The framework of bones and cartilage which protect organs, and provides a lever system that allows locomotion.

The SKELETAL System

SupportProtectionMovement FacilitationMineral Storage and HomeostasisHematopoiesisStorage of Energy

Functions of the Skeletal System

Osteoblasts OsteocytesOsteoclasts

Types of Bone Cells

Bone Cells

the process by which bones form in the body – 2 types

Intramembranous OssificationMembranes ----> Bone

Endochondral OssificationCartilage ----> Bone

Ossification/ Osteogenesis

Intramembranous Ossification

Endochondral Ossification

Bones are constantly undergoing ossification and remodeling

Replacing old bone matrix with new bone matrixbone reabsorption (osteoclasts)bone deposition (osteoblasts)

Allows injured or worn out bone to be replaced

Compact bone tissue is formed by the reorganization of spongy bone tissue

Homeostasis and Bone Remodeling

Periosteum – the outer covering Diaphysis - shaft of a long boneEpiphysis - ends of a long boneMedullary Cavity – contains marrowRed Marrow – where blood cells are

produced.Yellow Marrow – where fat is storedArticular Cartilage – thin layer of hyaline

cartilage covering the epiphyses to reduce friction during movement.

Endosteum – thin layer of cells which line the medullary cavity.

Long Bone Structure

Long Bone Structure

Compact Bone (Dense Bone)little space between the solid components of

boneSpongy Bone (Trabecular Bone)

made up of an irregular network of thin plates of bone with many intercellular spaces called trabeculae (spicules)spaces between trabeculae filled with red bone

marrow- responsible for reducing weight of boneresponsible for hematopoiesis

Classification of Bones

Compact Bone

Compact BoneYou Tube Video: Osteon Model found at http://www.youtube.com/watch?v=CQhUINnTdZI

Proximal End of a Long Bone

EpiphysealPlate

Spongy Bone Structure

Long BonesShort BonesFlat BonesIrregular BonesSesamoid Bones (not a classification used by

all anatomists)

Types of Bones

Types of Bones

Greater length than widthHave a distinct diaphysis and a variable

number of epiphysisSlightly curved for strengthExamples: humerus, ulna, radius, femur,

tibia, fibula, metacarpals, metatarsals, phalanges

Long Bones

Cube-shaped bonesNearly equal in length and widthSpongy texture on inside of the boneExamples: carpal and tarsal bones

Short Bones

Generally thin and flatCompact bone on anterior and posterior

surfaces with spongy bone in the middleProvides protection to organsLarge surface area for muscle attachmentExamples: cranial bones, sternum,

scapula, ribs

Flat Bones

Complex shaped bonesCannot be classified into other categoriesVary in the amount of spongy and compact

boneExamples: vertebrae, facial bones, patella

Irregular Bones

Foramen - an opening or hole in a bone.Bone Markings

Source: Mcstrother. (2010). File:Skull foramina labeled.svg Wikimedia Commons. Retrieved on October 16, 2011 from http://en.wikipedia.org/wiki/File:Skull_foramina_labeled.svg.

Meatus - a tube-like passageway within a bone

Bone Markings

Source: Pngnot. (2007). File:Gray908.png. Wikimedia Commons. Retrieved on October 16, 2011 from http://en.wikipedia.org/wiki/File:Gray908.png.

Sinus - a space within a bone lined with mucus membrane that reduces the weight of a bone

Bone Markings

Source: Arcadian. (2007). File:Illu09 sinuses.jpg. Wikimedia Commons. Retrieved on October 16, 2011 from http://en.wikipedia.org/wiki/File:Illu09_sinuses.jpg

Fossa - a depression or groove on a boneBone Markings

Source: Hughes, P. Shoulder Anatomy. Upper Limb Centre.Retrieved on October 16, 2011 from:http://www.upperlimbcentre.com/anatomy.htm

Source: Uwe Gille. (2007). File:Scapula ant numbered.png.Wikimedia Commons. Retrieved on October 16, 2011 from:http://en.wikipedia.org/wiki/File:Scapula_ant_numbered.png

Condyle - “Knuckle” - a large rounded

prominence on a bone

Bone Markings

Source: Pngbot. (2007). File:SFile:Gray347.png.Wikimedia Commons. Retrieved on October 16, 2011 from:http://en.wikipedia.org/wiki/File:Gray347.png

Tuberosity - an elevated, rounded, usually roughened area of a bone

Bone Markings

Source: Johnuniq. (2010). File: HumerusFront.png.Wikimedia Commons. Retrieved on October16, 2011 from http://en.wikipedia.org/wiki/File:HumerusFront.png

Trochanter - a large blunt process found only on the femur

Bone Markings

Source: Pngbot. (2010). File:Gray343.png.Wikimedia Commons. Retrieved on October16, 2011 from http://en.wikipedia.org/wiki/File:Gray343.png

Tubercle - a small rounded process

Bone Markings

Source: Bot. (2006). File:Gray122.png.Wikimedia Commons. Retrieved on October16, 2011 from http://en.wikipedia.org/wiki/File:Gray122.png.

Process - any projection from the surface of abone

Bone Markings

Source: Engusz. (2007). File:Processusmastoideusossistemporalis.PNGWikimedia Commons. Retrieved on October16, 2011 from hhttp://en.wikipedia.org/wiki/File:Processusmastoideusossistemporalis.PNG

Sutures are the joints between the skull bones. They fuse together between the ages of 18 months old and 3 years.

Fontanels are the soft, membranous spots of a baby’s skull that allows for brain growth and the delivery of the fetus through the birth canal.

Suture and Fontanel

Axial Skeleton - bones that lie along the long axis of the body. Includes the skull, hyoid bone, sternum, ribs, and vertebrae. There are 80 bones.

Appendicular Skeleton - bones of the extremities. There are 126 bones.

Divisions of the Skeleton

Bones of the Skeletal System

Skull – Anterior View- Identify Bones

Skull – Lateral View- Identify Bones

Skull – Posterior View- Identify Bones

SkullYou Tube Video: Skull Bones at http://www.youtube.com/watch?v=Nc5IRj3OJhE

Bones of the vertebral columnCervical vertebrae (7) - neckThoracic vertebrae (12) - ribsLumbar vertebrae (5) - lower backSacral vertebrae (5) - pelvic bonesCoccygeal vertebrae (4) - tail boneIntervertebral Foramina - openings

between the vertebrae for nerve exit

Vertebrae

Vertebral Column

Anatomy of the spine You Tube Video: Anatomy of the spinal http://www.youtube.com/watch?v=qigpRFN5o04&feature=related

The points of contact between bones, between bones and cartilage, or between teeth and bones.

Joints (Articulations)

Classification of joints based upon how they are held together

Fibrous Jointsheld together by fibrous connective tissue-

skull suturesCartilaginous Joints

held together by cartilage-holds rib and sternum together

Synovial Jointsjoint enclosed within a synovial or joint

capsule- knee cap

Structural Classification of Joints

JointsYou Tube Video: Joints of the skeleton found at http://www.youtube.com/watch?v=VsBJ4oUff10&feature=related

Enclosed within a joint or synovial capsulefibrous capsule - outer layer

attaches to periosteum of bonesynovial membrane - inner layer

secretes synovial fluidSpace between the ends of articulating

bones called a synovial spaceEnd of articulating bones are covered with

hyaline (articular) cartilage

Synovial Joints

Typical Synovial Joint

Pads of fibrocartilagenous discs found between bony surfaces in some joints

Allows the bones to fit together betterMaintains the stability of the jointAbsorbs shockDirects the flow of synovial fluid to areas of

greatest friction

Menisci

Sac-like structures that resemble joint capsules situated within body tissues

Function like ball-bearingsReduces friction between bones and soft

tissuesReduces friction between bones and skin

Bursae

Knee Joint

Shoulder Joint

Shoulder Joint

Hip Joint

Joint VideoYou Tube Video called Joint XL TM found at http://www.youtube.com/watch?v=-hZ8OGpWBrY

Tendons - connect muscle to boneA band or cord of dense fibrous connective

tissue extending from a muscle to a bone for attachment

Ligaments - connect bone to boneA band or cord of dense fibrous connective

tissue extending from one bone to another bone to provide a joint with structural stability

Tendons and Ligaments

Degenerative joint disease associated with aging

Usually preceded by traumatic joint injury

Characteristics:degeneration of articular cartilagedevelopment of bone spursusually effects large joints (knees, hips, etc)

Treatment:rest - removal of bone spursjoint replacement

Osteoarthritis

OsteoarthritisYou Tube video called osteoarthritis found at http://www.youtube.com/watch?v=0dUSmaev5b0

Rupture of the fibrocartilage discsUsually caused by compression forcesUsually occurs between L4 and L5 or

L5 and the 1st Sacral VertebraeDisc protrudes and exerts pressure on

spinal nervesTo decrease risk of herniated discs:

1. maintain optimal body weight2. strengthen abdominal muscles3. increase lower back flexibility

Herniated Discs(Slipped Discs)

Herniated Disc

Herniated DiscYou Tube Video called Disc Protrusion found at http://www.youtube.com/watch?v=zEOlXmUeK7o&feature=related

congenital defect where the neural arch fails to unit

usually involves the lumbar vertebraesymptoms may be mild to severe

usually results in paralysispartial or complete loss of bladder controlabsence of reflexes

can be diagnosed during pregnancy by sonography, amniocentesis, blood tests

Spina Bifida

Spina BifidaYou Tube Video called Spina Bifida Animation can be found at http://www.youtube.com/watch?v=ouMi5z1vwbE

Increases strength of the spineHelps maintain balanceDissipates vertical shockProtects spinal column from fractureAnterior Curves (Secondary Curves)

Cervical Vertebrae -Lumbar VertebraePosterior Curves (Primary Curves)

Thoracic Vertebrae -Sacral Vertebrae

Curvature of the Spine

Curvature of the Spine

Scoliosis - lateral curvature of the spineusually in thoracic and lumbar region

Kyphosis - hunchback/humpbackexaggeration of thoracic curvature

Lordosis - swayback (sprinters butt)exaggeration of lumbar curvature

Abnormal Curvatures of the Spine

Abnormal Curvatures

Curvature of the SpineYou Tube Video called Scoliosis Spinal Fusion Animation can be found at http://www.youtube.com/watch?v=WBIf4AQj5s0&feature=related

Decrease in bone mass and increased susceptibility to fractures.

Osteoporosis

Decreased estrogen productionPoor nutritional statusLow activity levelsWeightSmoking Drugs and alcohol consumptionGender/race/hereditary factors

OsteoporosisContributing Factors

Calcium supplementationEstrogen Replacement TherapyWeight-bearing exerciseSteroid treatment therapy

Osteoporosis - Treatment

OsteoporosisYou Tube video called Osteoporosis can be found at http://www.youtube.com/watch?v=5uAXX5GvGrI&feature=related