Arthrology: The Study of The Joints

Transcription

1 Arthrology: The Study of The Joints Jim Swan 1 These slides are from class presentations, reformatted for static viewing. The content contained in these pages is also in the Class Notes pages in a narrative format. Best screen resolution for viewing is 1024 x 768. To change resolution click on start, then control panel, then display, then settings. If you are viewing this in Adobe Reader version 7 and are connected to the internet you will also be able to access the enriched links to notes and comments, as well as web pages including animations and videos. You will also be able to make your own notes and comments on the pages. Download the free reader from [Adobe.com] 1

2 Classification of Joints by Movement Synarthroses (synarthrotic joints) non movable most fibrous joints e.g. sutures Amphiarthroses (amphiarthrotic joints) semimovable mostly cartilaginous e.g. intervertebral disks Diarthroses (diarthrotic joints) movable joints synovial joints 2 2

3 Classification of Joints by Structure Fibrous joints composed of fibrous (inelastic) connective tissue. sutures between cranial bones syndesmoses e.g. tibia-fibular joint, Non-movable 3 Fibrous joints are mostly non-movable joints, but some are slightly movable. 3

4 Sutures Dense fibrous connective tissue Figure In sutures there is a layer of dense fibrous (inelastic connective) tissue between the bones. 4

5 Syndesmoses Fibula Tibia Ligament Figure In syndesmoses there is a fibrous ligament connecting the bones together. 5

6 Cartilaginous Joints - formed by cartilage, are semimovable synchondroses costal cartilage and epiphyseal plate hyaline cartilage. symphyses intervertebral disks and symphysis pubis fibrocartilage 6 6

7 Synchondroses Costal cartilage First rib and sternum Hyaline cartilages Epiphyseal plate 7 Although all the cartilage connecting ribs with sternum is similar in structure, only that connecting the first rib is considered a synchondrosis. Epiphyseal plates are also considered as synchondroses, although they are no longer joints once ossification is complete. 7

8 Symphyses Intervertebral disk Symphysis pubis 8 Both the intervertebral disks and the symphysis pubis are composed of the same fibrocartilage structure. 8

9 Synovial Joints movable joints contain a joint capsule of synovial membrane 9 9

10 Figure 8.3 Structure of a Synovial Joint periosteum Extracapsular ligament Fibrous capsule } Articular Synovial membrane capsule Articular cartilage Joint cavity 10 The joint cavity inside the articular capsule is filled with synovial fluid which lubricates the movement of the joint. Extracapsular ligaments are found on virtually all synovial joints, as well as some other joints. They hold the bones in position. Certain synovial joints, for example the knee, also have intracapsular ligaments. These control degree and direction of movement. 10

11 Friction Reducing Structures: Bursae and Tendon Sheaths Bursitis inflammation Tendon sheathof a bursa, bursa usually caused by excessive use or injury. Subacromial bursa ligament Bursal cavity Articular cavity 11 Bursae and tendon sheaths are synovial sacks located outside the joint. They lubricate the movement of ligaments and tendons allowing them to slide against other structures without tearing. 11

12 Types of Synovial Joints: Non-axial Joints Figure 8.7 (a) Gliding or planar joints bones slide against one another. e.g. between carpals or tarsals 12 A Plane joint is a non-axial joint. Its sliding movement allows flexibility of the wrist and ankle. 12

13 Uniaxial Joints movement in one axis e.g. hinge joints: Elbow, knee. Pivot joints: e.g. radius with ulna and humerus, atlas-axis Figure 8.7 (b) 13 Hinge joints are uniaxial joints, they move in one plane or on one axis only. Flexion and extension are the reciprocal movements at these joints. 13

14 Movements at Uniaxial Joints: 180 o Flexion decreasing the angle between two bones or parts. Begin at anatomical position Reduce angle from 180 o 14 Consider each movement beginning with the body in anatomical position. A straight line drawn through the body indicates angles of 180 degrees at anatomical position. Reducing those angles ofr knee or brachium produces flexion. 14

15 Extension increasing the angle between two bones or parts. Increase angle back to anatomical position Beyond anatomical position is hyperextension Return to anatomical position 15 The reference axis is shown by the line running in a cephalocaudal direction through the entire body. 15

16 Hyperextension Flexion Flexion and Extension of the Verterbral Column Extension When extension proceeds beyond anatomical position it it is is called hyperextension. 16 The reference axis is shown by the line running in a cephalocaudal direction through the entire body. 16

17 Flexion and Extension of the Head Extension Flexion Hyperextension 17 Reference axis is shown by the line running in a cephalocaudal direction through the entire body. 17

18 Figure 8.7 (c) Pivot Joint -rotation Radius rotates on its own axis. Atlas and head rotate around odontoid process of axis 18 Pivot joints are also uniaxial, the one axis being in the center of the movement. 18

19 Rotation of the Head and Thigh 19 The brachium also rotates in the shoulder joint. To best demonstrate and distinguish between pronation and supination, first bend the elbow. 19

20 Rotation of the Radius Supination to move palm up Pronation to move palm down 20 Despite popular usage, supination and pronation refer only to the hand. 20

21 Biaxial Joints movement in two axes e.g. condyloid joints, saddle joint Other condyloid joints include the occipito-atlas and the tibia-talus joints. Figure 8.7 (d) 21 Condyloid and saddle joints are very similar with slightly different shapes. Both are biaxial joints. The movements performed are flexion, extension, adduction, and abudction, along with circumduction, a combination of the other four. 21

22 Abduction to move away from the midline or apart. Additional Movements at Biaxial Joints Adduction to move toward the midline or together. Circumduction a sequence of movements in which one end inscribes a circle. 22 The reference for abduction and adduction is the midline of the body, or another adjacent part. 22

23 Multiaxial Joints e.g. ball-and-socket joints: shoulder, hip Perform movements in more than two axes. Perform all movements discussed Flexion, extension, rotation, adduction, abduction, circumduction Figure 8.7 (f) 23 23

24 Movements of the Foot dorsiflexion: point toes up plantarflexion: point toes down 24 The axis for these movements runs bilaterally through the ankle. 24

25 Inversion and Eversion Inversion, incorrectly called supination Eversion, incorrectly called pronation Left foot 25 25

26 Other Movements Elevation to raise a part Depression to lower a part Protraction to move a part forward Retraction to move a part backward 26 You can elevate and depress many parts such as the scapula, pelvis, jaw, etc. These parts also can protract and retract. 26

27 bursae The Shoulder ligaments Tendon of the long head of the biceps brachii Articular capsule beneath ligament Tendon of subscapularis Figure 8.8 a 27 Multiple ligaments help to hold the humerus in position, but the primary structural support for the shoulder is the muscle group called the rotator cuff. 27

28 Right Shoulder Articular capsule Glenoid fossa Tendon of long head of biceps brachii Tendon of subscapularis Figure 8.8 b 28 Here you see some of the tendons of rotator cuff muscles (the biceps is NOT a rotator cuff muscle). 28

29 Left Shoulder, Ant. View glenoid fossa 29 Notice the shallowness of the glenoid fossa. For this reason it requires muscular support in the form of the rotator cuff. 29

30 Left Shoulder, extended 30 30

31 The Elbow Joint Figure 8.10 a Tendon of biceps b. trochlea Tendon of triceps b. synovial cavity Articular cartilage Trochlear notch 31 Located in the elbow actually are two joints: a hinge joint whose axis runs bilaterally through the trochlea; a pivot joint between the capitulum of the humerus and the head of the radius. 31

32 Collateral ligaments stabilize the joint on on each side, prevent lateral and medial displacement of of bones. Figure 8.10 b Annular ligament Articular capsule Radial (lateral) collateral ligament 32 The radial head fits neatly in the collar produced by the annular ligament and turns within this collar. 32

33 Figure 8.10 d Annular ligament Ulnar (medial) collateral ligament 33 33

34 Elbow radiograph, lateral view 34 The bones of the elbow and location of the articular capsules are clearly visible. 34

35 Elbow radiograph, dorsal view 35 The articular cartilage and capsule, not being radio-opaque, shows up clearly as a dark space between the bones. 35

36 Hip Joint Articular capsule Syovial cavity Ligamentum teres Intracapsular ligaments lie lie within the joint capsule to to stabilize and restrict range of of motion. Figure 8.9 a Articular capsule 36 Unlike the shoulder, the hip joint has a deep fossa which supports the tremendous force placed on it. Even walking normally places a force on this joint of many times the body s weight. 36

37 Extracapsular Ligaments of the Hip iliofemoral ligament Figure 8.9 c, d pubofemoral ligament ischiofemoral ligament 37 Each ligament which supports the hip joint has a name that indicates its location. 37

38 Hip Joint Radiograph 38 Notice the deep acetabular fossa, the sacroiliac joint, and the pubic symphysis, all soft tissues which show up as black areas between the bones. 38

39 Articular cartilage The Knee Articular capsule femur Quadriceps tendon patellaforms fulcrum for Synovial knee cavity movement bursae meniscus Patellar Absorbs ligament shock, tibia facilitates Inserts on tibial movement tuberosity Figure 8.11 (a) Midsagittal view of right knee 39 The knee has both extracapsular and intracapsular structures for support. The knee joint actually involves three bones: tibia, femur, and patella. 39

40 Lateral patellar retinaculum Lateral (fibular) collateral Retinacula ligament restrict lateral displacement of of the patella. Collateral ligaments control side-tos displacement of bones at the side Figure 8.11 (c) joint. Quadriceps tendon patella Medial (tibial) collateral ligament Medial patellar retinaculum Patellar ligament 40 40

41 Extracapsular Ligaments of the Knee Fibular (lateral) collateral ligament Tibial (medial) collateral ligament Tibiofibular ligament Patellar ligament Figure 8.11 (b) Anterior view of right knee 41 Hypothetically removing the articular capsule and opening up the knee reveals the intracapsular ligaments and the menisci. Only the extracapsular structures are labeled here. 41

42 Intracapsular Structures of the Knee Anterior cruciate ligament Lateral meniscus Posterior cruciate ligament Medial meniscus Cruciate ligaments control front-to-back displacement and twisting. Figure 8.11 (b) Anterior view of right knee 42 Here are labeled the intracapsular structures. 42

43 or posterior displacement of femur against tibia Intracapsular Ligaments Anterior cruciate Restricts anterior displacement of tibia against femur The anterior cruciate ligament attaches at an anterior position on the tibia. It restricts anterior displacement of tibia against femur, or posterior displacement of the femur against the tibia. 1

44 or anterior displacement of femur against tibia Intracapsular Ligaments Restricts posterior displacement of tibia against femur Posterior cruciate The posterior cruciate attaches at a posterior position of the tibia and restricts posterior displacement of tibia against femur, or the anterior displacement of the femur against the tibia. 2

45 Knee Radiograph 44 Articular capsules and other soft tissues appear as dark spaces between the bones. 44

46 Arthritis: Inflammation of the joints osteoarthritis most common type of arthritis (90%) deterioration of the articular cartilage which then leads to the formation of calcifications or bone spurs. little, if any, actual inflammation occurs. articular cartilage deteriorates because of age, stress, and injury

47 A B Above: Osteoarthritis of the shoulder joint (humeral head). Right: osteoarthritis of the vertebral column. 46 On the left is seen osteoarthritis of the shoulder joint. The normal articular cartilage is shown by A, the result of the arthritis is seen as the calcifications in B. Note the calcified masses between the vertebrae in the photo on the right. 46

48 Rheumatoid arthritis - the most severely debilitating form of arthritis affects less than 10% of arthritis sufferers. autoimmune disease: immune system cells release chemicals which attack the joint tissues. Severe inflammation results in great pain. fibrous tissue causes stiffness fibrous tissue may ossify to immobilize joint 47 Pain relieving drugs and surgery, even joint replacement, are the treatments. 47

49 Gouty arthritis - genetic disorder in the ability to metabolize uric acid. uric acid crystals build up in the soft joint tissues and causes their inflammation and destruction. Anti-inflammatory drugs and diet management used for treatment

50 Joint Injuries A sprain involves twisting of the joint, often with accompanying stretching and tearing of ligaments. A strain - a pulling of a muscle tendon and other connective tissues in muscles, but not the joint tissues. luxation is a dislocation in which a bone such as the humerus or femur pulls away from its position in the socket of the joint. A separation occurs when the fibrous tissue in a syndesmosis stretches or tears. 49 These ligaments are slow to heal because of their lack of vascularization; support or immobilization is the treatment. With very severe sprains involving intracapsular ligaments surgery may be performed to reattach the ligaments or replace them with a portion of a ligament from some other location. Small strains are normal and the inflammation produced causes the soreness you may experience after strenuous exercise. Major pulls result from more severe stretching and take longer to heal. A complete luxation may stretch or tear accompanying ligaments to the point they will not return to normal. Partial dislocation or subluxation is more common and the bone can usually be returned manually to its normal position. The most common separation is a shoulder separation in which the clavicle pulls away from its attachment to the acromion process of the scapula. 49