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