Download File - Mrs. Sanborn`s Science Class

Skull of the Adult
Skeleton
Found in the Axial Skeleton
http://anatomyphysiologystudyguide.com/acti
vities-by-system/skeletal-system
General Characteristics
• Usually 22 bones
• Sutures interlocking all bone except the
mandible.
• Cranium & Facial skeleton
Cranium
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Encloses and protects the brain.
Surface provides attachments for muscles
Sinuses- Air filled cavities
8 bones
• Frontal bone (1)-anterior portion of
the skull above the eyes(orange).
• Parietal bone(2)-located on each side
of the skull just behind the frontal
bone(blue).
• Occipital bone(1)-joins the parietal
bones & forms the back of the skull
Articulates with 1st vertebrae
(purple).
• Temporal bone(2)-beneath the
parietal bones on each side of the skull.
Articulates with the mandible and
houses the external/internal ear (red).
• Sphenoid bone(1)-Wedged between
several other bones in the anterior
portion of the cranium(rose).
• Ethmoid bone(1)-front of the sphenoid
bone(pink).
Facial Skeleton
• 13 immovable bones and a movable lower jaw.
• Forms face shape & facial expressions
• Provides attachments for muscles
• Maxillary bones(2)-upper jaw, keystone
of the face(yellow).
• Palatine bones(2)-L-shaped located
behind the maxillae. Form lateral walls
of nasal cavity(light blue).
• Zygomatic bones(2)-prominence of
cheek and sides of the eyes(green).
• Lacrimal bones(2)-thin, scale-like
structure located on the medial wall
of each orbit(blue).
• Nasal bones(2)-long , thin & nearly rectangular.
Lie side by side and are fused to form
nose(teal).
• Vomer bone(1)-thin, flat at midline
within nasal cavity(magenta)
• Inferior nasal conchae(2)-fragile, scrollshaped bones attached to the lateral wall
of the nasal cavity(blue).
• Mandible(1)-lower jawbone &
horseshoe shaped body(orangish).
Middle Ear Bones & Hyoid
Bone
Found in the Axial Skeleton
Middle Ear Bones
• 6 bones
• Malleus(2)-mallet
shape,vibrations
• Incus(2)-middle, vibrations
• Stapes(2)-stirrup-shaped
bone, transmits vibrations
from the incus
Hyoid Bone
• 1 bone
• Located in the neck between the lower jaw
and the larynx (voice box)
• Supports the tongue.
Vertebral Column
Found in the Axial Skeleton
Characteristics
• Extends from the skull to
the pelvis & forms the
vertical axis of the skeleton.
• Composed of many bones
called vertebrae separated
by fibrocartilage called
intervertebral discs.
• Supports head and trunk
• Protects spinal cord
• Infant=33 & Adult=26
• 4 curves which correspond
to their region in body:
cervical, thoracic, lumbar
and pelvic.
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Cervical
7 bones
Small but dense tissue
Atlas- C1, supports the head
Axis-C2, has a toothlike
process called dens the atlas
can pivot around when head
moves side to side.
Thoracic
• 12 bones
• Larger than cervical
• Pointed spinous process, slopes downward and has
facets on sides of it body which articulates with the
ribs.
• Increase in size inferiorly
Lumbar
• 5 bones
• Lower back
• Support more weight and are larger/stronger
Pelvic
• Consists of the Sacrum and Coccyx
• Sacrum- triangular structure at the base of the
vertebral column. Composed of five fused vertebrae.
• Coccyx-tailbone, four fused vertebrae.
Thoracic Cage
Found in the Axial Skeleton
Characteristics
• Includes the ribs, the thoracic vertebrae, the
sternum and the costal cartilages that attach
the ribs to the sternum
• Support shoulder girdle and upper limbs,
protect the viscera in the thoracic & upper
abdominal cavities and play a role in
breathing.
Ribs
• Usually 24 bones, attached to the 12 thoracic
vertebrae.
• First 7 rib pairs called true ribs-join the sternum by
their costal cartilage (hyaline cartilage)
• Next 5 pairs are called false ribs-cartilage doesn’t
reach the sternum directly.
– Last 2 ribs called floating ribs-only attached to
vertebrae
• Rib has a long, slender shaft which curves around
the chest and slopes downward.
Sternum
• Breastbone
• Located along the midline
in the anterior portion of
the thoracic cage.
• Flat, elongated bone-3
parts (upper manubrium,
middle body, lower
xiphoid)
Pectoral Girdle
Found in the Appendicular Skeleton
Characteristics
• Shoulder girdle
• Four parts: 2 clavicles (collarbones), 2 scapulae
(shoulder blades)
• Incomplete ring structure
• Supports upper limbs & attachment for several
muscles that move the limbs.
Clavicles
• Slender, rodlike bones with elongated S-shapes
• Located at the base of the neck, running
horizontally between the sternum and the
shoulders.
• Structurally weak
• Help holds shoulder in place
Scapulae
• Broad, triangular bones located on either side of the
upper back.
• Spine divides into unequal portions
Upper Limbs
Found in the Appendicular Skeleton
Characteristics
• Form the framework
of the arm, forearm
and hand.
• Include the humerus,
radius, ulna,
metacarpals and
phalanges.
Humerus
• Long bone that
extends from the
scapula to the elbow.
• Numerous tubercles
provide attachments
for muscles
Radius
• Located on the thumb side
of the forearm
• Somewhat shorter than ulna
• Extends from the elbow to
the wrist
Ulna
• Wrench-like opening at
proximal end
Hand
• Wrist, palm and fingers
• Each wrist has 8 small carpal bones (2 rows of 4)carpus.
• Each hand has 5 metacarpal bones in line with
each finger (numbered from thumb to pinkie)
• Each hand has 14 phalanges, which are the finger
bones. There are 3 in each finger-proximal, middle
and distal & 2 in the thumb.
Pelvic Girdle
Found in the Appendicular Skeleton
Characteristics
• Consists of two coxae or hipbones which
articulate with each other anteriorly.
• The sacrum, coccyx and pelvic girdle together
form the bowl shaped pelvis
• Supports the trunk of the body, provides
attachments for lower limbs, protects the
urinary bladder, distal ends of the large
intestines & the internal reproductive organs.
Characteristics cont.
• Each coxa, hipbone develops from three parts
– They fuse together in the region of a cup-shaped cavity
called the acteabulum which is where the femur bone
articulates.
• 3 bones:
– Illium-largest and most superior portion of the coxa
flares outward forming the prominence of the hip.
– Ishium-forms the lowest portion of the coxa, is L-shaped.
Helps support body while sitting.
– Pubis-anterior portion of the coxa. 2 pubic bones come
together to form a joint called the symphysis pubis.
• Ishium & pubis creates the largest foramen in the body.
Male vs. Female Pelvis
• Female illiac bones are more
flared & hips are broader
• Angle of female pupic arch
may be greater, greater
distance between ischial
spines and ischial tubersosity
& the sacral curvatures may
be shorter and flatter.
• Bones of female pelvis are
usually lighter, more delicate
and show less evidence of
muscle attachments.
Lower Limbs
Found in the Appendicular Skeleton
Characteristics
• Framework of the thigh, leg
and foot.
• They include the femur, tibia ,
fibula, tarsals, metatarsals and
phalanges.
Femur
• Thigh bone, longest bone
in the body and extends
from the hip to the knee.
Patella
• Knee cap is a flat sesamoid
bone located in a tendon
that passes anteriorly over
the knee.
Tibia
• Shin bone, larger of the two
leg bones & is located on
the medial side.
Fibula
• Long, slender bone located
on the lateral side of the
tibia.
Foot
• Made up of the ankle, the instep and the toes.
• Each ankle or tarsus is composed of 7 tarsal bones.
– Talus can move freely, but remaining 6 are firmly bound
together.
– Calcaneus or heel is the largest tarsal bone. Helps support
the weight of the body.
• Instep or metatarsus consists of 5 elongated metatarsal
bones
• Tarsals and metatarsals are arranged and bound by
ligaments to form the arches of the foot
• Phalanges of the toes are shorter but similar to the
fingers