2. TANVEER SAEED
Division of Skeleton
206 BONES: These bones can be grouped
in two divisions:
1. Axial Skeleton
2. Appendicular Skeleton
3. Division of Skeleton
• The 80 bones of the axial
skeleton form the vertical
axis of the body.
They include the bones of
the:
• head
• vertebral column
• ribs
• breastbone or sternum.
• The appendicular
skeleton consists of 126
bones and includes the:
• Free appendages and
their attachments to the
axial skeleton.
• The free appendages are
the upper and lower
extremities, or limbs, and
their attachments which
are called girdles.
8. Frontal and Parietal Bones
• Located anteriorly, forms part of orbital
roof, and anterior portion of cranial floor.
• Supraorbital margin – Arched ridge just
below eyebrows, forms superior edge of
orbits.
• Supraorbital foramina – in supraorbital
margin slightly medial to midpoint,
transmits nerve and blood vessels.
• Parietal Bones
• Superior lateral portion of cranium.
10. Occipital Bone
• Forms posterior wall and
floor of cranium.
• Foramen Magnum –
large passageway for
spinal cord exit from
cranium.
• Occipital Condyles –
located lateral to
foramen magnum
articulates with atlas
(C1).
• External Occipital
Protuberance –
prominent projection on
posterior surface.
12. Temporal Bone
Divided into four parts:
• Zygomatic process – projection that articulates
with zygomatic bone.
• Mastoid process – protuberance inferior and
posterior to ear, muscle attachment. Styloid
process – slender spike of bone extending
inferior and anteriorly.
• Squamous part - thin fan shaped part that
articulates with the parietal bone.
• Petrous portion- forms part of the base of the
skull and contains organ of hearing.
14. Sphenoid Bone
• Keystone of cranial floor.
• Resembles bat wings, lies deep and slightly
superior to nose and throat, forms parts of orbital
wall floor and posterior.
• Greater wings – lateral projection from body,
forms lateral wall of orbit.
• Lesser wings – superior portion of sphenoid
body, forms posterior orbital wall.
• Sella turcica –saddle shaped depression on
superior surface of body, contains Pituitary gland
(Hypophyseal gland).
17. Ethmoid
• Irregular bone that makes up the anterior portion
of cranial wall, medial wall of orbits, upper parts
of nasal septum, lateral nasal roof.
• Perpendicular plate – forms upper part of nasal
septum.
• Nasal Conchae – Upper and middle conchae
or turbinated processes.
• Horizontal (cribriform) plate – passage of
olfactory nerves through multiple openings.
18. Facial Bones
Zygomatics
• Cheekbone, forms part of anterior and lateral surface of orbit.
• Temporal process – articulates with zygomatic process of temporal
bone.
Lacrimals
• Posterior and lateral to nasal bones in median wall of orbits, forms
lateral of nasal cavity.
Palatines
• Posterior portion of hard palate, inferior and lateral surface of nasal
cavity, inferior surface of orbit.
Nasal bones
• Superior portion of nasal cavity.
Vomer
• Inferior and posterior nasal septum.
Inferior Nasal Conchae
• Turbinated bones forms posterior of nasal cavity.
20. Maxillae or Upper Jaw
• Upper jaw bones, part of floor of orbit,
anterior portion of roof of mouth and floor
of nose and part of lateral walls of nasal
cavity.
• Alveolar ridge or process-- carries teeth.
• Maxillary Sinus--- on each side lined with
ciliated mucous membrane.
21. Mandible or Lower Jaw
• Movable bone of the skull.
• Rami (ramus)
• Condyloid process – part of
each ramus that articulates
with mandibular fossa of
temporal bone forming
temporomandibular joint.
• Coronoid process--- gives
attachment to muscles and
ligaments.
22.
23. Paranasal Sinuses
• Spaces or cavities in bone those
associated with nasal cavity called
paranasal sinuses and includes:
• frontal, sphenoidal, ethmoidal, and
maxillary.
• Function – Humidify, warm and filter
inspired air through nasal cavity.
25. Fontanels
• “Soft spots” where ossification is incomplete at
birth, allows some compression of cranium at
birth to pass through the birth canal.
• Frontal (anterior) –intersection of sagittal and
coronal sutures, diamond shaped largest
fontanel.
• When does it closes?
• Occipital (posterior) – intersection of sagittal
and lambdoidal sutures.
• When does it closes?
27. Sutures
• Sutures are immovable joints between cranial
bones.
• Sagittal – between parietal bones.
• Squamous – between temporal and parietal
bones.
• Coronal (frontal) – between frontal and parietal
bones.
• Lambdoidal – between parietal and occipital.
