Skull Vertebral Column Hyoid Bone amp Thoracic Cage Functions T he Skeleton Supports rigid framework to support soft tissue that weighs 5x the amount of the skeleton Protects Organs are protected by ribs cage amp pelvis amp marrow is protected red ID: 1044100
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1. Skeletal System Axial SkeletonSkull, Vertebral Column, Hyoid Bone & Thoracic Cage
2. FunctionsThe Skeleton:Supports – rigid framework to support soft tissue that weighs 5x the amount of the skeletonProtects - Organs are protected by ribs cage & pelvis & marrow is protected; red blood cell made inside the bonesMoves - body movement occurs b/c the skeleton provides anchoring attachments for skeletal musclesProduces (Hemopoiesis) - blood cells are produced in bone marrow Stores (Mineral Storage) - calcium, magnesium, sodium, fluorine, phosphorous
3. Bone ShapesLong – longer than they are wideEx: most bones of the extremitiesShort – somewhat cubed shapedEx: carpal bones (wrist) and tarsal bones (ankle)Flat – have broad surfaces for muscle attachment or protection of underlying organsEx: cranial bones, ribs, scapula (pectoral girdle)Irregular – varied shapes and many surface features for muscle attachment and articulation. Protect nervous tissue and offer support.Ex: vertebra, sacrum, and hyoid bone
4. The Skeleton is Divided into 2 parts = 206 bones 1. Axial Skeleton – bones that form the upright axis of the body and support and protect the organs of the head, neck and trunkSkullRibcage (Thoracic cage)Vertebral ColumnHyoid Bone2. Appendicular Skeleton - Upper and lower extremities and bony girdles that anchor those appendages to the axial skeletonPectoral GirdleUpper ExtremityPelvic GirdleLower Extremity
5. Cranium, 22 bones (8 cranial & 14 Facial)1. Frontal Bone – anterior bone, above orbit: forms forehead roof of nasal cavity, and superior arch of orbit2. Parietal Bone (2) – between frontal bone and occipital bone3. Temporal Bone (2)– lateral bone, auditory opening and *zygomatic process of temporal bone4. Occipital Bone – posterior bone, forms the base of the skull has the foramen magnum & occipital condyles Foramen Magnum – opening in the skull for the spinal cord Occipital Condyles – articulating surface for C1, atlas5. Sphenoid – form the anterior base of the cranium (moth shaped), can be viewed laterally & inferiorly6. Ethmoid – anterior floor of cranium between the orbits, forms the roof of the nasal cavity7. Maxilla (2) – upper jaw, supports upper teeth forms roof of mouth and medical orbit8. Palatine Bone (2) - form the posterior third of the hard palate , part of the orbit & part of the nasal cavity9. Zygomatic Bone (2) – anterior bone, shapes cheek bones, forms lateral orbit and orbital floor: *temporal process of zygomatic bone* Zygomatic Arch = zygomatic process of temporal bone & temporal process of zygomatic bone articulate to form a bridge across the side of the skull10. Lacrimal (2) – form the anterior part of the medial wall of each orbit. These are the smallest facial bones11. Nasal Bone - bridge of nose12. Inferior Nasal Concha (2) – fragile scroll like bones that project horizontally & medially from the lateral wall of the nasal cavity13. Vomer – thin flattened bone that forms the lower part of the nasal septum14. Mandible – lower jaw, largest & strongest bone in the face, only moveable bone of the skull, articulates with the temporal bone* Orbit – cone shaped fossa, opening for the eyeMade up of 7 separate bones: frontal, sphenoid, zygomatic, maxilla, lacrimal, ethmoid, and palantine
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7. Cranium – Anterior View
8. Cranium – Inferior View
9. Bony Anatomy Cranium
10. Vertebral ColumnMade up of 7 Cervical Vertebrae, 12 Thoracic Vertebrae, 5 Lumbar Vertebrae, Sacrum & CoccyxThe vertebral column protects the spinal cord & nerve roots
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12. Cervical VertebraeSeven, C1 – C7C1 has no body & is called the ATLAS. C1 allows you to shake your head yes (flexion & extension). C1 also articulates with the occipital condyles of the skullC2 has the odontoid process, also called the dens . C2 is called the AXIS. C2 allows you to shake your head no (rotation)C7 has the most prominent spinous process of all cervical vertebrae.Cervical vertebrae are the smallest of all vertebrae, but the bone tissue is more dense than any other vertebrae.
13. Atlas & Axis
14. Thoracic VertebraeTwelve, T1 – T12The twelve thoracic vertebrae articulate with the ribs posteriorly (thoracic cage, anchors to axial skeleton through thoracic vertabrae)Thoracic vertebrae are bigger than cervical vertebrae.Each thoracic vertebrae gradually increases in size from T1 – T12.
15. Lumbar VertebraeFive, L1 – L5Lumbar Vertebrae have very heavy bodiesBack muscles attach to the very large, thick, blunt spinous processes.Lumbar vertebrae are the largest in the vertebral column.The sciatic nerve originates from the space between L4 & L5. The sciatic nerve is the longest nerve in the body.
16. Sacrum & CoccyxThe sacrum is the foundation of the pelvic girdle, but still part of the axial skeleton.The sacrum articulates with the ilium to form the Sacroiliac Joint. The SI joint is where the appendicular skeleton attaches to the axial skeleton (lower extremity)The sacrum is wedge shapedThe sacrum consists of 3-5 vertebrae that fuse after age 26The coccyx is also know as the tailbone.The coccyx is triangular in shapeThe coccyx consists of 3-5 fused coccygeal vertebrae.
17. Thoracic Cage, AKA RibcageThe thoracic cage is a cone shaped, flexible cage that encloses & protects vital body organs. The thoracic cage is directly involved in breathing. The thoracic cage is made up of 12 thoracic vertebrae, 12 pair of ribs, costal cartilage & the sternum. The thoracic cage protects the lungs, gall bladder, liver, kidneys, stomach, pancreas, spleen & heart.
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19. Ribs12 pair attach posteriorly to the thoracic vertebrae.All ribs have a neck, angle & body.TRUE RIBS 1st seven pair, anchored individually by costal cartilageFALSE RIBS Pair 8- 12, attach to sternum by a web of cartilage located at rib 7FLOATING RIBS Pair 11 & 12, do not attach to the sternum.
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21. SternumAlso known as the breastbone.The sternum protects the heart.The sternum also supports the pectoral girdle & upper extremities.The appendicular skeleton attaches to the axial skeleton at the Sternoclavicular Joint. The SC joint is where the sternum & clavicle articulate.The sternum is comprised of 3 separate bonesUpper = Maubrium (sword handle)Central = Body (sword blade)Lower = Xiphoid Process (sword tip)
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