Skeletal System

Created by AbbeIzFab 

Upgrade to
remove ads

bone

an individual organ of the skeletal system

two examples of structures formed by the fusion of fetal bones

- the skull
- pelvic bones

feature

any identifiable impression, depression, lump, bump, notch, hole, or part of the bone that is consistently identifiable in most humans

the two divisions of the skeletal system

- the axial (core) skeleton
- the appendicular (upper and lower extremities) skeleton

bones of the axial skeleton

- the skull
- vertebral column
- rib cage
- bones that form the front of the chest
- auditory ossicles
- hyoid bone
- 80 bones

bones of the appendicular skeleton

- the bones of the hand
- forearm
- arm
- shoulder girdle
- the foot
- thigh
- pelvic girdle
- 126 bones

condyle

- rounded process that usually articulates with another bone
- ex: occipital condyle of the occipital bone

crest

- narrow, ridgelike projection
- ex: iliac crest of the ilium

epicondyle

- projection situated above a condyle
- ex: medial epicondyle of the humerus

facet

- small, nearly flat surface
- ex: facet of a thoracic vertebra

fissure

- cleft or groove
- ex: inferior orbital fissure in the orbit of the eye

fontanel

- soft spot in the skull where membranes cover the space between bones
- ex: anterior fontanel between the frontal and parietal bones

foramen

- opening through a bone that usually serves as a passageway for blood vessels, nerves, or ligaments
- ex: foraman magnum of the occipital bone

fossa

- relatively deep pit or depression
- ex: olecranon fossa of the humerus

fovea

- tiny pit or depression
- ex: fovea capitis of the femur

head

- enlargement on the end of a bone
- ex: head of the humerus

linea

- narrow ridge
- ex: linea aspera of the femur

meatus

- tubelike passageway within a bone
- ex: external acoustic meatus of the temporal bone

process

- prominent projection on a bone
- ex: mastoid process of the temporal bone

ramus

- branch or similar extension
- ex: ramus of the mandible

sinus

- cavity within a bone
- cannot be seen unless the bone is sectioned or the skull is taken apart at the sutures
- often called the paranasal sinuses
- air-filled spaces within bones that connect with and play an important role in the respiratory system
- lined with pseudostratified ciliated columnar epithelial tissue

spine

- thornlike projection
- ex: spine of the scapula

suture

- interlocking line of union between bones
- ex: lambdoid suture between the occipital and parietal bones

trochanter

- relatively large process
- ex: greater trochanter of the femur

tubercle

- small, knoblike process
- ex: tubercle of a rib

tuberosity

- knoblike process usually larger than a tubercle
- radial tuberosity of the radius

alveolar process

- a bony ridge that contains sockets or holes that hold the teeth
- the holes for the teeth are called "alveoli"

compact bone tissue

- has a continuous extracellular matrix with no gaps

spongy bone tissue

- also called cancellous bone
- does not have Haversian (central) canal systems
- composed of many tiny branches of bone matrix called trabeculae that contain osteocytes in lacunae
- red bone marrow surrounds the trabeculae of the spongy bone matrix

red bone marrow

where blood stem cells divide to produce all types of blood cells

long bones

- longer than they are wide
- mostly made of compact bone tissue; spongy bone in the epiphyses at the ends
- diaphysis is hollow

epiphysis

expanded portion at the end of a long bone that articulates (or forms a joint) with another bone

diaphysis

the shaft of a long bone, between the epiphyses

medullary cavity

- the hollow space within the diaphysis of a long bone
- in large adult long bones, contains yellow bone marrow, a form of adipose connective tissue

examples of long bones

- humerus
- femur
- radius
- ulna
- metacarpals
- phalanges

short bones

- cube shaped; about equal in length and width
- surface is compact bone, inside is spongy bone

examples of short bones

- carpals except for pisiform
- tarsals except for calcaneus

flat bones

- thin, flat
- consist of two layers of thin, parallel plates of compact bone with spongy bone trapped between

examples of flat bones

- bones of the cranium
- sternum
- ribs
- scapulae

sutural bones

- small flat bones located within the sutures of cranial bones
- most often found where the fontanels existed in the baby

irregular bones

- complex shapes
- vary in amount of spongy and compact bone

examples of irregular bones

- vertebrae
- facial bones
- coxal bones
- calcaneus

sesamoid bones

- shaped like a sesame seed; vary from person to person
- develop within tendons; protect and increase mechanical effect of tendon by changing the direction of pull

examples of sesamoid bones

- patellae in the quadriceps femoris tendon; found in all people
- pisiform; a carpal bone found in most people

six fontanels

- anterior fontanel / frontal fontanel
- anterolateral fontanels / sphenoidal fontanels (2)
- posterolateral fontanels / mastoid fontanels (2)
- posterior fontanel / occipital fontanel

Please allow access to your computer’s microphone to use Voice Recording.

Having trouble? Click here for help.

We can’t access your microphone!

Click the icon above to update your browser permissions above and try again

Example:

Reload the page to try again!

Reload

Press Cmd-0 to reset your zoom

Press Ctrl-0 to reset your zoom

It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

Please upgrade Flash or install Chrome
to use Voice Recording.

For more help, see our troubleshooting page.

Your microphone is muted

For help fixing this issue, see this FAQ.

Star this term

You can study starred terms together

NEW! Voice Recording

Create Set