3a Axial Skeleton System Flashcards
Axial Skeleton Components
Skull, facial bones, spinal cord
5 basic types of bones
- long
- short
- flat
- irregular
- sesamoid
Long
compact (humerus)
short
spongy except surface (wrist-trapezoid)
Flat
plates of compact enclosing spongy (sternum and scapula)
Irregular
variable (vertebra)
Sesamoid
develop in tendons or ligaments (patella-knee caps)
Sutural bones
in joints between skull bones
immovable joints that hold the skull bones together
Skull is composed of how many bones and where
22 cranial and facial bones
Skull forms?
large cranial cavity and smaller cavities (including nasal cavity and orbits)
Paranasal sinuses
-Cavities in bones of the skull that communicate with the nasal cavity
~Mucous-lined cavities in the skull (filter and purify air) ~make the skull lighter
~Resonating chambers for speech
Mandible
only voluntary bone that we can move in the skull (other than the ear ossicles within the temporal bone)
The skull has how many cranial bones?
8
the skull has how many facial bones?
14
8 cranial bones purpose?
- protect brain & house ear ossicles
- muscle attachments for jaw, neck & facial muscles
14 facial bones purpose?
- protect delicate sense organs - smell, taste, vision
- support entrances to digestive and respiratory systems
8 cranial bones?
- frontal
- parietal (2)
- temporal (2)
- occipital
- sphenoid
- ethmoid
How many bones are in the human body?
206
How many bones are in the axial skeleton
80
Axial Skeleton
- lie along longitudinal axis
- skull, hyoid, vertebrae, ribs, sternum, ear ossicles
Appendicular skeleton composed of
Upper & lower limbs and pelvic & pectoral girdles
Frontal bone
-forehead, roof of orbits (eye sockets), anterior cranial floor
-supraorbital margin and frontal sinus(right above eye)
~a “black eye” not a lot of muscle and facia right there
Parietal bone
sides and roof of cranial cavity
Temporal bone
- two temporal bones connected by the temporal squama Sutures
- zygomatic process forms part of arch (stereotypical cheek bone)
- external auditory meatus (opening to the outside sound comes through)
- mastoid process (behind ear flat)
- styloid process (right below mastoid process for muscular attachment)
- stylomastoid foramen (VII) sits between styloid and mastoid process
- Mandibular fossa (TMJ)
- Petrous portion (VIII)
- carotid foramen (carotid artery) supplies blood to the brain
- jugular foramen (jugular vein) passes back to the heart through this
Occipital bone
-foramen magnum (spinal cord passes through connecting to the brain)
-occipital condyles (skull is going to sit on spinal cord)
-external occipital protuberance (bump of knowledge)
attachment for ligament nuchae (allows skull movement and supports spinal cord)
-superior (higher than inferior) and inferior nuchal lines (important for muscular and facia attachments)
Sphenoid bone (butterfly bone)
-Base of skull
(articulates with a number of bones)
-Pterygoid (p is silent) processes are attachment sites for jaw muscles
-Pterygoid plates
Sella turcica
holds pituitary gland (superior portion of the sphenoid bone)