Chapter 7: Axial Skeleton Flashcards
Axial skeleton bones and how many
- skull and facial bones
- vertebrae
- ribs
- sternum
- hyoid
80 bones
5 main types of bone
- long bones
- short bones
- flat bones
- irregular bones
- sesamoid bones
Long bones
greater in length than width
- example: limbs
Short bones
cube shaped
- example: most carpal and tarsal bones (wrist and ankle)
Flat bones
thin layers of parallel plates
- example: cranial bones, sternum, ribs, scapulae
Irregular bones
complex shaped
- example: vertebrae
Sesamoid bones
shaped like a sesame seed
- example patellae (knee cap)
- bones may vary from person to person
Suture bones
- small extra bone plates located within the sutures of cranial bones
- amount varies from person to person
Sutures
- are jointed areas where flat bones come together
- immovable joints
Different sutures on skull
- frontal/coronal suture
- saggital suture
- lambdoid suture
- squamous suture
What does the temporal bone form..
the external acoustic meatus
8 cranial bones
- frontal (1)
- parietal (2)
- temporal (2)
- occipital (1)
- sphenoid (1)
- ethmoid (1)
2 major types of surface markings in bones
- depressions and openings
- processes
Depressions and openings description + different types
allow the passage of soft tissue (nerves, blood vessels, ligaments, tendons) or formation of joints
- fissure, foramen, fossa, sulcus, meatus
Fissure
narrow slit between adjacent parts of bones through which blood vessels or nerves pass
example: superior orbital fissure of sphenoid bone
Foramen
opening through which blood vessels, nerves or ligaments pass. (hole)
example: optic canal of sphenoid bone
Fossa
shallow depression
example: coronoid fossa of humerus
Sulcus
furrow (groove) along bone surfaces that accommodates blood vessel, nerve, or tendon
example: inter-tubercular sulcus of humerus
Meatus
tube like opening
example: external acoustic meatus of temporal bone
Processes description + different types
projections or outgrowths on bone that form joints or attachment points for connective tissue, such as ligaments and tendons
- condyle, facet, head, crest, epicondyle, line, spinous process, trochanter, tuberosity
Condyle
large, round protuberance with a smooth articular surface at end of bone
Facet
smooth, flat slightly concave or convex articular surface
- example: superior articular facet of vertebra
Head
usually rounded articular projection supported on neck (constricted portion) of bone
example: head of femur
Crest
prominent ridge or elongated projection (little mountains going outwards)
- example: iliac crest of hip bone
Epicondyle
typically roughened projection above condyle
- example: medial epicondyle of femur
Line
long, narrow ridge or border (less prominent than crest) - similar to crest
- example: linea aspera of femur
Spinous process
sharp, slender projection
example: spinous projection of vertebra
Trochanter
very large projection
example: greater trochanter of femur
Tubercle
variably sized round projection
example: greater tubercle of humerus
Tuberosity
variably sized projection with rough, bumpy surface
example: ischial tuberosity of hip bone
Facial bones
- mandible
- maxilla
- zygomatic
- nasal bone
- palatine bone
- vomer
- lacrimal
- inferior concha
Which bones form part of inner nose
vomer and ethmoid bone
Frontal bone
- forms the forehead, anterior part of skull and roof of orbits
Parietal bones
- form greater portion of the sides and roof of the cranial cavity
- inner surfaces contain protrusions and depressions that accommodate the blood vessels
Temporal bones
- form inferior lateral aspects of cranial cavity
Occipital bone
- forms posterior part of cranial cavity and most of cranial base
- contains foramen magnum for spinal cord to go through
- contains occipital condyles on either sides of foramen magnum for the atlas to articulate
Sphenoid bone
- lies at the middle part of cranial base
- articulates with all other cranial cavity bones
- forms part of floor, side walls and rear wall of orbit
Ethmoid bone
- forms part of anterior portion of the cranial base
- forms medial wall of orbits
- is the superior portion of nasal cavity that divides the nasal cavity into left and right sides
Hyoid bone
- does not articulate with any other bone
- located between mandible and larynx and supports the tongue
- serves as an attachment point for the tongue
Nasal bones (2)
small rectangular-shaped bones that form the bridge of the nose
- resting place for eye glasses
Lacrimal bones (2)
- smallest facial bones
- form part of the medial wall in each orbit
- each contain a lacrimal fossa
- a structure that gathers tears and passes them to the nasal cavity
Palatine bones (2)
- form posterior portion of hard palate
- form small portion of floors of orbits
Inferior nasal concha bones (2)
- inferior to nasal portion of ethmoid bone
- inferior lateral wall NOT MEDIAL
- all 3 conchae (superior, middle, inferior) increase surface area of the nasal cavity and help swirl and filter air before it passes into the lungs
Vomer
- roughly triangular bone that forms inferior part of the nasal septum
- extends down from perpendicular plate of ethmoid bone
Maxillae (2)
- form upper jaw bone
- articulate with every other bone but the mandible
Zygomatic bones (2)
- cheek bones
- form part of lateral wall of orbits
- articulates with frontal, maxilla, sphenoid and temporal bones
Mandible
- lower jaw bone, strongest facial bone
- attaches to temporal bone with coronoid process
Only skull bones that move
mandible and ossicles
3 Ear bones
malleus (hammer)
incus (anvil)
stapes (stirrup)
The optic nerve goes through…
the sphenoid bone
Cribriform plate of ethmoid bone
allows for passage of olfactory nerves to the roof of the nasal cavity - full of holes
Crista galli of ethmoid bone
middle portion that sticks up into the cranial cavity
- serves as an attachment point for membranes surrounding the brain
Perpendicular plate of the ethmoid bone
descends from the under surface of the cribriform plate and assists in forming the septum of the nose
Condylar process
bump on the mandible that fits into the mandibular fossa
Mastoid
behind the ear
Paranasal sinuses
- mucus membrane-lined cavities in the frontal. maxillary, sphenoid and ethmoid bones
Function of paranasal sinuses
- allow the skull to increase in size without change in mass of the bone
- used as resonating chambers to enhance the voice
- increase the surface area of the nasal mucosa and help to moisten it as well
By what age does intramembranous ossification of the fontanels occur
2 years
Primary vs secondary curve of spinal cord
- primary is single curve in baby
- secondary is 4 curves in adults
Secondary curve (4 curves)
- cervical curve
- thoracic curve
- lumbar curve
- sacral curve
Intervertebral discs are not found in
C1 and occipital bone
Function of intervertebral discs
- absorb shock and separate the vertebrae from one another
What bones allow the head to nod yes (flex and extend)
occipital condyle and C1
What bones allow us to nod our head no
C1 and C2
True ribs and false ribs difference
- true ribs are the first 7 pairs and their cartilage connects directly to the sternum
- false ribs: next 5 pairs that indirectly connect to the sternum or do not connect at all
Scoliosis
lateral curvature (normally in thoracic region)
Kyphosis
hump back - increased thoracic curve
Lordosis
thic - increased lumbar curvature
Spina bifida occulta
- minor
- no symptoms
- only evidence is a small dimple with a tuft of hair in the overlying skin
Spina bifida cystica (meningocele)
- sac contains the meninges and cerebrospinal fluid
- cyst like sac protruding
