Chapter 7 review questions

Name the cranial and facial bones and compare and contrast the functions of the cranial and facial skeletons.

Cranial bones: parietal, temporal, frontal, occipital, sphenoid, and ethmoid. Facial bones: mandible, vomer, maxillae, zygomatics, nasals, lacrimals, palatines, and inferior conchae. Cranial bones provide sites for attachment and enclose and protect the brain. The facial bones form the framework of the face, hold eyes in position, provide cavities for organs of taste and smell, secure the teeth, and anchor facial muscles.

Distinguish between the anulus fibrosus and nucleus pulposus regions of a disc. Which provides durability and strength? Which provides resilience? Which part is involved in a slipped disc?

The annulus fibrosis, composed of fibrocartilage, is more external and contains the nucleus pulposus. The nucleus is the semifluid substance enclosed by the annulus. The annulus provides strength and durability. The nucleus provides resilience. Disc herniation involves protrusion of the nucleus pulposus through the annulus.

What is the function of the intervertebral discs?

The intervertebral discs act as shock absorbers and provide flexibility to the spine, allowing it to flex and extend.

Which vertebral curvatures are primary and which are secondary curvatures? Why are they called primary and secondary?

The thoracic and sacral curvatures are called primary curvatures because they are present at birth. The cervical and lumbar curvatures are called secondary because they develop after birth when the baby learns to lift its head (cervical curvature) and learns to walk (lumbar curvature).

List three important differences between male and female pelves.

1) The female pelvis inlet and outlet are wider; 2) the females pelvis is shallower, lighter, and rounder than that of the male; 3) and the female ischial tuberosities are farther apart.

How do the relative proportions of the cranium and face of a fetus compare with those of an adult skull?

At birth, the skull is huge relative to the facial skeleton. During childhood and adolescence, the face grows out from the skull. By adulthood, the cranial and facial skeletons are the appropriate proportional size.

Briefly describe the anatomical characteristics and impairment of function seen in cleft palate and hip dysplasia.

Both cleft palate and hip dysplasia are congenital abnormalities affecting skeletal formation. A cleft palate occurs if the fusion of the midline of the maxilla fails to occur. Problems may range from simple cosmetic abnormality to a complete lack of separation of the nasal and oral cavities. In such a case, the infant will have difficulty taking in food, and may even aspirate it, due to a lack of a palate to regulate breathing and swallowing. Hip dysplasia occurs if the acetabulum fails to form a complete socket around the head of the femur correctly, or if the ligaments securing the femur at the hip are too loose. The femur may easily slip out of its socket, creating difficulty walking. (p. 243)

List at least two specific anatomical characteristics each for typical cervical, thoracic, and lumbar vertebrae that would allow anyone to identify each type correctly.

Cervical vertebrae possess transverse foramina, have small bodies and bifid spinous processes; thoracic vertebrae possess facets for the ribs and have circular vertebral foramina; lumbar vertebrae have massive bodies and blunt spines. (pp. 219-220; Table 7.2)

Compare a young adult skeleton to that of an extremely aged person relative to bone mass in general and the bony structure of the skull, thorax, and vertebral column in particular.

In a young adult skeleton, the bone mass is dense, water content is normal in discs, the vertebral column is strong. In old age, the discs decline in water content and become thinner and less elastic, the spine shortens and becomes an arc, and all the bones lose mass. The thorax becomes more rigid with increasing age, mainly due to the ossification of costal cartilage. The cranial bones lose less mass with age than most bones, but the facial contours of the aged change.

Peter Howell, a teaching assistant in the anatomy class, picked up a hip bone and pretended it was a telephone. He held the big hole in this bone right up to his ear and said, "Hello, obturator, obturator (operator, operator)." Name the structure he was helping the students to learn.

Peter was having a little fun with the obturator foramen, the large opening in the hip bone through which pass some blood vessels and nerves.

Which ribs are floating ribs and why are they called that?

Rib pairs 11 & 12 are called floating ribs (or vertebral ribs) because they are not attached to the sternum anteriorly.