Joints of Joints of the Human the Human

BodyBody

JointsJoints

Joints are the points of Joints are the points of contact (or articulations) contact (or articulations) between two connected between two connected bones. bones.

Joints hold bones together Joints hold bones together and many allow for flexibility and many allow for flexibility and movement.and movement.

3 Types of Joints3 Types of Joints

1. Synarthrosis1. Synarthrosis

2. Amphiarthrosis2. Amphiarthrosis

3. Diarthrosis3. Diarthrosis

Synarthrosis Synarthrosis - immovable joints- immovable joints

Fibrous JointsFibrous Joints – Two bones grow together – Two bones grow together with only a thin layer of fibrous periosteum with only a thin layer of fibrous periosteum between thembetween them Example :Example : sutures of the skull, teeth in their sutures of the skull, teeth in their

socketssockets

AmphiarthrosisAmphiarthrosis – – semi-movable jointssemi-movable joints

a. a. LigamentousLigamentous - Slight movement permitted by - Slight movement permitted by meager elasticity of a ligament joining two bones, meager elasticity of a ligament joining two bones, which may be distinctly separated.which may be distinctly separated.

Example :Example : distal articulation of tibia to fibula distal articulation of tibia to fibula

b. Cartilaginous - Connected to bone by cartilage tissue. Bones are coated with hyaline cartilage, separated by a fibrocartilage disc and joined by ligaments.

Example : between vertebra (intervertebral discs), symphysis pubis

DiarthrosisDiarthrosis – freely movable joints– freely movable joints

SynovialSynovial - bony surfaces - bony surfaces

are separated by lubricating are separated by lubricating

fluid. They are also joined fluid. They are also joined

by ligaments, tough bands by ligaments, tough bands

of elastic tissue that of elastic tissue that

enclose the ends of enclose the ends of

articulating bones and form articulating bones and form

the capsule containing the the capsule containing the

synovial fluid.synovial fluid.

Synovial JointsSynovial Joints

1.1.GlidingGliding (arthrodial)(arthrodial) Allows gliding or twisting Allows gliding or twisting Example: between carpals or tarsalsExample: between carpals or tarsals2. 2. HingeHinge (ginglymus)(ginglymus) A concave surface glides around a A concave surface glides around a

convex surface allowing flexion and convex surface allowing flexion and extensionextension

Example: humerus to ulna, Example: humerus to ulna, phalangesphalanges

3. 3. PivotPivot (trochoid)(trochoid) Rotation around Rotation around

a vertical axis is allowed. Movement in one a vertical axis is allowed. Movement in one planeplane

Example : atlanto-axial jointExample : atlanto-axial joint

4.4.EllipsoidEllipsoid An oval ball and socket joint allowing flexion, An oval ball and socket joint allowing flexion,

extension, abduction, adduction and extension, abduction, adduction and circumduction but not rotation. One articular circumduction but not rotation. One articular surface slightly concave surface slightly concave

and the other slightly convex.and the other slightly convex. Example : radius and carpalsExample : radius and carpals

5. 5. SaddleSaddle Both bones have a saddle shaped Both bones have a saddle shaped

surface (fit into each other)surface (fit into each other) Allows flexion, extension, abduction, adduction, Allows flexion, extension, abduction, adduction,

and slight circumduction but NO rotation. and slight circumduction but NO rotation. ExampleExample : carpo-metacarpal articulation of : carpo-metacarpal articulation of

thumbthumb6. 6. Ball & SocketBall & Socket Spherical ball and socket. Allows flexion, Spherical ball and socket. Allows flexion,

extension, abduction, adduction, circumduction extension, abduction, adduction, circumduction and medial and lateral rotation.and medial and lateral rotation.

Example :Example : femur and acetabulum, humerus femur and acetabulum, humerus and glenoid cavity.and glenoid cavity.

WorkWork List the 6 MAJOR characteristics of List the 6 MAJOR characteristics of

synovial joints. (page 70)synovial joints. (page 70) Label the diagram: The Characteristics of Label the diagram: The Characteristics of

a Synovial Joint (page 70).a Synovial Joint (page 70).

Textbook WorkTextbook Work List the characteristics found in synovial joints.List the characteristics found in synovial joints. What are the two joints are found in the pectoral What are the two joints are found in the pectoral

girdle? Briefly explain how each are important.girdle? Briefly explain how each are important. Sternoclavicular Joint – joint must absorb all forces Sternoclavicular Joint – joint must absorb all forces

transmitted to the upper limb (lots of sports)transmitted to the upper limb (lots of sports) Acromioclavicular Joint – shoulder separations can Acromioclavicular Joint – shoulder separations can

occur in many sportsoccur in many sports What are three joints found in the elbow?What are three joints found in the elbow?

Humero-radial joint – flexion and extension, humero-Humero-radial joint – flexion and extension, humero-ulnar joint – flexion and extension, and radioulnar joint ulnar joint – flexion and extension, and radioulnar joint – pronation and supination– pronation and supination

Textbook WorkTextbook Work

Briefly describe the two joints of the pelvic Briefly describe the two joints of the pelvic girdle.girdle. Symphysis pubis – unites two pubic bones, Symphysis pubis – unites two pubic bones,

softens before child birthsoftens before child birth Sacroiliac joint – unites the sacrum with the Sacroiliac joint – unites the sacrum with the

paired iliapaired ilia

Related Joint StructuresRelated Joint Structures LigamentsLigaments

Strong connective tissues that run from bone to bone Strong connective tissues that run from bone to bone and help to maintain stability in a jointand help to maintain stability in a joint

They are not elastic and can lose their ability to They are not elastic and can lose their ability to perform correctly when stretchedperform correctly when stretched

FibrocartilageFibrocartilage Occupies the space between certain bones to form Occupies the space between certain bones to form

the articluar surface and can take on many sizes and the articluar surface and can take on many sizes and shapesshapes

Is round and are know as disks (e.g. those between Is round and are know as disks (e.g. those between the vertebrae of the spine), while others are flat or the vertebrae of the spine), while others are flat or circular in shape (e.g. knee)circular in shape (e.g. knee)

Is resilient and functions as the shock absorberIs resilient and functions as the shock absorber Not blood supply of its own and relies on synovial fluid Not blood supply of its own and relies on synovial fluid

for nourishmentfor nourishment

Synovial MembraneSynovial Membrane A thin tissue that surrounds most freely moving jointsA thin tissue that surrounds most freely moving joints Membrane secretes synovial fluid which provides Membrane secretes synovial fluid which provides

nourishment for cartilaginous disks, lubrication, and nourishment for cartilaginous disks, lubrication, and hydrostatic cushioninghydrostatic cushioning

Joint CapsuleJoint Capsule A tough fibrous sheet that surrounds many joints and A tough fibrous sheet that surrounds many joints and

functions to protect them and to provide stabilityfunctions to protect them and to provide stability Bursae Bursae

A liquid filled membrane that protects soft tissues as A liquid filled membrane that protects soft tissues as they pass by bony projectionsthey pass by bony projections

Others (found in some joints): Others (found in some joints): articular discs, articular discs, fibrocartilaginous labra, meniscus and intracapsular fibrocartilaginous labra, meniscus and intracapsular tendonstendons