Bone Classifications and Markings

long bone

at least twice as long as they are wide; common in the arms and legs

short bone

approximately cube shaped; common in the wrists and ankles

flat bone

flattened, thin appearance and will usually curve a bit; such as the sternum or cranium

irregular bone

odd shaped and don’t fit well in the other three categories; such as vertebrae and bones of the face

tuberosity

rough surface; helps with muscle and ligament attachment

trochanter

large prominence on one side of a bone; helps with muscle and ligament attachment

tubercle

Small, rounded process (extension of bone); helps with muscle and ligament attachment

epicondyle

A protuberance above a condyle (condyle is a rounded surface); helps with muscle and ligament attachment

spine

Sharp process (extension of bone); helps with muscle and ligament attachment

process

bony projection or outgrowth that extends from a larger bone; helps with muscle and ligament attachment

head

Projected, prominent rounded surface; help form joints

facet

Projected flat surface; help form joints

condyle

Projected rounded surface; help form joints

fissure

Slit through bone

foramen

Hole through bone

meatus

Opening into canal

sinus

Air-filled space in bone

fossa

shallow, elongated groove found on the surface of a bone

fontanelle

Soft spot in cranium

frontal sinus

ethmoidal sinus

sphenoidal sinus

maxillary sinus

posterior fontanelle

anterior fontanelle

sphenoid fontanelle

mastoid fontanelle

sesamoid bones

do not connect to (articulate with) other bones; such as the patella and hyoid

fovea

Small pit