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Cartilage. A non-vascular structural material found in various parts of the body. Forms most of the skeleton in infants. Replaced by bone through ossification during the maturing process. Temporary Cartilage – Cartilage which is naturally replaced by bone during ossification.
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Cartilage A non-vascular structural material found in various parts of the body. Forms most of the skeleton in infants. Replaced by bone through ossification during the maturing process.
Temporary Cartilage – Cartilage which is naturally replaced by bone during ossification. Permanent Cartilage – Cartilage which is designed to remain largely unossified throughout life. Cartilage Classified by Its Change During Maturation
Hyaline Cartilage Elastic Cartilage Fibrocartilage Types of Cartilage
TYPES OF CARTILAGE • Hyaline Cartilage • A gristly mass of firm consistency • Considerably elastic • Covered by a fibrous membrane called the perichondrium which provides its source of nutrition • PERICHONDRIUM NOT PRESENT IN ARTICULAR CARTILAGE
TYPES OF CARTILAGE (continued) • Elastic Cartilage • Yellowish in color • More flexible or rubbery than other types of cartilage • Contains elastic fibers imbedded in the cartilage matrix
TYPES OF CARTILAGE (continued) • Fibrocartilage • A mixture of white fibrous tissue and cartilaginous tissue • Flexibilty comes from the fibrous tissue • Toughness comes from the cartilaginous tissue
TYPES OF FIBROCARTILAGE • connecting fibrocartilage • intervertebral joints (vertebral symphysis) and pubic symphysis • adheres to opposing surfaces • found in joints which admit only slight mobility
Vertebrae – Cross Section intervertebral discs
TYPES OF FIBROCARTILAGE (continued) • interarticular fibrocartilage • menisci of knee • also found in temporomandibular, sternoclavicular, acromioclavicular and wrist joints • free on both surfaces - held in place by ligaments • Found in joints subject to frequent movement and high impact
medial meniscus lateral meniscus Menisci – Top View
TYPES OF FIBROCARTILAGE (continued) • circumferential fibrocartilage • labrum in shoulder and hip • deepens the joint to increase stability and contact area
Hip – Cross Section articular cartilage pelvis labrum articular cartilage femur labrum
TYPES OF FIBROCARTILAGE (continued) 4. stratiform fibrocartilage • forms a thin coating where tendons pass through grooves in the skeleton • develops in the tendons of some muscles where they glide over bones (examples: Peroneus Longus and Tibialis Posterior)
SITES OF STRATIFORM FIBROCARTILAGE Right Leg – Lateral View Right Ankle – Medial View
ANATOMICAL PRESENCE OF CARTILAGE • JOINT CARTILAGE • STRUCTURAL CARTILAGE • ELASTIC CARTILAGE • BONE CARTILAGE (TEMPORARY CARTILAGE)
A. JOINT CARTILAGE 1. Articular cartilage - surrounds ends of bones at articulations formed by hyaline cartilage assists in shock absorption - compression increases contact area low friction surface High in proteoglycans, some TypeII collagen
A. JOINT CARTILAGE (continued) 2. Fibrocartilage Assists in shock absorption Promotes a "tight fit“ in the joint Made of proteoglycans, Type I and II collagen
B. STRUCTURAL CARTILAGE • Performs a supportive structure like bones • Made of hyaline cartilage • Costal cartilage (continuation of the ribs) • Also found in nose, larynx, xiphoid process and most of the trachea
Thoracic Skeleton Costal Cartilage
C. ELASTIC CARTILAGE • Shapes or supports structures needing flexibility and elasticity • Found in external ear, Eustachian tube, epiglottis and parts of the larynx
D. BONE CARTILAGE • The temporary cartilage that ossifies during the maturing process. • Largely responsible for the structural differences between the bones of children and adults. • Because of the high cartilage content, children’s bones: • have lower strength • are less stiff • have lower energy to failure • have larger strain to failure • are subject to greenstick fractures
Susceptibility to Injury • Due to its lack of direct blood supply, cartilage has very limited ability for repair. • Susceptible to "wear and tear" injuries • Cushioning effect decreases with age
Joint Cartilage • ANISOTROPIC (has different structural properties in different directions) • High resistance to COMPRESSION • NOT to tension or shear • reduces stress by decreasing impact forces and increasing area of contact
Synovial Fluid • Secreted by synovial membrane • Lubricant in freely moveable (synovial) joints (i.e., reduces friction in joint while moving) • Not an oil! Composed of water, hyaluronic acid, glycoproteins (lubricin) • Most effective with healthy cartilage • The faster the joint is articulating (increased angular velocity) the greater the lubricating effect • Temperature dependent (Becomes less viscous with increased temperature)