Download Appendicular Skeleton (con`t)

The Skeletal System
You will have a working knowledge of the
functions of the skeletal system
The Skeleton
• skeletal system
– bones, joints, cartilages & ligaments
• 2 divisions
– axial  longitudinal axis
– appendicular  limbs & girdles
Overview
• Functions
– support  internal framework; anchors
soft organs
– protection  soft body organs (brain,
vertebrae. rib cage)
– movement  skeletal muscles (tendons)
– storage  fat (internal cavities); Ca 2+ ;
blood & bones, hormones; P
– blood cell formation  = hematopoiesis
Classification
• compact
– dense, smooth & homogeneous
• spongy
– small needle-like pieces; open spaces
• long
– longer than wide; shaft w/ heads @ both ends; mostly
compact; limbs EXCEPT wrist & ankle
• short
– cube-shape & spongy; sesamoid (form w/in tendons)
• flat
– thin, flat, curved; “sandwich” CSC; skull, ribs, sternum
• irregular
– don’t fit any category; vertebrae & hip
Structure of a Long Bone
• Gross Anatomy
– diaphysis (shaft); length; compact; covered by
periosteum =double layered CT that covers &
nourishes the bone (Sharpey’s fibers secure
periosteum to bone)
– epiphyses =ends of long bone; thin layer of
compact enclosing area w/ spongy
– articular cartilage (instead of perisoteum) covers
ext surface; glassy hyaline, smooth  friction
– epiphyseal line (remnant) & epiphyseal plate
(hyaline cartilage) in growing bones; plates cause
bone to lengthen; stops @ puberty (plates replaced
by bone lines left)
Structure of a Long Bone
(con’t)
• Gross Anatomy (con’t)
– shaft  stores fat; yellow marrow (medullary cavity);
infants forms bc’s & red marrow; adults red marrow in
cavities of spongy bone
– bone markings (uneven surface) where tendons,
muscles & ligaments were attached
– 2 categories
• 1. projections (processes) grow out
from bone surface (T)
• 2. depressions (cavities) indentations
in the bone (F) except facet
Bone Markings
• projections (muscular & ligament attachment)
– tuberosity
-- tubercle
– crest
-- epicondyle
– trochanter
-- spine
– line
-- process
• projections (form joints)
– head
-- condyle
– facet
-- ramus
• depressions & openings (passage of BV & nerves)
– meatus
– sinus
– fossa
– groove
– fissure
– foramen
Microscopic Anatomy
• structure
– nerves, bv’s  nutrients & passageway for waste
removal
– osteocytes = mature bone cell
– lacunae = depression/space in bone
– lamallae =lacunae arr in concentric
circles (Haversian)
– central (Haversian) canals consist of
– osteon (Haversian system) =system
of interconnected canals
Microscopic Anatomy (con’t)
• structure (con’t)
– canaliculi =small tube or canal that radiates
outward from central canal to all lacunae
– form a t-port system  bone cells to nutrient
source of hard bone matrix
– perforating (Volkmann’s) canals 
run into compact bone @ right angles
to the shaft
Bone Formation, Growth & Remodeling
• made of
– cartilage & bone (adult)
– bones replace cartilage
• ossification
– =bone formation
– 1. hyaline cartilage covered w/ bone matrix by
osteoblasts (=bone forming cells)
– 2. hyaline cartilage digested  medullary cavity
– EXCEPT 2 regions: articular cartilage (AC) (bone
ends) & epiphyseal plates (longitudinal growth)
– new  continuously formed on external face of AC
– old  touching internal face of AC & medullary
cavity is broken  replaced by bony matrix
Bone Growth & Formation (con’t)
• widen as they lengthen
– osteoblasts (periosteum) add bone tissue to
external face of diaphysis
– osteoclasts in endosteum remove bone
from inner face of diaphysis wall
• appositional growth
– bones  diameter
• growth hormone/sex hormone
– long bone growth controlled by hormones
– epiphyseal plate converted to bone
Bone Growth & Formation (con’t)
• dynamic
– responds to s
• 1. Ca levels in blood
– LOW: parathyroid glands release PTH  stimulates
osteoclasts (bone destroying cells) to break  matrix&
release Ca ions into blood
– HIGH: (hypercacemia) Ca deposited in matrix as
hard, Ca salts
• 2. pull of gravity on muscles on skeleton
Bone Remodeling
• essential
– retain normalcy (proportions & strength)
– thicken & forms large projections  strength
for muscular attachments
– osteoblasts provide new matrix  trapped
 osteocytes
– atrophy (=loss of mass)
– PTH determines IF/WHEN bone is broken 
OR needs more/fewer Ca ions in blood
– stresses determine WHERE matrix is
broken /formed
Bone Fractures
• fractures
– closed (simple)  clean break, no penetration
– open (compound)  break penetrates through
skin
– reduction  realignment of broken ends
• closed: bone ends coaxed into normal position
• open: surgery requiring pins &/or wires  cast
–
–
–
–
–
–
comminuted  breaks into fragments
compression  bone is crushed
depressed  broken portion pressed inward
impacted  broken ends forced into each other
spiral  twisting forces
greenstick  incomplete break
Bone Repair
1. hematoma formation
–
bv rupture  hematoma forms
2. fibrocartilage callus formation
–
–
–
fibrocartilage callus acts a bridge
new capillary growth into hematoma AND
phagocytes dispose of dead tissue form callus
callus—cartilage or bony matrix, collagen fibers
3. bony callus formation
–
ostebolasts & osteoclasts move into area,
fibrocartilage replaced by callus (spongy bone)
4. bone remodeling
–
callus remolded in response to mechanical
stresses, forming a patch at fracture site
Axial Skeleton
• axial (80 bones)
– longitudinal axis
– 3 parts:
• 1. skull
• 2. vertebral column
• 3. bony thorax
Axial Skeleton
• skull  cranium
– 8 large, flat bones
– all single bones EXCEPT
parietal & temporal (paired)
– frontal bone (forehead)
• bony projections under eyebrows
• superior part of eye’s orbit
Axial Skeleton
• skull  cranium
• parietal bone paired bones  superior &
lateral walls of cranium; meet in midline @
sagittal suture and form coronal suture
(frontal bone)
• temporal bones  inferior to parietal ; join @
squamous sutures
• bone markings
–
–
–
–
external auditory meatus (ear canal)
styloid process (muscle attachment)
zygomatic process bridge  cheekbone
mastoid process (mastoid sinuses;
muscular attachment)
– jugular foramen (passage of jugular vein)
– carotid canal (internal carotid artery blood)
Axial Skeleton (con’t)
• skull  cranium
– occipital
•
•
•
•
•
most posterior bone
forms floor & back wall of skull
join parietal @ lambdoid suture
foramen magnum  spinal cord to connect w/ brain
occipital condyles (lateral); rest on 1st vertebra
Axial Skeleton (con’t)
• skull  cranium (con’t)
– sphenoid
•
•
•
•
butterfly shape; width of skull
floor of cranial cavity
small depression (sella turcica) holds pituitary gland
foramen ovale (fibers of cranial nerve V
to pass to chewing muscles)
• sphenoid sinuses
– ethmoid
• irregular; anterior to sphenoid
• roof of nasal cavity & part of medial
orbital walls
• crista galli  projection (superior)
– (outermost brain attaches here)
• cribriform plates  nerve fibers
(olfactory receptors to reach brain)
Axial Skeleton (con’t)
• paranasal sinuses
Axial Skeleton (con’t)
• skull  facial bones
– maxillae  upper jaw; all facial bones join
 palatine processes (hard palate)
 paranasal sinuses
– palatine  posterior to palatine bones; form posterior hard
palate (lack of = cleft palate)
–
–
–
–
–
–
zygomatic  cheekbones; later walls of orbits
lacrimal  medial walls of each orbit; groove
nasal  rectangular bones form bridge of nose
vomer  single bone; medial line of nasal cavity septum
inferior conchae  thin, curved bones, lat walls (nasal)
mandible  lower jaw, joins temporal bones; freely movable;
horizontal (chin) upright rami (connect w/ temporal) alveoli (sockets)
– hyoid  not part of skull; no articulations; base for tongue;
attachment for muscles (talk & swallow)
Axial Skeleton (con’t)
• fetal skull
– face small compared to cranium
– skull is large compared to body length
– hyaline cartilage not ossified
• regions
•
•
•
•
•
fibrous membranes connecting bone =fontanels
soft spots
anterior fontanel (diamond shape)
posterior fontanel (triangular shape; small)
allows compression during birth
Axial Skeleton (con’t)
• vertebral column (spine)
– extends from skull to pelvis
– 26 irregular bones
– ligaments create a flexible, curved
structure
– 33 vertebrae separated by
intervertrebral discs (fibrocartilage)
• 9 form sacrum (5) & coccyx (4)
Axial Skeleton (con’t)
• vertebrae
–
–
–
–
body (centrum)  disclike, bears weight
vertebral arch  formed laminae & pedicles form body
vertebral foramen  canal where spinal cord passes
transverse processes  2 lat projections from vertebral
arch
– spinous process  single projection
from posterior of
vertebral arch
– superior & inferior
articular processes  paired; lateral
to vertebral
foramen;
vertebra form
joints w/
adjacent
vertebrae
Axial Skeleton (con’t)
• cervical vertebrae
–
–
–
–
C1-C7
1st & 2nd = atlas C1 (no body) & axis C2 (pivot)
C2 odontoid process (dens) pivot point
C3 C7 smallest & lightest
Axial Skeleton (con’t)
• thoracic vertebrae
– T1-T12
– larger than cervical
– heart-shaped w/ 2 articulating surfaces on either
side
• receive rib heads
• lumbar
– L1-L5
– blocklike; sturdiest
Axial Skeleton (con’t)
• sacrum
–
–
–
–
–
–
–
5 fused vertebrae
superiorly articulates w/ L5
alae articulate w/ hip bones  sacroiliac joints
forms posterior wall of pelvis
median sacral crest
dorsal sacral foramina
sacral canal
• coccyx
– fusion of 3-5 irregular vertebrae
– tailbone
Axial Skeleton (con’t)
• bony thorax
– sternum, ribs, thoracic vertebrae
– “thoracic cage”
• sternum (breastbone)
–
–
–
–
flat bone; attached to 1st 7 ribs
fusion of manubrium, body, xiphoid process
jugular notch (upper manubrium)
sternal angle (manubrium & body
meet
– xiphisternal joint (sternal body &
xiphoid process fuse)
• ribs (12 pair)  spaces intercostal muscles
– true (pair 1-7) attach directly to sternum
by costal cartilage
– false (pair 8-12) attach indirectly or NO
attachment (pair 11-12) floating ribs
Appendicular Skeleton
• appendicular skeleton
– 126 bones
– limbs, pectoral and pelvic girdles (attach
limbs to axial skeleton)
• shoulder (pectoral) girdle
– 2 bones
– clavicle & scapula
Appendicular Skeleton
• clavicle
– collarbone
– 2-curved bone
– attaches to manubrium @ medial end &
scapula laterally  shoulder joint
– holds arm away from thorax; prevents
dislocation
Appendicular Skeleton
• scapulae
– shoulder blade
– triangular; wing-like
– flattened body w/ 2 processes:
• 1. acromion  connects clavicle laterally @
acromioclavicular joint
• 2. coracoid  anchors some muscles of arm
• glenoid cavity
shallow socket
that receives head
of arm bone
Appendicular Skeleton (con’t)
• shoulder (con’t)
– free moving
• 1. sternoclavicular joint  only point where
shoulder girdle attaches to axial skeleton
• 2. loose attachment of scapula  mvmt back &
forth against thorax (muscular)
• 3. shallow glenoid cavity  poorly reinforced
ligaments  flexible but easily dislocated!
Appendicular Skeleton (con’t)
• bones of upper limbs
– 30 separate bones/limb
– arm, forearm, hand
• humerus
– long bone
– proximal  head  glenoid cavity
– greater & lesser tubercles (muscle
attachment)
– deltoid tuberosity (deltoid muscle)
– radial groove (groove for radial nerve)
– distal  trochlea & capitulum (forearm)
 coronoid fossa & olecranon fossa
(ulna  elbow flexes)
ant
post
Appendicular Skeleton (con’t)
• forearm
– 2 bones
• radius (anatomically/supine)
– lateral  thumb side
– proximally & distally  radioulnar joints
& connected by interosseous membrane
– head forms w/ capitulum (humerus)
– radial tuberosity (biceps attach)
• ulna
– medial  little finger side
– proximal  (a) coronoid process &
(p) olecranon process sep by
trochlear notch
 processes grip trochlea
• radius & ulna (pronate)
– distal radius  medial to ulna
Appendicular Skeleton (con’t)
• hand
– carpals, metacarpals, phalanges
• carpal bones
– 8 irregular bones in 2 rows
carpus (wrist)  ligaments
• metacarpals
– palm
– 1 (thumb) to 5 (pinky)
– fist  knuckles
• phalanges
– fingers
– 14: 3 proximal, mid & distal
(thumb only prox & dist)
Appendicular Skeleton (con’t)
• pelvic girdle
– 2 coxal bones {ossa coxae  hip bones} and
sacrum and coccyx  form bony pelvis
• bones
– large, heavy  attached to axial skeleton
– sockets  rec femur  deep & heavy ligaments
– function: ! bearing weight, protects repro organs &
bladder
Appendicular Skeleton (con’t)
• 3 bones
– ilium, ischium, pubis
• 1. ilium
– connects posteriorily w/ sacrum @ sacroiliac joint 
large flaring bone  forms most of hip bone
– alae are winglike portions  upper edge  iliac crest
– ends anterior and posterior superior spine
Appendicular Skeleton (con’t)
• 2. ischium
–
–
–
–
–
“sitdown bone”
inferior part of coxal bone
ischial tuberosity  rec’s weight when sitting
ischial spine narrows outlet for pregnant women
greater sciatic notch allows bv’s & sciatic to pass
from post. pelvis into thigh
Appendicular Skeleton (con’t)
• acetabulum
– fusion of ilium, ischium & pubis
– rec’s head of femur
• bony pelvis 2 regions
– false pelvis (greater)
• superior to true pelvis
• medial to flares of ilia &
pelvic brim
– true pelvis (lesser)
• surrounded by bone
• female different than male
Appendicular Skeleton (con’t)
• 3. pubis
– most anterior part of coxal bone
– fusion of rami (pubic) anteriorly & ischium
posteriorly forms a “bar of bone” enclosing the
obturator = opening allows bv & nerves to pass
into anterior thigh
– pubic bones (each hip) fuse anteriorly  pubic
symphisis (= cartilaginous joint)
Appendicular Skeleton (con’t)
• female pelvis
–
–
–
–
–
larger & more circular
shallower& bones; bones lighter & thinner
ilia flare more (laterally)
sacrum is shorter & less curved
ischial spines are shorter & further
apart  outlet larger
– pubic arch more rounded
b/c angle of pubic arch
is greater > 100°
Appendicular Skeleton (con’t)
• bones of lower limb
– carry total body weight
– 3 segments
• 1. thigh (femur)
– heaviest, strongest bone
– proximal  ball-like head,
neck, greater & lesser trochanters
sep (a) by intertrochanteric line
(p) by intertrochanteric crest
– gluteal tuberosity, trochanters,
& intertrochanteric crest  muscle attachment
– head articulates w/ acetabulum
– slants medially (knees align w/ center of gravity) females
different (wider pelvis)
– distal  lateral & medial condyles articulate w/ tibia; sep by
intercondylar notch; (a) patellar surface
Appendicular Skeleton (con’t)
• 2. leg (tibia & fibula)
– tibia (shinbone)  larger, more
medial
– proximal medial & lateral condyles
(sep by intercondylar eminence)
articulates w/ distal femurknee joint
– patellar ligament attaches to tibial
tuberosity (a) & (p) medial malleolus
(process)  bulge of ankle
– anterior  sharp ridge anterior crest
– fibula  forms joints (p & d); thin & sticklike
– does NOT form knee joint
– distal  lateral malleolus (outer ankle)
Appendicular Skeleton (con’t)
• 3. foot
– tarsals, metatarsals, phalnanges
– functions:
• 1. supports body weight
• 2. lever that propels body (walk/run)
– tarsus  posterior half
• 7 tarsal bones; 2 largest:
– 1. calcaneus (heelbone)
– 2. talus (ankle)  bet calcaneus &
tibia
– metatarsals
• 5  form sole of foot
– phalanges
• 14 (like hand, big toe only has 2)
Appendicular Skeleton (con’t)
• 3. foot (con’t)
– arranged  3 strong arches: longitudinal (medial &
lateral) transverse
– ligaments (bond foot bones together) and
tendons (muscle to bone)
Skeletal System
• joints
– sites where 2 bones meet
– articulations
– vary in structure
– classified acc’d to amt of mvmt allowed by
joint
• 1. structurally
• 2. functionally
– types
• 1. synathroses
• amphiarthroses
• diarthroses
Joints
• functional types
– 1. synarthroses (immovable)
• no active mvmt
• occur bet bones that are in close contact w/ one
another
• bones @ such joints are sep by a thin layer of
fibrous CT
• e.g. cranial bones (sutures)
Joints
• functional types (con’t)
– 2. amphiarthroses (slightly)
• fibrocartilage disks or ligaments
• e.g. vertebrae covered by hyaline cartilage
– 3. diarthroses (freely)
• most joints
• more complex structures
• ends covered w. hyaline cartilage & held
together by tubelike capsule fo dense fibrous
tissue
• flexibility varies
Joints
• structural types
– 1. fibrous
• fibrous tissue
• sutures
• syndesmoses connecting fibers are longer
than those of sutures BUT joint has more ‘give’
• e.g. ends of tibia & fibula
Joints (con’t)
• structural types
– 2. cartilaginous
• bone ends are connected by cartilage
• amphiarthrotic
• e.g. pubis symphysis, intevertebral joints of spine
– 3. synovial
• sep by joint cavity w/ synovial fluid
• 4 features
– 1. articular cartilage (hyaline)  covers bone ends
– 2. fibrous articular capsule  fibrous CT, capsule
lined w/ synovial membrane
– 3. joint cavity  articular capsule encloses cavity
containing synovial fluid
– 4. reinforcing ligaments  fibrous capsule reinforced
w/ ligaments
Joints (con’t)
• structural types
– 3. synovial
• associations
– bursae  flat, fibrous sacs lined w/ synovial
membrane & filled w/ synovial fluid; ligaments,
muscles, skin tendons or bones rub togehter
– tendon sheaths  elongated bursa; wraps
around a tendon that’s subjected to friction
Synovial Joint Types
• types
– multi-axial
• allow mvmts in all axes; including rotation; most
free moving synovial joints
– non-axial
• = gliding does not involve rotation around any
axis
– uni-axial
• = allow mvmt around 1 axis only
– bi-axial
• = mvmt around 2 axes
Synovial Joint Types
• hinge
– convex end (cylindrical) of 1 bone articulates w/ concave end
of another
– uniaxial
– ex: elbow joint, ankle joint, & joints bet phalanges of fingers
• pivot
– cylindrical surface of 1 bone fits into ring or sleeve of bone (&
fibrous tissue & ligaments)
– rotating bone turns around long axis
– uniaxial
– prx ends of tibia & fibula & ulna & radius
• ball-and-socket joint
– ball shaped head of 1 bone articulates
w/ cup shaped socket of another
– multiaxial
– ex: shoulder & hip
• condyloid joint
– oval shaped articular condyle of 1 bone articulates
w/ oval cavity of another
– bone moves 1. side to side 2. back & forth, but NO axis
– biaxial
– ex: knuckle  metacarpophalangeal joint
• plane (gliding)
–
–
–
–
art. surfaces are flat
slipping, gliding mvmts allowed
nonaxial
ex: bones of wrist & ankle
• saddle joints
– each articular surface (concave & convex);
surface of 1 fits into another
– biaxial
– ex: thumb  carpometacarpal joint
Joint Disorders
• arthritis
•
•
•
•
inflamed, swollen & painful joints
different types but same symptoms
acute = bacterial invasion; treated w/ antibiotics
chronic
– 1. rheumatoid
– 2. osteoarthritis
– 3. gout
Joint disorders
• 1. rheumatoid arthritis
– most painful & crippling
– synovial membrane of FMJ becomes inflamed,
grows thicker
–  by damaged of articular cartilage on ends of
bones & invasion of joint by fibrous CT
–  interferes w/ mvmt  tissue ossifies where
bones fuse together
– auto immune = body’s own immune system
destroys its own tissues
Joint disorders
• 2. osteoarthritis
– degenerative
– result of aging (most are 60+ years); athletes
– art cartilage softens & disintegrates gradually 
surfaces become roughened  joints sore & less
mvmt is possible
– OA most likely to affect joints that have rec’d
greatest amt of use over years  knees, vertebral
column (lower)
– “wear & tear”
Joint disorders
• 3. gout
– produces uric acid (normal waste product)
 accumulates in blood & deposited as
crystals in soft tissues  esp. feet
– untreated: bones fuse together & joint
becomes immobilized
– factors: undue stress, overweight,
excessive alcohol intake