Anatomy - Unit 7 (Skeletal and Arthrology)

what are the two divisions of the skeletal system

axial and appendicular

axial skeleton

head, vertebral column, bony thorax, hyoid bone

appendicular skeleton

lower and upper extremities, pelvis

what are the classifications of bones

long, short, flat, irregular, and sesamoid

long bones

bones with a long axis

long bone examples

humerus, radius, ulna, metacarpals, phalanges, femur, tibia, fibula, metatarsals

short bones

bones without a long axis

short bone examples

carpals and tarsals

flat bones

bones with a relatively flat surface

flat bones examples

ribs, sternum, scapula, clavicles, skull cap

irregular bones

oddly shaped bones not listed in other classes

irregular bone examples

vertebra, facial bones, skull bones

sesamoid bones

bones that do not articulate with other bones and serve no function relating to movement, "floating bones"

what is the main function of sesamoid bones

protection

sesamoid bone examples

patella and foot

what are all the bony projections/processes found on bones

condyle, head, trochanter, tuberosity, tubercle, spine, and crest

condyle

round projection that forms an articular surface

condyle examples

humeral, femoral, and mandibular condyles

head

round projection that extends from a constricted neck, forms an articular surface

head examples

femoral and humeral head

trochanter

very large projection for tendon attachment

trochanter examples

proximal femur

tuberosity

medium sized projection for tendon attachment

tuberosity examples

proximal humerus and radius

tubercle

small projection for tendon attachment

tubercle examples

proximal humerus and vertebral ends of ribs

spine

sharp projection

spine examples

pelvis (ilium) and posterior scapula

crest

ridge or edge running the length of the bone

crest examples

pelvis (ilium) and posterior scapula

what are the depressions or openings on or within a bone

fossa, fissure, sulcus, foramen, sinus, meatus

fossa

furrow or hollow area

fossa examples

distal femur and lateral scapula

fissure

narrow but deep slit like opening

fissure examples

orbital fissures in the eye socket

sulcus

aka groove

sulcus examples

proximal humerus, inside surface of ribs

foramen

round opening in bone for blood vessels and nerves

foramen examples

obturator foramen in pelvis and optic foramen in eye socket

sinus

air filled cavity in bones

sinus examples

cranial sinuses

meatus

opening into a canal

meatus examples

external auditory meatus (ear canal)

sectional structures of a bone

periosteum, cortical bone, cancellous bone, endosteum, medullary cavity, articular cartilage, red bone marrow and yellow bone marrow

periosteum

thin but dense outer covering of bones, not present at articular surfaces of long bones

cortical (compact) bone

thick, dense layer under the periosteum, provides the strength and support of bones

cancellous (trabecular or spongy) bone

very porous portion at end of long bones and in flat bones, contains red bone marrow

Trabeculae

refers to the web like structure of cancellous "spongy" bone (NOT COMPACT BONE)

is trabeculae visible radiographically?

yes

is trabeculae more evident at the end of long bones or in the shafts?

end of long bones

is bony trabeculae more evident with higher contrast images?

yes

why is bony trabeculae more evident on extremities than other bones?

because more surrounding soft tissue obscures bony detail

endosteum

trabecular membrane that lines the medullary cavity inside of compact bone, same structure as spongy bone

medullary cavity

central shaft of long bones, contains yellow bone marrow

articular cartilage

cartilage that covers the articular surface in long bones

bone marrow (yellow)

fat reservoir in the medullary cavities of long bones

bone marrow (red)

located on the cancellous (spongy) portion of long and flat bones where red blood cells are produced

do infants have any yellow marrow

no

___________ slowly turns into yellow marrow during childhood and adolescence

red marrow

adults have _______ red to yellow marrow

50/50

elderly have very little ________

red marrow

macroscopic anatomy of bone based on its development

diaphysis, epiphysis, epiphyseal plate, and metaphysis

diaphysis

shaft of long bones, primary center of ossification (first portion of bone to develop as a fetus

epiphysis

ends of long bones, secondary center for ossification (develops later in childhood)

epiphyseal plate

growth plate, between diaphysis and epiphysis, slowly narrows as bones mature and grow

metaphysis

wider portion of long bone where diaphysis transitions into epiphyseal plate

microscopic anatomy of a bone

osteons, haversian canal, osteocytes, osteoclasts, and osteoblasts

osteons

concentric rings of microscopic bone consisting of bone cells and protein fibers

osteons give ______________ its strength and rigidity

cortical bone

the center of each osteon is a:

haversian canal

blood cells are found within the haversian canals to deliver __________ to the bone tissue

nutrients

osteocytes

star shaped bone cells that are bound together by protein fibers collagen

____________ are more densely packed in compact bone than in spongy bone

osteocytes

osteoclasts

specialized bone cells that dissolve osteocytes and collagen as bone growth occurs

in other words, osteoclasts ___ bone

eat

osteoblasts

specialized bone cells that become osteocytes during bone repair or bone growth

in other words, osteoblasts _______ bone

build

osteoblasts are located in the

periosteum and endosteum

osteoblasts migrate to ________ to create new bone

osteon

ossification

process of bone forming from cartilage

two types of ossification

intramembranous and endochondral

intramembranous ossification

process of bone replacing cartilage in flat bones

example of intramembranous ossification

fusion of skull bones

endochondral ossification

process of bone replacing cartilage at the epiphyseal plate of long bones

bone remodeling

refers to the normal process of bone recycling itself

the entire adult skeleton is is replaced through remodeling every _ years

3