Axial Skeleton

• Functions of axial

  1. Supporting

  2. Protecting

  3. Carrying other organs
• What is the cranium?

  Protects brain (thin, but strong)

  1. Two parietal

  2. Two temporal

  3. Frontal

  4. Occipital

  5. Sphenoid

  6. Ethmoid
• Mandible


  largest and strongest bone of the face
• Maxilla


  Keystone and are central portion of the facial skeleton
• TMJ


  Temporal-Mandibular Joint

  
  

  Synovial (Hinge and lateral excursion allows elevation/depression and grinding)
• Three regions of axial skeleton

  1. Skull

  2. Vertebral column

  3. Thoracic Cage
• Vertebral Column


  1. Flexible, curved structure from skull to pelvis

  
  

  2. Transmits weight at pelvis to lower limbs

  
  

  3. Attachment points
• Curvature of Vertebral Column

  Concave- cervical and lumbar

  
  

  Convex- thoracic and sacral
• Abnormalities of Curvatures


  Scoliosis, kyphosis and lordosis
• What is the vertebral column split into?

  1. Cervical

  2. Thoracic

  3. Lumbar

  4. Sacrum

  5. Coccyx
• Structure of Cervical

  smallest and lightest, carries less weight

  
  

  oval body

  short spinous= bifid (split)

  large foramina

  no intervertebral discs
• Describe C1 and C2 interaction

  Atlas carries skull

  Axis has dens that protrudes body of atlas= odontoid process

  
  

  Overall pivot joint without vertebral disc
• Structure of Thoracic

  Two facets

  Two demi facets on heart shaped body

  Circular foramen

  Long spinous process

  
  

  allows rotation but prevents flexion and extension
• How many bones in Cervical?

  7
• How many bones in Thoracic?

  12
• How many bones in Lumbar?

  5
• How many bones in Sacrum?

  5 fused together
• How many bones in Coccyx?

  4 fused together
• Structure of Lumbar

  Weight bearing/stability= thick body

  
  

  Short pedicles and laminae

  
  

  Flat dagger spinous

  
  

  large bodies
• Structure of Sacrum

  Big, long bone

  Shape posterior wall of pelvis
• What divisions are the interverbal disc thickest in?

  Lumbar and Cervical to ensure flexibility
• Describe the centre of interverbal discs

  1. Nucleolus pulposus

  - inner gelatinous nucleus

  - elasticity and compression

  
  

  2. Annulus fibrosus

  - surrounding strong collar composed of collagen and fibrocartilage

  - resists tension, twisting and expansion forces
• General Structure of Intervertrbal disc

  1. Body or centrum

  - disc shape

  - weight bearing

  
  

  2. Vertebral arch

  - two pedicle (feet)

  - two laminae (plates)

  
  

  Together forms VERTEBRAL FORAMINA
• Two processes involved in interverbal disc

  1. Spinous (posteriorly)

  2. Transverse (laterally)
• Peripheral nerves from superior to inferior

  1. Vein

  2. Artery

  3. Nerve
• Define Roots

  Dorsal= sensory

  Ventral= motor

  segregated information
• Types of motor information

  1. Somatic

  - control voluntary movements

  
  

  2. Autonomic

  - regulates involuntary process

  - eg: heart rate, blood pressure and respiratory
• Define Rami


  Short, fusion of roots

  Mixed communication and nerves
• What is the skull broken into?

  1. Cranium

  2. Facial bones
• What ligaments are involved in the vertebral column

  1. anterior and posterior longitudinal ligaments

  - anterior= body and discs (hyperextension)

  - posterior= just discs (hyperflexion)

  
  

  2. Ligamentum flavum

  - elastic connective tissue

  - stretch and recoil