Organization of the Skeleton

Axial Skeleton Appendicular Skeleton

Axial Skeleton is the “blue” Appendicular Skeleton is the “purple”

The axial skeleton is composed of the skull, vertebral column, and thoracic cage. Each of these is essentially a “shaped box” which house and protect the most vital and vulnerable organs of the human body, such as the brain, spinal cord, and the heart, lungs, and kidneys.

Axial Skeleton

The Skull – consists of 29 bones and can be subdivided into five areas:

Part One

Five Subdivisions of the Skull:

• Cranium (8)

• Facial Bones (14)

• Hyoid Bone(1)

• Ossicles of the Ear (6)

• Wormian Bones (?)

Skull Subdivision One

• The Cranium

The Cranium (a.k.a. the “braincase”)

The cranium consists of eight (8) bones and is specifically defined as the rounded, bony case enclosing and protecting the brain. The cranium alsofunctions as an attachment surface for important groups of muscles, and in the formation of the sinuses, which serve as resonance chambers and help to reduce the total weight of the skull.

The bones of the cranium are as follows:

– the “forehead”1. Frontal Bone (1)

The bones of the cranium are as follows:

– “top & sides of the head”2. Parietal Bones (2)

The bones of the cranium are as follows:

– the “back” of the head3. Occipital Bone (1)

The bones of the cranium are as follows:

– the “temples”4. Temporal Bones (2)

back of the eye socket, anterior temples & base of cranium

Sphenoid Bone (1)

The bones of the cranium are as follows:

The bones of the cranium are as follows:

– the ?Ethmoid Bone (1)

Summary of the Cranial BonesBones of the cranium:

• Frontal Bone (1)

• Parietal bones (2)

• Occipital bone (1)

• Temporal bones (2)

• Sphenoid bone (1)

• Ethmoid bone (1)

Skull Subdivision Two

• The Facial Bones

The Facial Bones (a.k.a. the Face)

The facial bones consist of 14 bones that compose what is known as the human face. Along with the cranial bones, they help to form the nasal cavity and also provide numerous attachment sites for important muscles that control facial expressions and move the jaw.

The bones of the face are as follows:

1. Nasal bones (2) – “bridge of the nose”

The bones of the face are as follows:2. Maxillary bones or Maxillae (2) – anterior portion of the “roof of mouth” & “upper jaw”

*Note:Maxillae are also

the anterior, medial portion of

the eye socket

The bones of the face are as follows:

3. Zygomatic bones (2) – “cheek bones”

The bones of the face are as follows:

4. Mandible (1) – “jaw bone” or “lower jaw”

The bones of the face are as follows:

5. Lacrimal bones (2) – medial part of the eye socket

The bones of the face are as follows:6. Palatine bones (2) – posterior portion of the

roof of mouth & base of the eye socket

The bones of the face are as follows:

7. Inferior nasal conchae (2) – nasal cavity “baffles”

The bones of the face are as follows:8. Vomer bone (1)

Summary of the Facial Bones

• Nasal

• Zygomatic

• Maxilla

• Mandible

• Lacrimal

• Palatine

• Inferior Nasal Conchae

• Vomer

Bones of the face: