axial skeleton Flashcards
What are the two divisions of the skeletal system?
Axial & Appendicular
How many bones are in the axial skeleton?
80 bones
What are the three major segregations of the axial skeleton?
- Skull
- Vertebral column
- Thoracic cage
How many bones are in the appendicular skeleton?
126 bones
What do the appendicular bones consist of?
- Bones of upper limbs
- Bones of lower limbs
- Pectoral girdle
- Pelvic girdle
What is the composition of the skull?
- Cranial bones
- Facial bones
How many cranial and facial bones are there in the skull?
22 bones (8 cranial + 14 facial)
What is the primary function of the cranium?
Encloses and protects the brain
What are the cavities contained within the skull?
- Ear cavity
- Nasal cavity
- Orbital cavity
What are sinuses in the context of the skull?
Air-filled gaps in skull bones that lighten the skull
List the eight cranial bones.
- Frontal
- 2 Parietal
- 2 Temporal
- Occipital
- Sphenoid
- Ethmoid
What are sutures?
Immovable joints in the cranium
Name the four main sutures in the cranium.
- Squamous
- Lambdoid
- Coronal
- Sagittal
What are fontanelles?
Soft spots in the fetal skull present at birth
What is the hyoid bone?
A horse-shoe shaped bone that does not articulate with any other bone
What is the function of the hyoid bone?
Acts as a movable base for the tongue
How many vertebrae are in the vertebral column?
33 in embryo, 26 in adult
What are the types of vertebrae in the vertebral column?
- 7 Cervical
- 12 Thoracic
- 5 Lumbar
- 1 Sacral (5 fused)
- 1 Coccyx (3 or 4 fused)
What are the normal curves of the vertebral column?
- Cervical curve (concave)
- Lumbar curve (concave)
- Thoracic curve (convex)
- Sacral curve (convex)
What is lordosis?
Accentuation of lumbar curvature
What is kyphosis?
Dorsally exaggerated thoracic curvature
What is scoliosis?
Torsion with consequent lateral curvature of the spine
What are the main components of a vertebra?
- Body
- Vertebral arch
- 7 processes (transverse, spinous, superior & inferior articular)
What is the thoracic cage composed of?
- Sternum
- Costal/rib cartilages
- Ribs
- Bodies of T1-T12 vertebrae
What are the components of the sternum?
- Manubrium
- Body
- Xiphoid process
How many pairs of ribs are there and how are they classified?
- 12 pairs
- 1-7: True ribs (articulate directly with sternum)
- 8-12: False ribs
- 11-12: Floating ribs
