Download Answer Key: What Did You Learn

McKinley/O’Loughlin
Human Anatomy, 2nd Edition
CHAPTER 7
Answers to “What Did You Learn?”
1.
The skull is composed of both cranial and facial bones.
2.
The three skull sutues that can be seen from a superior view of the skull are the
coronal, sagittal and lambdoid sutures. The coronal suture is where frontal and
parietal bones articulate, sagittal suture is where the two parietal bones articulate,
and the lamboid suture is where the parietals and occipital bones articulate.
3.
The three parts of the temporal bone are the squamous part, tympanic part, and the
petrous part (where the mastoid process is located).
4.
The occipital bone contains the superior and inferior nuchal lines. They are
attachment sites for both muscles and ligaments that balance the weight of the
head over the vertebrae of the neck and stabilize its articulation at the occipital
condyles.
Male skulls tend to have more pronounced nuchal lines than female
skulls.
6.
Most of the hard palate is formed by horizontal medial extensions of the maxilla
called palatine processes. The posterior portion of the hard palate is formed by
the articulation of the palatine process of the maxilla with the horizontal plate of
the palatine bone.
7. The ethmoid, frontal, maxillae, and sphenoid bones of the skull contain the
paranasal sinuses.
8. The lateral wall of the orbit is formed from the orbital surface of the zygomatic,
the greater wing of the sphenoid, and the zygomatic process of the frontal bone.
9. The three tiny bones of the auditory ossicles are the malleus, incus, and stapes.
McKinley/O’Loughlin
10.
Human Anatomy, 2nd Edition
The female skull is generally more delicate than the male skull, which is robust
with prominent muscle markings. The external surface of the occipital bone in a
female is relatively smooth, with no major bony projections, while the male skull
has well-demarcated nuchal lines and a prominent bump for the external occipital
protuberances. The mastoid process in a female is smaller than that of a male.
The forehead in a female is usually more vertically oriented and rounded than
males. The female’s subraorbital margin exhibits a thin, sharp border, in contrast
with the male’s thick, rounded border. The females have less prominent and
bulky superciliary arches than males. The mandibles are smaller and lighter in a
female skull than in a male. Both the sinuses and teeth in a female skull are
smaller than those in a male skull.
11.
The two main fontanelles are the posterior fontanelle (which disappears by 9
months of age) and the anterior fontanelle (which disappears/closes by 15
months).
12.
The five vertebral regions, proceeding from superior to inferior ends are:
cervical, thoracic, lumbar, sacral, and coccygeal.
13.
The dens is located on the second cervical vertebra, called the axis. A fracture to
the dens would fracture the axis.
19.
The first seven pairs of ribs are called true ribs. At the anterior body wall the true
ribs connect individually to the sternum by separate cartilaginous extensions, the
costal cartilages. Ribs 8–12 are called false ribs because they do not attach
directly to the sternum.
McKinley/O’Loughlin
20.
Human Anatomy, 2nd Edition
The three components of the sternum are the manubrium, the body (gladiolus),
and the xiphoid process. Ribs 1-7 articulate directly with the sternum.
Answers to “Content Review”
1.
Facial bones form the bones of the face and they protect the entrances to the
digestive and respiratory systems. Cranial bones form the rounded cranium that
completely surrounds and encloses the brain.
2.
The parietal bones, the temporal bones, the sphenoid bone, and the first cervical
vertebra [the atlas] articulate with the occipital.
3.
The nasal conchae are thin, scroll-like bones that project into the nasal cavity and
they function to create turbulence in inhaled air. This slows air movement and
allows for warming, humidification and cleansing of inhaled air.
4.
Sutures are immovable fibrous joints that form boundaries between cranial bones.
They typically fuse in our adult years after skull growth is complete.
5.
The lumbar region is most at risk for disc herniation because of the relatively
great mobility here and because of the increased weight on the discs in this
region.
6.
The seven bones that form the orbit include: the frontal and sphenoid that form
the roof of the orbit; the maxilla and palatine bones that form the floor of the
orbit; the lacrimal and ethmoid bones form the medial wall of the orbit; and the
zygomatic, sphenoid and frontal form the lateral wall of the orbit. The sphenoid
forms the posterior wall of the orbit.
McKinley/O’Loughlin
7.
Human Anatomy, 2nd Edition
The first cervical vertebra, the atlas, lacks a spinous process and a vertebral body.
It has depressed , oval superior articular facets that articulate with the occipital
condyles of the occipital bone (the atlanto-occipital joint) and permit the
movement of the head called ‘nodding’ [a ‘yes’ movement]. The second cervical
vertebra, the axis, has a prominent odontoid process [the fused body of the atlas.
It rests in the articular facet of the atlas and is held in place by a transverse
ligament. The movement at this joint (the atlanto-axial joint) permits the shking
of the head ‘no’.
8.
Ribs are elongated, curved, flattened bones that originate on or between thoracic
vertebrae and usually end in the wall of the thoracic cavity. The first 7 pairs of
ribs, the true ribs, connect individually to the sternum by costal cartilage. Rib
pairs 8 – 12 are called false ribs because they do not connect directly to the
sternum. The pairs of ribs 8 – 10 have costal cartilages that connect to the costal
cartilage of rib pair 7. The last two pairs of false ribs, rib pairs 11 and 12 are
called floating ribs because they have no connection to the sternum.
9.
The cribriform foramina in the ethmoid bone provide passageways for the
olfactory nerves from the nasal cavity into the cranial cavity on their way to the
brain.
10.
The paranasal sinuses are cavities in the frontal, ethmoid, sphenoid and maxillary
bones. They have a mucus lining that helps to humidify and warm inhaled air.
Foreign particulate matter is trapped in this mucus and then eventually swallowed.
This helps to condition the inhaled air to protect the delicate gas exchange
McKinley/O’Loughlin
Human Anatomy, 2nd Edition
surfaces in the lungs. Additionally, the inclusion of these cavities helps to lighten
the skull and assists in resonance during sound production.