Chapter 7 - Axial Skeleton

What are the two divisions of the human skeleton?

Axial skeleton and Appendicular skeleton.

How many bones does the Axial skeleton consist of?

80 bones.

What is the primary function of the Axial skeleton?

It helps support the head, neck, and trunk.

The skull is formed by ____ and ____ bones.

Cranial, facial

What is the function of facial bones?

They form the framework of the face and cavities for sense organs.

Name each of the cranial bones and specify which are paired/unpaired.

• Temporal (paired)

• Parietal (paired)

• Frontal (unpaired)

• Occipital (unpaired)

• Sphenoid (unpaired)

• Ethmoid (unpaired)

What is the significance of the Sphenoid bone?

It is the 'keystone' cranial bone that articulates with every other cranial bone.

What are sutures?

Interlocking, immovable joints that unite the skull bones firmly together.

What are the four major sutures of the cranium and which bones do they articulate?

• Coronal - parietal + frontal

• Squamous - parietal + temporal

• Lambdoid - parietal + occipital

  • Occipitomastoid - occipital + mastoid process of temporal bone

• Sagittal - parietal + parietal

What is the ONLY bone in the skull that moves?

Mandible.

What structure does the tympanic region of the temporal bone contain?

Stylohyoid process

What is the role of the intervertebral discs and are they found between ALL vertebrae?

They cushion the vertebrae and absorb shock. No, they are ALMOST found between all vertebrae except for C1 and C2.

How many total vertebrae are there in an adult human spine?

26 bones.

What is the distinguishable feature of cervical vertebrae?

Their short, bifid spinous processes

What connects the ribs to the sternum?

Costal cartilage.

What are true ribs?

The ribs that connect directly to the sternum (1-7).

What is the purpose of the thoracic cage?

It protects thoracic organs and supports the shoulder girdle.

What part of the sternum is considered the 'handle of the dagger'?

Manubrium.

What is the distinguishable feature of thoracic vertebrae?

Their transverse processes form the letter ‘W’

What is the distinguishable feature of lumbar vertebrae?

Their very thick bodies and “hatchet” shaped spinous processes

What is the glabella and which bone cranial bone does it belong to?

The smooth part of the frontal bone between the superciliary arches.

The occipital bone forms walls to hold the ____.

Cerebellum

The foramen magnum marks the connection of the ____ to the ____.

Brain, spinal cord

The foramen magnum is flanked by ____.

The occipital condyles

What are the four main regions of the temporal bone?

• Squamous

• Tympanic

• Mastoid

• Petrous

Which bone spans the width of the cranial floor?

The sphenoid bone

What is the “turkish saddle” structure residing on the sphenoid bone and what is its depression called?

The sella turcica houses the hypophyseal fossa.

Which cranial bone contains olfactory foramina (tiny holes that olfactory nerves pass through)?

Ethmoid bone

Which cranial bone is most deeply situated into the skull?

Ethmoid bone

Name the facial bones and specify which ones are paired/unpaired.

• Mandible (unpaired)

• Vomer (unpaired)

• Maxillae (paired)

• Zygomatic bones (paired)

• Nasal bones (paired)

• Lacrimal bones (paired)

• Inferior nasal conchae (paired)

• Palatine bones (paired)

Which two structures form the temporomandibular joint?

The mandibular condyle and the temporal bone.

Which facial bone articulates w/ every other facial bone except for the mandible?

The maxillary bones

Which facial bones are described as “tear drop-shaped”?

The lacrimal bones

What bone is connected to the temporal bone via the stylohoid ligament but is not considered part of the skull?

The hyoid bone

What is the main feature that makes C1 and C2 different from the other cervical vertebrae?

C1 lacks a body and spinous process while C2 has a modified body and also lacks a spinous process.

How many cervical, thoracic, and lumbar vertebrae are there?

• 7 cervical vertebrae (C1-C7)

• 12 thoracic vertebrae (T1-T12)

• 5 lumbar vertebrae (L1-L5)