Articulations Chapter 9

Transcription

1 Articulations Chapter 9 Biology 210 Instructor: John McGill Original PowerPoint: Jack Bagwell Supplemental Notes: Beth Wyatt Last updated: October 2, 2007 INTRODUCTION TO ARTICULATIONS DEFINITION Articulations (joints) are the junctions between bones. FUNCTION They bind the various parts of the skeletal system together. They permit bone growth and enable body parts to move in response to skeletal muscle contractions. CLASSIFICATION-SUMMARY Joints vary greatly in structure and function. They can be classified by the types of tissues that bind the bones together at junctions Synarthroses-fibrous Amphiarthroses-cartilaginous Diarthroses-synovial 1

2 CLASSIFICATION OF JOINTS: Structural Based on Design, There Are 3 Types of Joints FIBROUS JOINTS Fibrous Tissue Located B/T Bones CARTILAGINOUS JOINTS Cartilage Located B/T Bones SYNOVIAL JOINTS Fluid-Filled Space Located B/T Bones CLASSIFICATION OF JOINTS: Functional Based on Degree of Movement Permitted, There Are 3 Types of Joints Synarthroses (fibrous) no movement (or very limited movement), suture bones at these joints are fastened tightly by a layer of fibrous connective tissue Amphiarthroses (cartilagenous) cartilaginous joints slightly moveable, symphysis pubis bones at these joints are connected by hyaline cartilage Diarthrosis (synovial) freely moveable, shoulder joint 7 major components of these joints Synarthroses (Fibrous joints) Syndesmoses Sutures Gomphoses 2

3 Synarthroses (Fibrous joints) Syndesmoses Bones are bound together by ligaments Limited movement is possible Ex: Joint between distal end of radius and ulna Synarthroses (Fibrous joints) Sutures Occur only between the flat bones of the skull. United by a connective tissue called a sutural ligament; eventually this ligament becomes ossified. Joints between skull bones Synarthroses (Fibrous joints) Gomphoses The union of a coneshaped bony process in a bony socket. Ex: a tooth is fastened to the jawbone by a peridontal ligament. 3

4 Amphiarthroses (Cartilaginous Joints) Synchondroses Sympheses Amphiarthroses (Cartilaginous Joints) Synchondroses United by bands of hyaline cartilage. Many of these joints are temporary structures that disappear as a result of the growth process Examples Epiphyseal plate between the epiphysis and the diaphysis costal cartilage (ribs articulate with sternum) Amphiarthroses (Cartilaginous Joints) Sympheses Joint in which a pad or disk of fibrocartilage connects two bones Most are located in the midline of the body. Example: symphysis pubis intervertebral disks 4

5 Structure of the Synovial (Diarthroses) Joint: Elbow, Knee, Shoulder, Hip, etc Joint capsule sleeve like extension of the periosteum forms a covering around the ends of the bones and binds the bones together. Synovial membrane moist membrane which lines the inner surface of the joint capsule secretes synovial fluid Articular cartilage covers and cushions the articulating surfaces of the bones Structure of the Synovial (Diarthroses) Joint: Joint cavity small space between the articulating surface of the 2 bones of the joint Structure of the Synovial (Diarthroses) Joint: Elbow, Knee, Shoulder, Hip, etc Mensci (articular disk) pads of cartilage between the articulating ends of bone 5

6 Structure of the Synovial (Diarthroses) Joint: Elbow, Knee, Shoulder, Hip, etc Ligaments helps hold the articular cartilages together Structure of the Synovial (Diarthroses) Joint: Elbow, Knee, Shoulder, Hip, etc Bursae pillow-like structure formed from the synovial membrane TYPES AND RANGE OF MOVEMENT AT SYNOVIAL/DIARTHROSES Angular movements Flexion decreases the angle between two bones bending a body part Extension increases the angle between two bones straightening a joint 6

7 ANGULAR DIARTHROTIC MOVEMENT Angular movements PLANTAR FLEXION Straightening the Foot Downward (Points Toes Downward) DORSIFLEXION Bending the Foot Upward ANGULAR DIARTHROTIC MOVEMENT Angular movements continued Abduction move a body part away from the midline Adduction moves body part toward the midline CIRCULAR DIARTHROTIC MOVEMENT CIRCULAR MOVEMENTS ROTATION Bone Pivots Around a Fixed Point CIRCUMDUCTION Moves a Body Part so That Its Distal End Describes a Circle 7

8 CIRCULAR DIARTHROTIC MOVEMENT CIRCULAR MOVEMENTS SUPINATION Moves the Forearm so as to Turn the Palm Up PRONATION Moves the Forearm so as to Turn the Palm Down GLIDING DIARTHROTIC MOVEMENT GLIDING MOVEMENTS Sliding Between Flat Surfaces Carpals & tarsals Articular facets GLIDING DIARTHROTIC MOVEMENT SPECIAL MOVEMENTS INVERSION Turns the Sole of the Foot Inward EVERSION Turns the Sole of the Foot Outward 8

9 SPECIAL DIARTHROTIC MOVEMENT SPECIAL MOVEMENTS continued PROTRACTION Moves a Body Part Forward Sticking out jaw RETRACTION Moves a Body Part Backward SPECIAL DIARTHROTIC MOVEMENT SPECIAL MOVEMENTS continued ELEVATION Raises a Body Part Closing one s mouth DEPRESSION Lowers a Body Part Opposite of elevation TYPES OF SYNOVIAL/DIARTHROSES (Moveable) Uniaxial joints Biaxial joints Multiaxial joints 9

10 Uniaxial joints-hinge Permit movement around one axis and in one plane. Hinge joints the convex surface of one bone fits into the concave surface of another bone. Elbows, phalanges, knee Flexion & Extension Uniaxial joints-pivot Permit movement around one axis and in one plane. Pivot joints the cylindrical surface of one bone rotates within a ring formed from the fibrous tissue of a ligament. Neck turning (1 st and 2 nd cervical vertebrae) Rotation Biaxial Joints-Saddle Permit movement around two perpendicular axes in 2 perpendicular planes. Saddle joints formed between bones whose articulating surfaces have both convex and concave regions. Thumb joint between first metacarpal and carpal bone Flexion, extension, abduction, adduction 10

11 Biaxial Joints-Condyloid Permit movement around two perpendicular axes in 2 perpendicular planes. Condyloid (ellipsoidal) joints a condyle fits into an elliptical socket. Joint between radius and carpal bones Flexion, extension, abduction, adduction Multiaxial joint-gliding Joint that permits movement around 3 or more planes Gliding joints articulating surfaces are nearly flat or slightly curved these joints only sliding (back and forth) motion (least movable) Processes between vertebrae (articular facets) gliding Multiaxial joint-ball and Socket Joint that permits movement around 3 or more planes Ball and socket joints consists of a bone with a slightly egg-shaped head that articulates with the cup-shaped cavity of another bone allows for the broadest range of movements. Shoulder and hip Flexion, extension, abduction, adduction, rotation, circumduction 11

12 REPRESENTATIVE SYNOVIAL JOINTS SHOULDER JOINT HIP JOINT KNEE JOINT SHOULDER JOINT The Most Moveable Diarthrosis Reason: Glenoid Cavity (Scapula) Shallow, Head of Humerus Doesn t Fit Deep HIP JOINT The Most Stable Diarthrosis Reason: Acetabulum (Os Coxa) Deep, Head of Femur Fits Deep 12

13 The Major Weight Bearing Diarthrosis The Most Frequently Injured Diarthrosis Reasons Fit Between Femur and Tibia (Condyles) Unstable Little Muscle Over Knee Joint KNEE JOINT Anatomy of the Knee mages/seif_what is ACL.jpg Diseases Normal Femur Osteoporotic Head 13

14 Resources tml Publisher site: oduct= Case Study oid_arthritis.htm s_bursitis.htm 14