Human Osteology - Osteological Terminology

coronal plane

divides the body into front and rear portions

sagittal plane

divides the body into right and left portions

transverse plane

any horizontal plane that divides the body into top and bottom portions

medial

a directional term meaning "towards the middle"; refers to the portion of a bone closer to the right-left center of the body

lateral

a directional term meaning "towards the sides"; refers to the portion of a bone farther from the midline of the body

superior

a directional term meaning "towards the top of the body" (in standard anatomical position)

inferior

a directional term meaning "towards the bottom of the body" (in standard anatomical position)

anterior

a directional term meaning "towards the front of the body" (in standard anatomical position)

posterior

a directional term meaning "towards the back of the body" (in standard anatomical position)

proximal

a directional term meaning "closer" and referring to that portion of a bone closer to the vertebral column

distal

a directional term meaning "farther away" and referring to that portion of a bone farther from the vertebral column

external

a directional term meaning "outer", the opposite of internal

internal

a directional term meaning "inner", the opposite of internal

ectocranial

a directional term meaning "inner", the opposite of internal

endocranial

a directional term meaning "inner", the opposite of internal

palmar

a directional term for the hand meaning "towards the palm"

plantar

a directional term for the hand meaning "towards the sole" (of the foot)

dorsal

a directional term meaning "towards the back"

axial

bones of the trunk; includes the vertebrae, sacrum, ribs, and sternum

appendicular

bones of the trunk; includes the vertebrae, sacrum, ribs, and sternum

cranial

bones of the skull; includes the mandible

cranium vs. skull

includes the mandible vs. doesn't include the mandible

postcranial

all bones in the skeleton except those of the cranium and mandible

long bones

limbs, metacarpals, metatarsals, phalanges

diaphysis

shaft of a long bone

epiphysis

the cap at the end of a long bone that develops from a secondary ossification center

short bones

carpals and tarsals

flat bones

cranial bones, ribs, sternum, scapula

irregular bones

vertebrae, sacrum

sesamoid bones

patella

flexion

a bending movement that decreases the angle between body parts

extension

a straightening movement that increases the angle between body parts

abduction

the movement of a body part, usually a limb, away from the sagittal plane

adduction

the movement of a body part, usually a limb, toward the sagittal plane

pronation

a rotary motion of the forearm that turns the palm from anteriorly facing to posteriorly facing; the thumb is medial

supination

a rotary motion of the forearm that turns the palm from posteriorly facing to anteriorly facing; the thumb is lateral

individual variation

variation between individuals; no two people are exactly alike

sexual dimorphism

variation due to the sex of an individual

ontogenetic variation

variation due to growth from a fetus to an adult

population level variation

variation due to geography or population (racial)

pathology

variation due to geography or population (racial)

articulation

a place where two anatomically adjacent bones contact

facet

a small articular surface

condyle

a rounded articular process

epicondyle

a nonarticular projection adjacent to a condyle; medial and lateral to the distal end of the humerus

head

a large, spherical, usually articular end of a bone

neck

a constricted anatomical feature between the head and shaft of long bones

process

a bony prominence; mastoid process

eminence

a bony projection; usually not as prominent as a process

spine

generally a longer, thinner, sharper process than an eminence; mental spine of the mandible

tuberosity

a large, usually roughened eminence of variable shape; often a site of tendon or ligament attachment

tubercle

a small, usually roughened eminence; often a site of tendon or ligament attachment

trochanter

one of to large, prominent, blunt, roughened processes found only on the femur

malleolus

a rounded protuberance adjacent to the ankle joint

boss

a smooth, round, broad eminence

torus

a bony thickening

ridge

a linear bony elevation, often roughened

crest

a prominent, usually sharp and thin ridge of bone; often formed between adjacent muscle masses

line

a raised linear surface, not as thick as a torus or as sharp as a crest

hamulus

a hook-shaped projection

fossa

a depressed area, usually broad and shallow

fovea

a pit-like, depressed area, usually smaller than a fossa

groove

a long pit or furrow

sulcus

a long, wide groove

foramen

an opening through a bone, usually a passage for blood vessels and nerves

canal

a tunnel-like passage, usually extending from a foramen

meatus

a short, wide canal

sinus

a void chamber in the cranial bones that enlarges with the growth of the face

alveolus

a tooth socket

structural bone functions

protects organs; support to resist the force of gravity

metabolic bone function

blood cell production

joint

any connection between different skeletal elements

ligament

a short band of tough, flexible, fibrous connective tissue that connects two bones or cartilages or holds together a joint

tendon

a flexible but inelastic cord of strong fibrous collagen tissue attaching a muscle to a bone

periosteum

thin tissue covering the outer surface of bones (except in areas of articulation)

cortical bone

the solid, dense bone that is found in the walls of bone shafts and on external bone surfaces; also called compact bone

trabecular bone

spongy, porous lightweight bone found under protuberances where tendons attach; in the vertebral bodies, in the ends of long bones, in short bones, and sandwiched within flat bones

endosteum

an ill-defined and largely cellular membrane that lines the inner surface of bones

medullary cavity

the canal inside the shaft of a long bone

bone marrow

a soft tissue inside the bone that produces blood cells

extracellular matrix

collagen and hydroxyapatite

collagen

a fibrous structural protein constituting about 90% of bone's organic content

hydroxyapatite

a dense, inorganic, mineral matrix; the second component of bone

woven bone

immature bone, seen during growth and during remodeling/healing processes

lamellar bone

bone whose microscopic structure is characterized by collagen fibers arranged in layers or sheets around Haversian canals

osteoblasts

the bone-forming cells responsible for synthesizing and depositing bone material

osteoclasts

cells responsible for the resorption of bone tissue

osteocytes

living bone cell developed from an osteoblast

osteons

a Haversian system; the structural unit of compact bone composed of a central Haversian canal and one concentric lamellae surrounding it

Haversian canal

freely anastomosing canals in compact bone that contains blood and lymph vessels, nerves, and marrow

lacunae

small cavities in bone that contain osteocytes

lamellae

rings around the central canal, sites of lacunae

canaliculi

small passages or ducts that forms a network connecting osteocytes

Volkmann's canal

horizontal canals between osteons; contain a nerve and a blood vessel

endochondral bone growth

one of the two processes by which bone is formed in mammals; first formed in cartilage and gradually replaced by bone tissue

cartilaginous model

approximates the size and shape of future bone and is gradually replaced by actual bone during development

primary ossification center

the first site where bone begins to form during growth; usually in the shaft of a long bone, or the body of other bones

secondary ossification center

center of bone formation that appears following the formation of the primary center, such as the epiphysis of a long bone

intramembranous

bones ossify by apposition on tissue within an embryonic connective tissue membrane; embryonic tissue forms a thick membrane that is gradually mineralized

Wolff's Law

bone grows or remodels in response to the demands placed on it; growth -> modeling -> remodeling