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Skeletal System: Day Two. Long Bone Anatomy, Microscopic Anatomy, Bone Composition, and Joint Anatomy. Structure of Long Bone – Gross Anatomy. Diaphysis (shaft) Epiphyses Epiphyseal Line Medullary Cavity Bone Markings. Long Bone. Diaphysis Shaft Makes up most of the bones length
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Skeletal System: Day Two Long Bone Anatomy, Microscopic Anatomy, Bone Composition, and Joint Anatomy
Structure of Long Bone – Gross Anatomy • Diaphysis (shaft) • Epiphyses • Epiphyseal Line • Medullary Cavity • Bone Markings
Long Bone • Diaphysis • Shaft • Makes up most of the bones length • Composed of compact bone • Covered and protected by a connective tissue membrane, the periosteum • Sharpey’s fibers secure the periosteum to the bone
Long Bone • Epiphyses • Ends of long bone • Thin layer of compact enclosing an area filled with spongy bone • Articular cartilage • instead of periosteum, covers its external surface • a glassy hyaline cartilage • Provides a smooth, slippery surface that decreases friction at joint surfaces
Long Bone • Epiphyseal Line • Thin line of bony tissue spanning the epiphysis that looks different from the rest of the bone in that area • Remnant (what’s left …) of the epiphyseal plate seen in young growing bone. • Epiphyseal plates cause the length wise growth of a long bone.
Long Bone • Medullary Cavity • In adults, the cavity is primarily for storage of adipose tissue (yellow marrow) • In infants, the cavity is used to form blood cells (red marrow) • In adults, red marrow is in the cavities of spongy bone located in the flat bone and the epiphysis (ends) of long bone ONLY.
Long Bone • Bone Markings • Reveal were muscles, tendons, and ligaments were attached and where blood vessels and nerves passed • Two categories: • Projections – grow out from bone • Depressions – indentations in the bone
CENTRAL CANAL CENTRAL CANAL VOLKMANN’S CANAL Structure of Long Bone – Microscopic Anatomy • Osteocytes • Lacunae • Lamellae • Central canals • Osteon • Canaliculi • Volkmann’s canals
Microscopic Anatomy of Long Bones • Osteocytes – mature bone cells • Found in lacunae (spaces) • Arranged in circles called lamellae • Lamellae circle around the Central Canal
Microscopic AnatomyOsteon • Osteon • Central canal plus the lamellae • Central Canal • runs lengthwise through bone carrying blood vessels and nerves to all parts of the bone. • Canaliculi • Tiny canals that extend out from the central canal to the lacunae. • Form a transportation system that connects all osteocytes (bone cells) to the nutrient supply • Volkmann’s canals • Communicate from outside of bone to the central canal • Run at right angles
CENTRAL CANAL CENTRAL CANAL VOLKMANN’S CANAL
Bone Composition Calcium Salts give bone its hardness Organic parts (collagen) give bone flexibility and tensile strength
Joints • With the exception of the hyoid bone, every bone in the body forms a joint with at least one other bone • Joints serve two functions • Hold the bones securely together • Give the rigid skeleton flexibility
Joint Classification • Functional: depends on the amount of movement allowed by the joint • Structural: depends on whether fibrous tissue, cartilage, or a joint cavity separates the bony regions at the joint
Three Types of Joints • Synarthrosis Joints – held together by collagenous fibers. The bones closely contact each other. Ex. Skull sutures, distal end of fibula and tibia • Amphiarthosis Joints – hyaline cartilage or fibrocartilage connect the bones. Ex. Vertebrae, pubis bone • Diarthrosis (Synovial Joint) – Most common joint and most complex
Ball and Socket Joint • Hip and shoulder are examples • Egg shaped head with a cup shaped cavity
Condyloid Joint • Metacarpals and phalanges
Gliding Joint • Joints of the wrist and ankle • Back and forth movement
Hinge Joint • Elbow • Concave and convex surfaces fit together
Pivot Joint • Rotation around a central axis • Radius and ulna, neck turning
Saddle Joint • Carpal and metacarpal of the thumb
Inflammatory Disorders of the Joints • Bursitis: inflammation of bursa (synovial membrane); water on the knee
Inflammatory Disorders of the Joints • Sprain • Ligaments or tendons reinforcing joint are damaged by excessive stretching or are torn away from bone • Slow to heal because of poor blood supply • Dislocation • When a bone is forced out of normal position in the joint cavity
Inflammatory Disorders of the Joints • Arthritis • Most widespread, crippling disease in the U.S. • 1 in 7 Americans suffer with it • Initial symptoms: Pain, stiffness, and swelling of the joint • Acute and Chronic Forms of Arthritis
Inflammatory Disorders of the Joints • Acute Arthritis • Result from bacterial invasion • Treated with antibiotic • Synovial membrane thickens and fluid production decreases, leading to increased friction and pain
Inflammatory Disorders of the Joints • Chronic Arthritis • Osteoarthritis • Most common form • Degenerative condition usu. affects the aged • Wear and tear affects • Can cause bone spurs which restrict joint movement • Rheumatoid arthritis • Occurs between 40-50 years old, but can occur at any age • Affects more women than men • Many joints affected at the same time and usu. in symmetrical manner (left elbow than right elbow) • Marked by remission (goes away) and flare ups (comes back) • Autoimmune disease – body attacks its own tissues • Gouty arthritis