How can we help?

You can also find more resources in our Help Center.

45 terms

Skeletal System

an individual organ of the skeletal system
two examples of structures formed by the fusion of fetal bones
- the skull
- pelvic bones
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
- rounded process that usually articulates with another bone
- ex: occipital condyle of the occipital bone
- narrow, ridgelike projection
- ex: iliac crest of the ilium
- projection situated above a condyle
- ex: medial epicondyle of the humerus
- small, nearly flat surface
- ex: facet of a thoracic vertebra
- cleft or groove
- ex: inferior orbital fissure in the orbit of the eye
- soft spot in the skull where membranes cover the space between bones
- ex: anterior fontanel between the frontal and parietal bones
- opening through a bone that usually serves as a passageway for blood vessels, nerves, or ligaments
- ex: foraman magnum of the occipital bone
- relatively deep pit or depression
- ex: olecranon fossa of the humerus
- tiny pit or depression
- ex: fovea capitis of the femur
- enlargement on the end of a bone
- ex: head of the humerus
- narrow ridge
- ex: linea aspera of the femur
- tubelike passageway within a bone
- ex: external acoustic meatus of the temporal bone
- prominent projection on a bone
- ex: mastoid process of the temporal bone
- branch or similar extension
- ex: ramus of the mandible
- 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
- thornlike projection
- ex: spine of the scapula
- interlocking line of union between bones
- ex: lambdoid suture between the occipital and parietal bones
- relatively large process
- ex: greater trochanter of the femur
- small, knoblike process
- ex: tubercle of a rib
- 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
expanded portion at the end of a long bone that articulates (or forms a joint) with another bone
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