NOTES: Skeletal Organization (Ch 7, part 2)
SKELETAL ORGANIZATION
The skeleton can be divided into 2 portions:
1) Axial Skeleton
2) Appendicular Skeleton
1) AXIAL SKELETON:
Components of
Axial Skeleton
This component includes…
SKULL Cranium (brain case) and the facial
bones
HYOID BONE Horseshoe-shaped bone in neck HYOID BONE Horseshoe-shaped bone in neck
(between lower jaw and larynx)
VERTEBRAL
COLUMN
Many vertebrae (separated by
cartilaginous intervertebral discs);
sacrum; and coccyx
THORACIC
CAGE
12 pairs of RIBS (most of which) are
connected to STERNUM (breastbone)
by costal cartilage
2) APPENDICULAR SKELETON:
Components of Appendicular Skel.
This component includes…
PECTORAL
GIRDLE
SCAPULA (“shoulder blade”) and
CLAVICLE (“collarbone”)
UPPER LIMBS HUMERUS (arm bone) and UPPER LIMBS HUMERUS (arm bone) and
RADIUS and ULNA (forearm
bones); and wrist bones and hand
bones (CARPALS,
METACARPALS, and
PHALANGES)
2) APPENDICULAR SKELETON:
Components of Appendicular Skel.
This component includes…
PELVIC GIRDLE Two COXAE (hipbones) which attach to each other on the anterior surface and to the SACRUM on the surface and to the SACRUM on the posterior surface; with the sacrum and coccyx, form the PELVIS
LOWER LIMBS FEMUR (thighbone), TIBIA(shinbone) and FIBULA; PATELLA(kneecap); and ankle bones and foot bones (TARSALS, METATARSALS, and PHALANGES)
SKULL
**The skull consists of 22 bones; 8 cranial
bones, 14 facial bones.
� CRANIUM:
• encloses and protects the brain
• some cranial bones contain air-filled SINUSES
� CRANIUM:• cranial bones include:
FRONTAL BONE ETHMOID BONE
OCCIPITAL BONE SPHENOID BONE
PARIETAL BONES (2)
TEMPORAL BONES (2)TEMPORAL BONES (2)
� FACIAL SKELETON:• facial bones form the basic shape of the
face and provide attachments for muscles
� FACIAL SKELETON:
• facial bones include:
MAXILLAE
MANDIBLE
ZYGOMATIC BONES
NASAL BONESNASAL BONES
LACRIMAL BONES
INFERIOR NASAL CONCHAE
PALATINE BONES
VOMER BONE
� INFANTILE SKULL:
• fontanels connect incompletely developed bones
• proportions of infantile skull are different from an adult skullfrom an adult skull
VERTEBRAL COLUMN
**The vertebral column
extends from the skull to the
pelvis and protects the
spinal cord. It is composed spinal cord. It is composed
of vertebrae, separated by
intervertebral discs.**
� A TYPICAL VERTEBRA:
• consists of a body and a bony vertebral arch, which surrounds the spinal cord
• notches on upper and lower surfaces provide intervertebral foramina through provide intervertebral foramina through which spinal nerves pass
**Foramina = openings through which
spinal nerves and/or blood vessels
pass**
� CERVICAL VERTEBRAE:
• the ATLAS (1st vertebra) supports and balances the head
• the dens of the AXIS (2nd vertebra) provides a pivot for the atlas when the head is turned from side to side
� CERVICAL VERTEBRAE:
� CERVICAL VERTEBRAE:
� THORACIC VERTEBRAE:
• thoracic vertebrae are larger than cervical vertebrae
• facets on the sides articulate with the RIBS
� THORACIC VERTEBRAE:
� LUMBAR VERTEBRAE:
• the vertebral bodies are large and strong
• they support more body weight than other vertebrae
� LUMBAR VERTEBRAE:
� SACRUM:
• the sacrum is a triangular structure formed of five fused vertebraefused vertebrae
• vertebral foramina form the sacral canal
� SACRUM:
� COCCYX:• the coccyx,
composed of four fused vertebrae, forms the lowest part of the vertebral of the vertebral column
• it acts as a shock absorber when a person sits
� COCCYX:
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