Download Structure of the Skeleton PPT

Chapter 7 Notes
Structure of the Skeleton
Structure of the Skeleton
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Skeletal tissue forms bones.
Bones are organized or grouped to
form major subdivisions.
Coordination of bones with joints and
muscles allows for movement.
Subdivisions of the Skeleton
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Axial - 80 bones
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Skull - face and cranium
Earbones - 3
Hyoid bone - in neck, not attached to any
other bone - helps in tongue movement
Spinal column
Sternum and ribs - thoracic cage
Hyoid Bone
Subdivisions of the Skeleton
Continued
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Appendicular skeleton - 126 bones
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Upper extremities
Lower extremities
Pectoral girdle - scapula and clavicle
Skull – 28 Bones - Major
Subdivisions
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Cranium - brain case
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Frontal - forehead and anterior top
Parietal (2) - give shape to top side of cranium
Temporal - lower sides of cranium
Skull - Major Subdivisions
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Occipital - framework for lower, posterior skull
Sphenoid - helps form the base of the cranium
Ethmoid - irregular bone, posterior to nasal bones
Skull - Major Subdivisions
Continued
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Face
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Maxilla
Mandible - lower
jaw, only movable
structure of face;
strongest of face
Zygomatic arch shapes cheeks
Nasal bones shapes nose
Skull
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Mastoiditis
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Inflammation of the air spaces within the
mastoid portion of the temporal bone.
Could spread to brain if left untreated.
Skull
Vertebral Column – Spinal
Column
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Longitudinal axis of skeleton
Flexible due to segmentation
Backbone of body
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head balanced on top
ribs suspended in front
lower extremities attached below
spinal cord enclosed within
Division of Column
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Cervical vertebrae - 7
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Framework for the neck
1st = atlas
2nd = axis – for neck
rotation
Thoracic vertebrae - 12
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Allows for rib attachment
Lumbar
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Support small of back
Sacrum and Coccyx
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Fusion of vertebrae
Structure of a Single
Vertebrae
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Body - flat, round
surface
Spinous process backwards
projections
Transverse process lateral projections
(winglike)
Vertebral foramen hole for spinal cord
Curved - allows for
strength and balance
Pathological Curvatures of the
Spine
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Lordosis
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curve in lumbar region is exaggerated in
concavity
Pathological Curvatures of the
Spine
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Scoliosis
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any region is abnormally curved laterally
Pathological Curvatures of the
Spine
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Kyphosis
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hunchback
convexity in thoracic region
Shoulder Girdle
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Clavicle
Scapula
Forms one joint
with trunk
between 2 bones.
All shoulder
movement involves
this joint.
Pelvic Girdle
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Stable, circular base,
supports trunk and
attaches lower
extremities.
Three Parts
Ilium - largest and
uppermost bone
Ischium - strongest
and lowermost bone
Pubis - anteriormost
bone
Strong ligaments
attach sacrum to each
hip bone.
Sternum
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Medial part of
anterior chest wall.
Xiphoid process
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cartilaginous lower tip
Ribs
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True Ribs – attached to
sternum
False Ribs – their
cartilages do not reach
sternum directly
Floating – no
attachment to sternum
Upper Limb
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Humerus
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Long bone that extends
from the scapula to the
elbow (when hit at
distal end it is known as
the funny bone).
Upper end has smooth
rounded head that fits
into cavity of scapula.
2 processes just below
the head, greater and
lesser tubercles .
Provide attachment
for muscles.
Upper Limb Continued
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Radius
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Located on the thumb
side of the forearm.
Extends from the
elbow to the wrist and
crosses over ulna.
Ulna
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Longer than the radius.
Overlaps the end of
the humerus
posteriorly.
Wrist and Hand
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Wrist - consists of 8
small bones - carpals
2 rows of 4 bones each
Hand - palm and 5
fingers
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Palm - metacarpals – 5 line up with each finger
Numbered 1 to 5 beginning
with metacarpal of thumb.
Fingers – phalanges - 14 in
each hand
3 in each finger
A proximal, a middle, and a
distal phalanx
2 in the thumb – missing
middle phalanx
Lower Limb
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Femur
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Thigh bone
Longest bone in the
body - extends from
the hip to the knee.
Patella
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Kneecap
Located in a tendon
that passes anteriorly
over the knee.
Lower Limb Continued
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Tibia
Largest and strongest
bone of the lower leg.
Located medially and
superficially.
Atriculates with the
fibula and talus to
form ankle joint.
Fibula
Smaller lower leg
bone.
Located laterally and
deep.
Foot
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Structure
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Arches allow for great
support.
Big toe much more
stable than thumb.
Tarsals (7)
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Create ankle bones
Strong ligaments and
leg muscle tendon
keeps arches of foot.
Foot Continued
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Metatarsals (5)
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Framework for soles of
feet.
Articulate with phalanges.
Numbered 1 to 5 beginning
on medial side.
Phalanges
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Shorter than that of the
fingers.
Align and articulate with
metatarsals.
Each toe has 3 phalanges
(same as hand).
Big toe has 2.
Skeletal Differences
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Males
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Larger and heavier
Pelvis is deep and funnel shaped
Pubic arch is narrow
Females
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Pelvis is shallow, broad and flaring
Pelvic arch is wider
Age Changes in Skeleton
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Incremental decrease in height that
begins about age 30.
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1/16 of an inch a year
Calcium levels fall
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Bones become brittle and increasingly
prone to fracture.
Osteoclasts outnumber Osteoblasts.