The skull is one of the major components of the axial skeleton. Name the other two.
Vertebrae and bony thorax
the spinal column
Bony thorax protects:
thoracic cavity (heart and lungs)
Interlocking joints; immovable joints that connect bones of skull
With one exception, the skull bones are joined by sutures. Name the exception.
What are four major sutures of the skull, and what bones do they connect?
Sagittal- two parietal bones
Coronal- parietals meet frontal bone
Squamous- temporal meets parietal
Lambdoid- temporal meets parietal
Name the eight bones composing the cranium.
Frontal, Ethmoid, Right temporal, Left temporal, Sphenoid, Right parietal, Left parietal, Occipital
Give two possible functions of the sinuses.
Lighten facial bones; act as resonance chambers for speech
What is the orbit?
The bony cavity containing the eyeball
Why can the sphenoid bone be called the keystone of the cranial floor?
The sphenoid boe forms a plateau across the width of the skull.
Bone forming anterior cranium.
Forms most of the hard palate
Bony skeleton of nose
Posterior roof of mouth
Bone pair united by the sagittal suture
Site of jugular foramen and carotid canal
Site of external auditory meatus
Contains a "saddle" that houses the pituitary gland
Has greater and lesser wings
Allows tear ducts to pass
Superior and medial nasal conchae are part of this bone
Its "holey" plate allows olfactory fibers to pass
Facial bone that contains a sinus
Three cranial bones containing paranasal sinuses
frontal, sphenoid, and ethmoid
Its oval shaped protrusions articulate with the atlas
Spinal cord passes through a large opening in this bone
Not really a skull bone
Forms the chin
Inferior part of nasal septum
Contain alveoli bearing teeth
Are the same skull bones seen in the adult also found in the fetal skull?
No, some areas still remain to be converted to bone.
How does the size of the fetal face compare to its cranium? How does this compare to the adult skull?
Face is smaller
Adult skull is 1/8th total body length whereas the fetal skull is 1/4th total body length
What are the outward conical projections in some of the fetal cranial bones?
These are ossification centers.
What is a fontanel? What is its fate?
Fibrous membranes between the bones of a fetal skull becomes bone by 22 months.
What is the function of the fontanels in the fetal skull?
Allows skull to be compressed during birth and allows for brain growth during late fetal life.
Vertebral type with a forked spinous process
Pivots on C2, Lacks a body
Bear facets for articulation with ribs; form part of bony thoracic cage
Twelve components; unfused
Forms a joint with the hip bone
Five components; fused
Vertebra with block like body and short stout spinous process
Five components; unfused
Articulates with he occipital condyles
What kind of tissue makes up the intervertebral discs?
What is a herniated disc? What problems might it cause?
A slipped disc; protruding cartilage from vertebra.
Pain and numbness
The major components of the thorax (excluding the vertebral column) are the
Sternum, and ribs
What is the general shape of the thoracic cage?
Why is the clavicle at risk to fracture when a person falls on his or her shoulder?
It is a slender bone.
Why is there generally no problem in the arm clearing the widest dimension of the thoracic cage?
The clavicle serves as a brace to hold the arm away from the top of the thorax.
What is the total number of phalanges in the hand?
What is the total number of carpals in the wrist?
Compare the pectoral and pelvic girdles in terms of flexibility, security, and ability to bear weight.
Flexibility: pectoral- more flexible
Security: Pelvic- more secure
Weight-bearing ability: pelvic- able to bear weight
What organs are protected, at least in part, by the pelvic girdle?
Reproductive organs, urinary bladder, and part of the large intestine
Distinguish between the true pelvis and false pelvis.
False pelvis- superior; supports abdominal viscera
True pelvis- inferior; limits delivery of baby
What does fallen arches mean?
The ligaments and tendons are weakened, allowing bones to "fall"
4 steps of bone repair.
1. Hematoma forms
2. The break is splinted by a fibrocartilage callus
3. The bony callus forms
4. Bone remodeling occurs
forms the forehead, the bony projections under the eyebrows and the superior part of each eyes orbit
inferior to parietal bones
Body or centrum of vertebra
disclike, weight bearing part of the vertebra facing anteriorly in the vertebral column
arch formed from the joining of all posterior extensions, the laminae and pedicles, from the vertebral body
canal through which the spinal cord passes
two lateral projections from the vertebral arch
single projection arising from the posterior aspect of the vertebral arch
Superior and inferior articular processes
paired projections lateral to the vertebral foramen, allowing a vertebra to form joints with adjacent vertebrae
slightly movable joints
freely movable joints
united by fibrous tissue, sutures of the skull
bone ends are connected by cartilage, amphiartrotic joints- spinal column, ribs, and pelvis
joints in which the articulating bone ends are separated by a joint cavity containing synovial fluid
bone breaks into many fragments
Common in older people whose bones are brittle
Bone is crushed
Common in porous bones
broken bone portion is pressed inward
Typical of skull fracture
broken bone ends are forced into each other
commonly occurs when one attempts to break a fall with outstretched arms
ragged break occurs when excessive twisting forces are applied to a bone
bone breaks incompletely, much in the way a green twig breaks