Bones - Axial Skeleton

Sutures

Immovable joints found only between skull bones, holds all the skull bones together, 4 types

Coronal suture

Between the frontal and parietal bones

Sagittal suture

Between the parietals

Lambdoidal suture

Between the parietals and occipitals

Squamos suture

Between parietals and temporals

Components of the axial skeleton

• skull

• hyoid

• ear bones

• vertebrael column

• thorax

Hyoid

Above the adams apple, protects the airway

What bones are the smallest in the body

Earbones

Thorax is made up of

• Sternum

• Ribs (24)

Skull is made up of

• Cranial bones

• Facial bones

Cranial bones

• Frontal bone (1)

• Parietal bones (2)

• Temporal bones (2)

• Occipital bone (1)

• Sphenoid bone (1)

• Ethmoid bone (1)

Frontal bone

• Forms the forehead

• Forms roofs of the orbits (eye sockets)

• At birth: 2 bones, fused by age 6

• Sinuses are found behind

Parietal bones

• Form portions of the sides and roof of cranial cavity

Temporal bones

• From the inferior of the cranium

• Forms the temple

4 portions of temporal

1. Zygomatic

2. Mastoid process

3. Styloid process

4. External auditory

Zygomatic

Forms outer side of the cheek bone

Mastoid process

Serves as point of attachment for neck muscles

Styloid process

Attachment for ligaments of tongue and neck

External auditory

Ear canal

Occipital bone

• Forms posterior and base of cranium

• Foramen magnum: large hole in inferior part of medulla oblongata, vertebrael and spinal arteries pass through

Sphenoid bone

• Middle part of the base of the skull

• Joins all other cranial bones and holds them together

Ethmoid bone

• Light spongelike bone located in anterior part of cranial floor (eye sockets)

Facial bones

• Nasal bones (2)

• Maxilla (2)

• Zygomatic bones (2)

• Mandible (1) - only bone in the skull that can move

• Lacrimal bones (2)

• Palantine bones (2)

• Vomer (1)

5 parts of vertebral column (26)

• Cervical (7)

• Thoracic (12)

• Lumbar (5)

• Sacrum (1)

• Coccyx (1)

Cervical

• Supports the head

• Bifid spinous that split

• C1: The first vertebrae is called the atlas, allows the head to nod yes

• C2: The second vertebrae is called the axis, and allows the head to rotate and signify

• top piece of C2 is the dens/odontoid

Thoracic

• downward spinous (giraffe)

• articulates with the ribs

Lumbar

• square spinous (moose)

• largest and strongest of the vertebrae

Sacrum

• permits the articulation of two hip bones

Coccyx

• is the remnant of a tail

• points inferiorly in females, anteriorly in males

Vertebral discs

Seperated by cartilage that cushion and absorb shock

Vertebrae Disorders

• Herniated disc/slipped discs

• Scoliosis: lateral bend of column

• Kyphosis: hunchbac

Rib cage

Consists of 12 pairs of ribs and the sternum

3 parts of the sternum

1. Manubrium

2. Body

3. Xiphoid

True ribs

1st-7th pairs of ribs connect directly to sternum

False ribs

7th-12th pairs of ribs do not connect directly, connect by cartilage

Floating ribs

11th and 12th pairs do not connect at all

Parts of a rib

• Head

• Tubercle

• Body

• Facets

• Intercostal spaces

Head of rib

Projection at posterior end

Tubercle of rib

On posterior surface, where neck joins body

Body of rib

Main part of rib

Facets of rib

Articulates with thoracic vertebrae

Intercostal spaces of ribs

Spaces between the ribs