Axial and Developmental Osteology Flashcards
Divide the bones of the head into four groups and list and enumerate the bones in each group.
- 8 which form the neurocranium (cranial vault around the brain)
- 14 which form the viscerocranium (the skeleton of the face)
- 6 auditory ossicles (tiny bones located within the air-filled cavity of the middle ear)
- malleus (in each middle ear)
- incus
- stapes - Hyoid bone (embedded in the muscles at the base of the tongue)
Define skull, clavaria, fontanel, foramen magnum, and zygomatic arch.
- Skull - the 22 bones forming the neurocranium and viscerocranium
- Zygomatic arch - most obvious landmark on the side of the skull; composed of the temporal bones and zygomatic bones
- Foramen Magnum - transmits the spinal cord; largest hole in skull
- Clavaria - superior aspect of the skull; consists of the frontal bone, left and right parietal bones, and occipital bone
- Fontanels - “soft spots”; there are six fontantels
- anterior fontanel
- posterior fontanel
- anterolateral fontanel
- posterolateral fontanel
State which bones of the neurocranium and which ones of the viscerocranium contribute to the orbit.
Neurocranium:
- Frontal bone - superior portion
- Ethmoid bone - part of medial wall
- Sphenoid bone - posterior wall
Viscerocranium:
- Zygomatic bone - inferolateral aspect
- Maxilla - inferomedial aspect
- Lacrimal bone - part of medial wall
- Palatine bone - part of inferior aspect
List the three bones that fuse to form the sternum.
- manubrium
- body
- xiphoid process
Endochondral Ossification
- a hyaline cartilage model of the bone forms from tissues derived from the mesoderm. this model resembles the bone it is to become in shape
- the cartilage mineralizes to become calcified cartilage (only time cartalage has mineral in it)
- the mineralized cartilage is reabsorbed by chondroclasts
- as the cartilage is reabsorbed, cells differentiate into osteoblasts, secrete osteoid, and then bone salts (minerals) precipitate onto the collagenous fibers to complete the formations of definitive bone tissue (laying down of bone tissue)
What does endochondral ossification contribute to skeletal development?
it is the mechanism by which the majority of bones in the body initially develop (how we get linear growth in bone)
Intramembranous ossification
fibroblasts within c.t. proper membranes simply undergo metaplasia and differentiate into osteoblasts. these osteoblasts then form osteoid to complete the process.
What does intramembranous ossification contribute to skeletal development?
it is involved in the original formation of some flat bones of the body and also is the major mechanism by which most bones grow diametrically
Primary centers of ossification
first area in a developing bone where the 4 steps of endochondral ossification are completed (near the center of the bone)
Secondary centers of ossification
days or weeks later, other areas in the same bone will complete the same four steps. these areas are known as secondary centers of ossification. (in each epiphysis)
Explain how the medullary cavity gets larger in a growing long bone.
Osteoclastic activity
State how the inferior nasal conchae differ from the superior and middle nasal conchae.
The superior and middle nasal conchae are parts of the ethmoid bone. The inferior nasal concha is a separate bone. Note that both left and right maxillae and both palatine bones contribute to the bony palate.
Be able to sketch a typical vertebra. What are the parts common to each?
1 - vertebral foramen 1 - spinous process 2 - superior articular process 2 - transverse process 1- body pg. 174
What is the human vertebral formula? Be able to sketch a curved line representing the vertebral column in lateral perspective and label the cervical, thoracic, lumbar, and pelvic curvatures. Note which two are concave and which two are convex anteriorly.
pg. 172
C(7)T(12)L(5)S(5)Cy(4)
What ribs are true ribs?
1-7
