Joints & ArticulationsJoints & Articulations

Classification Of JointsClassification Of Joints Classification By Function (degree of Classification By Function (degree of

movement possible):movement possible):1.1. SynarthrosesSynarthroses (Syn=connected, immovable)(Syn=connected, immovable)

Joints with little or no movementJoints with little or no movement Skull sutures, cranium (minus the mandibleSkull sutures, cranium (minus the mandible))

2.2. AmphiarthrosesAmphiarthroses (Amphi = on both sides, between)(Amphi = on both sides, between) Slightly moveable jointsSlightly moveable joints Intervertebral discs, costosternal joints, cartilaginous Intervertebral discs, costosternal joints, cartilaginous

joints(vertebrate between spine)joints(vertebrate between spine)

3.3. DiarthrosesDiarthroses (Diar=passing through, free moving)(Diar=passing through, free moving) Freely moveable jointsFreely moveable joints Shoulder, knee, hip, elbow, interphalangeal, tarsal, Shoulder, knee, hip, elbow, interphalangeal, tarsal,

and carpal jointsand carpal joints

Joint ClassificationJoint Classification Classification by Classification by

structure:structure:1.1. Synovial jointsSynovial joints::

Bones separated Bones separated by a joint cavity; by a joint cavity; lubricated by lubricated by synovial fluid; synovial fluid; enclosed in a enclosed in a fibrous joint fibrous joint capsule.capsule.

Shoulder, hip, Shoulder, hip, elbow, knee, elbow, knee, carpal, carpal, interphalangealinterphalangeal

How would we classify these joints functionally?

Joint ClassificationJoint Classification

2.2. Fibrous jointsFibrous joints:: Bones held together Bones held together

by collagenous fibers by collagenous fibers extending from the extending from the matrix of one bone matrix of one bone into the matrix of the into the matrix of the next.next.

No joint cavityNo joint cavity Skull sutures, teeth Skull sutures, teeth

in joints, distal in joints, distal radioulnar joints & radioulnar joints & tibiofibular jointstibiofibular joints

Joint ClassificationsJoint Classifications3.3. Cartilaginous jointsCartilaginous joints::

Bones held together by cartilage; no joint cavityBones held together by cartilage; no joint cavity Epiphyseal plates of long bones, costosternal joints, Epiphyseal plates of long bones, costosternal joints,

pubic symphysispubic symphysis, intervertebral discs, intervertebral discs

Structure and FunctionStructure and Function Joints are designed Joints are designed

for their function.for their function. Let’s look at sutures Let’s look at sutures

as our 1as our 1stst example: example: Name 4 sutures!Name 4 sutures! What function do you What function do you

suppose sutures are suppose sutures are designed for?designed for?

(1) Immovable: fixed joint such as the cranium

(2) Ball-and-socket joints: such as the shoulder and hip joints, allow backward, forward, sideways, and rotating movements.

(3) Hinge joints: such as in the fingers, knees, elbows, and toes, allow only bending and straightening movements.

(4) Pivot joints: such as the neck joints, allow limited rotating movements.

(5) Sliding Joint: found in the vertebral column and allows small sliding movements. The vertebrae have pads of cartilage between them, and the bones slide over these pads. This is what makes the backbone so flexible.

(6) Ellipsoidal Joint: similar to a ball and socket joint. They allow the same type of movement to a lesser magnitude such as the wrist

Types of Joints in the Human Types of Joints in the Human BodyBody

Structure and FunctionStructure and Function Now let’s talk about Now let’s talk about

synovial joints.synovial joints. 5 main structural 5 main structural

characteristics:characteristics:

1.1. Articular cartilageArticular cartilage What kind of What kind of

cartilage is it?cartilage is it?

Where do we find it? Where do we find it? What does it do?What does it do?

Structure and FunctionStructure and Function2.2. Articular capsuleArticular capsule

2 layered. Surrounds both 2 layered. Surrounds both articular cartilages and the articular cartilages and the space btwn them.space btwn them.

External layer is made of External layer is made of dense irregular CT & is dense irregular CT & is continuous w/ the perisoteum.continuous w/ the perisoteum.

Inner layer is a synovial Inner layer is a synovial membrane made of loose membrane made of loose connective tissue.connective tissue. It covers all internal joint surfaces It covers all internal joint surfaces

except for those areas covered except for those areas covered by the articular cartilage.by the articular cartilage.

Structure and FunctionStructure and Function3.3. JointJoint (Synovial) Cavity(Synovial) Cavity

The potential space within The potential space within the joint capsule and the joint capsule and articular cartilagearticular cartilage

4.4. Synovial FluidSynovial Fluid A small amount of slippery A small amount of slippery

fluid occupying all free fluid occupying all free space w/i the joint capsulespace w/i the joint capsule

Formed by filtration of Formed by filtration of blood flowing thru blood flowing thru capillaries in the synovial capillaries in the synovial membranemembrane

Synovial fluid becomes Synovial fluid becomes less viscous as joint less viscous as joint activity increases. activity increases.

Structure and Structure and FunctionFunction

5.5. ReinforcingReinforcing LigamentsLigaments What kind of tissue are What kind of tissue are

they?they? What do you suppose What do you suppose

their function is?their function is? Double-jointed-ness Double-jointed-ness

results from extra-results from extra-stretchy ligaments and stretchy ligaments and joint capsules. Is this joint capsules. Is this necessarily a good necessarily a good thing?thing?

Other Synovial StructuresOther Synovial Structures The knee and hip joints The knee and hip joints

have cushioning fatty pads have cushioning fatty pads btwn the fibrous capsule btwn the fibrous capsule and the synovial membrane and the synovial membrane or bone.or bone.

Discs of fibrocartilage (i.e., Discs of fibrocartilage (i.e., meniscimenisci) which improve the ) which improve the fit between bone ends, thus fit between bone ends, thus stabilizing the joint.stabilizing the joint. Found in the knee, jaw, and Found in the knee, jaw, and

sternoclavicular joint.sternoclavicular joint. BursaeBursae are basically bags are basically bags

of lubricant - fibrous of lubricant - fibrous membrane bags filled with membrane bags filled with synovial fluid. Often found synovial fluid. Often found where bones, muscles, where bones, muscles, tendons, or ligaments rub tendons, or ligaments rub together.together.

Types of Synovial Types of Synovial JointsJoints

1.1. PlanePlane jointsjoints Articular surfaces are flat and Articular surfaces are flat and

allow short slipping or gliding allow short slipping or gliding movements.movements.

Intercarpal and intertarsal Intercarpal and intertarsal jointsjoints

2.2. Hinge jointsHinge joints A cylindrical projection of one A cylindrical projection of one

bone fits into a trough-bone fits into a trough-shaped surface on another shaped surface on another (like a hotdog in a bun)(like a hotdog in a bun)

Movement resembles a door Movement resembles a door hinge.hinge.

Elbow joint – ulna and Elbow joint – ulna and humerus; Interphalangeal humerus; Interphalangeal joints joints

Type of Synovial Type of Synovial JointsJoints

3.3. Pivot jointsPivot joints Rounded end of one bone Rounded end of one bone

protrudes into a ring formed by protrudes into a ring formed by another bone or by ligaments of another bone or by ligaments of that bone.that bone.

Proximal radioulnar jointProximal radioulnar joint Atlas-axial jointAtlas-axial joint

4.4. Condyloid jointsCondyloid joints Oval articular surface of one Oval articular surface of one

bone fits into a complementary bone fits into a complementary depression on another.depression on another.

Radiocarpal jointsRadiocarpal joints Metacarpophalangeal jointsMetacarpophalangeal joints

Types of Types of Synovial JointsSynovial Joints5.5. Saddle jointsSaddle joints

Each articular surface has convex Each articular surface has convex and concave areas. Each and concave areas. Each articular surface is saddle-articular surface is saddle-shaped.shaped.

Carpometacarpal joints of the Carpometacarpal joints of the thumbs.thumbs.

6.6. Ball-and-Socket jointsBall-and-Socket joints Spherical or semi-spherical head Spherical or semi-spherical head

of one bone articulates with the of one bone articulates with the cuplike socket of another.cuplike socket of another.

Allow for much freedom of Allow for much freedom of motion.motion.

Shoulder and hip joints.Shoulder and hip joints.

The KneeThe Knee Largest and most complex Largest and most complex

diarthrosis in the body.diarthrosis in the body. Primarily a hinge joint, but Primarily a hinge joint, but

when the knee is flexed, it is when the knee is flexed, it is also capable of slight rotation also capable of slight rotation and lateral gliding.and lateral gliding.

Actually consists of 3 joints:Actually consists of 3 joints: Patellofemoral jointPatellofemoral joint Medial and lateral tibiofemoral Medial and lateral tibiofemoral

jointsjoints The joint cavity is only partially The joint cavity is only partially

enclosed by a capsule – on enclosed by a capsule – on the medial, lateral, and the medial, lateral, and posterior sides.posterior sides.

The KneeThe Knee The lateral and medial The lateral and medial

condyles of the femur condyles of the femur articulate with the articulate with the lateral and medial lateral and medial condyles of the tibia. condyles of the tibia. Between these Between these

structures, we have the structures, we have the lateral and medial lateral and medial menisci.menisci.

Anteriorly, the patellar Anteriorly, the patellar ligament binds the ligament binds the tibia (tibia (wherewhere?) to the ?) to the inferior portion of the inferior portion of the patella. The superior patella. The superior portion of the patella portion of the patella is then connected to is then connected to the quadriceps the quadriceps femoris musclefemoris muscle

The KneeThe Knee At least a dozen At least a dozen bursae are associated bursae are associated with the knee.with the knee.

Multiple ligaments are Multiple ligaments are present.present. The The fibular collateral fibular collateral

ligamentligament extends from extends from the lateral epicondyle the lateral epicondyle of the femur to the of the femur to the head of the fibula. head of the fibula.

The The tibial collateral tibial collateral ligamentligament connects connects medial epicondyle of medial epicondyle of the femur to the medial the femur to the medial condyle of the tibial condyle of the tibial shaft and is also fused shaft and is also fused to the medial to the medial meniscus.meniscus.

Both of these Both of these ligaments prevent ligaments prevent excessive rotationexcessive rotation

The KneeThe Knee The The anterior and posterior anterior and posterior cruciate ligamentscruciate ligaments are are also very important.also very important. ACL connects the ACL connects the anterioranterior

intercondylar area of the intercondylar area of the tibia to the medial side of the tibia to the medial side of the lateral femoral condyle.lateral femoral condyle. Prevents forward sliding of Prevents forward sliding of

the tibia and hyperextension the tibia and hyperextension of the knee.of the knee.

PCL connects the PCL connects the posteriorposterior intercondylar area of the intercondylar area of the tibia to the lateral side of the tibia to the lateral side of the medial femoral condyle.medial femoral condyle. Prevents backward Prevents backward

displacement of the tibia or displacement of the tibia or forward sliding of the femur.forward sliding of the femur.

http://video.about.com/sportsmedicine/Anterior-Cruciate-Ligament.htm

http://video.about.com/sportsmedicine/Medial-Meniscus-Injury.htm

ACLACL VideosVideos

Articulations (Movements)Articulations (Movements)

Clinical Conditions

ArthritisArthritis describes about describes about 100 different types of 100 different types of inflammatory or inflammatory or degenerative joint degenerative joint diseases.diseases.

OsteoarthritisOsteoarthritis Most common arthritis. Most common arthritis. Normal joint use prompts Normal joint use prompts

the release of cartilage-the release of cartilage-damaging enzymes. If damaging enzymes. If cartilage destruction cartilage destruction exceeds cartilage exceeds cartilage replacement, we’re left with replacement, we’re left with roughened, cracked, roughened, cracked, eroded cartilages. eroded cartilages.

Eventually bone tissue Eventually bone tissue thickens and forms spurs that thickens and forms spurs that can restrict movement.can restrict movement.

Most common in C and L Most common in C and L spine, fingers, knuckles, spine, fingers, knuckles, knees, and hips.knees, and hips.

Clinical Conditions

Rheumatoid arthritisRheumatoid arthritis Chronic inflammatory Chronic inflammatory

disorderdisorder Marked by flare-upsMarked by flare-ups Autoimmune disease.Autoimmune disease.

Body creates antibodies Body creates antibodies which attack the joint which attack the joint surfacessurfaces

The synovial membrane The synovial membrane can inflame and eventually can inflame and eventually thicken into a thicken into a pannuspannus – an – an abnormal tissue that clings abnormal tissue that clings to the articular cartilage.to the articular cartilage.

Gouty arthritisGouty arthritis When nucleic acids are metabolized uric When nucleic acids are metabolized uric

acid is produced. Normally uric acid is acid is produced. Normally uric acid is excreted in the urine.excreted in the urine.

If blood [uric acid] rises due to decreased If blood [uric acid] rises due to decreased excretion or increased production, it may excretion or increased production, it may begin to form needle-shaped crystals in begin to form needle-shaped crystals in the soft tissues of joints.the soft tissues of joints.

Inflammation ensues causing painful Inflammation ensues causing painful arthritis.arthritis.

Clinical Conditions