joints Chapter 9 9.1 Joints and their Classifications - PowerPoint Presentation

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joints

Chapter 9

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9.1 Joints and their Classifications

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9.1 Joints and their classifications

Joint

:

any point where two bones meet; both movable and immovable

Arthrology

: science of joint structure, function and dysfunctionKinesiology: study of musculoskeletal movementBranch of biomechanics, which deals with body movements in general

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9.1 Joints and their classifications

Names of joints are typically derived from the names of the bones involved…

Atlantooccipital

joint

Glenohumeral

jointRadioulnar jointEtc.

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9.1 Joints and their classifications

Joints are classified according to the manner in which the adjacent bones are bound to each other

Bony

Fibrous

Cartilaginous

Synovial

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9.1 Joints and their classifications

Joint Classification

Bony

– (

synostosis

) immovable joint formed when the gap b/t two bones ossifies and they become a single bone

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9.1 Joints and their classifications

Joint Classification

Fibrous

– (

synarthrosis

) adjacent bones are bound by collagen fibers

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9.1 Joints and their classifications

Fibrous

Sutures:

immobile or only slightly moveable; closely bind skull bones to each other

Gomphoses

: attachment of a tooth to its socketSyndesmoses: fibrous joint at which two bones are bound by relatively long collagenous fibers; radius to ulna

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9.1 Joints and their classifications

Joint Classification

Cartilaginous

– (

amphiarthrosis

) two bones are linked by cartilage

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9.1 Joints and their classifications

Cartilaginous

Synchondroses

:

joint in which bones are bound by

hyaline cartilage; growth plates, first rib attachment to sternumSymphyses: two bones are joined by

fibrocartilage

; pubic symphysis, between two vertebrae

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9.2 Synovial joints

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9.2 Synovial Joints

Synovial joints

: (

diarthrosis)

Most familiar type

Most freely movableMost structurally complexMost likely to develop uncomfortable and crippling dysfunctions

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9.2 Synovial Joints

Structural Anatomy

Articular cartilage

: layer of hyaline cartilage on the facing ends of two bones

Joint cavity

: narrow space separating bone surfacesSynovial fluid: Slippery lubricant which nourishes the cartilage

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9.2 Synovial Joints

Structural Anatomy

Joint capsule

: connective tissue which encloses cavity and retains fluid

Fibrous capsule (outer)

: continuous with periosteum of adjoining bonesSynovial membrane (inner): secretes synovial fluid

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9.2 Synovial Joints

Structural Anatomy

In a few synovial joints, fibrocartilage grows inward from joint capsule, forming a pad in b/t bones

Jaw, radius/ulna, ulna and carpal bones =

articular disc

Knee = meniscus

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9.2 Synovial Joints

Structural Anatomy

Accessory structures

are also associated with synovial joints:

Tendon

- strip/sheet of touch collagenous CT that attaches muscle to bone (tendon sheaths)Ligament – attaches one bone to anotherBursa – fibrous sac filled with synovial fluid; located b/t two muscles

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Exercise and Articular Cartilage

When synovial fluid is warmed by exercise, it becomes thinner and more easily absorbed by the articular cartilage.

Repetitive compression of the cartilage, during exercise, is important to its nutrition and waste removal.

Swimming

is one of the best ways of exercising the joints with minimal damage

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9.2 Synovial Joints

Terms associated with levers…

Effort arm

: portion o f lever from fulcrum to point of effort (muscle)

Resistance arm

: portion of lever from fulcrum to point of resistance (object or body itself)Fulcrum: (joint)Joints and Lever SystemsMany bones, especially the long bones, act as

levers

to enhance the speed or power of limb movements

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9.2 Synovial Joints

1

st

class lever

– teeter-totter/muscles of the back of the neck pulling on occipital bone

2nd class lever – wheel barrow/quads of thigh elevating the knee3rd class lever – canoe paddle/ biceps flexing the elbow

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9.2 Synovial Joints

Normally determined by…

Structures of articulating surfaces

Strength and tautness of ligaments and joint capsules

Action of the muscles and tendons

Range of Motion (ROM): degrees through which a joint can move

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9.2 Synovial Joints

Multiaxial

– three degrees of rotation (shoulder)

Biaxial

– two degrees of rotation (metacarpophalangeal)

Monoaxial- one degree of rotation (elbow)Axes of Rotation: pass through bone in a direction perpendicular to the plan of movement

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9.2 Synovial Joints

Ball-and-socket

– smooth hemispherical head fitting into a cuplike socket

Condylar

- oval convex surface fitting into a complementary shaped depression

6 class of jointsDistinguished by

shapes

of surfaces and

degrees of freedom

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9.2 Synovial Joints

Saddle

– both bones have a saddle shaped surface – concave in one direction

Plane

– Surfaces are flat or only slightly curved

6 class of joints

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9.2 Synovial Joints

Hinge

– cylindrical surface which fits into corresponding depression

Pivot

– bone spins on its longitudinal axis

6 class of joints

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9.2 Synovial Joints

Movements of Synovial Joints

Kinesiology, physical therapy and other medical and scientific fields have a specific vocab. for movements of synovial joints

All return to

zero position

– position when person is viewing in anatomical position

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9.2 Synovial Joints

Movements of Synovial Joints

Flexion

: mvmt that decreases a joint angle

Extension

: mvmt that straightens a joint; returns to 0

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9.2 Synovial Joints

Movements of Synovial Joints

Hyperextension

: extension of the joint beyond the 0 position

Ligaments or bone structure typically prevents this.

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9.2 Synovial Joints

Movements of Synovial Joints

Abduction

: mvmt away from the midline of the body

Adduction

: mvmt back toward the midline

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9.2 Synovial Joints

Movements of Synovial Joints

Elevation

: mvmt that raises a body part

Depression:

mvmt that lowers a body part

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9.2 Synovial Joints

Movements of Synovial Joints

Protraction

: mvmt of a body part in the anterior

Retraction:

mvmt of body part in posterior direction

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9.2 Synovial Joints

Movements of Synovial Joints

Circumduction

: One end of an

a

ppendage remains fairly stationary while other makes a circular motionRotation: Mvmt in which bone spins on long. axis

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9.2 Synovial Joints

Movements of Synovial Joints –

Primarily forearm movements

Supination

: Mvmt that turns pal to face up or outward

Pronation: Mvmt causing palm to face down or backwards

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9.2 Synovial Joints

Movements of Synovial Joints –

Special movements of the head/trunk

Lateral flexion

: tilting head or trunk to R of L of midline

Right or left rotation: twisting at waist or turning of head

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9.2 Synovial Joints

Movements of Synovial Joints –

Special movements of the mandible

Lateral/medial excursion

: movement to the L or R of zero position

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9.2 Synovial Joints

Movements of Synovial Joints –

Special movements of the hands/digits

Ulnar flexion

: tilts hand

twd little fingerRadial flexion: tilts hand twd thumb

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9.2 Synovial Joints

Movements of Synovial Joints –

Special movements of the hands/digits

Radial abduction

: moving thumb away from index finger (

forming an L)Palmar abduction: move thumb away from plane of hand (like wrapping hand around a tool handle)Opposition/reposition: Moving thumb to touch tip of any finger; returning to zero

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9.2 Synovial Joints

Movements of Synovial Joints –

Special movements of the foot

Dorsiflexion

: mvmt in which toes are elevated

Plantar flexion: mvmt in which toes point downwardsInversion/Eversion: Tilting soles medially or laterally (respectively)

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9.3 Anatomy of Selected Diarthroses

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9.3 anatomy Selected diarthroses

The joints discussed in this section are the most likely to require medical attention and have strong bearing on athletic performance and everyday mobility

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9.3 anatomy Selected diarthroses

Jaw joint:

Temporomandibular joint (TMJ)

Articulation of the condyle of the mandible with the mandibular fossa of the temporal bone

Lateral ligament

– prevents posterior displacementTMJ Syndrome

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9.3 anatomy Selected diarthroses

Shoulder joint:

Glenohumeral

(humeroscapular) joint

Articulation of the

humerus and the glenoid cavity of the scapulaRotator cuff: several tendons which fuse to the joint capsule to stabilize the jointShoulder dislocation

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9.3 anatomy Selected diarthroses

Elbow joint:

Two articulations –

humeroulnar

joint and the

humeroradial jointOlecranon bursa: eases movement of tendons over jointBursitis

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9.3 anatomy Selected diarthroses

Hip joint:

Coxal

joint

Articulation of the head of the femur with the acetabulum of the hip bone

In a standing position, various ligaments twist to pull head of femur tightly into socketHip dysplasia

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9.3 anatomy Selected diarthroses

Knee joint:

Tibiofemoral joint

Largest and most complex

Mainly stabilized by quadriceps tendon in from and semimembranosus muscle in the rear

Menisci: c-shaped cartilages (lateral and medial); absorb shock of body weight

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9.3 anatomy Selected diarthroses

Knee joint:

Collateral ligaments

(

lateral and medial

) prevent knee from rotating when joint is extendedCruciate ligaments (anterior and posterior) prevent hyperextension and prevent the femur from sliding off the front of the tibia

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9.3 anatomy Selected diarthroses

Ankle Joint:

Talocrural

joint

Two articulations – tibia to talus and fibula to talus

Malleoli – knobs of the ankles; restricts ROMCalcaneal tendon – extends from calf muscles to calcaneus and allows for dorsiflexion and plantar flexion

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9.3 anatomy Selected diarthroses

Table 9.1 on page 306

lists a number of common joint disorders and the various clinical applications in this chapter cover other joint disorder/injury related topics

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Chapter 9 Review:

www.studystack.com/menu-845748