Lab 10: Joints

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

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

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

9-3 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 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

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

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

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

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

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

Figure 9–5a Special Movements. Eversion Inversion

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

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