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Chapter 9Chapter 9Joints = ArticulationsJoints = Articulations

Where ANY bones come together

FunctionalFunctional Classification of Classification of JointsJoints

1) Synarthrosis (no movement)• Fibrous (Sutural or Gomphosis)• Cartilaginous (Synchondrosis often becomes

synostosis)• Bony Fusion (Synostosis)2) Amphiarthrosis (little movement)• Fibrous (Syndesmosis – tibia to fibula) • Cartilaginous (Symphysis)3) Diarthrosis (free movement)

Three types of movementSix Types of structure

Structural Structural Classification of Classification of Joints (Joints (Marieb utilizes Marieb utilizes Structural Classification Structural Classification (p 205)(p 205)

1. Fibrous (no joint cavity) Almost no movement, little CT E.g, Sutures in calvarium

2. Cartilaginous E.g., Symphysis pubis, IV disks

3. Synovial – by far most important

1. Fibrous1. Fibrous (no joint (no joint cavity)cavity)

SuturesSutures Only in the skullOnly in the skull

Lambdoidal, Coronal, etc.Lambdoidal, Coronal, etc. Minimal movementMinimal movement Growth allowedGrowth allowed

Syndesmosis (pl. syndesmoses)Syndesmosis (pl. syndesmoses) Ligamentous attachmentsLigamentous attachments Minimal movementMinimal movement E.g., distal tibia to distal fibulaE.g., distal tibia to distal fibula

Gomphosis (pl. gomphoses)Gomphosis (pl. gomphoses) TeethTeeth Periodontal ligamentPeriodontal ligament

2. Cartilaginous2. Cartilaginous = = Union by cartilageUnion by cartilage

Synchondrosis Epiphyseal plates May become

synostosis Symphysis

Fibrocartilage Intervertebral

Disks, symphysis pubis

3. Synovial3. Synovial (with egg white) (with egg white) – – most important! most important!

1.1. Articular CartilageArticular Cartilage1.1. HyalineHyaline

2.2. Joint Cavity or SpaceJoint Cavity or Space3.3. Synovial MembraneSynovial Membrane

1.1. Synovial FluidSynovial Fluid1.1. NourishesNourishes2.2. CushionsCushions3.3. LubricatesLubricates

4.4. Joint CapsuleJoint Capsule5.5. Reinforcing LigamentsReinforcing Ligaments6.6. Nerves and blood Nerves and blood

supplysupply

3. Synovial, 3. Synovial, cont’dcont’d

Depends on: Shape of articular

surfaces Supporting Ligaments Muscle Tone

Joint Stability

Bursae and Tendon Bursae and Tendon SheathsSheaths

Bags of synovial fluidBags of synovial fluid Lubrication and cushionLubrication and cushion

TendonsTendons LigamentsLigaments

N.B.: Tendinitis, Synovitis

Three Types of Motion at Three Types of Motion at Synovial JointsSynovial Joints

Linear motion = gliding

Angular motion : flexion, extension,

hyperextension ab-, adduction circumduction

Rotation left - right, internal or

medial, external or lateral C1 – C2 , leg/foot, radius

Special MovementsSpecial Movements

Supination, Pronation Radius/ulna

Dorsiflexion, plantar flexion

Elevation, depression

Eversion, Inversion

Table 9.4

6 types of 6 types of Diarthroses Diarthroses (p 216)(p 216)

1 Plane (Gliding) Joint

2 Hinge Joint

3 Pivot Joint

4 Condyloid (Ellipsoidal) Joint

5 Saddle joint

6 Ball & Socket joint

Representative Representative ArticulationsArticulations

Temporomandibular JointMostly hinge joint, some gliding and

rotationArticular disc

Intervertebral Intervertebral articulationsarticulations

Gliding joints between vertebrae (facets)

Intervertebral discs: (Amphiarthroses)  annulus fibrosus: tough outer layer

(fibrocartilage) nucleus pulposus: soft, gelatinous

core

Account for ~25% of vertebral column height – H2O loss during aging

Glenohumeral (shoulder) Glenohumeral (shoulder) JointJoint

Greatest range of motion (due to loose capsule and shallow glenoid)

Most frequently dislocated

Stability provided by rotator cuff

Hip JointHip Joint

Deep well fitted ball and socket joint

Stabilization: Extracapsular and

intracapsular ligaments (ligamentum teres = ligamentum capitis femoris)

Strong joint capsule

Extensive surrounding musculature

Knee JointKnee Joint

Much more complex than elbow

Less stable than other hinge joints Some gliding and rotation

Structurally 3 separate joints

No single joint capsule

More KneeMore Knee

Extra- and intracapsular structures Medial and lateral

meniscus

Cruciate ligaments

Collateral ligaments (extracapsular)

Fat Pads

Patella and Patellar Tendon/ligament

Anterior Posterior

Knee, sagittal sectionKnee, sagittal section

Ant. Cruc. Lig.

The infamous ACLThe infamous ACL

Twisting Soccer, skiing, etc.

8X more common in women Hormones Strength Geometry

Surgery is optional Several techniques

Post-op period

Total Knee ReplacementTotal Knee Replacement

Total Knee ReplacementTotal Knee Replacement

The Ankle and FootThe Ankle and Foot

Hinge Joint Deltoid and three Lateral

Ligaments Calcaneous = Heel Bone

Calcaneal/Achilles Tendon Talus articulates with tibia Intertarsal and

Tarsometatarsal Joints Cunieform bones Metarsal and phalangeal

bones Similar to the hand