Download the skeletal system

The Axial Skeleton
THE SKELETAL SYSTEM
„ The
skeleton consists of
„ Bones
(206)
„ Cartilages
„ Joints ±also called articulations, are the junctions
between skeletal elements
„ Ligaments ±connect bones
„ Divided
into axial and appendicular parts
„ Axial skeleton - forms
„ Skull
„ Vertebral column
„ Thoracic cage
long axis of body
skeleton ±appendages and
what they attach to
„ Appendicular
„ Upper
limbs (arms)
„ Pectoral girdle (shoulder)
„ Lower limbs (legs)
„ Pelvic girdle
Axial skeleton
Skull
Vertebral column
Thoracic cage
Axial skeleton is shown in green
The Skull
„ Cranial bones (or cranium)
„ Enclose the cranial cavity, which supports and protects the brain
„ Attachment sites for some head and neck muscles
„ Facial bones (anterior aspect of skull)
„ Form framework of face
„ Form cavities for sense organs of sight, taste and smell
„ Provides openings for passage of air and food
„ Hold the teeth
„ Anchor the muscles of the face
Cranium
„ Vault
±³FDOYDULD´
VNXOOFDS
… Forms
superior, lateral and
posterior aspects of skull,
and forehead
„ Base
or floor: inferior part
… Prominent
Anterior cranial
fossa
Middle cranial
fossa
bony ridges divide
FUDQLDOEDVHLQWR³IRVVDH
(steps) ±anterior, middle and
Posterior cranial
fossa
posterior
(looking down on the floor of the skull)
Cranial bones
„ Frontal
bone
„ Parietal bones (paired)
„ Occipital bone
„ Temporal bones (paired)
„ Sphenoid bone
„ Ethmoid bone
Cranial bones
frontal
parietal
parietal
parietal
_______sphenoid
temporal
_____ethmoid
occipital
occipital
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Sphenoid
Ethmoid
Sutures
„ Immovable,
interlocking joints of flat bones of
skull
„ Irregular, saw-toothed appearance
„ Largest 4 skull sutures: where bones articulate
with parietal bones
Coronal
„ Sagittal
„ Squamous
„ Lambdoid
„
Find: sagittal and lambdoid sutures
Facial bones
„ Mandible
„ Vomer
„ Maxillae
(paired)
„ Zygomatics (paired)
„ Nasal (paired)
„ Lacrimal (paired)
„ Palatines (paired)
„ Inferior nasal conchae (paired)
The Vertebral Column
„ Fetus
and infant: 33 separate
bones, or vertebrae
„ Adult:
24 vertebrae
…Inferior
„ The
9 have fused forming
sacrum (5) and
„ The coccyx (4)
Vertebrae
±7
„ Thoracic - 12
„ Lumbar - 5
„ Sacrum (5 fused)
„ Coccyx (4 fused)
„ Cervical
Structure of a typical vertebra
Cervical vertebrae (C1-C7)
C1 (atlas)
C2 (axis)
Cervical Vertebrae
„
„
„
„
„
„
Smallest
Lightest
Most flexible
Triangular vertebral
foramen
Transverse
processes have
foramina
(transverse
foramen)
Spinous process
bifid (forked) except
for C7
Thoracic Vertebrae T1-T12
„ Heart
shaped
body
„ Additional small
costal facets
(costal=ribs)
„ Round or oval
vertebral
foramen
„ Form posterior
part of rib cage
Lumbar Vertebrae L1-L5
„ Massive
blocklike
bodies
„ Short, thick
hatchet-shaped
spinous
processes
„ Limited mobility
Shapes posterior wall of pelvis
The Sacrum Composite bone of 5 fused vertebrae
Sacral foramina allow passage of vessels & nerves
Coccyx
(the tailbone)
The Thoracic Cage
Sternum
Ribs
„ Manubrium
„ True
„ Body
„ False
„ Xiphoid
process
ribs 1-7
ribs 8-12
„ Floating
ribs 11,12
Vertebral and Sternal Articulations