chapter 5: the skeletal system—part b
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Chapter 5:The Skeletal System—
Part B
Fracture - A break in a bone Types of bone fractures
Closed (simple) fracture – break that does not penetrate the skin
Open (compound) fracture – broken bone penetrates through the skin
Bone fractures are treated by reduction (realignment of bone ends) and immobilization (cast)6-8 weeks healing
Bone Fractures
Common Types of Fractures
Table 5.2
Bone fractures
Hematoma (blood-filled swelling) is formed Break is splinted by fibrocartilage to form a
callus of cartilage, bone, & collagen Fibrocartilage callus is replaced by a bony
callus formed of spongy bone Bony callus is remodeled to form a
permanent patch
Repair of Bone Fractures
Stages in the Healing of a Bone Fracture
Figure 5.5, step 1
Hematoma
Hematomaformation
Stages in the Healing of a Bone Fracture
Figure 5.5, step 2
HematomaExternalcallus
Newbloodvessels
Internalcallus(fibroustissue andcartilage)
Spongybonetrabecula
Hematomaformation
Fibrocartilagecallus formation
Stages in the Healing of a Bone Fracture
Figure 5.5, step 3
HematomaExternalcallus
Bonycallus ofspongybone
Newbloodvessels
Internalcallus(fibroustissue andcartilage)
Spongybonetrabecula
Hematomaformation
Fibrocartilagecallus formation
Bony callusformation
Stages in the Healing of a Bone Fracture
Figure 5.5, step 4
HematomaExternalcallus
Bonycallus ofspongybone
Healedfracture
Newbloodvessels
Internalcallus(fibroustissue andcartilage)
Spongybonetrabecula
Hematomaformation
Fibrocartilagecallus formation
Bony callusformation
Bone remodeling
Forms the longitudinal part (central line) of the body
Divided into three partsSkullVertebral columnBony thorax
The Axial Skeleton
The Axial Skeleton
Figure 5.6
Two sets of bonesCranium (encloses brain)8 bones
Facial bones14 bones
Bones are joined by sutures--interlocking immovable joints
Only the mandible is attached by a freely movable joint
The Skull
8 large flatbonesParietal & temporal – pairedParietal – superior & lateral
Meet midline at sagittal sutureMeet frontal bone at coronal suture
Temporal – meet parietal at squamous sutureExternal auditory meatus – canal to eardrumMastoid & styloid processes – attach neck
musclesFrontal – foreheadOccipital – posteriorMeets parietal at lambdoid suture
Cranium
Sphenoid - eye orbits & floor of cranial cavityOptic canal – nerve to eye
Ethmoid – roof of nasal cavity & medial eye orbitsCrista galli = cock’s comb; attaches brainCribriform plates – holes for olfactory nerves
Bones of the Skull
The Skull
Figure 5.7
Bones of the Skull
Figure 5.11
Sphenoid boneSella turcica = Turk’s saddle
Holds pituitary glandForamen ovale – cranial nerves
Between temporal & occipitalJugular foramen – junction of occipital & temporal
bonesPassage of jugular vein
Temporal boneInternal acoustic meatus – cranial nerves VII & VIICarotid canal
For carotid artery Occipital bone
Foramen magnum – spinal cord to brain
Bone Markings
Human Skull, Superior View
Figure 5.8
Lacrimal – 2; contain tear ducts Mandible – 1; largest & strongest face bone Maxilla – 2; fuse = upper jaw Zygomatic – 2; cheek bones & eye sockets Palatine – 2;
Hard palate – maxilla & palatine bonesCleft palate if not fused
Vomer – 1; forms nasal septum Inferior nasal conchae – 2 Nasal - 2
Facial Bones (14)
Human Skull, Inferior View
Figure 5.9
Paranasal Sinuses Hollow portions of bones surrounding the nasal cavity
HobanFigure 5.10
Paranasal Sinuses Functions of paranasal sinuses
◦Lighten the skull◦Give resonance and amplification to voice
HobanFigure 5.10
2006Hoban
Note how the sinuses drain into the nasal cavity…
SinusitisRecall that “-itis” means inflammation of◦Sinuses are continuous with nasal passages and throat◦Infections can travel up to sinuses
The Hyoid Bone The only bone that
does not articulate with another bone
Serves as a moveable base for the tongue
Aids in swallowing and speech
Figure 5.12
The Fetal Skull The fetal skull is large compared to the infant’s
total body length◦Adult skull – 1/8 body length
Newborn skull – ¼ body length Fontanelles – fibrous membranes connecting
the cranial bones◦Allow fetal skull to be compressed during birth◦Allow the brain to grow◦Convert to bone within 24 months after birth
Figure 5.13
The Fetal Skull
Figure 5.13
Fetal SkeletonNote how large the head is compared to the rest of the body…
Checkpoint:What is the advantage of a larger head area to the developing baby?
More area for the brain to develop properly…
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