The Axial Skeleton Flashcards
- The Skull
The cranium is composed of
8 flat bones
Frontal bones are
unpaired
Frontal ones join the
parietal bones at the coronal suture
Parietal bones are
paired
parietal bones meet in
the midline at the sagittal suture
Temporal bones are
paired
Temporal bones join the
parietal bones at the squamosal suture
Occipital bones are
unpaired
Occipital bones join the
parietal bones at the lambdoidal suture
the sphenoid bone is
unpaired
the ethmoid bone is
unpaired
- Bones of the skull
Temporal bones
- External Acoustic Meatus
- Styloid process
- Zygomatic process
- Mastoid Process
- Jugular Foramen
- Internal acoustic meatus
- Carotid Canal
External acoustic meatus
canal leading to the ear drum
styloid process
sharp needle like projection for attachment of neck muscles
zygomatic process
thin bridge of bone that join the zygomatic bone anteriorly
mastoid process
contains mastoid sinus. It is so close to the middle ear and the brain
- Attachment site for some neck muscles
jugular foramen
at the junction for the occipital and temporal bones, allow passage of the jugular vein
internal acoustic meatus
transmits cranial nerves 7 & 8
carotid canal
through which the internal carotid artery runs
Sphenoid bone
butterfly shaped, forms the floor of the cranial cavity
- contains sphenoid sinus
Sella Turcica
a small depression in the midline forms a snug enclosure for the all important pituitary gland, the master gland of the endocrine system
foramen ovale
large opening allow passage of CN 5
Two opening that forms part of the orbital cavity
- optic canal
- superior orbital fissure
optic canal
allows optic nerve to pass
superior orbital fissure
allows passage of CN 3, 4, and 6
Crista Galli
a central projection from its superior surface
- outermost covering of the brain (dura mater) attaches to this
Cribriform plates
many small holes on either side of the crista galli allow nerve fibers carrying olfactory impulses from the nose to the brain
superior and middle nasal concahe
extensions of the ethmoid bone, form the lateral walls of the nasal cavity
- Facial Bones
How many facial bones are there
14
how many facial bones are paired
12
what are the facial bones that are paired
- maxillae
- palantine
- zygomatic
- lacrimal
- nasal
- inferior nasal conchae
how many facial bones are unpaired
2
what are the facial bones that are unpaired
- mandible
- vomer
- the fetal skull
The fetal skull is ___ of the body length compared to adult skull which is ___
- 1/4th
- 1/8th
fontanels
fibrous membranes connecting the cranial bones
fetal skull purpose
- allows skull compression during birth
- allow the brain to grow during later pregnancy and infancy
- convert to bone within 12 to 24 months after birth
- The bony Thorax
what are the 3 parts of the bony thorax
- sternum
- ribs
- thoracic vertebrae
parts of the Sternum
- manubrium sterni
- body
- xyphoid process
what are the 3 land marks of the sternum
- Jugular notch
- sternal angle
- xiphisternal joint
What are the 3 types of ribs
- true ribs
- false ribs
- floating ribs
true ribs
(vertebrosternal)
- pairs 1-7
- connected posteriorly to the vertebra and anteriorly to the sternum
false ribs
(vertebrochondral)
pairs 8-10
- connected posteriorly to the vertebra and anteriorly to the cartilage of the previous rib
floating ribs
(vertebral)
pairs 11-12
- connected only posteriorly to vertebra, no anterior attachment
The vertebral column has a stack of
26 vertebral bones separated by intervertebral discs
how many cervical vertebrae are in the neck
7
how many thoracic vertebrae are in the chest region
12
how many lumbar vertebrae are associated with the lower pack
5
Nine vertebrae fuse to form two composite bones known as
- sacrum
- coccyx
sacrum
fusion of 5 vertebrae
coccyc
fusion of 4 vertebrae
primary curvatures
the spinal curvatures of the thoracic and sacral regions
secondary curvatures
the spinal curvatures of the cervical and lumbar regions
- abnormal curvatures of the spine
Kyphosis
an exaggerated posterior curvature of the spine usually in thoracic region
- also known as hunchback
Lordosis
an exaggerated anterior curvature of the spine usually in the lumbar region
- also known as sway back
scoliosis
abnormal lateral curvature of the spine
two types of scoliosis
- congenital
- acquired
congenital scoliosis
resulting from one leg being longer than the other
acquired scoliosis
resulting from chronic poor posture during childhood while the vertebrae are still growing
The 1st cervical vertebra is known as
Atlas
The second cervical vertebra is known as
Axis
A protuberance of the axis is known as the
odontoid process or dens
the atlantoaxial joint between the atlas and axis is a
pivot type of joint
Large, triangular vertebral foramen
since the spinal chord is so large here, the vertebral foramen must also be large to accommodate it
Transverse process with foramen transversarium
its function is to allow the passage of the vertebral artery, accompanying vertebral veins
the vertebral arch is composed of the
peduncles posteriorly and the laminae anteriorly
the vertebral arch encloses the
posterior vertebral foramen and protects the spinal chord
spina bifida
the laminae of the vertebra fail to unite during development and the vertebral arch remains incomplete
each disc is composed of
annulus fibrosus and nucleus pulposus
annulus fibrosus
tough outer layer of fibrocartilage
nucleus pulposus
an elastic central mass
ruptured or herniated disc
may cause back pain and numbness or loss of muscular function in the parts innervated by the affected spinal nerve
