Osteology Paul Conroy BScHons AWCF Mark Caldwell Ph
Osteology Paul Conroy BSc(Hons). , AWCF. & Mark Caldwell Ph. D. , FWCF. ‘Burning to learn’ scientifichorseshoeing. co. uk
Osteology The scientific study of bones, looking at everything to do with bones including… Ø Skeleton Ø Teeth Micro bone Morphology Ø Ø Function Disease Pathology Process of ossification Ø Ø Ø ‘Burning to learn’ Biophysics scientifichorseshoeing. co. uk
Types of Bone Ø Ø Two types of Bone Tissue Cortical Ø ‘Burning to learn’ scientifichorseshoeing. co. uk Cancellous
Cortical Bone Ø Closely packed Osteons forming Hard Exterior Ø Ø Ø Hard compact bone Supports the Body's Weight Stores and Releases chemical elements and minerals (Mainly Calcium) Made up of Osteons –Anatomical and Functional unit of Cortical Bone. ‘Burning to learn’ scientifichorseshoeing. co. uk
What is an Osteon? ‘Burning to learn’ scientifichorseshoeing. co. uk
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Cancellous Bone Definition: Osseous Tissue filling the interior cavity of bone, largely consisting of mineralised bars called TRABECULAR Features: Less Dense, Lighter, 3 D latticework (Honeycomb) structure, Contains Red Marrow Function: Less Dense 20% Mass 80% Surface Similar to support beams of a Roof Arrange in a Honeycomb structure Lacks the Haversian Structure Metabolic Activity – exchange of Calcium Ions ‘Burning to learn’ High surface to area ratio Highly Vascular and contain Bone Marrow scientifichorseshoeing. co. uk
What is Trabecular? ‘Burning to learn’ scientifichorseshoeing. co. uk
Bone Classification 5 Classifications of bone Flat: Thin and often Curved Irregular: Complex Shaped Long: Cylinder like shape, longer than it is wide Short: Cube like, often equal in length, width and thickness Sesamoid: Small and Round, often embedded in tendons ‘Burning to learn’ scientifichorseshoeing. co. uk
Periosteum Membrane of Bone - Skin of Bone Covers outer surface of all bones, (other than areas of articulation) Contains Dense Irregular Connective Tissue Contains two layers: • Outer Fibrous Layer • Inner Cellular Layer ‘Burning to learn’ scientifichorseshoeing. co. uk
Periosteum Inner Cellular Layer Outer Fibrous Layer Contains: Fibroblasts Sharpey's Fibres Osteogenic Layer – Bone Producing Contains: Progenitor Cells - Similar to Stem Cell but more of a ‘Target’ Cell Osteoblasts - Responsible for Bone growth – Intermembraneous Growth (Width) Osteoclasts – Bone reabsorbing cells found more so towards to Endosteum. Protects the underlying cellular layer ‘Burning to learn’ scientifichorseshoeing. co. uk
Periosteum contains a Sensory (Afferent) Nerve endings Provides nourishment by providing the blood supply Attached to bone by strong fibres known as Sharpey's Fibres which provide the attachment for muscles and tendons ‘Burning to learn’ scientifichorseshoeing. co. uk
Progenitor Cells ‘Burning to learn’ scientifichorseshoeing. co. uk
Osteoblast Single Nuclei cell that synthesises Bone Arise from Mesenchymal Stem Cells found in the Periosteum Work in teams to lay down bone Firstly lay down bone mainly collagen called osteoid (unmineralized and great tensile strength) Continue to mineralise with calcium and phosphorus to harden and give great compressive strength. ‘Burning to learn’ This process is known as: Bone Deposition scientifichorseshoeing. co. uk
Osteoclast Multi Nuclei cell that break down bone tissue Responsible for: Maintenance, Repair and Remodelling of bone Dissembles and digests the Hydrated Proteins and Minerals of bone, secreting acid and collagenase as by products. This process is know as Bone Reabsorption ‘Burning to learn’ scientifichorseshoeing. co. uk
Osteocyte A cell that lies within the substance of fully formed bone. Most abundant cell in mature bone Occupies a small chambers known as a ‘Lacuna’ contained with the bones Calcium Matrix Responsible for: Maintenance of surround bone tissue Metabolic activity and Mineral Homeostasis Osteoblasts then have become entrapped in the bone laid down around them Lay relatively inert but communicate with others through Canaliculi ‘Burning to learn’ scientifichorseshoeing. co. uk
Sharpey’s Fibres A matrix of connective tissue consisting of bundles of strong collagenous fibres connecting periosteum to bone. Part of the outer fibrous layer of the periosteum, Sharpey's fibres attach tendons and ligaments to the bone by merging with the fibrous periosteum and underlying bone Bond via Sharpey’s fibres is extremely strong Tension on a tendon or ligament can break the bone before the collagen fibres are pulled away from the bone (an avulsion fracture). ‘Burning to learn’ scientifichorseshoeing. co. uk
Osteogenesis (growth of bone) The young horses bones grow via a process called osteogenesis, this occurs until the horse is about 2 ½ years old. Before birth – all bones are made of cartilage At birth – Most of the cartilage forming the diaphysis (shaft) has ossified. After birth – The epiphysis of the bone rapidly ossify. A layer of epiphyseal cartilage (growth plate) separates the diaphysis from the epiphysis. The epiphyseal plates control growth of bones lengthways and periosteum controls the growth of bone width. ‘Burning to learn’ scientifichorseshoeing. co. uk
Osteogenesis (growth of bone) Epiphyseal plates are influenced by endogenous and exogenous factors. Endogenous = Factors within body i. e. hormonal or genetic make up Exogenous = Factors outside the body i. e. diet or trimming etc ‘Burning to learn’ scientifichorseshoeing. co. uk
Osteogenesis (growth of bone) 2 ways bone develops Intramembranous Ossification – Growth in width. Inner layer of periosteum Produces lots of osteoblasts. In medullary cavity endosteum is producing lots of Osteoclasts which increase the size of the cavity. Endochondral Ossification – Growth in length from the epiphyseal cartilage. As the Cartilage cells produced here start to ossify to form bone tissue the bone increases in length. When all cartilage is ossified bone cannot grow any more. ‘Burning to learn’ scientifichorseshoeing. co. uk
Osteogenesis (growth of bone) 1. Zone of resting: This zone is found at the top of the epiphyseal plate and contains small scattered chondrocytes with large gaps between them. 2. Zone of proliferation: The chondrocytes start to divide and arrange themselves into longer and longer columns in the direction of growth. 3. Zone of maturation: The cells in this zone are stacked into columns and enlarge even further; 4. Zone of calcification: chondrocytes in this zone begin to degenerate and die. When they die, they leave spaces and cavities that will later become invaded by bone forming cells (osteoblasts). 5. Zone of ossification: Blood enters the growth plate from the diaphysis This blood contains osteoblasts. Ø The osteoblasts build new bone from the diaphysis to the epiphysis. Ø A growth plate in long bones ossifies from the diaphysis to the epiphysis. ‘Burning to learn’ scientifichorseshoeing. co. uk
Osteogenesis (growth of bone) Growth Plate **Closure dates are important as if you have a youngster that has an angular limb deformity, attempts to correct it MUST be made before the growth plates close. Otherwise, no corrective growth can occur. ** ‘Burning to learn’ Distal radius Distal 3 rd metacarpal Distal Tibia Distal 3 rd Metatarsal Proximal Phalanx Proximal middle Phalanx scientifichorseshoeing. co. uk Age at closure Rapid growth period 2. 5 years 0 -8 months 1 year 0 -3 months 2 years 1 year 6 months 0 -6 months 0 -3 months
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