bones Flashcards
Skeletal system
bones, cartilage, ligaments and joints
• framework that help maintain body shape and allow movement
• bones very strong and can resist tremendous bending and compression forces without breaking
fracture
crack or break produced by extreme loads, sudden impacts, or stresses from unusual directions
- named according to external appearance, location and nature of crack or break
closed (simple) fractures
completely internal, seen only by x-rays and do not break the skin
displaced fractures
produce new and abnormal arrangements
non-displaced fractures
retain normal alignment of bone
transverse fractures
break in bone shaft across its long axis
compression fractures
occur in the vertebrae
spiral fractures
♣ produced by twisting stresses that spread along length of bone
epiphyseal fractures
♣ at growth plate where bone matrix is undergoing calcification
commuted fractures
shattering of affected area into multiple bony fragments
greenstick fractures
♣ only one side of the shaft is broken, other is bent – typically seen in children
Colles fracture
♣ break in distal portion of radius – typical result of reaching out to cushion fall
Pott’s fracture
break at ankle affecting both tibia and fibula
open (compound) fractures
project through the skin and more dangerous due to possibility of infection or uncontrolled bleeding
Classification of Bone is based on …
• based on shape
flat
o thin parallel surfaces of compact bone with spongy bone in center – skull bones, ribs, scapulae
sutural (Wormian)
small, flat bones found between sutures (joints) of skull
pneumatized bone –
contain numerous air pocket – ethmoid bone
short bones
boxlike appearance and interior contains spongy bone – carpal and tarsal bones
sesamoid bones
o small, rounded, flat bones found between tendons of joints – patella
long bones –
o long and slender and have medullary cavity – bones of upper and lower limbs
irregular bones –
vertebrae, coxal bones
what are bone markings ?
o fixed landmarks that help determine position of soft tissue components
o based on distinctive shape of bone
process ?
♣ projection or bump
a bone marking
ramus
♣ extension of bone making an angle to the rest of the structure
(a bone marking)
name elevations and projections where ligaments and tendons are attached to
tubercle = small, rounded projection tuberosity = rough projection crest = prominent ridge spine = pointed process line = low ridge
name where the bone articulates with adjacent bones
♣ head = expanded articular end of long bone
♣ facet = small, flat articular surface
♣ condyle = smooth, rounded articular surface
♣ trochlea = smooth, grooved articular surface shaped like a pulley
o depressions, grooves, tunnels, and chamber are where ..
where muscles, nerves and blood vessels lie and/or penetrate bone, or air is located
fossa
shallow depression
sulcus
narrow groove
meatus or canal
passageway though the bone
fissure
elongated cleft
foramen
rounded passageway for blood vessels and/or nerves
sinus or antrum
chambers within bone filled with air
how many bones are there in the adult skeleton ?
206 bones in adult skeleton
what are the major sub-divisions in bones ?
axial and appendicular skeleton
Axial skeleton consist of …
skull and associated bones, thoracic cage, and vertebral column
what are the function of the axial skeleton ?
- protects brain and spinal cord and vital organs within the thorax
- attachment site for muscles that allow stabilization of body and positional and respiratory movements
- red marrow of vertebrae, sternum and ribs produce blood cells
the skull contains how many bones ?
contains 22 separate bones
the skull houses what ?
• houses special sense organs – eyes (vision), ears (hearing, equilibrium), tongue and palate (taste), nose (smell)
the cranium has how many bones ?
= 8 bones that enclose cranial cavity
what is the the function of the cranium ?
o surrounds and protects brain
how do you call the skull cap ?
calvaria (cranial vault)
top of the skull
includes the occipital, parietal and frontal bones
the facial bones has how many bones ?
14 bones
function of the facial bones ?
o protect and support entrances to digestive and respiratory tract
facial bones : mandible
o mandible detaches readily from rest of the skull
what are sutures ?
immovable joints and mark the boundaries between skull bones
what makes up the associated bones ?
- auditory ossicles
* hyoid bone
auditory ossicles , what is it ?
and function ?
smallest bones of the body located within each temporal bone
o 3 for each ear (incus, malleus, stapes)
o magnify and transfer sound waves from the outer ear to the inner ear
hyoid bone . what is it ?
and function
inferior to skull (superior aspect of neck just below the mandible)
o only bone that does not articulate with others
o attachment site for muscles associated with movement of tongue and larynx (“voice box”)
o bone that is broken by strangulation
bones of the cranium ?
• occipital bone (1), parietal bones (2), frontal bone (1), temporal bones (2), sphenoid (1), ethmoid (1)
lambdoid suture ?
joins occipital bone posteriorly located to parietal bones
occasionally extra sutural (Wormian) bones form along suture
saggital suture ?
joins 2 halves of parietal bones together along the midline of the skull
runs between lambdoid suture posteriorly and coronal suture anteriorly
o Coronal suture –
runs across the superior surface of the cranium joining the parietal bones posteriorly to the frontal bone anteriorly
joined to parietal bones by coronal suture
How many Squamous sutures are there ?
there is 2
o Squamous sutures
runs along each side of the cranium and join the parietal bones (2) superiorly to the temporal bones (2) inferiorly
o Frontonasal suture
boundary between superior aspect of nasal bones (2) of face and inferior aspect of frontal bone of cranium
what is a fontanels ? Purpose of it ?
present in fetal and infant skulls
o fibrous connective tissue connecting cranial bones prior to formation of sutures
flexible and skull can be distorted without damage during delivery
allows growth of brain and skull
sutures completed by age 5
parietal bones ? It has …
o superior and inferior temporal lines – external surface
attachment points of temporalis muscle – a major muscle that closes the month
Frontal bone , major features ?
o starts as two bones that fuse at frontal suture – suture usually disappears by age 8
o squamous part = convex anterior surface (forehead)
frontal bone, supercilliary arches
thickened ridges above the supra-orbital margins that support eyebrows
superior orbital margins
o end of frontal part and superior limits of orbits
♣ supra-orbital foramen or notch – center of supraorbital margin
• for supra-orbital artery and ophthalmic nerve
(frontal bone)
orbital part
o roof of each orbit
♣ lacrimal fossa = location of lacrimal gland
frontal sinuses
air pockets that vary in size and time of development (usually beginning after age 6)
temporal bones ?
o form lateral and inferior walls of cranium and zygomatic arches of cheek
o articulates with mandible, zygomatic, parietal, sphenoid and occipital bones
o protects sense organs of inner ear
squamous part of temporal bone
o lateral portion joined to parietal bone by squamous suture
♣ inferior margin - zygomatic process (anterior projecting) of the temporal bone
• joins with the temporal process of zygomatic bone to form zygomatic arch (“cheekbone”)
mandibular fossa
o site of articulation with mandible
♣ located inferior to zygomatic process
(temporal bone)
external auditory meatus
o canal) – posterior and lateral to mandibular fossa
♣ transmits sound waves toward tympanic membrane of ear
(temporal bone)
mastoid process
o posterior and inferior to external auditory meatus
♣ projection of bone filled with air cavities = mastoid air cells
♣ mastoid air cells connected to middle ear
♣ attachment site of neck muscles that rotate head
(temporal bone)
petrous part
o thick bony ridge on interior and inferior to squamous part
♣ hollow and contains the middle (containing auditory ossicles) and inner ears
internal acoustic meatus
(auditory canal) – carries blood vessels and nerves to inner ear
petrous part
carotid canal
♣ anterior and medial to jugular fossa (anterior half of jugular foramen)
• passageway for internal carotid artery (main blood supply to brain)
♣ thin plate of bone separates the carotid canal from the middle ear allowing person to hear their own heartbeat (pulsing of carotid blood flow) when frightened or after running
styloid processes
petrous part
♣ long pointed projection of bone from the floor of the temporal bone
= bony attachment for muscles that move tongue, pharynx and larynx
sphenoid bone
o articulates with all cranial bones and palatine, zygomatic, maxilla and vomer bones of facial complex
shaped like a giant bat with wing extending from one side to the other across floor of cranium
sella turcica
o central prominence on superior surface of sphenoid bone
♣ cradles pituitary gland
(sphenoid bone)
greater wings of sphenoid bone
o extend laterally from sella turcica and immediately anterior to temporal bone
♣ foramen rotundum – medially and anteriorly located
♣ foramen ovale – laterally and posteriorly located
• carry blood vessels and nerves to structures of orbit, face and jaws
lesser wings of sphenoid bone
o ridge and wings anterior to sella turcica form that articulates with frontal bone
♣ optic groove = transverse groove with optic canals carries optic nerve from eyes to brain
♣ superior orbital fissure – inferior surface forming part of orbit and passageway for blood vessels and nerves
pterygoid processes
o vertical projections from inferior surface between greater and lesser wings
♣ medial and lateral plates attachment site for muscles that help move the mandible and soft palate
Ethmoid bone
o forms anteromedial floor of cranium and part of orbital wall
cribriform plate
o superior portion of ethmoid bone
♣ contains cribriform foramina – tiny sieve-like perforations
• allows passage of olfactory (smell) sensory nerve endings to enter from the nasal cavity and coalesce to form the olfactory bulbs
(part of ethmoid bone)
crista galli
o prominent ridge separating right and left sides of cribriform plate
♣ attachment point for dura mater = thick connective tissue and outermost of the meninges
(part of ethmoid bone)
nasal conchae (superior and middle)
o bony shelves that increase surface area in nasal cavity
♣ turbulent air movement facilitates moistening, warming and removal of particles in inhaled air, facilitates exposure to olfactory endings
(part of ethmoid bone)
perpendicular plate –
forms part of nasal septum
part of ethmoid bone
Cranial Fossae
depressions found in the floor of the cranium
consist of anterior , middle and posterior cranial fossa
anterior cranial fossa
• frontal, ethmoid and greater wings of sphenoid bones
o cradles frontal lobes of the cerebral hemisphere
middle cranial fossa
• sphenoid, temporal and parietal bones – contains several important foramen
o houses temporal lobes of cerebral hemispheres, diencephalon (thalamus, hypothalamus) and anterior portion of brain stem (mesencephalon)
posterior cranial fossa
• mainly formed by the occipital bone (contributions from temporal and parietal bones)
o supports occipital lobes of cerebral hemispheres, cerebellum and posterior brain stem (pons and medulla oblongata)
Facial Bones
• Maxilla (upper jaw) (Fig 6.12) – anterior and inferior to zygomatic bone
o orbital surface = protection for the eye
infraorbital foramen
o passageway for major sensory nerve from face and penetrates orbit rim
frontal process
articulates with frontal bone and nasal bone
alveolar process
contains superior set of teeth
maxillary sinuses
o largest sinuses of skull
palatine processes
o form most of the bony palate (roof) of the mouth
♣ cleft lip – occurs when maxillary bones don’t form normally
♣ cleft palate – occurs when palatine processes of maxillary bones don’t fuse with one another
• produces opening between oral and nasal cavities making it difficult to eat, drink or speak
Palatine bones
• small L-shaped bones that articulate with the maxillae to form posterior portions of bony palate
o nasal crest – articulates with vomer bone
Nasal bones
• articulates with frontal bone superiorly and maxillae laterally
o cartilage attaches to inferior margin
Inferior nasal conchae
paired scroll-like bones attached to palatine bone in lateral wall of nasal cavity
Zygomatic bone
• cheek bone (surface anatomy landmark)
o articulates with sphenoid bone posteriorly, temporal bone laterally and maxillae medially
Lacrimal bones
• sits medially in orbit and articulates with frontal bone, maxilla and ethmoid
o lacrimal groove leads to lacrimal canal formed by maxilla and lacrimal bone and encloses tear duct that empties into nasal cavity
vomer bone
forms inferior portion of nasal septum
