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Skeletal SystemMrs. NortheimPart 1 of 2Anatomy & Physiology

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Skeletal/Bone

Introduction Classification by shape Classification by division 3 main components of axial division Diagram bones

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Introduction

Bones provide the body with structure and support

206 bones with joints and connective tissue

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Bone Structure Classification by shape

Long bones – located primarily in the arms and legs Femur (thigh bone) Humerus (upper arm bone)

Short bones – small bones located in the wrists and ankles

Carpals (wrist bones) Tarsals (ankle bones)

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Bone Structure (cont.)

Flat bones – located in the skull and rib cage Ribs Frontal bone

Irregular bones Vertebrae Bones of the pelvic girdle

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How we will study the bones. Divisions

Axial – 80 bones Skull Vertebral column Rib cage

Appendicular – 126 bones Arms and legs Pectoral girdle Pelvic girdle

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Main parts of axial skeleton Skull Vertebral column Thoracic cage

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Cranium - Skull1. Cranial bones

Frontal bone – forehead Parietal bone – top sides Temporal bones – hence the name “temples” Occipital bone – back of head Sphenoid bone – resembles a bat with wings.

Anchors the frontal, parietal, occipital and ethmoid bones

Ethmoid bone – medial walls of eye orbit.

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Facial bones

Maxillae – upper jaw Mandible – lower jaw Zygomatic bones – cheek bone Nasal bones – upper nose between eye orbits,

“bridge of nose” Lacrimal bone – fingernail shaped bones by

tear ducts (nasal lacrimal ducts) Palatine bones – forms hard (anterior) portion

of palate Vomer – inside bone of nose

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Bony Structures (cont.)

Term Definition

Condyle A rounded process that usually articulates with another bone

Crest A narrow, ridge-like projection

Epicondyle A projection situated above a condyle

Foramen An opening through a bone that is usually a passageway for blood vessels, nerves, or ligaments

Fossa A relatively deep pit or depression

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Bony Structures (cont.)

Term Definition

Head An enlargement on the end of a bone

Process A prominent projection on a bone

Suture An interlocking line of union between bones

Trochanter A relatively large process

Tubercle A small, knoblike process

Tuberosity A knoblike process, usually larger than a tubercle

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Hyoid Bone U shaped bone in the neck below the

mandible and above the larnyx “Adam’s apple”…..more defined in men

– determines the tone of the larynx

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Vertebral column 24 vertebrae + sacrum + coccyx It is flexible because it is segmented Vertebral anatomy

encases the spinal cord balances the head on top Serves as point of attachment for ribs and

lower extremities

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Vertebral column Cervical vertebra

7 in the neck. Called C1-C7. Top one holds the head on – called the atlas. The second one allows the head to “swivel” – called the axis

Thoracic vertebra 12 of them, called T1-T12

Lumbar vertebra 5 of them, called L1-L5

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Vertebral column Sacral vertebrae “sacrum”

A fusion of 5 bones, S1-S5 Coccyx – “tail bone”

A single bone. Fusion of 4 or 5.

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The Spinal Column

7 cervical vertebrae 12 thoracic vertebrae 5 lumbar vertebrae Sacrum Coccyx

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Vertebrae ComparedSuperior View of Cervical, Thoracic & Lumbar VertebraePosterior View of the Sacrum

1. Body 2. Vertebral foramen 3. Anterior tubercle 4. Posterior tubercle 5. Foramen transversarium

or transverse foramen 6. Demifacet for head of rib 7. Superior articular process 8. Pedicle 9. Lamina 10. Transverse process 11. Spinous process or spine 12. Lateral mass 13. Posterior sacral foramina 14. Coccyx 15. Sacral hiatus

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Sternum Dagger shaped bone, called “breastbone” Manubrium

Top part of sternum Body

Mid part of sternum bone below Manubrium and above Xiphoid process.

Xiphoid process Little point at the end of the sternum. Often breaks

during CPR if hands are not positioned correctly.

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The Rib Cage (cont.)

12 pairs of ribs All are attached

posteriorly to thoracic vertebrae

True First seven pairs of

ribs Attach to sternum by

costal cartilage

False Rib pairs 8, 9, and 10 Attach to the costal

cartilage of rib pair 7 Floating

Rib pairs 11 and 12 Do not attach anteriorly

to any structure

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