CHAPTER 7!!!!

Question 1

How many bones do we have at birth? About how many as adults?

Answer 1

• About 270 bones at birth.
• As you grow, some fuse together → adults have about 206 bones.

Question 2

What types of bones can add to this number for adults?

Answer 2

− Even though adults usually have 206 bones, extra bones can occur:
* Sesamoid bones – small bones that form inside tendons (ex: extra bones near the big toe or in the hands).
* Sutural (wormian) bones – tiny bones found within cranial sutures of the skull.

These vary from person to person, so the total number of bones can be slightly higher than 206.

Question 3

What are the functions of the axial skeleton?

Answer 3

• Supports and protects the brain, spinal cord, and organs in the thorax.
• Attachment for muscles of head, neck, and trunk.
• Stabilizes parts of the appendicular skeleton (limbs).

Includes: skull, vertebral column, and thoracic cage (ribs + sternum).

Question 4

What is the function of the skull?

Answer 4

• Protects the brain.
• Houses sensory organs (eyes, ears, nose, tongue).
• Provides attachment for muscles of chewing, facial expression, and head movement.

Question 5

To what does the external auditory canal lead?

Answer 5

• It leads to the eardrum (tympanic membrane) and the middle ear cavity.

Question 6

What is found within the sella turcica?

Answer 6

• The pituitary gland (endocrine gland that controls many hormones).
• Located on the sphenoid bone.

Question 7

What is the purpose of the nasal conchae?

Answer 7

• Swirl and warm incoming air, trapping particles and adding moisture before it enters the lungs.
• Increases the surface area inside the nasal cavity.

Question 8

Know the 4 cranial fossae and where they are located.

Answer 8

1. Anterior cranial fossa: Front part; holds the frontal lobes of the brain.
2. Middle cranial fossa: Center area; holds the temporal lobes and pituitary gland.
3. Posterior cranial fossa: Back part; holds the cerebellum and brainstem.
4. (Sometimes listed) — Internal cranial base refers to the floor formed by all three fossae together.

Question 9

What is the purpose of the paranasal sinuses? Where are they found?

Answer 9

• Purpose:
• Lighten the skull.
• Add resonance to voice.
• Produce mucus that drains into the nasal cavity.
• Found in:
• Frontal bone
• Maxilla
• Sphenoid bone
• Ethmoid bone

Question 10

Know the auditory ossicles.

Answer 10

− Malleus (hammer)
− Incus (anvil)
− Stapes (stirrup)
They transmit sound vibrations from the eardrum to the inner ear.

Question 11

Know that the hyoid bone doesn’t articulate with any other bones. Where is it found?

Answer 11

• Doesn’t articulate with any other bone.
• Found in the neck, between the mandible (jaw) and larynx (voice box)*
• Function:
• Supports the tongue.
• Provides attachment for muscles involved in swallowing and speech

Question 12

What are the fontanels? Why is it beneficial for the cranial bones to have some movement?

Answer 12

• Definition: Flexible areas of fibrous connective tissue between cranial bones in babies.
• Purpose/Benefit:
• Allows the skull to compress during birth.
• Allows for brain growth after birth.
• Eventually they ossify into sutures.

Question 13

When do the sutures form?

Answer 13

• Form during childhood as fontanels close.
• Fully fuse in adulthood (by about age 20–30).

Question 14

Know how many vertebrae are in each region of the vertebral column.

Answer 14

• Cervical: 7
• Thoracic: 12
• Lumbar: 5
• Sacrum: 5 (fused)
• Coccyx: 4 (fused)

Question 15

What are the functions of the vertebral column?

Answer 15

• Supports the body’s weight.
• Protects the spinal cord.
• Allows flexibility and movement.
• Acts as a shock absorber with intervertebral discs.

Question 16

Know the abnormal spinal curvatures.

Answer 16

1. Scoliosis: Sideways (lateral) curve of the spine.
2. Kyphosis: Exaggerated thoracic (upper back) curve — “hunchback.”
3. Lordosis: Exaggerated lumbar (lower back) curve — “swayback.”

Question 17

Know the 2 parts of the intervertebral discs.

Answer 17

1. Nucleus pulposus: Soft, gel-like center that absorbs shock.
2. Annulus fibrosus: Tough outer ring that holds the disc together.

Question 18

What 2 features do cervical vertebrae have that other vertebrae do not?

Answer 18

− Transverse foramina – holes in the transverse processes that allow blood vessels to pass to the
brain.

− Bifid spinous processes – the spinous process is split into two “forked” tips (except C7)

Question 19

What are the names of the top two cervical vertebrae?

Answer 19

− C1 – Atlas → supports the skull; allows “yes” (nodding) motion.
− C2 – Axis → has a projection called the dens (odontoid process) that allows “no” (rotating)
motion.

Question 20

Does the C1 allows a “yes” motion and supports the skull.

Answer 20

yes!

Question 21

True or False: C2 has the dens, which allows rotational movement of the skull.

Answer 21

yes!

Question 22

which ribs are true ribs, false ribs, and floating ribs

Answer 22

True ribs: Pairs 1–7 — attach directly to the sternum by cartilage.

False ribs: Pairs 8–12 — attach indirectly or not at all to the sternum.

Floating ribs: Pairs 11–12 — no front attachment to the sternum.

Question 23

The costal facets are found on the thoracic vertebrae.

Answer 23

− Found on thoracic vertebrae.
− They are smooth areas where ribs articulate (connect) with the vertebrae

Question 24

What is a cleft palate? What is craniosyntosis?

Answer 24

Cleft palate: A split in the roof of the mouth that happens when the palate doesn’t fuse properly during development.

Craniosynostosis: A condition where one or more skull sutures close too early, causing abnormal head shape and possible pressure on the brain