The Axial Skeleton

1
The Axial Skeleton

• Alyssa, Dustin, Molly and Ericka

2
Vertebrae

• Vertebrae are bony segments of the spinal column
  (backbone).
• The crisscross-like structure of the cancellous
  (spongy interior) bone in a vertebra absorbs
  external pressure

3
Types of Vertebrae

• There are three types of vertebrae
• Cervical Vertebrae
• Thoracic Vertebrae
• Lumbar Vertebrae
• Sacral Vertebrae

4
Cervical Vertebrae

• Refers to the first seven vertebrae
• They have eight pairs of cervical nerves
• They are abbreviated C1, C2, C3, C4, C5, C6 and C7

5
Thoracic Vertebrae

• Also called the vertebral column
• Stack vertically on top of each other
• Abbreviated T1, T2, T3, T4, T5, T6, T7, T8, T9,
  T10, T11, and T12

6
Lumbar Vertebrae

• Five segments of the vertebral column between the
  last thoracic vertebra and the first sacrum
  vertebra
• Abbreviated L1, L2, L3, L4, L5

7
Sacral Vertebrae

• Located just below the lumbar vertebrae and right
  above the coccyx
• They are in the lowest segment of the vertebral
  column
• Abbreviated S1, S2, S3, S4, S5

8
Atlas

• The atlas is the first cervical vertebra (C1) of
  the neck
• Supports the skull and articulates with the
  occipital bone (bone at the back of the skull)
  and rotating around the dens of the axis

9
Axis

• Second cervical vertebra (C2)
• Working with the atlas, serves as a pivot for
  turning the head

10
Sacrum

• The triangular bone just below the lumbar
  vertebrae
• Formed usually by five fused vertebrae and lodged
  dorsally between the hip bones
• The previously individual sacrum vertebrae are
  usually fused between the ages of 16-25

11
Coccyx

• Otherwise known as the tailbone, posterior to the
  sacrum
• Formed by the union of three to five undeveloped
  vertebrae
• The coccyx is the most posterior bone in the
  spinal column

12
Disorders
Kyphosis
Scoliosis
13
Kyphosis

• Kyphosis (or Scheuermanns disease in children)
  is the rounding of the top of the spine resulting
  in a sort of hunch back appearance
• Caused by trauma, developmental problems,
  degenerative diseases (ie arthritis)
• Symptoms include difficulty breathing, fatigue,
  mild back pain, round back appearance, stiffness
  in spine
• Treatments include corrective surgery and
  medications, brace and physical therapy

14
Scoliosis

• Scoliosis is the abnormal curvature of the spine
• The cause is unknown, but it does run in families
• Symptoms include Uneven shoulders, one shoulder
  blade that appears more prominent than the other,
  uneven waist, one hip higher than the other,
  leaning to one side, and fatigue
• More common in girls
• Treatments include braces, medicatons, and
  surgery

15
Discs

• Discs are types of cartilage that contain many
  fibers
• They serve as a cushion between all of the
  vertebrae of the spinal column
• They act as a ligament to hold the vertebrae
  together

16
Rib Cage

• Rib Cage is the structure formed by thoracic
  vertebrae and ribs, sternum, and the costal
  cartilages
• It protects the heart and lungs
• Also called a thoracic cage

17
True Ribs

• True ribs are the first seven pairs of ribs
• It is true if it attaches to the sternum
• Also called sternal ribs

18
False Ribs

• False ribs are the lower five ribs
• They do not directly attach to the sternum
• The upper three false ribs connect to costal
  cartilages

19
Floating Ribs

• The Floating ribs have no ventral attachment
• They are the last two false ribs
• Also called fluctuating or vertebral ribs

20
Costal Cartilages

• Costal cartilage is a bar of hyaline cartilage
  that attaches the rib to the sternum in the case
  of true ribs
• It links false ribs together

21
Sternum

• The Sternum is a long flat bone in most
  vertebrates that is situated along the ventral
  midline of the thorax and is surrounded by the
  first seven ribs
• Also called the breast bone
• It has three parts
• Body
• Manubrium
• Xiphoid Process

22
Parts of Sternum

• Manubrium- also called the handle
• Located at the top of the sternum
• Moves slightly
• Connected to the first two ribs
• Body- also called the blade or the gladiolus
• Located in the middle of the sternum
• Connects the third to seventh ribs directly and
  the eighth to tenth ribs indirectly
• Xiphiod Process- also called the tip
• Located at the bottom of the sternum
• Often cartilaginous
• Becomes bony in later years
• These three segments of bone are usually fused in
  adults