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Axial Skeleton
Skull
 Cranial Bones
 Facial Bones
Cranial Bones
 Frontal Bone – Forms the forehead, the
roofs of the orbits, and most of the
anterior part of the cranial floor
Cranial Bones
 Parietal Bones – form the greater portion
of the sides and roof of the cranial cavity
Cranial Bones
 Temporal Bones – Form the inferior
lateral aspects of the cranium and part of
the cranial floor
Cranial Bones
 Occipital Bone – Forms the posterior part
and most of the base of the cranium
Cranial Bones
 Sphenoid Bone – Lies at the middle part
of the base of the skull
Cranial Bones
 Ethmoid Bone – a light, sponge-like bone
located on the midline in the anterior part
of the cranial floor medial to the orbits.
Facial Bones
 Nasal Bones – meet at the midline and
form part of the bridge of the nose
Facial Bones
 Maxillae – unit to form the upper jaw.
Cleft Palate
 If the maxillary bones do not unite during
the weeks 10 to 12 of embryonic
development, cleft palate occurs.
Facial Bones
 Zygomatic Bones – (cheekbones) form
the prominence of the cheeks and part of
the lateral wall and floor of each orbit.
Facial Bones
 Lacrimal Bones – They are posterior and
lateral to the nasal bones and form part
of the medial wall of each orbit.
Facial Bones
 Palatine Bones – They form the posterior
part of the hard palate, part of the floor
and lateral wall of the nasal cavity, and a
small part of the floor of the orbits.
Facial Bones
 Inferior Nasal Concha – form a portion of
the inferior lateral wall of the nasal cavity
and project into the nasal cavity
Facial Bones
 Vomer – A rough triangular bone on the
floor of the nasal cavity
Facial Bones
 Mandible – lower jawbone
Nasal Septum
 Divides the nasal cavity into R. and L.
sides
 Consists of vomer, septal cartilage
(hyaline cartilage), and perpendicular
plate of the ethmoid bone
Deviated nasal septum
 This occurs when the nasal septum is
deflected laterally from the midline of the
nose
Orbits
Made up of seven bones;
1. Frontal
2. Sphenoid
3. Ethmoid
4. Palatine
5. Zygomatic
6. Lacrimal
7. Maxilla
Paranasal Sinus
 Paired cavities found in the frontal,
sphenoid, ethmoid, and maxillary
Paranasal Sinus
 Lined with mucous membranes that are
continuous with the lining of the nasal
cavity
Fontanels
 Soft spots – membrane filled spaces
Fontanels
 Allow rapid growth of brain during infancy
Fontanels
 Allow skull to change shape as it passes
through the birth canal
Fontanels
 Bone ossification occurs via
intramembranous
Hyoid Bone
 Between mandible and larynx
Hyoid Bone
 Not adam’s apple
Hyoid Bone
 Suspended from the styloid processes of
the temporal bones by ligaments and
muscles.
Hyoid Bone
 Some tongue muscles attach here
Vertebral Column
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7 cervical vertebrae
12 thoracic vertebrae
5 lumbar vertebrae
Sacrum – five fused vertebrae
Coccyx – four fused vertebrae
Normal Curves
 Cervical and lumbar are convex (bulging
out)
Normal Curves
 Thoracic and sacral are concave
(cupping in)
Sternum
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Breastbone
Superior part – manubrium
Middle part – body
Inferior part – xiphoid process
Ribs
 12 pairs
Ribs
 1 – 7 pairs increase in size
 8 – 12 pairs decrease in size
Ribs
 1 – 7 true ribs (costal cartilage directly
attaches to sternum)
 8 – 12 false ribs (indirect attachment or
not at all)
Ribs
 11 – 12 floating ribs (no attachment to
sternum)