroiliac
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Structural and Functional Characteristics of Body joints: shoulder (glenohumeral)
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Structural and Functional Characteristics of Body joints: sternocostal
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Structural and Functional Characteristics of Body joints: sternocostal (first)
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Structural and Functional Characteristics of Body joints: strernoclavicular
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Structural and Functional Characteristics of Body joints: tarsometatarsal
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Structural and Functional Characteristics of Body joints: tibiofibular (distal)
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Structural and Functional Characteristics of Body joints: tibiofibular (proximial)
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Structural and Functional Characteristics of Body joints: toe (interphalangeal)
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Structural and Functional Characteristics of Body joints: vertebrocostal
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Structural and Functional Characteristics of Body joints: wrist (radiocarpal)
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What is a joint?
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anatomy of joint capsules
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benefits of joint capsules
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Types of fibrous joints
1. Suture (short fibers, immobile) 2. Syndesmosis (long fibers, slightly mobile) 3. Gomphosis (periodontal ligament, immobile)
Types of Cartilaginous joints
1. Synchondrosis (hyaline cartilage, immobile) 2. Symphysis (fibrocartilage, slightly movable)
Movements allowed by synovial joints
1. angular 2. gliding 3. rotation
What are the 4 ligaments that surround the sternoclavicular joint
1. anterior sternoclavicular ligaments 2. posterior sternoclavicular ligaments 3. interclavicular ligament 4. costoclavicular ligaments
Types of angular movements
1. flexion 2. extension 3. abduction 4. adduction 5. circumduction
Name two types of rotation
1. medial rotation 2. lateral rotation
rotation
1. medial rotation 2. lateral rotation
What are the two locations sternoclavicular joints are found?
1. sternoclavicular joint 2. Joint btwn the trapezium and metacarpal 1 (thumb)
What are the four tendons of the rotator cuff?
1. subscapularis 2. supraspinatus 3. infraspinatus 4. teres minor
Structural characteristics of synovial joints
Adjoining bones separated by a joint cavity *covered with articular cartilage *enclosed within an articular capsule lined with synovial membrane
Structural characteristic of cartilaginous joints
Adjoining bones united by cartilage
Structural characteristic of fibrous joints
Adjoining bones united by collegenic fibers
abduction
An angular movement -"moving away" -the movement of a limb away from the body midline
circumduction
An angular movement -"moving in a circle" -moving a limb or finger so that it describes a cone in space -combines flexion, abduction, extension, and adduction in succession
adduction
An angular movement -"moving toward" -is the opposite of abduction:movement of limb toward the body midline
Flexion
An angular movement -movement that decreases the angle between the bones -brings bones closer together -motion usually occurs in the sagittal plane of the body
Extension
An angular movement -the reverse of flexion -occurs at the same joints -increases the angle between the joining bones -is a straightening action
glenohumeral ligaments
Anterior part of the capsule of the shoulder thickens slightly to form....Three weak, fibrous bands that strengthen the front of the shoulder joint
glenoid labrum
Fibrous connective tissue and fibrocartilage that increases the deepth of glenoid fossa and increases the stability of the GH joint.
sutures
Fibrous joint *means "seams" the bones are tightly bound by minimal amount of fibrous tissue *only occur between bones of the skull *their fibrous tissue is continuous with the periosteum around these flat bones
Gomphosis
Fibrous joint -means "bolt" -a peg-in-socket joint -only one example in body *articulation of a tooth with its socket (connecting ligament called the periodontal ligament)
periodontal ligament
Fibrous joint of gomphosis -short fibrous ligament of a tooth with its socket
Types of Synovial joints
Freely movable movements depend on design 1. Plane 2. hinge 3. Pivot 4. Condyloid 5. Saddle 6. Ball and socket
General Structure of Synovial Joints
Have following basic features: 1. Articular cartilage 2. Joint cavity (synovial cavity) 3. Articular capsule 4. Synovial fluid 5. Reinforcing ligaments 6. Nerves and vessels
Special movements:Elevation and Depression
Occur in a few joints During chewing mandible ia alternately elevated and depressed *Elevation -lifting a body part superiorly *Depression -moving the elevated part inferiorly
Special movements: protraction and retraction
Occur in a few joints Mandible is protracted when jaw juts out, retracted when you bring it back *protraction -nonangular movement in the anterior direction *reaction -nonangular movement in the posterior direction
Special movements: supination and pronation
Occur in a few points Movements of the radius around the ulna *supination -forearm rotates laterally so that the palm face anterioly, hand lying on its back,anatomical position *pronation -forearm rotates medially, palm faces posteriorly, hand lying belly side down -brings radius across the ulna so that the 2 bones form an X
Special movements: dorsflexion and eversion
Occur in a few points Up and down movements of the foot at the ankle *dorsiflexion -lifting the foot so that its superior surface approaches the shin *plantar flexion -pointing the toes
Special movements: opposition
Occur in a few points in the palm *saddle joints -btween metacarpal 1 and the carpals allow this movement Allows you to touch your thumb across the palm and touch all fingers
Special movements: inversion and eversion
Occur in a few points movements of the foot *invert the foot -turn sole medially *evert the foot -turn sole laterally
What joint is the most movable in the body?
Synovial joints all are diarthroses (freely movable)
Most joints of the body are in this class.
Synovial joints especially limbs
Both the sternoclavicular and temporomandibular joints contain an articular disc. What is the function of this disc in each of these joints?
The articular disc in the sternoclacicular and the temporomandibular joints divide each joint cavity and enable multiple complex movements of each joint
Which other joint described in this chapter contains an articular disc?
The knee also contains an articular disc.
Movements Allowed by Synovial Joints
Three basic types: 1.gliding (one bone surface across another) 2.angular movements (change the angle between the two bones) 3.rotation (about a bone's long axis)
TMJ lateral ligament
a loose articular capsule, the lateral aspect of which is thickened encloses the joint
General Structure of Synovial Joints: Joint cavity (synovial cavity)
a potential space that holds a small amount of synovial fluid
rotator cuff
a supporting structure of the shoulder consisting of the muscles and tendons that attach the arm to the shoulder joint and enable the arm to move
Classification of joints
classified by function or structure
functional classification of joints
focuses on the amount of movement allowed -synarthroses (immovable joints) -amphiarthroses (slightly movable joints) -diarthroses (freely movable joints)
How is the ball and socket joint created?
formed by the head of the humerus and the shallow glenoid cavity of the scapula -though glenoid deepened by rim called glenoid labrum, its contributes little to joint stability
Weakest point of skeleton
joints
Elevation
lifting a body part superiorly
medial rotation
lower limb, the limb's anterior surface turns toward the median plane of the body
reaction
movement in the posterior direction mandible is protected when you jut your jaw and retractred when you bring it back.
flexion
movement that decreases the angle between the bones bringing these bones closer together - motion occurs in the sagittal plane of the body -examples -flexion of the the neck or trunk -flexion of the fingers, as in making a fist - flexion of the forearm toward the arm at the elbow -arm flexed at the shoulder when moved in an anterior direction - -hiop is flexed when the thigh moves anteriorly
depression
moving the elevated part inferiorly
What contributes to most of the shoulders stability?
muscle tendons that cross the shoulder joint
gliding
nearly flat surfaces of two bones slip across each other -occurs at the joints between the carpals and tarsal - occur between the flat articular processes of the vertebrae
Example of flexion movement
neck or trunk flexion of fingers in making a fist flexion of forearm toward the arm at the elbow hip is flexed when the thigh moves anteriorly
protraction
nonangular movements in the anterior and posterion directions
synovial membrane
part of the inner layer of articular capsule -composed of loose connective tissue -lines the joint capsule -covers all the internal joint surface not covered by cartilage -its function is to make synovial fluid
fibrous capsule
part of the outer layer of articular capsule -dense irregular connective tissu that is continuous with the periosteum layer of the joining bones -strengthens the joint so bones are not pulled apart
opposition
saddle joint btwn metacarpal 1 and the carpals allows movement called this -action by which you move your thumb across the palm enabling it to touch the tips of the other fingers on the same hand.
articular capsule
sleevelike structure around a synovical joint composed of a fibrous capsule and synovial membrane