Anatomy and Physiology: Chapter 9- Articulations

Circumduction

( combination of flexion, extension, abduction and adduction ex. Draw circle on board)

Flexion

(decrease angle between articulating bones ex. Bending arm)

Hyperextension

(extension past anatomical position )

Extension

(increase angle between articulating bones ex. Straightening arm)

Abduction

(movement away from body along frontal plane ex. Move arm away from side)

Adduction

(movement toward body along frontal plane ex. Bring arm close to body)

Slightly moveable joint

AMPHIARTHROSIS

General Structure of a Synovial Joint

Articular cartilage

Joints are classified in two ways

Functional (physiology) Structural (anatomy)

Immovable joint

SYNARTHROSIS

Freely moveable joint

SYNOVIAL

shapes

There are many different types of joints which are classified on the basis of the ______________ of the articulating bones. Each joint type permits a different type and range of motion.

Circumduction

a more complex angular motion. Example is drawing a circle on the board . The result is that that your hand moves in a circle but your arm doesn't rotate

Structural (anatomy)

a)Fibrous b)Cartilagenous c)Boney d)Synovial

Functional (physiology)

a)Immovable joint b)Slightly moveable joint c)Freely moveable joint

Primary functions-3 of Synovial fluid

a)Lubrication b)Nutrient distribution c)Shock Absorption

Hinge joint

allows for angular motion in a single plane ex-elbow, knee

Joints

also called articulations, are where two bones come together. At all of these there is a compromise between the need for strength and the need for mobility. Thus, the more mobile a joint, the weaker it is.

Lubrication

articular cartilages act like sponges filled with synovial fluid that when compressed squeeze out fluid and coats surfaces. When compression stops, fluid is picked back up by cartilage

Symphysis

articulating bones are separated by pad of fibrocartilage -cartilagineous ex. Intervertabral discs, pubic symphysis-between coxal bones.

Ligaments

attach bone to bone at joint-stabilize joint

Tendons

attach muscle to bone-may limit range of motion of joint & provide support

Sutures

between bones of the skull, bones interlocked and bound together by dense fibrous connective tissue

Gomphosis

binds teeth to boney sockets in mandible and maxilla, fibrous tissue

Syndesmosis

bones connected by a ligament-fibrous, ex. Distal articulation of tibia & fibula

Saddle joint

both bones have a concave face like a saddle, allowing bones to nestle together- ex. Base of thumb

Articular cartilage

cartilage-covers articulating surfaces a)Resembles hyaline cartilage but has no perichondrium and matrix contains more water b)Slick and smooth c) two cartilages always separated by thin layer of synovial fluid (lubricant)

Shock Absorption

cushions shocks in joint.

Rotation

described in reference to anatomical position. Left or right rotation of head Lateral or medial rotation of arm supination pronation

Meniscus

fibrocartilage pad between opposing bones within synovial joint-protect and stabilize joint

Plane Joint

flattened or slightly curved faces which allows for minimal sliding motion ex, clavicle & sternum

Dorsiflexion

flexion of ankle joint-point toes upward

DIARTHROSIS

freely moveable - 1 type

Collagen fibers

from joint capsule, ligaments

Accessory Structures

help joint work better a)Meniscus b)Fat pads c)Ligaments d)Tendons e)Bursa f)Synovial Tendon Sheath

SYNARTHROSIS

immovable joint-4 types: 1)Sutures 2)Gomphosis 3)Synchondrosis 4)Synostosis-totally rigid immovable joint created when two separate bones fuse and boundary between them disappears examples-metotopic suture of frontal bone, epiphyseal line of mature bones.

Synovial cavity

joint cavity surrounding articulating bones-contains synovial fluid

Synovial joint

joint-allow for wide range of movement ex. Shoulder, knee, hip, elbow

Ball and socket joint

joint-round head of one bone rests in a cup-like depression of other bone. Allows for all types of angular motion ex. Hip, shoulder

three types of movement

linear, angular and rotation

Fat pads

localized mass of adipose tissue covered by synovial membrane-protect articular cartilage, space filler

Synovial fluid

made of hyaluronic acid-similar to interstitial fluid but has a high concentration of proteoglycans-secreted by the fibroblasts of the synovial membrane

Opposition

movement of thumb toward fingers-grasping motion

Protraction

moving part of your body anteriorly along a horizontal plane-bite upper lip with lower teeth

Retraction

moving part of your body posteriorly along a horizontal plane-reverse of protraction

Angular motion

occurs when there is a change in angle between two bones such as bending arm at elbow.

Linear movement

occurs when two opposing surfaces slide past one another. This kind of motion is called Gliding and can occur in any direction and is a slight movement. Occurs between articulating carpel bones, tarsal bones, clavicle and sternum

Condylar joint

oval articular face nestles in depression on opposing surface, allows for angular motion in two planes Ex. Between metacarpels and phlanges

Pronation

palm facing down

Supination

palm turned upward

Pivot joint

permits rotation only ex. Atlas and axis of vertebral column

Synchondrosis

rigid cartilaginous bridge between two articulating bones- ex. first rib & sternum

Rotation

similar to spinning around a point.

AMPHIARTHROSIS

slightly moveable joints-2 types

Bursa

small fluid-filled pockets in connective tissue, contain synovial fluid & lined by synovial membrane. Formed where tendon or ligament rub against another tissue thus reducing friction.

Plantar flexion

stand on toes

Articular capsule

surrounds synovial cavity but doesn't cover articulating surfaces. Composed of an outer fibrous layer and an inner synovial membrane

Nutrient distribution

synovial fluid circulates continuously to provide nutrients and pick up waste from chondrocytes of articular cartilage.

Synostosis

totally rigid immovable joint created when two separate bones fuse and boundary between them disappears examples-metotopic suture of frontal bone, epiphyseal line of mature bones.

Synovial Tendon Sheath

tubular bursa (shaped like a donut) with tendon running thru center hole. Found where tendon is touching bone surfaces from many sides.

Inversion

turn sole of foot inward

Eversion

turn sole of foot outward

Lateral flexion

vertebral column bends side to side

Elevation

when structure move in an superior direction-close mouth

Depression

when structure moves in an inferior direction-open mouth

Factors that stabilize joints

•Collagen fibers •Shape of articulatng surfaces and mensci ( plueral for meniscus)-may prevent movement in specific direction •Presence of other bones, skeletal muscle & fat around the joint •Tension in tendons attached to articulating bones

Types of Angular Motion-paired

•Flexion •Extension •Hyperextension -Abduction •Adduction •circumduction

Special Movements-in pairs

•Inversion •Eversion •Dorsiflexion •Plantar flexion •Opposition •Protraction •Retraction •Depression •Elevation Lateral flexion