Bell RingerName 10 bones of the human body.

Turn your bell ringers into the tray.

Skeletal System

Skeletal SystemSkeleton: from Greek for “dried-up body” Infant backbone begins as an arch (C-

shape); changes to a swayback, then quickly forms the common S-shape of the adult spine

Two divisions: Axial Skeleton Appendicular Skeleton

Also includes: joints, cartilage, and ligaments

FunctionsSupportProtection

Of soft body organsMovement

Assisted by muscles and tendonsStorage

Fat inside the cavitiesMineral storage (calcium, phosphorous, etc)

Blood cell formation (Hematopoiesis)Occurs in the marrow cavities

Classification of BonesTypes of bone tissue

Compact boneDense, looks smooth

Spongy boneMade of small needlelike pieces of bone (lots of

open space)Shapes of bones

Long (shaft with a head at each end; mostly compact)

Short (generally cube shaped; mostly spongy)Sesamoid bones – form within tendons

Flat (thin, flat, usually curved; two thin layers of compact bone with spongy bone inbetween)

Irregular

Structure of a Long BoneGross Anatomy

Diaphysis (shaft)Composed of

compact boneCovered by

periosteumHeld by Sharpey’s

fibersEpiphysis (ends)

Spongy bone covered with compact bone

Covered by articular cartilage (hyaline cartilage)

Epiphyseal plate (childhood) becomes epiphyseal line (adult) – hyaline cartilage as the bone grows

Structure of a Long BoneGross Anatomy

Medullary cavity In the shaftHolds the yellow

marrow (fat tissue)

Holds red marrow in infants (blood formation)

Red marrow in adults in cavities of spongy bone of the flat bones and the epiphyses of some long bone

Bone MarkingsProjections or

processesDepressions or

cavities

Bony LandmarksProjections that are sites of muscle and

ligament attachmentTubercle: small rounded projection or processTuberosity: large rounded projection; may be

roughenedTrochanter: very large, blunt, irregularly

shaped processCrest: narrow ridge of bone; usually

prominentLine: narrow ridge of bone; less prominent

than a crestSpine: sharp, slender, often pointed

projectionEpicondyle: raised area on or above a

condyleRamus: armlike bar of bone

Projections that help to form jointsHead: bony expansion carried on a narrow

neckFacet: smooth, nearly flat articular surfaceCondyle: rounded articular projection

Bony LandmarksDepressions and openings allowing blood

vessels and nerves to passMeatus: canal-like passagewaySinus: cavity within a bone, filled with air and

lined with mucous membraneFossa: shallow, basinlike depression in a

bone, often serving as an articular surfaceGroove: slitlike furrowFissure: narrow, slitlike openingForamen: round or oval opening through a

bone

Structure of a Long BoneMicroscopic Anatomy

Osteocytes (mature bone cells)Lacunae (cavity within the bone matrix)

Arranged in concentric circles – lamellae; around a Haversian (central) canal

Haversian system (osteon)Run lengthwise Contains a central canal, a matrix of rings, and a

blood vesselCanaliculi

Tiny canals that radiate outward from the central canals

Volkmann’s (perforating) canalCommunication pathway from the outside of the

bone to its interior Run at right angles to the shaft

Microscopic Anatomy

Bone Formation, Growth & RemodelingSkeleton made of cartilage and bone

As an embryo – skeleton of hyaline cartilageYoung child – most cartilage replaced by

boneMost bones develop using hyaline cartilage

as the model (flat bones use fibrous membranes)Ossification – bone formationOsteoblasts (bone forming cells) cover

hyaline with boneEnclosed hyaline digested to leave medullary

cavityTwo regions left as hyaline cartilage

Articular cartilageEpiphyiseal plates

Bone Formation, Growth & RemodelingBones grow in length by adding hyaline

cartilage at the epiphyseal plateBones grow in width by osteoblasts in the

periosteum adding osteocytes to the external surface of the diaphysis & osteoclasts remove bone from the inner surface of the diaphysis

Appositional growthProcess of bones increasing in diameterControlled by growth hormones and sex

hormones (during puberty)

Bone Formation, Growth & RemodelingBones are not static – continually changing

in response to body changesCalcium levels in the blood

Levels drop, parathyroid glands stimulated to release PTH

PTH activates osteoclasts to break down bone matrix and release calcium ions into the blood

Levels rise, calcium is deposited in the bone matrix as calcium salts

Pull of gravity and muscles on the skeletonIncrease pull will influence where calcium is

deposited

Bone FracturesClosed (simple) fracture – does not

penetrate the skinOpen (compound) fracture – does

penetrate the skinCorrection:

Closed reduction: physician guides the bone into realignment

Open reduction: realignment achieved during surgery

Healing:Simple fracture – healing time 6-8 weeksLonger healing time for larger bones and for

elderly

Repair of Bone Fractures1. Hematoma forms

Blood filled swellingBones deprived of

nutrition die2. Fibrocartilage callus

formsNew capillaries grow

into the clotted bloodDead tissue removed

by phagocytesConnective tissue forms

a mass (callus) containing cartilage matrix, bony matrix, and collagen fibers

Closes the gap in the broken bone

Repair of Bone Fractures3. Bony callus forms

As osteoblasts and osteoclasts move into the area and multiply

Made of spongy bone4. Bone remodeling

Occurs over the next few months to form a permanent patch

Bell RingerDefine fracture. Which fracture types are

most common in the elderly? Why are greenstick fractures more common in children?

Axial SkeletonSkull

CraniumFacial bonesSkull bones held together by sutures

(immovable); except for the mandibleVertebral column (spine)

From the skull to the pelvis26 irregular bones protecting the spinal cordPlus the sacrum and coccyx

Bony thorax (thoracic cage)Consists of the sternum, ribs, & thoracic

vertebraeProtects heart, lungs, and major blood

vessels

SkullCranium (eight large,

flat bones)Frontal boneParietal bonesTemporal bonesOccipital boneSphenoid boneEthmoid bone

Facial BonesMaxillae (Maxillary

bones)Palatine bonesZygomatic bonesLacrimal bonesNasal bonesVomer boneInferior ConchaeMandible

Hyoid bone

CraniumFrontal Bone

Forehead, bony projections under eyebrows, superior part of the orbit

Bony marking: Glabella, supraorbital marginParietal Bones (2)

Most superior and lateral walls of craniumMeet at the midline to form the sagittal sutureMeets the frontal bone to form the coronal sutureBony markings: Parietal eminence, temporal line

Occipital BoneMost posterior – forms the floor and back wall of the

skullMeets the parietal bone to form the lambdoid sutureForamen magnum – large opening in the base for the

extension of the spinal cord from the brainOccipital condyles allow the occiput to rest on the first

vertebra

CraniumTemporal Bones (2)

Inferior to parietal bonesMeets parietal bones to form squamous

suturesBony Markings:

External auditory meatus – canal leading to the ear drum

Styloid process – sharp, projection inferior to external auditory meatus; attachment point for many neck muscles

Zygomatic process – bridge of bone meeting the zygomatic bone (cheek)

Mastoid process – posterior and inferior to external auditory meatus, full of mastoid sinuses (air); attachment site for some neck muscles

Jugular foramen – at junction of occipital and temporal bone; allows passage of jugular vein (drains the brain)

Carotid canal – anterior to jugular foramen; allows passage of internal carotid artery

CraniumSphenoid Bone

Butterfly shapedSpans width of skull and forms part of the

floor of the cranial cavityAlso forms part of the eye orbits and the

lateral surface of the skullBone markings:

Sella turcica (Turk’s saddle)Small depression at the midline; holds the

pituitary glandForamen ovale

Large oval opening for the passage of cranial nerve V to supply the masseter muscle

Sphenoid sinuses (air cavities)

CraniumEthmoid Bone

Anterior to sphenoidIrregularly shapedForms roof of nasal cavity and medial walls of

orbitsBone Markings:

Crista galli (Cock’s comb)Projects from superior sufaceAllows for attachment of dura matter

Cribriform platesHoles on either side of crisa galliAllow nerve fibers from olfactory receptors to

reach the brain

Facial BonesMade of fourteen bones (twelve are paired)Maxillae (maxillary bones)

Fuse to form the upper jawAll facial bones (except mandible) join the

maxillaeBone Markings:

Alveolar margin – location of teethPalatine processes

Extensions that form the anterior part of the hard palate

Paranasal sinusesPalatine Bones

Posterior to palatine process of maxillaeForm posterior part of hard palateCleft palate: failure of the palatine or the

palatine processes to fuse

Facial BonesZygomatic Bones

Cheekbones; also form part of lateral walls of orbitsBony Markings: zygomatic arch; temporal process

Lacrimal BonesForm medial walls of orbitHas a groove that serves as the passageway for tears

(lacrima = tears)Nasal Bones

Form the bridge of the noseVomer Bone

Single bone in the median of the nasal cavity Inferior Conchae

Thin curved bones projecting from lateral walls of nasal cavity

Superior and middle conchae part of ethmoid bone

Facial BonesMandible

Lower jawLargest and strongest bone of the faceOnly freely movable joints in the skull (joins

temporal bones)Bone Markings:

Body – horizontal part of mandibleRami – upright bars extended from bodyAlveoli (sockets) for the teethAlveolar margin – superior edge of mandibular bodyMental foramen

Hyoid BoneHyoid Bone

Not technically part of the skullOnly bone that does not articulate directly

with another boneSuspended above the laynx, anchored by

ligamentsServes as a movable base for the tongue and

an attachment point for neck musclesBone Markings:

BodyHorns (Cornua)

Fetal SkullNot fully formed at birth – spaces in-

between the bones (fontanels)Fontanels are covered with a fibrous

membraneAllow the skull to collapse slightly during

birth and for additional growth of the brain after birth

Completely closed by 24 months of ageAnterior (largest) – diamond-shapedPosterior – triangularSphenoidal Mastoid

Vertebral Column (Spine)26 irregular bones33 bones before birth (9 fuse to form the sacrum

and coccyx)7 cervical vertebrae12 thoracic vertebrae5 lumbar vertebraeSeparated by intervertebral disc

Flexible fibrocartilage90% water in a young person; decreases with age –

causing less compressibilityCurvatures

Primary curvatures – present at birthSecondary curvature – develop later (with raising head

and walking)

Vertebral ColumnStructures of Vertebrae

Body (centrum)Weight-bearing partAnterior

Vertebral archFormed by joining all

posterior extensions Laminae – posterior

portion Pedicle – anterior

portionVertebral foramen

Canal for spinal cord

Transverse processesLateral projections from

vertebral archSpinous process

Fused laminae forming a single projection to the posterior

Superior and inferior articular processPaired projections,

lateral to vertebral foramen

Allow vertebra to form joints with adjacent vertebrae

Also unique characteristics based on region

Cervical VertebraeC1 – C7

C1 – atlasNo bodyDepressions to receive the occipital condylesAllow for “yes” nodding

C2 – axisOdontoid process (dens) – acts as a pivot pointJoint between C1 & C2 allow for “no” movement

C3 – C7 (typical cervical vertebrae)Smallest, lightest vertebraeSpinous processes short and generally split in two

(bifurcated)Transverse processes contain foramina for the

vertebral arteries to pass through

Thoracic & Lumbar VertebraeThoracic Vertebrae

T1 – T12Larger than cervical vertebraeBody somewhat heart shaped with two costal

demifacets to receive the heads of the ribsSpinous process long and hooks sharply

downwardLumbar Vertebrae

L1 – L5Massive, block-like bodiesSpinous process is short and hatchet-shaped

Sacrum & CoccyxSacrum

Formed by fusion of 5 vertebraeForms the posterior wall of pelvisAlae: lateral winglike portion that articulates

with the hip bones to form sacroiliac jointMedian sacral crest: dorsal midline surface

Fused spinous processesSacral Foramina: holes for nerves to enter

the legsSacral canal: continuation of vertebral canal

CoccyxFormed by fusion of 3-5 tiny vertebraeHuman “tailbone”

Bony ThoraxSternum

Flat boneSternal puncture: process of obtaining

hematopoietic tissue for the diagnosis of blood diseases (use the sternum because of proximity to body surface)

Created by fusion of three bonesManubriumBodyXiphoid Process

Attached to first seven pairs of ribsBony landmarks

Jugular notch – concave, superior border of manubrium

Sternal angle – slight angle where manubrium and body meet

Xiphisternal joint

Bony ThoraxRibs

Twelve pairsAll ribs articulate with the vertebral column,

then curve downward and toward the anterior body surface

True ribs – first 7 pairs, attach directly to the sternum

False ribs – next 5 pairs either attach indirectly to the sternum or not at allFloating Ribs – the last 2 pairs (lack sternal

attachments)

Intercostal spaces – filled with intercostal muscles to assist in breathing

Bell RingerWhich bones have the following landmarks:

A. Manubrium, body, xiphoid processB. Body, rami, mental foramenC. Condyles, foramen magnumD. Crista galli, cribiform platesE. Odontoid process, transverse foramen

Appendicular SkeletonComposed of 126 bonesIncludes: appendages (limbs), pectoral and

pelvic girdlesBones of the Pectoral (shoulder) Girdle

Clavicle (collarbone)Slender, double curved boneAttaches to manubrium medially and scapula

laterally Acts as a brace to hold the arm away from the top of

the thorax and helps prevent shoulder dislocationBony Processes: Costal tuberosity, Conoid tubercle,

Subclavian groveBroken clavicle: shoulder region caves in medially

Scapulae (shoulder blades); wings

Bones of the Shoulder GirdleScapulae

Bony Processes:Acromion: enlarged end of the spine of the scapulaCoracoid process: beaklike, points over the top of the

shoulderAcromioclavicular jointSuprascapular notch: medial to coracoid process, serves

as a nerve passagewayBorders:

Superior Medial (vertebral) Lateral (axillary)

Angles Superior Inferior Lateral

Glenoid Cavity: shallow socket that receives that head of the humerus

Bones of the Shoulder GirdleShoulder Girdle is very light and allows for

exceptionally free movement because:1. Shoulder girdle attaches to axial skeleton

at one point – sternoclavicular joint2. Loose attachment of scapula allows for

sliding against thorax as muscles act3. Glenoid cavity is shallow, shoulder joint

reinforced by ligamentsAll this extra movement leads to the

shoulder being easy to move and easy to dislocate

Bones of the Upper LimbsArm, forearm, and hand – 30 bonesHumerus (arm)

Head: proximal end, fits into glenoid cavityGreater and lesser tubercles: also on proximal end,

sites for muscle attachmentDeltoid tuberosity: roughened area in the midpoint of

the shaft; allows attachment of the deltoid muscleRadial groove: runs obliquely down the posterior shaft;

makes the course for the radial nerveTrochlea: distal end, medialCapitulum: distal end, lateralCoronoid fossa: depression superior to trochlea on the

anterior sideOlecranon fossa: depression superior to trochlea on

the posterior sideMedial and lateral epicondyle: on either side of the

olecranon fossa

Bones of the Upper LimbsForearm: Two bones – Radius and Ulna

Radiculoulnar joints (proximal and distal)Interosseous membrane: connects along the

entire lengthRadius – lateral in anatomical position

Head: proximal Radial tuberosity: inferior to head;

connection point for biceps tendonUlna – medial in anatomic position

Coronoid process: anterior on the proximal end

Olecranon process: posterior on the proximal end

Trochlear notch: separates the coronoid and olecranon processes

Bones of the Upper LimbsHand: Carpals,

Metacarpals, and Phalanges

Carpal bones Form the carpus

(wrist) Two bands of four

bones each (8 total)TrapeziumTrapezoidCapitateHamateScaphoidLunateTriquetralPisiform

Bound together by ligaments

MetacarpalsForm the palmHeads of metacarpals –

knucklesNumbered 1 -5 starting at

the thumbPhalanges

Bones of the fingers3 per finger

ProximalMiddleDistal

2 per thumbProximal and Distal

Stop Letting Those PeopleTouch The Cadaver’s Hand

Bones of the Pelvic GirdleFormed by the Coxal bones (ossa coxae)Commonly called the hip bones

Together with the sacrum, forms the bony pelvis

Inside the bony pelvis: reproductive organs, urinary bladder, and part of the large intestine

Each Ossa Coxae is actually three fused bonesIliumIschiumPubis

Ossa Coxae Ilium

Connects with sacrum to form sacroiliac joint

Makes most of the hip bone

Alae: winglike portionIliac crest: upper edge

of alaeAnterior superior iliac

spine: anterior end of iliac crest

Posterior superior iliac spine: posterior end of iliac crest

Anterior/Posterior inferior iliac spine

Ischium“Sitdown bone”Most inferior part of

coxal boneIschial tuberosity:

Rough area that receives body weight while sitting

Ischial spine: superior to tuberosity (narrows the outlet that a baby must pass through)

Greater sciatic notch: allows blood vessels and the sciatic nerve to pass from the pelvis posteriorly to the thigh

Ossa CoxaePubis

Most anterior part of coxal boneRami: bony bar reaching back to ischiumObturator foramen: anterior rami of pubis

meets posterior ischial ramus to create an opening; allows blood vessels and nerves to go into the anterior part of thigh

Pubic symphysis: pubic bones fuse anteriorly to form a cartilaginous joint

Acetabulum: deep socket that receives the head of the femur; fusion of ilium, ischium, and pubis

Ossa CoxaeBony pelvis divided into two regionsFalse pelvis

Superior to true pelvisArea medial to the flaring ilia

True pelvisSurrounded by bone; inferior to false pelvisInlet: superior openingOutlet: inferior opening

Male vs. Female PelvisFemale inlet larger and more circularFemale pelvis shallowerFemale pelvis bones are lighter and thinnerFemale ilia flare more laterallyFemale sacrum is shorter and less curvedFemale ischial spines are shorter and

farther apart (larger outlet)Female pubic arch is more rounded

because the angle of the pubic arch is greater

Bones of the Lower LimbsFemur (thigh)Heaviest and strongest bone in the body

Proximal MarkingsHead: ball like, fits into acetabulumNeck: narrow portion inferior to the headGreater and lesser trochanters: muscle attachment Intertrochanteric line: anterior Intertrochanteric crest: posterior; muscle attachmentGluteal tuberosity: muscle attachment

Distal MarkingsLateral and Medial Condyles: articulate with tibia Intercondylar notch: posteriorPatellar surface: anterior; forms joint with patella

Slant medially to the knees

Bones of the Lower LimbsLeg: 2 bones – Tibia & Fibula

Interosseous membrane: connects the two bones along their length

Tibia (shinbone)Larger & MedialProximal end

Medial and lateral condyles: make a joint with the femur Intercondylar eminence: separates the condylesTibial tuberosity: rough area on the anterior surface for the

patella tendon attachmentDistal end

Medial malleolus: inner bulge of ankleAnterior crest: anterior surface of the tibia; sharp ridge

FibulaHead: proximal endLateral malleolus: distal end; outer part of ankle

Bones of the Lower LimbsFoot – Tarsals, metatarsals, & phalanges

Tarsus (seven tarsal bones)Calcaneus (heelbone)Talus (ankle): between tibia and calcaneusNavicularCuboidMedial, Intermdiate, and Lateral Cuneiform

Metatarsals (5): sole of footPhalanges (14): toes (similar layout as

fingers)Forms 3 arches

Medial and lateral longitudinal archTransverse arch

Bell Ringer

Describe how to differentiate between a male and female pelvis.

JointsEvery bone in the body forms at least one joint with

another bone (except the hyoid bone) Joints also called articulationsTwo functions:

Hold bones togetherProvide mobility

Classification methods:Functional

Synarthrosis (immovable)Amphiarthroses (slightly movable)Diarthroses (freely movable)

StructuralFibrous (most are immovable)Cartilaginous (mostly amphiarthrotic)Synovial (freely movable)

JointsFibrous Joints

Sutures of the skullIrregular edges of the bones interlock; bound tightly

together by connective tissue fibersSyndesmoses: type of fibrous joint where the fibers

are longer allowing more give; found in the distal end of the tibia and fibula

Cartilaginous JointsBone ends connected by cartilageAmphiarthrotic examples: pubic symphysis and

intervertebral jointsSynarthrotic examples: the hyaline cartilage

epiphyseal plates of growing bones and the cartilaginous joints between the ribs and the sternum

JointsSynovial Joints

Articulating bone ends separated by a joint cavity containing synovial fluid

Four distinct features:1. Articular cartilage: covers the ends of the bones2. Fibrous articular capsule: Joint surface enclosed

by a capsule of fibrous connective tissue; lined with a smooth synovial membrane

3. Joint cavity: contains the synovial fluid4. Reinforcing ligaments: ligaments that reinforce

the fibrous capsuleBursa: flattened fibrous sacs filled with

synovial fluid; common where ligaments, muscles, skin, tendons, or bones rub together

Tendon sheath: an elongated bursa that wraps around a tendon subjected to friction

Types of Synovial Joints (Shape) Shape of joint determines the movements allowed

(Structure determines function) Plane (Gliding) Joint: essentially flat; nonaxial movement

Ex: intercarpal joints Hinge Joint: cylindrical end of one bone into a trough-

shaped surface of another; uniaxial movement – around one axisEx: elbow

Pivot Joint: rounded end of one bone fits into a sleeve or ring of bone; uniaxial movement – rotate around the long axisEx: Proximal radioulnar joint

Condyloid (Ellipsoidal) Joint: egg shaped end of one bone fits into an oval concavity of another; biaxial – side to side movement and back and forth movementEx: Metacarpophalangeal joints

Saddle Joint: each articular surface has both a convex and concave area; biaxialEx: Thumb

Ball-and-Socket Joint: Spherical head of one bone fits into a round socket of another; multiaxial – movements in all axes, including rotationEx: Shoulder

Inflammatory Disorders of JointsBursitis: swollen bursa due to injurySprains: ligaments or tendons damaged by

excessive stretching, or torn away from the bone; heal slowly because of lack of blood supply

Arthritis: joint inflammation; encompasses over 100 different inflammatory or degenerative diseasesAcute forms of arthritis: usually due to an

infectionChronic forms of arthritis: Osteoarthritis (OA),

Rheumatoid (RA), and Gouty arthritis

Chronic ArthritisOsteoarthritis (OA)

Most common formSoftening, fraying, and breakdown of

articular cartilageExposed bone thickens and extra bone tissue

(bone spurs) formSpurs may protrude into the joint space

limiting movementCommonly affects: fingers, cervical and

lumbar joints, knees and hipsSlow and irreversible progressionTreatment: analgesics, capsaicin (hot pepper

extract) rubbed on the skin, or glucosamine-chondroitin sulfate (nutritional supplement)

Chronic ArthritisRheumatoid arthritis (RA)

Chronic inflammatory disorder; more common in women

Commonly affects: fingers, wrists, ankles, and feet (usually symmetrical)

Marked by remissions and flare-upsAn autoimmune diseaseBegins with inflammation of the synovial membranes,

membranes thicken and joints swellWhite blood cells enter the joint cavity and produce

pannus (abnormal tissue that clings to and erodes articular cartilage)

Scar tissue forms and connects the bone ends; tissue eventually ossifies and fuse the joint (ankylosis)

Tx: Methotrexate and cyclosporin – drugs to neutralize the inflammatory chemicals; exercise is recommended for joint mobility; cold packs to relieve swelling; heat to reduce morning stiffness

Chronic ArthritisGouty Arthritis (Gout)

Uric acid accumulates in the blood and may be deposited (as needle-shaped crystals) in the soft tissues of joints

Very painful – usually only affecting one joint (most often the big toe)

More common in malesUntreated gout can be very destructive

(fusing the bone ends together)Tx: Colchicine, Ibuprofen; weight loss if

obese; avoid liver, kidneys, sardines, and alcohol

Developmental ConsiderationsFetal skeleton – cartilage; bones ossify after

birthFontanels allow for continued brain growth

Spinal curvature: starts as a “C” at birth and progresses to an “S” shape

Osteoporosis: bone thinning diseaseLinked to inactivity, poor diet, estrogen

deficiency, & smokingMay lease to pathologic fractures

(spontaneous breaks without injury)