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Skeletal System
Mrs. Northeim
Part 1 of 2
Anatomy & Physiology
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
25-2
Skeletal/Bone
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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
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Classification by shape
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Long bones – located primarily in the arms and legs
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Femur (thigh bone)
Humerus (upper arm bone)
Short bones – small bones
located in the wrists
and ankles
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Carpals (wrist bones)
Tarsals (ankle bones)
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Bone Structure (cont.)
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Flat bones – located in the
skull and rib cage
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Ribs
Frontal bone
Irregular bones
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Vertebrae
Bones of the pelvic girdle
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How we will study the bones.
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Divisions
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Axial – 80 bones
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Skull
Vertebral column
Rib cage
Appendicular – 126 bones
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Arms and legs
Pectoral girdle
Pelvic girdle
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Main parts of axial skeleton
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Skull
Vertebral column
Thoracic cage
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Cranium - Skull
1. 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
A relatively deep pit or depression
Fossa
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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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25-14
Hyoid Bone
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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
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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
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Cervical vertebra
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Thoracic vertebra
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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
12 of them, called T1-T12
Lumbar vertebra
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5 of them, called L1-L5
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Vertebral column
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Sacral vertebrae “sacrum”
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A fusion of 5 bones, S1-S5
Coccyx – “tail bone”
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A single bone. Fusion of 4 or 5.
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The Spinal
Column
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7 cervical vertebrae
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12 thoracic vertebrae
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5 lumbar vertebrae
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Sacrum
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Coccyx
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Vertebrae Compared
Superior View of Cervical, Thoracic & Lumbar Vertebrae
Posterior View of the Sacrum
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7.
8.
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11.
12.
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Body
Vertebral foramen
Anterior tubercle
Posterior tubercle
Foramen transversarium
or transverse foramen
Demifacet for head of rib
Superior articular process
Pedicle
Lamina
Transverse process
Spinous process or spine
Lateral mass
Posterior sacral foramina
Coccyx
Sacral hiatus
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Sternum
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Dagger shaped bone, called “breastbone”
Manubrium
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Top part of sternum
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Body
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Mid part of sternum bone below Manubrium
and above Xiphoid process.
Xiphoid process
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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.)
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12 pairs of ribs
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All are attached
posteriorly to thoracic
vertebrae
True
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First seven pairs of ribs
Attach to sternum by
costal cartilage
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False
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Rib pairs 8, 9, and 10
Attach to the costal
cartilage of rib pair 7
Floating
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Rib pairs 11 and 12
Do not attach anteriorly
to any structure
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