Transcript Lecture 9
Joints Articulations Joint A point of contact between two bones, between bone and cartilage, or between bone and teeth Structural Classification Presence of synovial cavity? Type of connective tissue? Types of Joints based on Structure Fibrous Cartilaginous Synovial Fibrous Fibrous connective tissue Lack a synovial cavity Cartilaginous Cartilage Lack a synovial cavity Synovial Dense irregular connective tissue Acessory ligaments Synovial Cavity present Functional Classification Degree of movement they permit Type of Joints Based on Function Synarthrosis Amphiarthrosis Diarthrosis Synarthrosis Immovable joint Amphiarthrosis Slightly movable joint Diarthrosis Freely movable joints All are synovial joints Three types of Fibrous Joints Sutures Syndesmoses Gomphoses Suture A fibrous joint composed of dense fibrous connective tissue that unite skull bones only. Suture Synarthrosis (immovable) Suture Example: coronal suture Syndesmoses A fibrous joint Syndesmoses More distance between bones than sutures Syndesmoses Fibrous connective tissue arranged as a ligament (bundle) or interosseous membrane (sheet) Syndesmoses Amphiarthrosis (slightly movable) Syndesmoses Example: distal tibiofibular joint Gomphosis A fibrous joint in which a cone-shaped peg fits into a socket Gomphosis Articulation between roots of teeth and sockets of the maxillae and mandible. Gomphosis Dense fibrous connective tissue is the periodontal ligament Gomphosis Synarthrosis (immovable joint) Types of Cartilaginous Joints Synchondroses Symphyses Synchondroses Hyaline cartilage Synchondroses Synarthrosis (immovable joint) Synchondroses Example: epiphyseal plate and first rib and manubrium of sternum Symphyses Fibrocartilage connects the bones Symphyses Amphiarthrosis (slightly movable) Symphyses Example: pubic symphysis Synovial Joints All diarthrosis Synovial Joints Contain Synovial Cavity (presence of space between articulating bones) Synovial Joints Ends of bones covered by articular cartilage Articular Capsule of Synovial Joints • Encloses the synovial cavity and unites the articulating bones Articular Capsule of Synovial Joints • Fibrous capsule – outer layer composed of dense connective tissue Articular Capsule of Synovial Joints • Synovial membrane – inner layer composed of areolar connective tissue Synovial Fluid of the Synovial Joint Fluid in the joint cavity secreted by fibroblasts of the synovial membrane Synovial Fluid of the Synovial Joint 1. Reduces friction Synovial Fluid of the Synovial Joint 2. Supplies nutrients and removes wastes from chondrocytes within articular cartilage Accessory Ligaments of the Synovial Joint Extracapsular ligaments – lie outside the articular capsule (Fibular and Tibular Collateral Ligaments) Accessory Ligaments of the Synovial Joint Intracapsular ligaments – occur within the articular capsule (Anterior and Posterior Cruciate Ligament) Articular Discs of Synovial Joints Fibrocartilage that lie between the articular surfaces of the bones Articular Discs of Synovial Joints Allow two bones of different shapes to fit more tightly Articular Discs of Synovial Joints Directs flow of synovial fluid to the areas of greatest friction Types of Synovial Joints Planar Hinge Pivot Condyloid Saddle Ball and Socket Planar Articulating surfaces are flat or slightly curved Planar Permits side to side and back and forth gliding movement Planar Example: intercarpal, intertarsal, sternoclavicle, acromioclavicular, sternocostal, vertebrocostal Hinge Convex surface of one bone fits into the concave surface of another bone Hinge Monoaxial Hinge Examples: knee, elbow, ankle, and interphalangeal Pivot Rounded or pointed surface of one bone articulates with a ring formed by another bone and ligament Pivot Monoaxial Pivot Example: radioulnar joint Condyloid Convex oval-shaped projection of one bone fits into the oval-shaped depression of another bone Condyloid Biaxial Condyloid Example: wrist and metacarpophalangeal joints Saddle Articular surface of one bone is saddle shaped, and the other bone fits into the saddle Saddle Biaxial Saddle Example: carpometacarpal joint of the thumb Ball and Socket Consists of the ball-like surface of one bone fits into a cup-like depression of another bone Ball and Socket Multiaxial Ball and Socket Example: shoulder and hip joints Torn Cartilage The tearing of articular discs or menisci in the knee. Occurs among athletes Sprains This occurs when a joint is twisted and stretches or tears its ligaments but does not dislocate the bones. Sprains Ankle joint and lower back are commonly sprained Dislocation The displacement of a bone from joint, with resultant tearing of ligaments, tendons, and articular capsules Dislocation The shoulder joint is the most common joint dislocated due to shallowness of the socket. Dislocation Hip joint not common due to acetabular rim is smaller than the head of the femur Shoulder Joint Glenohumeral joint Shoulder Joint Ball and socket joint Shoulder Joint Head of the humerus and glenoid cavity of the scapula Shoulder Joint / Anatomical Features Glenoid labrum – A narrow rim of fibrocartilage around the edge of the glenoid cavity. Shoulder Joint / Anatomical Features Glenoid labrum deepens and enlarges the glenoid cavity Shoulder Joint / Anatomical Features Bursae – fluid filled saclike structures that reduce friction in synovial joints Shoulder Joint / Movements Flexion, extension, abduction, adduction, medial rotation, lateral rotation, and circumduction Shoulder Joint / Strength Attains most support from the rotator cuff muscles (supraspinatus, infraspinatus, teres minor, and subscapularis) which join the scapula to the humerus Shoulder Joint / Strength Rotator cuff muscles hold the head of the humerus in the glenoid cavity Elbow Joint Hinge joint Elbow Joint Involves the trochlea of the humerus, the trochlear notch of the ulna, and the head of the radius Elbow Joint / Movements Flexion and extension Hip Joint Ball and socket Hip Joint Head of the femur and the acetabulum of the hip bone Hip Joint / Anatomical Features Acetabular labrum – Fibrocartilage rim attached to the margin of the acetabulum. Hip Joint / Anatomical Features Acetabular labrum enhances the depth of the acetabulum Hip Joint / Movements Flexion, extension, abduction, adduction, circumduction, medial rotation, and lateral rotation of the thigh Knee Joint One synovial cavity Knee Joint 3 joints Knee Joint 1. Tibiofemoral joint – hinge joint/ between the lateral condyle of the femur, lateral meniscus, and lateral condyle of the tibia Knee Joint 2. Tibiofemoral joint – hinge joint/ between the medial condyle of the femur, medial meniscus, and medial condylye of the tibia Knee Joint 3. Patellofemoral joint – planar joint/ between the patella and the patellar surface of the femur Knee Joint / Anatomical Features Medial meniscus and Lateral meniscus Knee Joint / Anatomical Features Contains bursae Knee Joint Flexion, extension, slight medial rotation, lateral rotation of leg in flexed position