Skeletal System Basics
What are the two main subdivisions of the skeletal system?
Axial and appendicular skeleton
How many bones form the adult skull?
22
How many vertebrae are in the adult vertebral column?
33 (of which 24 are known as articulating or moveable vertebrae, and are separated from each other by an intervertebral disc. The remaining 9 vertebrae lack the intervertebral disc and for two sets of fused structures
How many pairs of ribs are there?
12 pairs
The skeletal system develops from which germ layer?
Mesoderm
Name one major function of the skeletal system.
Support, protection, movement, mineral storage, or blood cell production
Name the four major sutures of the skull.
Coronal, sagittal, lambdoid, and squamous
What is the distinguishing feature of cervical vertebrae?
Transverse foramina
What are the first seven pairs of ribs called?
True ribs (vertebrosternal)
What embryonic structures give rise to vertebrae?
Sclerotomes (from somites)
About how many bones make up the adult human skeleton?
206
What is the purpose of the cranial fossae?
They house different parts of the brain
Which vertebra is known as the “atlas”?
C1
The sternum consists of what three parts?
Manubrium, body, and xiphoid process
The skull develops from which two types of ossification?
Intramembranous and endochondral ossification
The axial skeleton forms the ____ axis of the body.
Longitudinal
Which bone contains the foramen magnum?
Occipital bone
What type of curvature does the thoracic spine have?
Primary (kyphotic) curvature
Which ribs are called “floating ribs”?
Ribs 11 and 12
What is the name of the soft spots in an infant’s skull?
Fontanelles
Which bones protect the brain, spinal cord, heart, and lungs?
Skull, vertebrae, ribs, and sternum of the axial skeleton
Name two bones that form part of the orbit (eye socket).
Frontal, sphenoid, zygomatic, maxilla, lacrimal, ethmoid, or palatine (any two)
What is an intervertebral disc composed of?
Annulus fibrosus and nucleus pulposus
Name one function of the thoracic cage.
Protects thoracic organs, aids respiration, supports shoulder girdle
Failure of vertebral laminae to fuse during development results in what condition?
Spina bifida