Anatomy - ch. 5 skeletal system

skeleton

� "dried-up body"
� functions in body protection & motion.
� divided into: axial & appendicular skeleton

axial skeleton

� bones that form longitudinal axis of body.
� divided into 3 parts: skull, vertebral column, & bony thorax.

appendicular skeleton

� bones of limbs & girdles of the body (126).

skeletal system

bones, joints, cartilages, & ligaments of the body.

ligaments

fibrous cords that bind the bones together at joints.

joints

give the body flexibility & allow movement to occur.

functions of the bone

1.) support
2.) protection
3.) movement
4.) storage
5.) blood cell formation

support of bones

�"steel girders" & "reinforces concrete"
� Functions to:
- internal framework that supports the body.
- cradles soft organs.

protection of bones

� Functions to:
- protect soft body organs

movement of bones

� Functions to:
- skeletal muscles attached to bone by tendons use the bones as levers to move the body & its parts.

storage of bones

� Functions to:
- stores fat in internal cavities
- serves as a storehouse for minerals - Ca & P

blood cell formation

� Functions to:
- occurs within the marrow cavities of certain bones.

classification of bones

� adult - 206 bones
� 2 types of osseous (bone) tissue: compact & spongy bone.
� classified according to shape: long, short, irregular flat.

compact bone

type of bone that looks smooth & homogeneous

spongy bone

type of bone that is composed of small needlelike pieces of bone & lots of open space.

long bones

� type of bone that is typically longer than they are wide.
� have a shaft with heads at both ends.
� mostly compact bones
� all bones EXCEPT patella, wrist, & ankle bones.

short bones

� type of bone that is cube-shaped and contain mostly spongy bone.
� make up the wrist and ankle
� Ex: seasmoid bones &
patella

Seasmoid bones

� special type of short bone.
� form within tendon sheaths.

flat bones

� type of bone that is thin, flattened, & usually curved.
� have 2 thin layers of compact bone sandwiching a layer of spongy bone between them.
� Ex: skull, ribs, & sternum.

irregular bones

� type of bones that do not fit one of the other bone categories.
� Ex: vertebrae & hip bones.

diaphysis

� shaft
� structure that makes up most of the bone's length
� composed of compact bone.
� covered by the periosteum.

periosteum

fibrous connective tissue membrane that covers the diaphysis.

Sharpey's fibers (perfoated fibers)

� hundreds of connective tissue fibers
� secure the periosteum to the underlying bone.

epiphyses

� ends of the long bone.
� consists of a thin layer of compact bone enclosing an area filled with spongy bone.

articular cartilage

� covers the external surface of the bone.
� glassy hyaline cartilage that provides a smooth, slippery surface that decreases friction at joint surfaces.

epiphyseal line

� remnant of the epiphyseal plate.
� seen in a young, growing bone.

epiphyseal plate

� flat plate of hyaline cartilage.
� cause the lengthwise growth of a long bone.
� replaced by the epiphyseal line during at the end of puberty when hormones inhibit long bone growth.

medullary cavity

� In adults - cavity of the shaft is a storage area for yellow marrow.
� In infants - cavity forms blood cells & stores red marrow.

yellow marrow

adipose (fat) tissue that is stored in the medullary cavity.

red marrow

� In infants - marrow stored in medullary cavity.
� In adults - marrow confined to cavities in the spongy bone of flat bones & epiphyses of some long bones.

bone markings

� bumps, holes, and ridges on the bone.
� reveal where muscles, tendons, & ligaments were attached and where blood vessels and nerves passed.
� 2 categories: projections (T) & depressions (F).

projections (processes)

bone markings that grow out of the bone surface.

depressions (cavities)

bone markings which are indentations in bone.

osteocytes

� mature bone cells of compact bone
� found within lacunae

lacunae

� tiny cavities that house osteocytes in compact bone.
� arranged in lamellae around central Haversian canals.

lamellae

� concentric circles within the compact bone where lacunae are arranged.
� surround central Haversian canals.

central Haversian canals

� canals that house the blood vessels within compact bone.
� surrounded by lamellae.
� runs lengthwise through the bony matrix & carries blood vessels and nerves to all areas of the bone.

osteon (Haversian system)

complex consisting of central haversian canal and matrix rings within compact bone.

Canaliculi

� tiny canals within compact bone.
� radiate outward from the central canals to all lacunae.
� form a transportation system that connects all the bone cells to the nutrient supply through the hard bone matrix.

perforating (Volkmann's) canals

� communication pathway from the outside of the bone to its interior (and the central canals).
� run into the compact bone at right angles to the shaft.

bone

� hardest material in the body due to calcium salts deposited in matrix.
� light in weight.
� ability to resist tension, compression, & other forces acting on it.
� organic parts (collagen fibers) give flexibility & strength.
� dynamic & active tissue.

skeletal tissues

� cartilage & bone.
� In embyros - made of hyaline cartilage.
� In young child - most cartilage is replaced by bone.
� Cartilage only in isolated areas - bridge of nose, parts of ribs, & joints.

ossification

� bone formation.
� involves 2 major phases:
1.) hyaline cartilage model is covered with osteoblasts.
2.) enclosed hyaline cartilage model is digested away, opening up medullary cavity with newly formed bone.

osteoblasts

bone-forming cells that cover the bone matrix of the hyaline cartilage model.

appositional growth

� process by which bones increase in diameter.
- osteoblasts in periosteum add bone tissue to the external face of the diaphysis as osteoclasts in the endosteum remove bone from the inner face of the diaphysis wall. End during adolescence.

growth & sex hormones

hormones that control the process of long-bone growth.

Factors that influence bone remodeling

� factors:
1.) calcium levels in the blood.
2.) pull of gravity and muscles on the skeleton.

osteoclasts

� giant bone-destroying cells
� activated by PTH to break down bone matrix & release calcium ions into the blood when blood calcium levels drop below homeostatic levels.

hypercalcemia

high blood calcium levels.

bone remodeling

� essential if bones are to retain normal proportions & strength during long-bone growth as the body increases in size & weight.
� accounts for the fact that bones become thicker & form larger projections to increase their strength in areas where bulky mu

rickets

� disease of children in which bones fail to calcify.
� result - bones soften & weight-bearing bones of legs show definite bowing.
� due to lack of calcium in the diet or lack of vitamin D - needed to absorb calcium into bloodstream.

fractures

� breaks in bones
� result from trauma that twists or smashes the bones.
� occur more often in old age when bones are thin & weak.

closed (simple) fracture

fracture in which the bone breaks cleanly but does not penetrate the skin.

open (compounded) fracture

broken bone ends that penetrate through the skin.

comminuted fracture

� bone breaks into many fragments.
� common in older people with brittle bones.

compression fracture

� bone is crushed
� common in porous bones

depressed fracture

� broken bone portion is pressed inward.
� typical of skull fracture

impacted fracture

� broken bone ends are forced into each other
� commonly occurs when one attempts to break a fall with outstretched arms.

spiral fracture

� ragged break occurs when excessive twisting forces are applied to a bone.
� common sports fracture.

greenstick fracture

� bone breaks incompletely, much in the way a green twig breaks.
� common in children, whose bones are more flexible than those of adults.

reduction

� realignment of broken bone ends
� 2 types: closed & open reductions.
� immobilized by a cast or traction to allow healing to begin.
- 6-8 weeks but longer for large bones & older people.

closed reduction

bone ends are coaxed back into their normal position by the physician's hands.

open reduction

surgery is performed and bone ends are secured together with pins or wires.

4 major events of repairing bone fractures

1.) A hematoma forms.
2.) The break is splinted by a fibrocartilage callus.
3.) The bony callus forms.
4.) Bone remodeling occurs.

hematoma

blood-filled swelling when blood vessels are ruptured when the bone breaks.

fibrocartilage callus

mass of repair tissue that acts to "splint" the broken bone, closing the gap.

bony callus

spongy bone that replaces fibrocartilage callus when more osteoblasts & osteoclasts migrate into the area of bone damage.

skull

� formed by two sets of bones: cranium & facial bones.
� joins together bones by sutures

cranium

� bone of the skull that encloses & protects the fragile brain tissue.
� composed of 8 large flat bones - 2 paired bones (parietal & temporal bones)

facial bones

� bone of the skull that holds the eyes in an anterior position
� allow facial muscles to show emotion through smiles or frowns.
� composed of 14 bones - 12 paired & 2 are single (mandible & vomer).

sutures

interlocking, immovable joints that join together skull bones.

frontal bone

� bone of the cranium that forms the:
- forehead
- bony projections under the eyebrows
- superior part of each eye's orbit.

parietal bones

� paired bones that form the most superior & lateral walls of the cranium.
� bones meet at the sagittal suture & cornoal suture.

sagittal suture

midline of the skull that where the 2 parietal bones meet.

coronal suture

suture of the skull where the 2 parietal bones meet the frontal bone.

temporal bones

bones of the cranium that lie inferior to the parietal bones.

squamous sutures

suture that joins the temporal bones to parietal bones of the cranium.

external acoustic meatus

� bone marking on temporal bone.
� canal that leads to the eardrum & middle ear.
� route by which sound enters the ear.

styloid process

� bone marking on the temporal bone.
� sharp, needlelike projection inferior to the external auditory meatus.
� used by neck muscles as an attachment site.

zygomatic process

� bone marking on the temporal bone.
� thin bridge bone that joins with the cheek-bone (zygomatic bone) anteriorly.

mastoid process

� bone marking on the temporal bone.
� full air cavities
� rough projection posterior & inferior to the external acoustic meatus.
� provides attachment for some neck muscles.

mastoid sinuses

� cavities filled with air on the temporal bone.
� close to the middle ear.
� high risk for mastoditis

mastoditis

� condition in which the mastoid process of the temporal bone is infected.
� may spread to the brain due to its proximity.

jugular foramen

� bone marking of the temporal bone.
� junctions at the occipital & temporal bones.
� allows passage of jugular vein to drain the vein.

internal acoustic meatus

� bone marking of the temporal bone.\
� anterior to the jugular foramen.
� transmits cranial nerve VII & VIII.

carotid canal

� bone marking of the temporal bone.
� anterior to the jugular foramen on skull's inferior aspect.
� houses the internal carotid artery supplying blood to the brain.

occipital bone

� most posterior bone of the cranium.
� forms the floor & back wall of the skull.

lambdoid suture

suture that joins the occipital bone & the parietal bones anteriorly.

foramen magnum

� large opening on the base of the occipital bone.
� surrounds the lower part of the brain & allows the spinal cord to connect with the brain.

occipital condyles

� bone marking of the occipital bone that are lateral to each side of the foramen magnum
� rest on the first vertebra of the spinal column.

sphenoid bone

butterfly-shaped bone of the cranium that spans the width of the skull and forms part of the floor of the cranial cavity.

sella turcia (Turk's saddle)

� small depression in the midline of the sphenoid bone.
� forms a snug enclosure for the pituitary gland.

foramen ovale

� large oval opening of the sphenoid bone that lines with the posterior end of the sella turcica.
� allows fibers of cranial nerve V to pass the chewing muscles of the mandible.

optic canal

� openings of the sphenoid bone that can be seen exteriorly forming part of the eye orbits.
� allows the optic nerve to pas the eye.

superior orbital fissure

� slitlike opening of the sphenoid bone that can be seen exteriorly forming part of the eye orbits.
� bone marking that allows the cranial nerves controlling eye movements (III, IV, & VI) to pass through.

sphenoid sinuses

air cavities of the central part of the sphenoid bone.

ethmoid bone

� bone of the cranium that is irregularly shaped & lies anterior to the sphenoid bone.
� forms the roof of the nasal cavity & part of the medial walls of the orbits.

crista galli

� "cock's comb"
� projections of the superior surface of the ethmoid bone.
� attaches to the outermost covering of the brain.

cribiform plates

� small holey areas that are on each side of the crista galli of the ethmoid bone.
� allows nerve fibers carrying impulses from the olfactory receptors of the nose to reach the brain.

superior & middle nasal conchae

� extensions of the ethmoid bone.
� form part of the lateral walls of the nasal cavity.
� increase the turbulence of air flowing through the nasal passages.

maxillae (maxillary bones)

� facial bones that fuse to form the upper jaw.
� join all facial bones except the mandible.
� main (keystone) bones of the face.

alveolar margin

area of the maxillae that carries the upper teeth.

palatine processes

� extensions of the maxillae.
� form the anterior part of the hard palate of the mouth.

maxillary sinuses

paranasal sinuses that drain into the nasal passages.

paranasal sinuses

� sinuses that surround the nasal cavity.
� lightens the skull bones & amplifies the sounds of speech.
� can causes sinusitis.

sinusitis

� infections of the mucosa lining the sinuses continuous with that in the nasal passages & throat.

palatine bones

� facial bones that lie posterior to the palatine processes of the maxillae.
� form the posterior part of the hard palate.

cleft palate

failure of the palatine processes to fuse medially.

zygomatic bones

� facial bones that are commonly referred to as the cheekbones.
� form a good-sized portion of the later walls of the orbits or eye sockets.

lacrimal bones

� fingernail-sized facial bones forming part of the medial walls of each orbit.
� has a groove that serves as a passageway for tears.

nasal bones

small rectangular facial bones forming the bridge of the nose.

vomer bone

� single facial bone in the median line of the nasal cavity.
� forms most of the bony nasal septum.

inferior nasal conchae

thin, curved facial bones projecting medially from the lateral walls of the nasal cavity.

mandible

� largest & strongest facial bone that makes up the lower jaw.
� joins the temporal bones of each side of the face
� forms only freely moveable joints in the skull.

body of the mandible

� horizontal part of the mandible.
� forms the chin.

rami

� upright bars of bone that extend from the body to connect the mandible with the temporal bone.

alveoli

sockets within the mandible where the lower teeth lie.

alveolar margin

superior edge of the mandibular body where the lower teeth of the alevoli lie.

hyoid bone

� only bone of the body that does not articulate directly with any other bone.
� suspended in the midneck region above the larynx - anchored by ligaments to the styloid processes of the temporal bone.
� horse-shoe shaped body & 2 pairs of horns (cornua)

fetal skull

� skull as a whole is larger compared to an infant's total body length (1/4 long).
� has hyaline cartilage & fontanels that still remain to be ossified, converted to bone.

fontanels

� fibrous membranes that connect the cranial bones of the fetal skulls.
� "soft spot" - where baby's pulse can be felt.
� allow fetal skull to be compressed slightly during birth.
� flexible & allow the infant's brain to grow during the later part of preg

anterior fontanel

� largest fontanel of the fetal skull.
� diamond-shaped.

vertebral column (spine)

� serves as axial support of the body.
� extends from the skull - supports it - to the pelvis - transmits weight of the body to the lower limbs.
� formed from 26 irregular bones connected & reinforced by ligaments - flexible, curved structure.
� surrounds

vertebrae

� before birth - 33 bones that make up the spine, but 9 eventually fuse to form the 2 composite bones.

sacrum & coccyx

� two composite bones of the vertebrae formed by fusion of 9 bones.
� construct the inferior portion of the vertebral column.

cervical vertebrae

� 7 vertebral bones of the neck (C1-C7)
� C1-C2 - rotate head side to side to indicate "no"
� C3-C7 - smallest, lightest vertebrae
- transverse processes - contain foramina through which vertebral ateries pass on their way to the brain.

thoracic vertebrae

� 12 vertebral bones below the cervical vertebrae (T1-T12)
� typical, larger than cervical vertebrae & only vertebrae to articulate with the ribs.

lumbar vertebrae

� 5 vertebral bones supporting the lower back (L1-L5)
� sturdiest of the vertebrae.

intervertebral discs

� pads of flexible fibrocartilage that separate the individual vertebrae.
� cushion the vertebrae & absorb shocks while allowing the spine flexibility.
� young person - high water content, spongy & compressible but decreases with age - harder & less compr

herniated discs

� drying of discs + weakening of ligaments of the vertebral column.
� results when vertebral column is subjected to exceptional twisting forces.
� excruciating pain or numbness.

primary curvatures

C-shaped spinal curvatures in the thoracic & sacral regions when born.

secondary curvatures

� curvatures in the cervical & lumbar regions of the spine.
� center body weight on lower limbs with minimal effort.
� cervical curvature - appears when baby begins to rise head.
� lumbar curvature - develops when baby begins to walk.

abnormal spinal curvatures

� scoliosis, kyphosis, & lordosis (see fig.5.16)
� may be present at birth, result from disease, poor posture, or unequal pull of spine.

body (centrum)

disclike, weight-bearing part of the vertebra facing anteriorly in the vertebral column.

vertebral arch

� arch formed from the joining of all posterior extensions - laminae & pedicles - of the vertebra.

vertebral foramen

canal of the vertebra through which the spinal cord passes.

transverse processes

two lateral projections from the vertebral arch.

spinous processes

� single projection arising from the posterior aspect of the vertebral arch.
� actually fused with laminae.

superior & inferior articular processes

� paired projections lateral to the vertebral foramen
� allows a vertebra to form joints with adjacent vertebrae.

atlas

� C1 of the cervical vertebrae.
� has no body.
� superior surfaces of its transverse processes contain large depressions that receive the occipital condyles of the skull.
- joint allows to nod "yes

axis

� C2 of the cervical vertebrae.
� acts as a pivot for the rotation of the atlas above.
� has dens

dens

� large upright process of the axis
� acts as the pivot point

sacrum

� formed by the fusion of five vertebrae
� superiorly articulates with L5 & inferiorly connects with coccyx.
� forms posterior walls of the pelvis.

alae

� winglike bone marking of the sacrum that articulates laterally with the hip bones.
- forms the sacroiliac joints

median sacral crest

� roughened, posterior midline surface of the sacrum.
� fused spinous processes of the sacral vertebrae.
� flanked laterally by the posterior sacral foramina.

posterior sacral foramina

laterally flanks the median sacral crest.

sacral canal

canal inside the sacrum where the verteral canal continues through the sacral hiatus

sacral hiatus

large inferior opening of the sacrum where the vertebral canal exits.

coccyx

� formed from the fusion of 3-5 tiny, irregular shaped vertebrae.
� human "tailbone" - remnant of the tail that other vertebrate animals have.

bony thorax (thoracic cage)

� sternum, ribs, & thoracic vertebrae.
� forms protective, cone-shaped cage of slender bones around the organs of the thoracic cavity.

sternum

� breastbone - typical flat bone
� results from the fusion of 3 bones: manubrium, body & xiphoid process.
� attached to the first seven pairs of ribs.
� 3 important landmarks: julgar notch, sternal angle, & xiphisteral joint.

jugular notch

� concave upper border of the manubrium.
� generally at the level of the third thoracic vertebrae.

sternal angle

� results where the manubrium & body of the sternum meets at a slight angle to each other.
� forms tranverse ridge @ the level of the 2nd ribs.
� provides a handy reference point for counting ribs to locate the second intercoastal space for listening to c

xiphisternal joint

� point where the sternal body & xiphoid process fuse.
� lies at the level of the 9th thoracic vertebra.

sternal puncture

procedure in which a needle is inserted into the marrow of the sternum to draw a blood sample.

ribs

� 12 pairs of bones that form the walls of the bony thorax.
� articulate with the vertebral column posteriorly & curve downward & toward the anterior body surface.

true ribs

first 7 pairs of ribs that attach directly to the sternum by coastal cartilages.

false ribs

� next 5 pairs of ribs after the true ribs.
� either attach indirectly to the sternum or are not attached to the sternum at all.

floating ribs

last 2 pairs of false ribs that lack the sternal attachments.

shoulder girdle (pectoral girdle)

� girdle that is make of a clavicle & scapula.
� very light & allows the upper limb to have exceptionally free movement.

clavicle (collarbone)

� slender, doubly curved bone.
� attaches to the manubrium of the sternum medially & to the scapula laterally to form the shoulder joint.
� acts as a brace to hold the arm away from the top of the thorax.
� helps prevent shoulder dislocation.
� when broke

scapula (shoulder blades)

� triangular bone - "wings"
� flare when arms are move posteriorly.
� has flattened body & 2 important processes: acromion & coracoid.
� not directly attached to the axial skeleton - loosely held by trunk muscles.

acromion

� enlarged end of the spine of the scapula.
� connects with the clavicle laterally.

acromioclavicular joint

joint where the acromion & clavicle connect, laterally.

coracoid process

� process of the scapula that points over the top of the shoulder & anchors some muscles of the arm.

suprascapular notch

� medial to the coracoid process
� serves as a nerve passageway.

glenoid cavity

shallow socket of the scapula that receives the head of the arm bone, in the lateral angle.

factors that allow the shoulder girdle free movement

� Factors:
1.) Each shoulder girdle attaches to the axial skeleton at only one point.
2.) Loose attachment of the scapula allow it to slide back & forth against the thorax as muscles act.
3.) Glenoid cavity is shallow, & shoulder joint is poorly reinforce

humerus

� typical long bone of the arm.
� proximal end is a rounded head that fits into the shallow glenoid cavity of the scapula.

anatomical neck

slight constriction, inferior to the head of the humerus.

intertubercular sulcus

separates the greater & lesser tubercles of the humerus.

greater & lesser tubercles

� projections of the humerus, anterolateral to the head.
� separated by intertubercular sulcus.
� sites of muscle attachment.

surgical neck

� distal to the greater & lesser tubercles of the humerus.
� most frequently fractured part of the humerus.

deltoid tuberosity

� roughened midpoint area of the shaft of the humerus.
� attachment of large, fleshy deltoid muscle of the shoulder.

radial groove

� groove that runs obliquely down the posterior aspect of the shaft of the humerus.
� marks the course of the radial nerve - important nerve of the upper limb.

trochlea

� spool-like bone marking at the medial-distal end of the humerus.
� articulates with the bones of the forearm.

capitulum

� ball-like bone marking at the distal end of the humerus.
� articulates with the bones of the forearm.

coronoid fossa

� depression anteriorly above the trochlea of the humerus.
� flanked by medial & lateral epicondyles.

olecranon fossa

� depression on the posterior surface of the humerus.
� flanked by medial & lateral epicondyles.

medial & lateral epicondyles

bone marking of the humerus that allows the corresponding processes of the ulna to move freely when the elbow is bent & extended.

radius

� bone of the forearm
� in anatomical position - lateral bone, thumb side of the forearm.
� palm facing backward - crosses over & ends up medial to ulna.

radioulnar joints

small joints that articulate the radius & ulna, both proximally & distally.

interosseous membrane

flexible membrane that joins the radius & ulna along its entire length, & the tibia & fibula.

styloid process

process that can be found at distal ends of the radius & ulna.

radial tuberosity

� bone marking of the radius below the head.
� area where tendon of the biceps muscles attach.

ulna

� bone of the forearm.
� in anatomical position - medial bone, little finger side.

coronoid process

� anterior process on the proximal end of the ulna.
� grips the trochlea of the humerus in a pliers-like joint.

olecranon process

� posterior process on the proximal end of the ulna.
� grips the trochlea of the humerus in a pliers-like joint.

trochlear notch

bone marking that separates the coronoid & olecranon processes of the ulna.

carpal bones

� 8 bones of the hand
� arranged in 2 irregular rows of 4 bones each.
� form the carpus
� bound together by ligaments that restrict movements between them.

carpus

wrist of the hand made up of the carpal bones.

metacarpals

� bones that make up the palm of the hands.
� #1-5 from thumb side of hand toward the little finger.
� become obvious as "knuckles" when hand is in a fist.

phalanges

� 14 bones that make up the fingers of the hands and toes.
- 3 in each finger/toe (proximal, medial, distal)
except in thumb/great toe which as 2 (proximal & distal)

pelvic girdle

� girdle formed by 2 coxal bones (ossa coxae) aka hip bones
- bones are large & heavy.
- attached securely to the axial skeleton
- sockets receive the thigh bones

bony girdle

� bones of the saccrum, coccyx, & hip bones.
� protects the reproductive organs, urinary bladder, & part of the large intestines.

coxal bones (ossa coxae)

� also known as hip-bones
� fusion of 3 bones: ilium, ischium, & pubis.

ilium

� large, flaring bone that forms most of the hip bone.
� connects posteriorly with the sacrum.

sacroiliac joint

joint that connects the ilium posteriorly with the sacrum.

alae

winglike portions of the ilia that can be felt when hands are on hips.

iliac crest

� upper edge of an ala
� ends anteriorly in the anterior superior iliac spine & posteriorly in the posterior superior iliac spine.

ischium

� "sit-down" bone of the coxal bone.
� forms the most inferior part of the coxal bone.

ischial tuberosity

roughened area of the ischium that receives body weight when sitting.

ischial spine

� landmark of the ischium superior to the ischial tuberosity.
� particularly in pregnant women because it narrows the pelvis through which the baby must pass during the birth process.

greater sciatic notch

landmark of the ischium that allows blood vessels & large sciatic nerve to pass from the pelvis posteriorly into the thigh.

pubis (pubic bone)

most anterior part of the coxal bone

obturator foramen

� enclosed by the fushion of the rami of the pubis anteriorly & the ischium posteriorly.
� opening that allows blood vessels & nerves to pass into the anterior part of the thigh.

pubic symphysis

cartilaginous joint that fuses the pubic bones of each hip bone anteriorly.

acetabulum

� deep socket where the ilium, ischium, & pubis fuses.
� receives the head of the thigh bone.

false pelvis

� superior region to the true pelvis.
� area medial to the flaring portions of the ilia.

true pelvis

� surrounded by the bone & lies inferior to the flaring parts the ilia & pelvic brim.
� important in women because it must be large enough to allow the infant's head to pass during childbirth.
� outlet & inlet determine measurement by obstetrician.

outlet

inferior opening of the pelvis measured between the ischial spines.

inlet

superior opening between the right & left sides of the pelvic brim.

characteristics of a female pelvis

� inlet is larger & more circular.
� pelvis is shallower & bones are lighter & thinner.
� ilia flare more laterally.
� sacrum is shorter & less curved.
� ischial spines are shorter & further apart = outlet is larger.
� pubic arch is more rounded because t

femur (thigh bone)

� only bone in the thigh.
� heaviest, strongest bone in the bone.

greater & lesser trochanters

� landmark at the proximal end of the femur.
� separated anteriorly by the intertrochanteric line & posteriorly by the intertrochanteric crest.

intertrochanteric line

landmark on the femur that anteriorly separates the greater & lesser trochanters.

intertrochanteric crest

landmark on the femur that posteriorly separates the greater & lesser trochanters.

gluteal tuberosity

� located on the shaft of the femur.
� serves as sites for muscles attachment.

lateral & medial condyles

� landmark distally on the femur.
� articulate with the tibia below.

intercondylar fossa

landmark on the femur that posteriorly separates the lateral & medial condyles.

patellar surface

� smooth landmark anteriorly on the distal femur.
� forms a join with the patella.

tibia (shinbone)

larger & more medial bone of the leg.

intercondylar eminence

� landmark of the tibia that separates the medial & lateral condyles.
� articulate with the distal end of the femur to form the knee joint.

tibial tuberosity

� roughened area on the anterior tibial surface.
� attaches to the patellar ligament.

medial malleolus

distal process of the tibia that forms the inner bulge of the ankle.

anterior border

� sharp ridge on the anterior surface of the tibia.
� protected by muscles & felt easily beneath the skin.

fibula

� leg bone that lies alongside the tibia & forms joints with it both proximally & distally.
� thin & sticklick.
� has no part in forming the knee joint.

lateral malleolus

distal end of the fibula that forms the outer part of the ankle.

foot

� composed of tarsals, metatarsals, & phalanges.
� supports our body weight & serves as a lever that allows us to propel our bodies forward when we walk & run.
� has (medial, lateral) longitudinal & transverse arches.

tarsus

bone that forms the posterior half of the foot.

tarsal bones

� 7 bones that make up the tarsus.
� carry body weight

calcaneous (heel bone)

largest tarsals that carry mostly carry the body weight.

talus

� "ankle"
� bone that lies between the tibia & the calcaneus.

metatarsals

5 bones that form the sole of the foot.

joints (articulations)

� 2 functions:
1.) hold the bones together securely
2.) give the rigid skeleton mobility.

synarthroses

� immovable joints
� restricted mainly to the axial skeleton.

amphiarthroses

� slightly movable joints
� restricted mainly to the axial skeleton.

diarthroses

� freely movable joints
� predominate in the limbs where mobility is important.

fibrous joints

� type of immovable joints where bones are united by fibrous tissue.
� Ex: sutures of the skull.

syndesmoses

� type of fibrous joint that has more "give"
� has connecting fibers that are longer than those of sutures.
� Ex: joint connecting the distal ends of tibia & fibula.

cartilaginous joints

� type of joints where bone ends are connected by cartilage.
� Ex:
- pubic symphysis & intervertebral joints - amphiarthrotic.
- first ribs & sternum - synarthrotic.

synovial joints

� joints in which the articulating bone ends are separated by a joint cavity containing synovial fluid.
� account for all joints of the limbs.
� 4 distinguishing features:
1.) Articular cartilage.
2.) Fibrous articular capsule.
3.) Joint cavity
4.) Reinfo

articular cartilage

� feature of synovial joints.
� covers the ends of the bones forming the joints.

fibrous articular capsule

� feature of synovial joints
� sleeve or capsule of fibrous connective tissue that encloses the joint surfaces.
� lined with a smooth synovial membrane

joint cavity

� feature of synovial joints
� contains lubricating synovial fluid that is enclosed by the articular capsule.

reinforcing ligaments

� feature of synovial joints.
� fibrous capsule reinforced with ligaments.

bursae

� flattened fibrous sacs lined with synovial membrane.
� contains a thin film of synovial fluid.
� common where ligaments, muscles, skins, tendons, or bones rub together.

tendon sheath

an elongated bursa that wraps completely around a tendon subjected to friction.

dislocation

happens when a bone is forced out of its normal position in the joint cavity.

reduction

� process of returning the bone to its proper position.
� should be done only by a physician to prevent more harm.

plane joints

� shape of joint where articular surfaces are essentially flat & only short slipping or gliding movements are allowed.
� movement of joints are nonaxial.
� Ex: intercarpal joints of the wrist.

nonaxial

movement of joints where gliding does not involve rotation around any axis.

hinge joints

� shape of joint where the cylindrical ends of one bone fits into a trough-shaped surface on another bone.
� movement is uniaxial.
� Ex: elbow, ankle, & phalanges of fingers joints.

uniaxial

movement of joints that allow movement around one axis only.

pivot joints

� shape of joint where the rounded end of one bone fits into a sleeve or ring of bone.
� movement is uniaxial.
� Ex: proximal radioulnar joint & joint between the atlas & dens of the axis.

condyloid joints

� shape of joint where the egg-shaped articular surface of one bone fits into an oval concavity in another.
� movement is biaxial
� Ex: knuckle joints.

biaxial

movement of joint where the bone travels: 1.) from side to side & 2.) back & forth but the bone cannot rotate around its long axis.

saddle joints

� shape of joint where each articular surface has both convex & concave area.
� movement is biaxial.
� Ex: carpometacarpal joints in the thumb.

ball-and-socket joints

� shape of joint where the spherical head of one bone fits into a round socket.
� movement is multiaxial.
� Ex: shoulder & hips

multiaxial

movement of joints that allow movement in all axes, including rotation & are the most freely moving synovial joints.

bursitis

� inflammation of bursae or synovial membrane.
� ex: falling on knee - "water on the knee.

sprain

� ligaments or tendons reinforcing a joint are damaged by excessive stretching, or they are torn away from the bone.
� blood supply is poor so healing is slow & extremely painful.

arthritis

� describes over 100 different inflammatory or degenerative diseases that damage the joints.
� most widespread, crippling disease in the US.
� all forms have same initial symptoms: pain, stiffness, & swelling of the joint.

osteoarthritis (OA)

� most common type of arthritis of the fingers, cervical & lumbar joints of the spine, knees & hips - 85% of people in U.S.
� "wear-&-tear arthritis" - affects articular cartilages.
� cartilage softens, frays, & eventually breaks down.
� bone spurs form.

bone spurs

extra bone tissue of thickened exposed bone that grows around the margins of the eroded cartilage & restricts joint movement.

crepitus

crunching noise of affected stiff joints when moved.

Rheumatoid arthritis

� chronic inflammatory joint disorder between the ages of 40-50 women.
� affects fingers, wrists, ankles, & feet at the same time in a symmetrical manner.
� autoimmune disease - body's immune system attempts to destroy its own tissues.
� creates pannus &

pannus

abnormal tissue that clings to and erodes articular cartilages of thickened, inflammed synovial membrane.

ankylosis

fused & deformed ossified scar tissue & bone ends.

gouty arthritis

� disease in which uric acid accumulates in the blood & may be deposited as needle-shaped crystals in the soft tissues of joints.
� typically affects a single joint, often in great toe.
� bone ends fuse & joint becomes immobilized.

osteoporosis

� bone-thinning disease that afflicts half of woman over 65 & 20% of men over 70.
� makes bones so fragile that it is susceptible to fractures such as spine & neck of femur.
� results in kyphosis
� caused by estrogen deficiency.

kyphosis

� collapse of vertebral column.
� hunched over posture
� aka. dowager's hump.

pathologic fractures

� spontaneous breaks of bones without apparent injury.
� usually occur because older people do not do anything physical.