Chapter 7 Flashcards
How many bones make up the skeleton?
206
2 parts to the skeleton
- Axial
2. Appendicular
Axial Skeleton
- what does it form
- what does it include
- what does it support
- Forms longitudinal axis of the body
- skull, hyoid bone, vertebral column, and thoracic
- Framework that supports the brain, spinal cord and organs of the ventral body cavity
Appendicular skeleton
Bones of the limbs and girdles that connect them to the axial skeleton
What is the function of bone markings?
Attatchment of muscles, grooves for nerves and blood vessels, bone articulations
How can bone markings be useful to forensic scientists, anthropologists and pathologists?
Help determine size, age and sex; help determine general appearance of an individual
How many bones does the skull contain?
22
Cranium
- definition
- function
- how many bones
Helmet-like covering that encloses cranial cavity
- houses and protects brain
- 8 bones
cranium bones
-6 parts (8 bones in total)
- Frontal
- Parietal
- Temporal
- Occipital
- Ethmoid
- Sphenoid
Frontal
- number of bones
- function
- what does it contain
- what is it formed by
- 1
- forms forehead and upper parts of orbits
- frontal sinus-mucus cavity
- formed by union of 2 bones at metopic suture
when does the metopic suture usually disappear by
by age 8 when bones fuse
Parietal
- number of bones
- function
- special features/landmarks
- 2 (both sides)
- Forms sides and roof of cranium
- none
Temporal
- number of bones
- function
- 5 processes
- 2
- forms lateral wall of cranium and part of cranial floor
- Zygomatic process
- Mastoid process
- Styloid process
- External auditory canal
- Mandibular fossa
- Zygomatic process
Zygomatic process
forms posterior part of the zygomatic arch
Mastoid process
rounded projection behind ear
Styloid process
slender spike extending downward
External auditory canal
canal leading to middle ear
Mandibular fossa
depression on inferior surface which forms socket for mandible
Occipital
- number of bones
- function
- 2 special features
- 1
- forms much of the posterior and inferior surfaces of the cranium
- Occipital condyles
- Foramen Magnum
- Occipital condyles
Occipital Condyles
Oval processes that articulate with the first cervical vertebrae
Foramen Magnum
- Large hole
- connects the cranial canal to the spinal cavity
- surrounds connection between brain and spinal cord
Ethmoid
- number of bones
- what does it look like
- function
- 5 special features/landmarks
- 1
- Irregularly shaped
- forms inner surface of cranial floor, medial walls of orbit, roof of nasal cavity, and superior part of nasal septum
- Cribiform plate
- Crista galli
- Superior and middle nasal conchae
- Perpedicular plate
- Ethmoid sinus
- Cribiform plate
Cribiform plate
- definition
- what does it contain
Forms floor of cranium and roof of nasal cavity
-contains perforations (olfactory bulbs)
Crista galli
- definition
- attactment site for what
upward projecting triangular process
-for meninges of brain
Superior and Middle nasal conchae
forms lateral masses that form walls of nasal cavity
Perpendicular plate
slender process in midline that forms upper part of nasal septum
Ethmoid sinus
mucus lined cavities
Sphenoid
- number of bones
- 3 functions
- what does it resemble
- 4 special features/landmarks
-1
-1. Keystone of cranial floor
2. acts as a cross brace to strengthen skull by extending from one side of cranium to the other
3. forms side of skull, most of cranial floor and part of the orbit
-resembles bat with wings extended
-1. body
2. sella turcica
3, greater wing
4. sphenoidal sinus
Body of sphenoid
central portion
Sella Turcica
- definition
- what sits there
saddle shaped depression on superior surface
-pituitary gland
Greater wing
lateral projections that form part of orbit and lateral walls of skull anterior to temporal bone
Sphenoid sinus
mucus lines cavities
Facial bones
- contains 8 parts
- how many bones all together
- Nasal
- Maxillary
- Zygomatic
- Mandible
- Lacrimal
- Palatine
- Inferior Nasal Conchae
- Vomer
- 14 bones
Nasal bone
- number of bones
- function
- special features
- 2
- forms bridge of nose
- none
Maxillary
- number of bones
- function
- special features
- 2
- forms upper jaw and parts of orbit, anterior part of roof of mouth (palate = hard palate)
- maxillary sinus
- palatine process
Maxillary sinus
Mucus lined cavity
Zygomatic
- number of bones
- function
- special features
- 2
- forms part of zygomatic arch and part of outer wall and floor of orbit
- none
Palatine process
- horizontal projection that forms boney roof of mouth
- anterior 2/3 of hard plate
Mandible
- number of bones
- function
- 3 special features
- 1
- lower jaw
- main horizontal part forms chin
1. Alveolar processes
2. mandibular condyle
Alveolar processes
sockets for teeth
mandibular condyle (condylar process)
articulates with mandibular fossa of temporal bone
Lacrimal
- number of bones
- definition
- function
- special features
- 2
- smallest of the facial bones
- tiny bones that form medial walls of orbit
- none
Palatine
- number of bones
- function
- special features
- 2
- forms posterior part of hard palate and small part of orbit floor
- none
Inferior nasal conchae
- number of bones
- 3 functions
- special features
- 2
- forms lower part of lateral walls of nasal cavity
- helps to create turbulence in air passing through the nasal cavity
- promotes warming and humidification of inhaled air
- none
Vomer
- number of bones
- function
- special features
- 1
- forms lower part of nasal septum
- none
Sutures
immovable joints between the skull bones
Squamous suture
boundary between temporal and parietal
Wormian (sutural bone)
Usually present along lambdoid suture
Orbit
Made up of several bones
-bony recesses that contain eyes
The nasal septum
- superior portion
- inferior portion
- perpendicular plate of ethmoid bone
- vomer
The bridge of the nasal complex
formed by paired nasal bones
paranasal sinuses
- helps to lighten the skull
- extensive area of mucous epithelium
fontanelles
- definition
- 2 functions
- large fibrous areas between cranial bones
- distortion of skull for delivery
- allows for brain growth and to continue after birth
- distortion of skull for delivery
Bones of the spine
-5
- Hyoid (cervical)
- Thoracic
- Lumbar
- Sacral
- Coccyx
Hyoid (cervical)
- how many bones
- function
- special features
- 7
- horseshoe shaped bone between mandible and larynx
- supports tongue and serves as attachment for muscles
vertebral column
- how many bones
- function
- special features
- 26
- a flexible segmented rod that is shaped like an elongated S
- forms axis of body and encloses spinal cord
How many bones in the throacic
12
How many bones in the lumbar
5
How many bones in the sacral
5 fused bones
how many bones in the coccyx
3-5 fused bones
How long does it take for the sacral and coccyx to fuse its bones
not fused until 25-30 years old
Why is the spinal column curved?
Allows body to remain in balance when standing upright
Curves that are posteriorly
- name
- 2
- concave
- Thoracic and sacral
Curves that are anteriorly
- name
- 2
- convex
- cervical and lumbar
development of the curves
- which curve develops at about 3 months
- which curve develops at about 1 year
- cervical (hold head up)
- lumbar (ability to stand and walk)
Primary curves
Ones you are born with
-thoracic and sacral
Secondary curves
Ones you develop after birth
-cervical and lumbar (compensation curves)
Kyphosis
- meaning
- definition
- hunchback
- exaggeration of the thoracic curve
Lordosis
- meaning
- definition
- swayback
- exaggeration of the lumbar curve
Scoliosis
abnormal lateral curvature of spine
Cervical
-3 features
- small
- spinous process is split (bifid) (C2 to C6)
- Transverse foramen in transverse processes (blood vessels - C1-C6)
Cervical - C1
- name
- body?
- spinous process?
- 2 features
- the atlas
- no
- no
- large round foramen
- contains superior articular surfaces for articulation with occipital condyles
- large round foramen
How does the atlas get its name
Hold up head
What action is provided by the joint between the atlas and the occipital condyles?
Able to nod head
Cervical - C2
- name
- body?
- what does it contain
- the axis
- yes
- contains a peg like projection called the odontoid process or dens that extends into the atlas
What action is provided by the joint between the axis and the atlas?
Rotation of the head
Cervical - C7
- name
- 2 features
- the vertera prominens
- long non-bifid spinoud process (does have a transverse foramina)
- the largest cervical vertabrae
- long non-bifid spinoud process (does have a transverse foramina)
Thoracic
-4 features
- larger than cervical vertebrae
- spinous process in long, pointed and directed inferiorly
- long and heavy transverse process that have facets for articulations with ribs
- bodies have facets or partial facets (demi-facets) for articulations with ribs
Lumbar
-3 features
- Largest and strongest vertebrae
- Thick, oval, flat bodies
- spinous process is square and projects posteriorly
Sacrum (anterior part)
-2 features
- Transverse lines
2. anterior sacral foramina
Transverse lines
points where vertebrae have fused
Anterior sacral foramina
four pairs of foramina that communicate with posterior foramina
Sacrum ( posterior part)
-3 features
- median sacral crest
- posterior sacral foramina
- sacral canal
Median sacral crest
ridge formed by spinous processes of fused vertebrae
Sacral canal
inferior extension of vertebral canal
Sacrum (superior part)
-1 feature
Sacral promontory
Superior promontory
Superior border on anterior surface
Sacrum (lateral part)
-1 feature
Auricular surface
Coccyx
-what type of tail
vestigial tail
Thorax
- definition
- 2 parts
- bony cage formed by sternum, costal cartilages, ribs and bodies of thoracic vertebrae
1. sternum
2. ribs
Costal cartilages
- type of cartilages
- function
- hyaline
- joins ribs to sternum
Sternum
- how many bones
- 3 parts
- 1
- manubrium
- body
- Xiphoid
- manubrium
Manubrium
triangular superior portion
Body of the sternum
Middle, tongue shaped, largest portion
Xiphoid
process: inferior, smallest portion
Ribs
- how many? pairs?
- 3 features
- 2 articulations
- 24 ribs = 12 pairs
- head
- tubercle
- Body/shaft
- head
- Head of ribs fits into facets of bodies of one to 2 adjacent throacic vertebrae
- Tubercle of rib fits into facets of transverse process of vertebrae
- Head of ribs fits into facets of bodies of one to 2 adjacent throacic vertebrae
Head of ribs
Projection at posterior end of rib
Tubercle
knoblike elevation
Body/shaft of ribs
flat, main part of rib
True ribs
- classification
- anterior articulation
- posterior articulation
- vertebrosternal (1-7)
- costal cartilages of sternum
- Thoracic vertebrae
False ribs
-2 branches
- Vertebrochondral
2. Vertebral/floating
Vertebrochondral
- rib number
- anterior articulation
- posterior articulation
- 8-10
- Costal cartilage of rib 7
- throacic vertebrae
Vertebral/floating
- rib number
- anterior articulation
- posterior articulation
- 11 and 12
- NOT attached directly
- thoracic vertebrae