IB Joints and Cartilage POST PDF

© Joints and Cartilage Dr. Sean McWatt, PhD [email protected] Learning Outcomes By the end of this lesson, you will be able to… Explain the basic composition of hyaline and fibrocartilage and compare their functions Review the types of joint classifications and...

© Joints and Cartilage Dr. Sean McWatt, PhD [email protected] Learning Outcomes By the end of this lesson, you will be able to… Explain the basic composition of hyaline and fibrocartilage and compare their functions Review the types of joint classifications and the different shapes of synovial joints Describe the basic features and functions of different types of joints with reference to extracapsular and intracapsular structures Describe the factors that influence joint stability versus mobility and consider how extrinsic factors (i.e., age and injury) may impact that relationship Musculoskeletal System Muscular System Skeletal System Muscles Bones Tendons/aponeuroses Cartilage Motor unit Ligaments Functions Functions Skeletal movement Support Maintaining posture and position Protection Opening and closing of orifices Force translation Maintaining homeostasis Blood cell production Mineral storage Anterior views http://tiny.cc/ukmzaz https://www.pinterest.ca/pin/231231762096235747/ Cartilage Types of Cartilage The most prevalent Chondrocytes cartilage types in the musculoskeletal system are hyaline cartilage and fibrocartilage Elastic cartilage Hyaline cartilage Fibrocartilage Specialized tissue with elastic Most abundant, but weakest Durable shock-absorber, fibers cartilage type high amount of collagen Strength and elasticity to Smooth surface for glide, flexibility, Joint support and maintain structure shape and support at synovial joints cushioning Epiglottis, auricle, laryngeal Articular cartilage, Intervertebral discs, cartilages trachea/bronchi, epiphyseal plates pubic symphysis, menisci Hyaline Cartilage: Synovial Joints Hyaline cartilage is found primarily on the ends of articulating bones within synovial joints, hence it’s alternative name ‘articular’ cartilage Synovial cavity Articular Filled with synovial fluid cartilage It is also found in Hyaline Joint capsule synchondrosis joints Fibrous membrane Synovial membrane Drake, Gray’s Anatomy for Students, 2nd Ed., Copyright © 2009 by Churchill Livingstone Hyaline Cartilage Femoral condyles Hyaline cartilage Covered in hyaline cartilage Viscoelastic connective tissue Time → Avascular: No blood supply, lymph channels, or Distributes load over wider area nerve supply! to decrease stress on joint surfaces How does it stay alive? Smooth surface reduces friction Hyaline cartilage is smooth, which reduces friction in the joint. Its viscoelastic properties also allow it to absorb forces, but makes it pliable and relatively weak Anterior view Gilroy, Anatomy: An Essential Textbook, Copyright © 2013 by Thieme Hyaline Cartilage Hyaline cartilage LOAD e.g., body weight Collagen fibers Type II Joint capsule Synovial Nutrient membrane and waste Filled with exchange synovial fluid via synovial fluid! Superficial Force distribution Hyaline cartilage Middle Fluid storage Proteoglycans Deep Bony connection When the joint is loaded, the pressure forces fluids out of the middle section of the hyaline cartilage and into the synovial cavity. When that pressure is released, fresh fluid with nutrients rushes in Arthritis Severe Which type is more inflammation Causing cartilage likely to be found in degradation more than one joint? Synovial membrane Why? and fluid Healthy Loss of Fibrous tissue hyaline cartilage infiltration From ‘wear and tear’ ‘Fuses’ joint Hyaline cartilage Healthy Osteoarthritis (OA) Rheumatoid arthritis (RA) Most common type of arthritis Autoimmune disease Gradual loss of cartilage from Inflammation of synovial cavity and ‘wear and tear’ cartilage decreases mobility over time Common cause of hip and knee Eventually cartilage degrades (nutrient replacements exchange issues) exposing bone ends Copyright © Mayo Foundation for Medical Education and Research Fibrocartilage: Solid Joints Gomphosis Suture Fibrous Fibrocartilage offers strong support and is therefore found in symphysis joints, which often need to withstand large forces http://tiny.cc/eztzaz Gilroy, Anatomy: An Essential Textbook, Copyright © 2013 by Thieme Cartilaginous Synchondrosis Hyaline cartilage Symphysis Fibrocartilage © Dr. Sean C. McWatt Fibrocartilage Lateral and medial menisci Stabilize the knee joint Fibrocartilage Essentially, hyaline cartilage + dense connective tissue Contains Type I and Type II collagen Creates disc-like structures within joints to increase their stability Labrums, menisci, articular discs Glenohumeral labrum https://www.shoulderdoc.co.uk/imag es/uploaded/labrum_depth.jpg Fibrocartilage is also used in joint elements designed to add Pubic symphysis stability or cushioning to a synovial joint Anterior views Gilroy, Anatomy: An Essential Textbook, Copyright © 2013 by Thieme Joint Stability Classifications of Synovial Joints Planar (gliding) Biaxial Uniaxial The shape of a joint not only dictates its function, Pivot Hinge but also how stable it is, based on how tight the contacts are between adjacent bones Saddle Multiaxial Ball and socket Condyloid For example, how would the stability of a planar joint compare to that of a hinge joint? Gilroy, Anatomy: An Essential Textbook, Copyright © 2013 by Thieme Synovial Joint Components Fibrocartilage elements Labrum, meniscus, etc. Bursae for stability Sacs filled with synovial fluid to reduce friction There are several Joint additional elements capsule included in synovial joints Synovial that are to balance membrane stability with mobility Tendinous Hyaline synovial sheaths cartilage To reduce friction Articulation points Fat pads Cushioning Bones At least two Drake, Gray’s Anatomy for Students, 2nd Ed., Copyright © 2009 by Churchill Livingstone Stability vs. Mobility Glenohumeral labrum Fibrocartilage Factors contributing to range of motion: Shape and arrangement of articulating surfaces VS. For example, glenohumeral vs. humeroulnar joints Extra structures (menisci, labrums, etc.) Ligaments crossing the joint Elbow vs. knee Rotator cuff Medial view More ligaments and tighter ligaments muscles = more stability Extracapsular Surrounding muscles ligaments Higher tone = more stability Aging and injury = muscle loss (atrophy) = more mobility/less stability VS. Intracapsular It’s a balancing act to maximize ligaments function while limiting chances of injury Stability Mobility Anterior views Gilroy, Anatomy: An Essential Textbook, Copyright © 2013 by Thieme Ligament Sprains Sprains Grade 1: Stretching or slight tearing Grade 2: Incomplete tear Grade 3: Complete tear Torn ligaments Protection are called Rest sprains, whereas Ice torn muscles or Compression tendons are Elevation called strains SURGERY Grade 3 Grade 1 Grade 2 Grade 3 Medial views Learning Outcomes By now, you should better understand how to… Explain the basic composition of hyaline and fibrocartilage and compare their functions Review the types of joint classifications and the different shapes of synovial joints Describe the basic features and functions of different types of joints with reference to extracapsular and intracapsular structures Describe the factors that influence joint stability versus mobility and consider how extrinsic factors (i.e., age and injury) may impact that relationship  © [email protected]