Skeletal System Joint NotesSkeletal System Joint Notes

Joints perform two functionsJoints perform two functions

1. Hold bones together1. Hold bones together 2. Allow rigid skeleton some flexibility so 2. Allow rigid skeleton some flexibility so

movement can occur.movement can occur.

Structural or Functional??Structural or Functional??

Structure – presence of CT fibers, cartilage Structure – presence of CT fibers, cartilage or a joint cavity between bones.or a joint cavity between bones.– Examples – fibrous, cartilaginous & synovialExamples – fibrous, cartilaginous & synovial

– Function – amount of movement at the jointFunction – amount of movement at the joint» Immovable, slightly movable or freely movingImmovable, slightly movable or freely moving

Fibrous Joints(Synarthrosis)Fibrous Joints(Synarthrosis)

Fibrous JointsFibrous Joints

1. Joined by fibrous tissue(CT)1. Joined by fibrous tissue(CT) 2. No joint cavity2. No joint cavity 3. Most permit no movement3. Most permit no movement 4. Lie between bones that closely contact 4. Lie between bones that closely contact

one anotherone another

Fibrous Joint ExamplesFibrous Joint Examples

Sutures, space between tibia & fibulaSutures, space between tibia & fibula

Cartilaginous Cartilaginous Joints(Amphiarthrosis)Joints(Amphiarthrosis)

Cartilaginous JointsCartilaginous Joints

1 No joint cavity1 No joint cavity 2. Fibro cartilage (shock absorber) , hyaline2. Fibro cartilage (shock absorber) , hyaline 3. Slightly movable3. Slightly movable 4. Symphyses – growing together, bones 4. Symphyses – growing together, bones

connected by a flat disc of fibro cartilageconnected by a flat disc of fibro cartilage 5. Synchondroses – hyaline cartilage, 5. Synchondroses – hyaline cartilage,

epiphyseal plates, long bonesepiphyseal plates, long bones

Cartilaginous Joint ExamplesCartilaginous Joint Examples

Synovial Joints (Diarthrosis)Synovial Joints (Diarthrosis)

Synovial JointsSynovial Joints

1. Most common , 1. Most common , most complexmost complex

2. Articulating bone 2. Articulating bone ends separated by a jt. ends separated by a jt. Cavity with synovial Cavity with synovial fluid.fluid.

3. Freely movable3. Freely movable 4. Mobility varies4. Mobility varies

Synovial Joints cont.Synovial Joints cont.

5. Joint surfaces enclosed by two layer 5. Joint surfaces enclosed by two layer capsulecapsule

6. Inner layer smooth CT membrane with 6. Inner layer smooth CT membrane with lubricating fluid. Outer layer - dense lubricating fluid. Outer layer - dense fibrous CT.fibrous CT.

7. Hyaline cartilage covers the surfaces7. Hyaline cartilage covers the surfaces 8. Ex. knee & shoulder8. Ex. knee & shoulder

Synovial Joint DiagramSynovial Joint Diagram

Types of synovial jointsTypes of synovial joints

1. Ball & socket1. Ball & socket– Ball shaped head fits into caplike depressionBall shaped head fits into caplike depression– Multi – axialMulti – axial– Wider range of motion than any otherWider range of motion than any other– Shoulder & hipShoulder & hip

CondyloidCondyloid

1.oval shaped condyle 1.oval shaped condyle fits into elliptical fits into elliptical cavity of another cavity of another

2. Biaxial2. Biaxial 3. Radio carpal (wrist) 3. Radio carpal (wrist)

and and metacarpophalangealmetacarpophalangeal

GlidingGliding

1. Articulating 1. Articulating surfaces flat or slightly surfaces flat or slightly curvedcurved

2. Sliding movements 2. Sliding movements in one or two planesin one or two planes

3. Intercarpal & 3. Intercarpal & intertarsal jts.intertarsal jts.

HingeHinge

1. Rounded process of 1. Rounded process of one bone fits into one bone fits into concave surface of concave surface of anotheranother

2. Uniaxial2. Uniaxial 3. Resembles hinge of 3. Resembles hinge of

a doora door 4. Elbow & 4. Elbow &

interphalangeal jts.interphalangeal jts.

PivotPivot

1. Rounded or 1. Rounded or cylindrical surface cylindrical surface rotates within a ring rotates within a ring formed of bone and formed of bone and fibrous tissuefibrous tissue

2. Uniaxial rotation2. Uniaxial rotation 3. Proximal ends of 3. Proximal ends of

radius and ulna, C1 – radius and ulna, C1 – C2C2

SaddleSaddle

1. Articulating 1. Articulating surfaces have both surfaces have both concave & convex concave & convex surfacessurfaces

2. Biaxial2. Biaxial 3. Metacarpal & 3. Metacarpal &

trapeziumtrapezium

MeniscusMeniscus

Flattened shock absorbing pads of fibro Flattened shock absorbing pads of fibro cartilagecartilage

Medial & lateralMedial & lateral

MeniscusMeniscus

BursaeBursae

Fluid filled sac, lined with synovial Fluid filled sac, lined with synovial membranemembrane

Located between the skin and underlying Located between the skin and underlying bony prominencebony prominence

Aids in movement of tendons that pass over Aids in movement of tendons that pass over bony partsbony parts

Patella & olecranonPatella & olecranon

Bursae Bursae

BuraseBurase