Presentation on theme: "Long Bone Anatomy Diaphysis: Shaft of the bone Made of compact bone"— Presentation transcript:
1Long Bone Anatomy Diaphysis: Shaft of the bone Made of compact bone Epiphysis: Ends of the boneMade mostly of spongy boneThere is a little compact bone on the outer surfaceArticular Cartilage: cap of hyaline cartilage on each epiphysis which articulates with the next boneMedullary canal: contains fatPeriosteum: thin layer like an onion-skin that wraps around the bone. It is anchored to the bone by fibers called Sharpie’s fibers.Nutrient foramen is in the shaft to allow passage for nutrient artery to the bone.
3Compact Bone AnatomyCompact bone is organized into cylinders called osteons.The functional unit of compact bone is the osteon. It is the functional unit because all of the osteon’s functions occur within the osteon.
5Osteon Anatomy Osteoblasts are immature bone cells. They first arrive through the nutrient artery in the embryo bone when it is still made out of cartilage.Osteoblast cells are shaped like stars. They align themselves in concentric circles, as though they are holding hands. One ring of osteoblasts form a large circle, then the next ring inside is smaller, with a smaller ring inside that, and so on. The rings they form are called lamellae (from the word “laminate”, which means to lay on top of something. The rings lay on top of each other).
7Osteoblasts mature into osteocytes The osteoblasts start to secrete hydroxyapatite (calcium and phosphate, which is bone) outside of themselves.When they do this, they become trapped in the cave that they have made out of bone.They are now called osteocytes (mature bone cell).They cave they are trapped in is called a lacunae.
8Osteocytes (mature bone cells) trapped in their lacunae (caves) Compact BoneOsteocytes (mature bone cells) trapped in their lacunae (caves)
9Osteon AnatomyEach osteocyte is star shaped, so they seem to have arms and legs. These appendages also are trapped in the bone cave, so they form little canals.These canals that hold their arms and legs are called canaliculi (little canals).Canaliculi are needed to allow for diffusion of nutrients and wastes between the osteoblasts.
10Canaliculi (little canals) hold the arms and legs of the osteocytes
11Osteon Blood SupplyThe nutrient artery, which entered the shaft of the bone, branches out and one branch runs through the center of each osteon.The canal in the center of each osteon which contains the artery is called the Haversian canal, or central canal.The blood supply needs to connect to the adjacent osteons, so there is a transverse canal, called Volkmann’s canal, or the perforating canal.
15Tendons and LigamentsTendons attach muscle to bone. Tendons are not muscle tissue; they are connective tissue.Ligaments attach bone to bone.Tendons and ligaments are both made from dense regular connective tissue.An aponeurosis is a modified tendon that flares out and attaches into connective tissue instead of bone. There is one that attaches the frontalis muscle (raises eyebrows) to the skull. Another one is in the palm of the hand.
17Terms to Know Osteon: functional unit of compact bone. hydroxyapatite The crystalline structure of calcium and phosphate that make up bone matrixlamellae The circular and concentric layers of collagen fiberslacunae The pockets or cavities in which the cells are trappedHaversian (or central) canal The large channels containing a blood vessel which run longitudinally down the center of each unitcanaliculi The “tiny channels” which run transversely through the layers of bone and allow for diffusion of nutrients and wastes to the cellsperforating canal: connects one Haversian canal to anotherosteocytes The mature bone cells which are trapped in the matrix and help to maintain itOsteoblasts: bone cells that lay down new boneOsteoclasts: bone cells that reabsorb bone
18Terms to Know Periosteum (secured to the bone by Sharpey’s fibers) Sharpey’s fibers (anchor the outer wrapping to the bony matrix below it)Articular Cartilage (cap around long bone)Epiphysis (ends of long bones)Diaphysis (shaft of long bone)Medullary Cavity (hollow area inside long bone)Spongy Bone (contains trabeculae instead of osteons and lamellae)Trabeculae (web-like formation, like a sponge)Tendon (attaches muscle to bone)Ligament (attaches bone-to-bone)Aponeurosis (modified tendon)
20Bone Characteristics Vascular (has own blood supply) Regenerates well (because it is vascular)Contains hydroxyapatite (calcium and phosphate)Forms mostly after birthIs not flexible
21Formation of Endochondral (Embryonic) Bone In the embryo, hyaline cartilage develops in the general shape of the future bone.Periosteum forms on the outside of the developing bone.Osteoblasts enter through the nutrient artery and deposit bony tissue in place of disintegrating cartilage.
22Two Centers of Ossification Primary OssificationStarts in diaphysis; turns cartilage into bone.Then the medullary canal hollows outSecondary OssificationStarts in epiphysis; turns cartilage into boneIt leaves behind a growth plate (epiphyseal line) to allow the child’s bone to grow
24Types of Bones Long Bones Sesamoid Bones Flat Bones Irregular Bones Arms and legsSesamoid BonesDevelop inside tendons and near jointsFlat BonesSkull bones and scapulaIrregular BonesVertebrae
25CartilageWhat are the three types of cartilage and where in the body can each of these three types of cartilage be found?Hyaline cartilage (most of the joints)Fibrocartilage (vertebral discs, pubic symphysis)Elastic cartilage (ears)What type of cartilage does an embryonic skeleton have?Hyaline
26Cartilage Characteristics Avascular (no blood supply)Does not regenerate well (because it is avascular)Contains no calciumBegins conversion to bone before birthIs flexible
27Joint Disorders and Joint Injuries Structure of joints makes them prone to traumatic stressFunction of joints makes them subject to friction and wearAffected by inflammatory and degenerative processesSprains – ligaments reinforcing a joint are stretched or tornDislocation – occurs when the bones of a joint are forced out of alignmentTorn cartilage – common injury to meniscus of knee joint
28Inflammatory and Degenerative Conditions Bursitis – inflammation of a bursa due to injury or frictionTendonitis – inflammation of a tendon sheathArthritis – describes over 100 kinds of joint-damaging diseasesOsteoarthritis – most common type – “wear and tear” arthritisRheumatoid arthritis – a chronic inflammatory disorderGouty arthritis (gout) – uric acid build-up causes pain in jointsLyme disease – inflammatory disease often resulting in joint pain; Lyme disease is caused by a bacterium and is transmitted to humans by the bite of infected blacklegged ticks. Typical symptoms include fever, headache, fatigue, and skin rash. If left untreated, infection can spread to joints, the heart, and the nervous system.
29Osteoporosis: loss of minerals Normal BoneOsteoporosisFigure 6.15
30Stages of Healing a Fracture Four Stages of Fracture RepairSpongy Bone callousOsteoclasts remove excess boneFibrous callousBlood escapesFigure 6.14
32CLASSIFICATION OF FRACTURES CLOSEDSkin is not brokenRequires castOPENBone has broken through the skinIncreased chance of infections, which can be life-threatening.Requires surgery, hospitalization and IV antibiotics
33CLASSIFICATION OF FRACTURES INCOMPLETEOnly one side of the bone is brokenExamplesHairline (stress) fractureGreenstick fractureCOMPLETEBoth sides of bone is broken
34CLASSIFICATION OF FRACTURES Stress (hairline) fractureGreenstick fractureEpiphyseal fractureTransverse fractureOblique fractureSpiral fractureComminuted fractureAvulsion fractureImpacted fractureCompression fractureDepression fractureOnce you have described if the fracture is open or closed, and complete or incomplete, then you describe the fracture shape:
35Types of Fractures http://video.about.com/orthopedics/Fractures-1.htm
36STRESS FRACTURESTRESS FRACTURE: least serious, get tiny, almost invisible breaks. Usually from overexertion. Muscle builds up faster than bone. Six weeks into military basic training camp, see lots of stress fractures from too much new running. Can’t see it on x-ray for three weeks. Diagnose it by placing a tuning fork on the bone, but not at the area of tenderness…the vibration travels down the shaft of the bone until it reaches the fracture site. This will be very painful if it is a stress fracture.
38GREENSTICK FRACTUREGREENSTICK FRACTURE: most common in children; like breaking a green twig, it’s not completely broken. It breaks on one side but bends on the other. Bones in children are not fully mineralized.
40Epiphyseal Fracture EPIPHYSEAL FRACTURE The growth plate in the bone of a child is called the epiphyseal growth plate. That area is weaker than bone, so the whole thing can be broken through during an injury.It is very serious because the bone may grow crooked thereafter. May need repeated surgeries to straighten the bone as it grows.
51IMPACTED FRACTUREIMPACTED FRACTURE: Pressure was exerted on both ends of the SAME bone. The bone is crushed Often seen in femur after falling from a height.
52Impacted fracture of the femur The person fell from a height, and the head of the femur jammed into the neck of the femur.
53COMPRESSION FRACTURECOMPRESSION FRACTURE TWO bones are forced together Bone is crushed. Example would be two vertebrae being crushed together from a fall from a height. People with osteoporosis (loss of bone minerals) often get this type of fracture spontaneously.
61OSTEOARTHRITIS OSTEOARTHRITIS: more common the older you get. The articular cartilage begins to break down, and bone spurs start to grow. The surface is no longer smooth, and movement now causes pain.It is also known as “wear and tear” arthritis.This is the most common disorder of joints.Can be mild to severe, needing joint replacement. These people can actually predict the weather, since the synovial fluid is under pressure. As air pressure changes, fluid expands and hurts more.
63RHEUMATOID ARTHRITISRHEUMATOID ARTHRITIS: not a disease of old age. It’s an autoimmune disease where body attacks and destroys the cartilage in synovial joints. It is not known for spur formation, unlike osteoarthritis. They swell and become unusable, causing knarled hands and feet. Usually need joint replacements, but that will only last about 15 years. First replacement in 60 years old is ok, but in a 30 year old, eventually bone degrades and can no longer take the stem of the implant. It does NOT make many bone spurs; it is degenerative in nature.
65GOUTY ARTHRITIS (GOUT) Gout is caused by a genetic error in the metabolism of uric acid. An gouty episode is triggered by eating too much red meat or protein. The breakdown product of proteins is urea, which leads to uric acid crystals in the cooler areas of the body, especially the MPJ’s (metatarsal-phalangeal joints) of the base of the big toes. The crystals poke the cartilage like needles. Gout is not known for spur formation, unlike osteoarthritis Was more common years ago when people ate nothing but meat. The crystals cause the joint to swell up.
66OTHER BONE DISORDERSOsteomalacia (“malformed bones”) is a genetic malformation of the bones. The epiphyseal plates are particularly affected.Rickets is a type of osteomalacia that is NOT genetic; it is caused by lack of vitamin D. Like all types of osteomalacia, rickets also particularly affect the epiphyseal plates.
67OTHER BONE DISORDERSOsteomalacia (genetic) Rickets (not genetic)
68OTHER BONE DISORDERSOsteomyelitis is an infection of bone.
69OTHER BONE DISORDERSAchondroplasia is a genetic condition where the bones don’t develop properly, especially in the epiphyseal plates, and causes a type of dwarfism.
70CHONDROMALACIA Means a problem with the shape of a cartilage joint. Chondromalacia patella is a condition in which the patella rubs on the femur in the knee joint, becomes scratched or deformed, causing pain. Don’t get this confused with achondroplasia, which is dwarfism!
71OTHER BONE DISORDERSPaget’s disease is more common in older persons, and may be related to a viral infection.It is characterized by excessive bone deposition.
73OTHER BONE DISORDERSANKYLOSING SPONDYLITIS: is a disorder in which vertebrae bind strongly together to limit the flexibility of the spine.
74OTHER JOINT DISORDERSSynovitis is inflammation of the synovial tissues. May need cortisone injections.Arthroplasty is a surgical procedure to repair or remodel a damaged joint.Lyme disease is an inflammatory arthritis of the knee joint, caused from a bacterial infection after a tic bite.
75Polydactyly (Many digits) The extra digit is usually a small piece of soft tissue; occasionally it contains bone without joints; rarely it may be a complete, functioning digit.The extra digit is most common on the ulnar (little finger) side of the hand, less common on the radial (thumb) side, and very rarely within the middle three digits.These are respectively known as postaxial (little finger), preaxial (thumb), and central (ring, middle, index fingers) polydactyly.Polydactyly can occur by itself as an autosomal dominant mutation in a single gene.But, it usually is one feature of a syndrome of congenital anomalies.1 in every 500 live births
81Syndactyly (Fused digits) In fetal development, syndactyly is normal.At about 16 weeks of gestation, an enzyme dissolves the tissue between the fingers and toes, and the webbing disappears.In some fetuses, this process does not occur completely between all fingers or toes and some residual webbing remains.Simple syndactyly can be full or partial, and is present at birth (congenital).
82Syndactyly (Fused digits) Due to an abnormal gene.Syndactyly can be simple or complex.In simple syndactyly, adjacent fingers or toes are joined by soft tissue.In complex syndactyly, the bones are fused.Syndactyly can be complete or incomplete.In complete syndactyly, the skin is joined all the way to the tip of the fingerIn incomplete syndactyly, the skin is only joined part of the distance to the fingertip.
86Syndactyly (Fused digits) Fenestrated syndactyly means the skin is joined for most of the digit but in a proximal area there is gap in the syndactyly with normal skin.This type of syndactyly is found in amniotic band syndrome.
87Amniotic band syndrome Congenital disorder caused by entrapment of fetal parts (usually a limb or digits) in fibrous amniotic bands while in utero.
89End of LectureThe rest of this PPT is not on the exam
90There is a disc between each bone in the spine. The nerves exit the bone to supplyall the parts of the body.
91If you choke off a nerve by twisting the bone around it, the bone starts to crush the nerve.Just like a light with a dimmer switch;if you turn the electrical current down,the light won’t shine as brightly.If you cut off some of the nerve supply to an organ, the organ isn’t going to function as well.
92The discs are made out of something like jelly The discs are made out of something like jelly. As long as your spine is aligned,the jelly will stay in the center.But if the spinebecomes twisted,the jelly will get pushedin the opposite direction, and the shock absorption will be lost.
93TEARS IN THE DISCIf you lift a box while you are standing and twisting,that’s when you gettears in the disc.The fluid in the disc begins to leak out the side of the disc.
94“Wear and Tear” Arthritis Or Degenerative Arthritis OsteoarthritisAlso Known As:“Wear and Tear” ArthritisOr Degenerative ArthritisOccurs when cartilage wears away, leaving raw bone to rub against raw bone.
95PROPER DESK WORK STATION Phone headset for hands-free useComputer at eye leveland 18-25” away from your faceChair with good lumbar support or$10 lumbar pillowKeyboard padunder your wristsThe front of the chairshould drop offAdjustable seat: Feet flat to the floorOr a foot rest under the feet