1. Joints Function: hold bones together & Increase mobility

2. Classification of Joints
Structural classification -binding material & presence or absence of a joint cavity
Fibrous
Cartilagenous
Synovial
Functional classification - amount of movement
Synarthroses (immovable joints)
Amphiarthroses (slightly movable joints)
Diarthroses (freely movable joints)

3. Fibrous joints/Synarthroses
Bones connected by
dense regular connective tissue
No joint cavity
Slightly immovable or
not at all
Types
Sutures
Between tibia/fibula

4. Cartilagenous joints/ Amphiarthoroses
Articulating bones united by cartilage
Lack a joint cavity
Not highly movable Ex
Intervertebral discs
Pubic symphysis of the pelvis

5. Amphiarthroses
Also pubic symphsis

6. Synovial joints/ Diarthroses
Include most of the body’s joints
freely movable
All contain fluid-filled joint cavity

7. General Structure of Synovial Joints
Articular cartilage
Spongy cushions absorb compression
Protects ends of bones from being crushed
Synovial cavity
Potential space
Small amount of synovial fluid
3. Articular capsule
layered covering of joint

8. General structure of synovial joints (cont.)
4. Synovial fluid
Nourishes cartilage and functions as slippery lubricant
5. Reinforcing ligaments (some joints) link bones
6. Nerves
Detect pain
Monitor stretch
7. Blood vessels

9. General structure of synovial joints

10. Joint stability Articular surfaces Ligaments Muscle tone
Shape usually plays only minor role
Some deep sockets or grooves do provide stability
Ligaments
Usually the more, the stronger the joint
Can stretch only 6% beyond normal length before tear
Once stretched, stay stretched
Muscle tone
Constant, low level of contractile force
Keeps tension on the ligaments
Especially important at shoulders, knees, arches of foot

12. Movements allowed by synovial joints
Gliding
Angular movements: hor i the angle between two bones DO TOGETHER
Flexion
Extension
Abduction
Adduction
Circumduction
Rotation
Special movements

13. Special movements Pronation Protraction Supination Retraction
Dorsiflexion
Plantar flexion
Inversion
Eversion
Protraction
Retraction
Elevation
Depression
Opposition

14. Joint movements pics (from Marieb, 4th ed.)

20. Synovial joints classified by shape (of their articular surfaces)
Plane (see right)
Hinge (see right)
Pivot
Condyloid
Saddle
Ball-and-socket

22. Shoulder (glenohumeral) joint
Selected synovial joints
Shoulder (glenohumeral) joint
Stability sacrificed for mobility
Ball and socket: head of humerus with glenoid cavity of scapula
Glenoid labrum: rim of fibrocartilage
Thin, loose capsule
Strongest ligament: coracohumeral
Muscle tendons help stability
Disorders
Rotator cuff muscles add to stability
Biceps tendon is intra-articular

23. Elbow joint Hinge: allows only flexion and extension
Annular ligament of radius attaches to capsule
Capsule thickens into:
Radial collateral ligament
Ulnar collateral ligament
Muscles cross joint
Trauma

24. Wrist joint Two major joint surfaces Several ligaments stabilize
Radiocarpal joint
Between radius and proximal carpals (scaphoid and lunate)
Condyloid joint
Flexion extension adduction, abduction, circumduction
Intercarpal or midcarpal joint
Between the proximal and distal rows of carpals

25. Hip (coxal) joint Ball and socket
Moves in all axes but limited by ligaments and deep socket
Three ext. ligaments “screw in” head of femur when standing
Iliofemoral
Pubofemoral
Ischiofemoral

26. Acetabular labrum diameter smaller than head of femur
Dislocations rare
Ligament of head of femur supplies artery
Muscle tendons cross joint
Hip fractures common in elderly because of osteoporosis

27. Right hip, AP view

28. Knee joint Largest and most complex joint Primarily a hinge
Compound and bicondyloid: femur and tibia both have 2 condyles
Femoropatellar joint shares joint cavity
At least a dozen bursae
Prepatellar
Suprapatellar

29. Lateral and medial menisci
“torn cartilage”
Capsule absent anteriorly
Capsular and extracapsular ligaments
Taut when knee extended to prevent hyperextension

30. Fibular and tibial collateral ligaments
Patellar ligament
Continuation of quad tendon
Medial and lateral retinacula
Fibular and tibial collateral ligaments
Called medial and lateral
Extracapsular
Oblique popliteal
Arcuate popliteal

31. Cruciate ligaments Cross each other (cruciate means cross)
Anterior cruciate (ACL)
Anterior intercondylar area of tibia to medial side of lateral condyl of femur
Posterior cruciate
Posterior intercondylar area of tibia to lateral side of medial condyl
Restraining straps
Lock the knee

32. Cruciate ligaments

33. Knee injuries Flat tibial surface predisposes to horizontal injuries
Lateral blow: multiple tears
ACL injuries
Stop and twist
Commoner in women athletes
Heal poorly
Require surgery

34. Ankle joint Hinge joint Distal tibia and fibula to talus
Dorsiflexion and plantar flexion only
Medial deltoid ligament
Lateral ligaments: 3 bands
Anterior talofibular
Posterior talofibular
Calcaneofibular
Anterior and posterior tibiofibular (syndesmosis)

35. Right ankle, lateral view

38. Temporomandibular joint (TMJ)
Head of mandible articulates with temporal bone
Disc protects thin mandibular fossa of temporal bone
Many movements
Demonstrate movements together
Disorders common

39. Table of Joint Types Functional across Structural down Synarthroses
(immovable joints)
Amphiarthroses
(some movement)
Diarthroses
(freely movable)
Bony Fusion
Synostosis (frontal=metopic suture; epiphyseal lines)
Fibrous
Suture (skull only)
-fibrous tissue is continuous with periosteum
Gomphoses (teeth)
-ligament is periodontal ligament
Syndesmoses
-ligaments only between bones; here, short so some but not a lot of movement (example: tib-fib ligament)
-ligament longer (example: radioulnar interosseous membrane)
Cartilagenous
(bone united by cartilage only)
Synchondroses
-hyaline cartilage (examples: manubrium-C1, epiphyseal plates)
Sympheses
-fibrocartilage (examples: between discs, pubic symphesis
Synovial
Are all diarthrotic

40. Sternoclavicular joint
Saddle joint
Only other example is trapezium and metacarpal 1 (thumb), allowing opposion
Sternum and 1st costal (rib) cartilage articulate with clavicle
Very stable: clavicle usually breaks before dislocation of joint
Only bony attachment of axial skeleton to pectoral girdle
Demonstrate movements together

41. Disorders of joints Injuries Inflammatory and degenerative conditions
Sprains
Dislocatios
Torn cartilage
Inflammatory and degenerative conditions
Bursitis
Tendinitis
Arthritis
Osteoarthritis (“DJD” – degenerative joint disease)
Rheumatoid arthritis (one of many “autoimmune” arthritites)
Gout (crystal arthropathy)