Fundamentals of Anatomy & Physiology Eleventh Edition Chapter 9 Joints Lecture Presentation by Deborah A. Hutchinson Seattle University

Learning Outcomes 9-1 Contrast the major categories of joints, and explain the relationship between structure and function for each category. 9-2 Describe the basic structure of a synovial joint, and describe common synovial joint accessory structures and their functions. 9-3 Describe how the anatomical and functional properties of synovial joints permit movements of the skeleton. 9-4 Describe the joints between the vertebrae of the vertebral column.

Learning Outcomes 9-5 Describe the structure and function of the elbow joint and the knee joint. 9-6 Describe the structure and function of the shoulder joint and the hip joint. 9-7 Describe the effects of aging on joints, and discuss the most common age-related clinical problems for joints. 9-8 Explain the functional relationships between the skeletal system and other body systems.

An Introduction to Joints Joints (articulations) Where two bones meet Where body movement occurs A tradeoff exists between strength and mobility Two classification schemes Structural (anatomy) Functional (range of motion) Joint structure determines function

9-1 Classification of Joints Structural classifications Fibrous Cartilaginous Bony Synovial Functional classifications Synarthrosis (immovable joint) Amphiarthrosis (slightly movable joint) Diarthrosis (freely movable joint)

9-1 Classification of Joints Synarthrosis (immovable joint) Very strong Edges of bones may touch or interlock May be fibrous or cartilaginous Four types of synarthrotic joints Suture Gomphosis Synchondrosis Synostosis

9-1 Classification of Joints Synarthrosis Suture - Found only between bones of skull Edges of bones interlock Bound by dense fibrous connective tissue Gomphosis - Binds teeth to bony sockets Fibrous connection (periodontal ligament) Synchondrosis - Rigid cartilaginous bridge between two bones Found between vertebrosternal ribs and sternum Also, epiphyseal cartilage of growing long bones Synostosis - Created when two bones fuse Example: metopic suture of frontal bone And epiphyseal lines of mature long bones

9-1 Classification of Joints Amphiarthrosis More movable than a synarthrosis Stronger than a diarthrosis May be fibrous or cartilaginous Two types of amphiarthroses Syndesmosis—bones connected by a ligament Symphysis—bones connected by fibrocartilage

9-2 Synovial Joints Synovial joints (diarthroses) Freely movable joints At ends of long bones Surrounded by joint capsule (articular capsule) Contains synovial membrane Synovial fluid from synovial membrane Fills joint cavity Articular cartilage covers articulating surfaces Prevents direct contact between bones

9-2 Synovial Joints Synovial fluid Has the consistency of egg yolk Contains proteoglycans Primary functions include Lubrication Nutrient distribution Shock absorption Synovial joints are mobile but relatively weak Stabilized by accessory structures Cartilages and fat pads Ligaments Tendons Bursae

9-2 Synovial Joints Cartilages Fat pads Ligaments Tendons Bursae Meniscus—fibrocartilage pad between opposing bones Fat pads Adipose tissue covered by synovial membrane Protect articular cartilages Ligaments Support and strengthen joints Sprain—ligament with torn collagen fibers Tendons Attach to muscles around joint Bursae Small pockets of synovial fluid Cushion areas where tendons or ligaments rub against other tissues

Figure 9–1a The Structure of a Synovial Joint. Medullary cavity Spongy bone Periosteum Components of Synovial Joints Fibrous joint capsule Synovial membrane Articular cartilages Joint cavity (contains synovial fluid) Ligament Metaphysis Compact bone a Synovial joint, sagittal section

Figure 9–1b The Structure of a Synovial Joint. Quadriceps tendon Patella Accessory Structures of a Knee Joint Joint capsule Femur Synovial membrane Bursa Fat pad Joint cavity Articular cartilage Meniscus Ligaments Tibia Extracapsular ligament (patellar) Intracapsular ligament (cruciate) b Knee joint, sagittal section

9-2 Synovial Joints Factors that stabilize synovial joints Prevent injury by limiting range of motion Collagen fibers of joint capsule and ligaments Shapes of articulating surfaces and menisci Other bones, muscles, or fat pads Tendons attached to articulating bones

9-3 Movements at Synovial Joints Axes of Motion Movement of joints can also be described by the number of axes that they can rotate around. A joint that permits movement around one axis is called monaxial, a joint that permits movement around two axes is called biaxial, and one that permits movement around three axes, is called triaxial. Superior–inferior axis Lateral–medial axis Anterior–posterior axis Movements are described in terms that reflect the Plane or direction of movement Relationship between structures Planes of movement Monaxial—1 plane (e.g., elbow) Biaxial—2 planes (e.g., wrist) Triaxial—3 planes (e.g., shoulder)

9-3 Movements at Synovial Joints Types of movement at synovial joints Gliding movement Angular movement Circumduction Rotational movement Special movements Simple Model of Articular Motion Take a pencil as your model and stand it upright on the surface of a desk. The pencil represents a bone, and the desk is an articular surface. A lot of twisting, pushing, and pulling will demonstrate that there are only three ways to move the pencil.

9-3 Movements at Synovial Joints Gliding movement When two flat surfaces slide past each other Example: between carpal bones Moving the Point Linear motion Possible movement 1 shows the pencil can move. If you hold the pencil upright, without securing the point, you can push the pencil across the surface. This kind of motion is called gliding. You could slide the point forward or backward, from side to side, or diagonally.

9-3 Movements at Synovial Joints Changing the Shaft Angle Angular motion Possible movement 2 shows the pencil shaft can change its angle with the surface. With the tip held in position, you can move the eraser end of the pencil forward and backward, from side to side, or at some intermediate angle. Angular movement Flexion and extension are movements in the anterior– posterior plane Flexion - Decreases angle between articulating bones Extension - Increases angle between articulating bones Hyperextension - Extension past anatomical position

Figure 9–3a Angular Movements and Circumduction. Extension Flexion Hyperextension Flexion Flexion Hyper- extension Extension Extension Flexion Hyperextension Extension a Flexion/extension

9-3 Movements at Synovial Joints Angular movement Abduction and adduction are movements in the frontal plane Abduction Movement away from longitudinal axis Adduction Movement toward longitudinal axis

Figure 9–3b Angular Movements and Circumduction. Abduction Abduction Adduction Adduction Abduction Adduction Abduction Adduction b Abduction/adduction relative to the midline of the body

Figure 9–3c Angular Movements and Circumduction. Adduction Abduction c Adduction/abduction relative to central digit

9-3 Movements at Synovial Joints Circumduction A complete circular movement without rotation Changing the Shaft Angle Circumduction A more complex angular motion is possible. Grasp the pencil eraser and move the pencil in any direction until it is no longer vertical. Now, swing the eraser through a complete circle in a movement called circumduction.

Figure 9–3d Angular Movements and Circumduction.

9-3 Movements at Synovial Joints Rotational movement Rotation in reference to anatomical position Example: left or right rotation of head Limb rotation is relative to longitudinal axis of body Medial rotation (internal rotation toward long axis) Lateral rotation (external rotation away from body) Rotating the Shaft Rotation Possible movement 3 shows that the pencil shaft can rotate. If you keep the shaft vertical and the point at one location, you can still spin the pencil around its longitudinal axis in a movement called rotation. No joint can freely rotate because this would tangle blood vessels, nerves, and muscles, as they crossed the joint.

Figure 9–4a Rotational Movements. Head rotation Right rotation Left rotation Atlanto-axial joint Lateral (external) rotation Medial (internal) rotation a Rotation

9-3 Movements at Synovial Joints Rotational movement Pronation Rotates forearm so that radius rolls across ulna Results in palm facing posteriorly Supination Turns palm anteriorly Forearm is supinated in anatomical position

Figure 9–4b Rotational Movements. Supination Pronation b Supination/pronation Supination Pronation

9-3 Movements at Synovial Joints Special movements Inversion Twists sole of foot medially Eversion Twists sole of foot laterally Dorsiflexion Flexion at ankle (lifting toes) Plantar flexion Extension at ankle (pointing toes)

Figure 9–5a Special Movements. Eversion Inversion

Figure 9–5b Special Movements. Dorsiflexion (flexion at ankle) Plantar flexion (extension at ankle) b

9-3 Movements at Synovial Joints Special movements Opposition Movement of thumb toward palm or other fingers Reposition Opposite of opposition Protraction Anterior movement in horizontal plane (forward) Retraction Opposite of protraction (pulling back)

Figure 9–5c Special Movements. Opposition c Opposition Movement of thumb toward palm or other fingers Reposition Opposite of opposition Retraction Protraction d Protraction Anterior movement in horizontal plane (forward) Retraction Opposite of protraction (pulling back)

9-3 Movements at Synovial Joints Special movements Depression Moving a structure inferiorly (down) Elevation Moving a structure superiorly (up) e Depression Elevation

Figure 9–5f Special Movements. Lateral flexion Bending vertebral column to the side f Lateral flexion

9-3 Movements at Synovial Joints Classification of synovial joints Plane (gliding) Hinge Condylar (ellipsoid) Saddle Pivot Ball-and-socket

9-3 Movements at Synovial Joints Plane joint (gliding joint) Flattened or slightly curved surfaces Limited motion (nonaxial) Plane joint Plane joints, or gliding joints, have flattened or slightly curved surfaces that slide across one another, but the amount of movement is very slight. Movement: Gliding. Slight nonaxial Clavicle Manubrium Examples: • Acromioclavicular and claviculosternal joints • Intercarpal joints • Vertebrocostal joints • Sacro-iliac joints Hinge joint Angular motion in a single plane (monaxial) Hinge joint Hinge joints permit angular motion in a single plane, like the opening and closing of a door. Movement: Angular. Monaxial Humerus Ulna Examples: • Elbow joint • Knee joint • Ankle joint • Interphalangeal joint

9-3 Movements at Synovial Joints Condylar joint Oval articular face within a depression Motion in two planes (biaxial) Condylar joint Condylar joints, or ellipsoid joints, have an oval articular face nestled within a depression on the opposing surface. Movement: Angular. Biaxial Radius Examples: • Radiocarpal joint Scaphoid bone • Metatarsophalangeal joints Ulna • Metacarpophalangeal joints 2–5 Saddle joint Articular faces fit together like a rider in a saddle Biaxial Saddle joint Saddle joints have complex articular faces and fit together like a rider in a saddle. Each face is concave along one axis and convex along the other. Movement: Angular. Biaxial III II Metacarpal bone of thumb Examples: • First carpometacarpal joint Trapezium

9-3 Movements at Synovial Joints Pivot joint Rotation only Monaxial Pivot joint Pivot joints only permit rotation. Movement: Rotation. Monaxial Examples: Atlas • Proximal radio-ulnar joint Axis • Atlanto-axial joint Ball-and-socket joint Round head in a cup-shaped depression Triaxial Ball-and-socket joint In a ball-and-socket joint, the round head of one bone rests within a cup-shaped depression in another. Movement: Angular, circumduction, and rotation. Triaxial Humerus Scapula Examples: • Shoulder joint • Hip joint

9-4 Intervertebral Joints First two cervical vertebrae are joined by a synovial joint Synovial joints lie between adjacent articular processes Adjacent vertebral bodies form symphyses

9-4 Intervertebral Joints Intervertebral disc Separates vertebral bodies Anulus fibrosus Tough outer layer of fibrocartilage Attaches disc to vertebrae Nucleus pulposus Elastic, gelatinous core Absorbs shocks Vertebral end plates of cartilage Cover superior and inferior surfaces of disc

9-4 Intervertebral Joints Normal intervertebral disc L1 Bulging L2 A lateral view of the lumbar region of the spinal column, showing a bulging intervertebral disc a Damage to intervertebral discs Bulging disc Bulge in anulus fibrosus Invades vertebral canal

Clinical Note 9-1b Damage to Intervertebral Discs. Herniated disc Nucleus pulposus breaks through anulus fibrosus Compresses spinal nerves Compressed area of spinal nerve Nucleus pulposus of herniated disc Spinal nerve Spinal cord Anulus fibrosus A sectional view through a herniated disc, showing the release of the nucleus pulposus and its effect on the spinal cord and adjacent spinal nerves b

9-4 Intervertebral Joints As vertebral column moves Nucleus pulposus compresses Disc shape conforms to motion Intervertebral ligaments Bind vertebrae together Stabilize the vertebral column Vertebral movements Flexion Extension Lateral flexion Rotation

9-4 Intervertebral Joints Superior articular process Intervertebral Ligaments Ligamenta flava Posterior longitudinal ligament Anterior longitudinal Anterior view a Intervertebral ligaments Ligamenta flava Connect laminae of adjacent vertebrae Posterior longitudinal ligament Connects posterior surfaces of vertebral bodies Anterior longitudinal ligament Connects anterior surfaces of vertebral bodies

9-4 Intervertebral Joints Superior articular facet Intervertebral foramen Intervertebral Disc Vertebral end plate Anulus fibrosus Nucleus pulposus Spinal cord Spinal nerve Lateral and sectional view b Intervertebral ligaments Interspinous ligaments Connect spinous processes of adjacent vertebrae Supraspinous ligament Connects tips of spinous processes (C7 to sacrum) Continuous with ligamentum nuchae (C7 to skull)

9-5 Elbow and Knee Joints Elbow joint Hinge joint Articulations involve humerus, radius, and ulna Joints of the elbow Humero-ulnar joint Largest, strongest joint at elbow Between trochlea of humerus and trochlear notch of ulna Limited movement Humeroradial joint Smaller joint Articulation between capitulum of humerus and head of radius

Anular ligament (covering head and neck of radius) 9-5 Elbow and Knee Joints Humerus Radial collateral ligament tuberosity Antebrachial interosseous membrane Radius Ulna Capitulum Anular ligament (covering head and neck of radius) Lateral view a Structures of the elbow Biceps brachii muscle Attaches to radial tuberosity Controls elbow motion Elbow ligaments Radial collateral Anular Ulnar collateral

Figure 9–7b The Right Elbow Joint Showing Stabilizing Ligaments. Tendon of biceps brachii muscle Anular ligament Humerus Articular capsule Antebrachial interosseous membrane Medial epicondyle Ulnar collateral ligament Radius Ulna Olecranon of ulna b Medial view

9-5 Elbow and Knee Joints Knee joint Complex hinge joint Transfers weight from femur to tibia Three articulations Two femur–tibia articulations At medial and lateral condyles One between patella and patellar surface of femur Joint capsule and joint cavity of knee Medial and lateral menisci Fibrocartilage pads At femur–tibia articulations Cushion and stabilize joint

9-5 Elbow and Knee Joints Seven major supporting ligaments Patellar ligament (anterior) 2. & 3. Two popliteal ligaments (posterior) 4. & 5. Anterior and posterior cruciate ligaments (inside joint capsule) 6. & 7. Tibial collateral ligament (medial) and fibular collateral ligament (lateral)

Figure 9–8a The Right Knee Joint. Quadriceps tendon Ligaments that Stabilize the Knee Joint Patella Patellar retinaculae Tibial collateral ligament Fibular collateral ligament Patellar ligament Fibula Tibia a Anterior view, superficial layer

Figure 9–8b The Right Knee Joint. Patellar surface Ligaments that Stabilize the Knee Joint Posterior cruciate ligament Lateral condyle Medial condyle Anterior cruciate ligament Tibial collateral ligament Menisci Medial Fibular collateral ligament Tibia Lateral Cut tendon of biceps femoris muscle Fibula b Deep anterior view, flexed

Figure 9–8c The Right Knee Joint. Plantaris muscle Gastrocnemius muscle, medial head Femur Gastrocnemius muscle, lateral head Ligaments that Stabilize the Knee Joint Bursa Tibial collateral ligament Joint capsule Fibular collateral ligament Popliteal ligaments Cut tendon of biceps femoris muscle Popliteus muscle Tibia Fibula c Posterior view, superficial layer

Figure 9–8d The Right Knee Joint. Femur Ligaments that Stabilize the Knee Joint Anterior cruciate ligament Fibular collateral ligament Posterior cruciate ligament Medial condyle Lateral condyle Menisci Lateral Medial Cut tendon Tibia Fibula d Deep posterior view, extended

9-6 Shoulder and Hip Joints Shoulder joint (glenohumeral joint) Ball-and-socket diarthrosis Between head of humerus and glenoid cavity of scapula Greatest range of motion of any joint Most frequently dislocated joint Supported by skeletal muscles, tendons, and ligaments

9-6 Shoulder and Hip Joints Joint capsule and joint cavity of shoulder Glenoid labrum Rim of fibrocartilage Extends beyond bony rim and deepens socket of glenoid cavity Acromion and coracoid process of scapula Project laterally, superior to humerus Help stabilize the joint

9-6 Shoulder and Hip Joints Acromioclavicular ligament Tendon of supraspinatus muscle Articular capsule Subdeltoid bursa Synovial membrane Humerus Coraco-acromial Clavicle Coracoclavicular ligaments Acromion Coracoid process Scapula Articular cartilages Joint cavity Glenoid labrum Articular capsule Anterior view, frontal section a Shoulder ligaments Acromioclavicular Coracoclavicular Coraco-acromial Coracohumeral Glenohumeral Shoulder separation Partial or complete dislocation of acromioclavicular joint

9-6 Shoulder and Hip Joints Muscles of rotator cuff Supraspinatus Infraspinatus Teres minor Subscapularis Shoulder bursae Subdeltoid Subcoracoid Subacromial Subscapular Subcoracoid bursa Tendon of biceps brachii muscle Subacromial bursa Muscles and Tendons of the Rotator Cuff Tendon of supraspinatus muscle infraspinatus Teres minor Subscapularis Scapula Lateral view of pectoral girdle Ligaments Stabilizing the Shoulder Joint Clavicle Acromioclavicular ligament Coracoclavicular ligaments Coraco-acromial Coracohumeral ligament (cut) Glenohumeral Subscapular bursa Glenoid cavity Glenoid labrum Articular capsule Acromion b

9-6 Shoulder and Hip Joints Between head of femur and acetabulum of hip bone Strong ball-and-socket diarthrosis Wide range of motion Acetabular labrum Rim of fibrocartilage Increases depth of joint cavity Seals in synovial fluid

Figure 9–10a The Right Hip Joint. Iliofemoral ligament Articular cartilage Acetabular labrum Acetabulum Ligament of the femoral head Transverse acetabular ligament (spanning acetabular notch) Fat pad in acetabular fossa A lateral view with the femur removed a

Ligaments of the hip joint Iliofemoral Pubofemoral Ischiofemoral Transverse acetabular Ligament of the femoral head Pubofemoral ligament Greater trochanter Iliofemoral Lesser An anterior view b Iliofemoral ligament Ischiofemoral Greater trochanter Lesser Ischial tuberosity A posterior view, showing additional ligaments that add strength to the capsule c

9-7 Effects of Aging on Joints Degenerative changes Rheumatism Pain and stiffness in musculoskeletal system Arthritis (joint inflammation) All rheumatic diseases that affect synovial joints Osteoarthritis Caused by wear and tear of joint surfaces, or genetic factors affecting collagen formation Generally affects people over age 60

9-7 Effects of Aging on Joints Degenerative changes Rheumatoid arthritis An inflammatory condition Immune system attacks joint tissues Gouty arthritis Crystals of uric acid form within synovial fluid

9-7 Effects of Aging on Joints Degenerative changes Can be caused from joint immobilization Reduces flow of synovial fluid Can cause symptoms of arthritis Treated by continuous passive motion (CPM) As we age Bone mass decreases Bones weaken Risk of fractures increases

9-8 Integration with Other Systems Living bones undergo remodeling that involves Bone formation (osteoblasts) And bone recycling (osteoclasts) Factors affecting the balance between bone formation and recycling Age Physical stresses Hormone levels Calcium and phosphorus uptake and excretion Genetic or environmental factors

9-8 Integration with Other Systems Other systems interact with the skeletal system Muscles attach to bones Bones are controlled by endocrine system Digestive and urinary systems provide calcium and phosphate minerals to bones for growth Skeleton serves as a reserve for calcium, phosphate, and other minerals