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Presentation on theme: "Joints."— Presentation transcript:

1 Joints

2 Classification of Joints
Functional classification (Focuses on amount of movement) Synarthroses (immovable joints) Amphiarthroses (slightly movable joints) Diarthroses (freely movable joints) Structural classification (Based on the material binding them and presence or absence of a joint cavity) Bony fusion Fibrous Cartilagenous Synovial

3 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

4 Fibrous joints Bones connected by fibrous tissue: dense regular connective tissue No joint cavity Slightly immovable or not at all Types Sutures Syndesmoses Gomphoses

5 Sutures Only between bones of skull
Fibrous tissue continuous with periosteum Ossify and fuse in middle age: now technically called “synostoses”= bony junctions

6 Syndesmoses In Greek: “ligament” Bones connected by ligaments only
Amount of movement depends on length of the fibers: longer than in sutures

7 Gomphoses Is a “peg-in-socket” Only example is tooth with its socket
Ligament is a short periodontal ligament

8 Cartilagenous joints Articulating bones united by cartilage
Lack a joint cavity Not highly movable Two types Synchondroses (singular: synchondrosis) Sympheses (singular: symphesis)

9 Synchondroses Literally: “junction of cartilage”
Hyaline cartilage unites the bones Immovable (synarthroses) Examples: Epiphyseal plates Joint between first rib’s costal cartilage and manubrium of the sternum

10 Sympheses Literally “growing together” Fibrocartilage unites the bones
Slightly movable (amphiarthroses) Resilient shock absorber Provide strength and flexibility Hyaline cartilage on articular surfaces of bones to reduce friction Examples Intervertebral discs Pubic symphysis of the pelvis

11 Synchondroses and sympheses
Also pubic symphsis

12 Synovial joints Include most of the body’s joints
All are diarthroses (freely movable) All contain fluid-filled joint cavity

13 General Structure of Synovial Joints
Articular cartilage Hyaline Spongy cushions absorb compression Protects ends of bones from being crushed Joint (synovial) cavity Potential space Small amount of synovial fluid

14 General structure of synovial joints (cont.)
3. Articular (or joint) capsule Two layered Outer*: fibrous capsule of dense irregular connective tissue continuous with periosteum Inner*: synovial membrane of loose connective tissue (makes synovial fluid) Lines all internal joint surfaces not covered by cartilage* * * *

15 General structure of synovial joints (cont.)
4. Synovial fluid Filtrate of blood Contains special glycoproteins Nourishes cartilage and functions as slippery lubricant “Weeping” lubricatioin 5. Reinforcing ligaments (some joints) Capsular (most) – thickened parts of capsule Extracapsular Intracapsular

16 General structure of synovial joints (cont.)
6. Nerves Detect pain Monitor stretch (one of the ways of sensing posture and body movements) 7. Blood vessels Rich blood supply Extensive capillary beds in synovial membrane (produce the blood filtrate)

17 General structure of synovial joints

18 Some joints… Articular disc or meniscus (literally “crescent”)
Only some joints Those with bone ends of different shapes or fitting poorly Some to allow two kinds of movement (e.g. jaw) Of fibrocartilage Examples: knee TMJ (temporomandibular joint) sternoclavicular joint

19 Bursae and tendon sheaths
Contain synovial fluid Not joints but often associated with them Act like ball bearings Bursa means “purse” in Latin Flattened sac lined by synovial membrane Where ligaments, muscles, tendons, or bones overlie each other and rub together Tendon sheath Only on tendons subjected to friction

20 Bursae and tendon sheaths

21 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

22 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

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

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






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


32 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

33 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

34 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

35 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

36 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

37 Right hip, AP view

38 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

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

40 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

41 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

42 Cruciate ligaments

43 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

44 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)

45 Right ankle, lateral view



48 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

49 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

50 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)

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