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