Skeletal System

1
Skeletal System

• Bones are divided into 2 main parts axial
  skeleton appendicular skeleton
• Male bones tend to be larger heavier than
  female skeleton Female pelvic cavity is wider to
  accommodate childbirth
• Babies are born with 270 soft bones. By adulthood
  there are 206 bones. (fusions)

2
Functions of Skeletal System

• SUPPORT - organs and tissues of the body are
  held in place by the skeleton.
• PROTECTION provides a rigid surface for
  protection of vital organs i.e. cranium protects
  the brain

• MOVEMENT bones provide a base for muscle
  attachment. It allows movement of the body
  through using the bones as levers.
• PRODUCTION STORAGE bones provide a site for
  manufacture of red white blood cells and
  storage of minerals. i.e. calcium

3
Bones

• Consist of microscopic cells called osteocytes.
• Made up of 35 organic material
• 65 inorganic salts, minerals water
• Organic part derived from collagen
• Bone formation
• Embryonic skeleton consists of collagenous
  protein fibers secreted by osteoblasts
• During embryonic development, ossification
  begins mineral matter replaces cartilage bone

4
Structure of a Long Bone

• Diaphysis shaft of bone
• At each end of bone is an epiphysis
• In center of shaft is the broad medullary cavity,
  filled with yellow bone marrow
• Medullary cavity is surrounded by compact bone
  that carries blood vessels to nourish osteocytes
• Where less strength is needed, hard bone
  dissolves to spongy bone
• Outside of bone is covered with periosteum,
  necessary for bone growth, repair nutrition

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Types of Bones

• Long Bones
• Much longer than they are wide.
• All bones of the limbs except for the patella
  (kneecap), and the bones of the wrist and ankle.
• Consists of a shaft plus 2 expanded ends.
• Short Bones
• Cube-like in shape
• Found in carpals (wrist bones) tarsals (ankle
  bones)

• Flat Bones
• Thin, flattened, and usually a bit curved.
• Scapulae, sternum, (shoulder blades), ribs and
  most bones of the skull.
• Irregular Bones
• Have weird shapes that fit none of the 3 previous
  classes.
• Vertebrae, hip, 2 skull bones (sphenoid the
  ethmoid bones).

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Types of Bones
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Axial Skeleton (green)

• Includes 80 bones
• Consists of skull, spine, ribs, sternum
• Responsible for protection support

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Skull (28 bones)

• Cranial Bones
• Parietal (2)
• Temporal (2)
• Frontal (1)
• Occipital (1)
• Ethmoid (1)
• Sphenoid (1)
• Facial Bones
• Maxilla (2)
• Zygomatic (2)
• Mandible (1)
• Nasal (2)
• Palatine (2)
• Inferior nasal concha (2)
• Lacrimal (2)
• Vomer (1)
• Hyoid
• Auditory Ossicles
• Malleus (2)

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Vertebral Column

• Divided into 5 sections
• Cervical vertebrae
• Thoracic vertebrae
• Lumbar vertebrae
• Sacral vertebrae
• Coccyx
• Strong flexible
• Supports head provides attachment for the ribs
• Encloses spinal cord

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Cervical Spine

• Cervical Spine
• First seven bones of the spinal column
• C1 (Atlas) articulates with the axis and
  occipital bone
• Allows us to nod head
• C2 (Axis) articulates with atlas
• Allows us to turn our heads

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Thoracic Lumbar Spine

• Thoracic Spine
• 12 segments of the vertebral column that
  articulate with ribs to form part of the thoracic
  cage
• Lumbar Spine
• 5 vertebrae located in the lower lumbar region of
  the back
• Have larger bodies to bear most of body weight

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Spine

• Sacrum
• Wedge-shaped unit formed by 5 fused bones
• Forms posterior pelvic girdle
• Serves as articulation point for the hips

• Coccyx
• Known as tailbone
• Last bone of the spinal column
• Formed by four fused bones

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Parts of a Vertebra
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Vertebral Characteristics
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Ribs Sternum

• Supports protection of thoracic cavity
• Ribs
• 7 TRUE ribs
• 5 FALSE ribs
• 1st 3 pairs connected to the 7th true rib
• Last 2 pairs have no anterior connection
  (Floating Ribs)
• Sternum Breastbone located between ribs
• Manubrium
• Body
• Xiphoid Process

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Appendicular Skeleton

• Bones of the upper extremity (UE)
• Shoulder girdle
• Arm, Wrist, Hand
• Bones of the lower extremity (LE)
• Pelvic Girdle
• Leg, Ankle, Foot

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Upper Extremity

• Shoulder Girdle
• Scapula
• Clavicle
• Humerus
• Forearm
• Ulna
• Radius
• Carpals (8)
• Metacarpals (5)
• Phalanges (14)

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Carpal/Hand Bones

• Carpals
• Proximal (Lat.-Med.)
• Scaphoid
• Lunate
• Triquetral
• Pisiform
• Distal (Lat.-Med.)
• Trapezium
• Trapezoid
• Capitate
• Hamate
• Metacarpals (1-5)
• Phalanges (1-5)
• Proximal
• Middle
• Distal

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Lower Extremity

• Pelvic Girdle (2 Hip Bones)
• Ischium
• Ilium
• Pubis
• Upper Leg
• Femur
• Patella
• Lower Leg
• Tibia
• Fibula
• Tarsals (7)
• Metatarsals (5)
• Phalanges (14)

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Pelvic Girdle
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Foot/Ankle Bones

• Ankle Tarsals
• Talus
• Calcaneus
• Navicular
• Cuboid
• Cuneiforms
• Lateral
• Intermediate
• Medial
• Metatarsals (1-5)
• Sesamoid bones (hallux only)
• Phalanges (1-5)
• Proximal
• Middle
• Distal