Ch. 5 - The Skeletal System

What are the five major regions of the vertebral column?

1) Cervical; 2) Thoracic; 3) Lumbar; 4) Sacral; 5) Coccygeal.

The bony thorax:

1) Forms a cage to protect major organs 2) Consists of three parts: a) Sternum b) Ribs c) Thoracic vertebrae

Compare the amount of movement possible in synarthrotic, amphiarthrotic, and diarthrotic joints.

1) Synarthroses = immovable joints; 2) Amphiarthroses =slightly movable joints; 3) Diarthroses = freely movable joints. Freely movable joints predominate in the limbs, where mobility is important. Immovable and slightly movable joints are restricted mainly to the axial skeleton, where firm attachments and protection of internal organs are priorities.

Name the eight bones of the cranium.

1. Frontal bone 2. Occipital bone 3. Ethmoid bone 4. Sphenoid bone 5-6. Parietal bones (pair) 7-8. Temporal bones (pair)

A passageway connecting neighboring osteocytes in an osteon is what?

A canaliculus.

Is a floating rib a true or a false rib? Why are floating ribs easily broken?

A false rib. Because they lack the sternal attachments.

What is a fracture? What two fracture types are particularly common in older people?

A fracture is a break in a bone. Compression and comminuted fractures are common in the elderly.

What is a true rib? What is a false rib?

A true rib is attached directly to the sternum by its own costal cartilage. A false rib attaches indirectly (by the costal cartilage of a superior rib) or not at all.

Bones that articulate with the sphenoid include which of the following? a. Parietal b. Vomer c. Maxilla d. Zygomatic e. Ethmoid

All of them. The parietal, vomer, maxilla, zygomatic, and ethmoid all articulate with the sphenoid.

How can you distinguish a lumbar vertebrae from a cervical vertebrae?

All typical cervical vertebrae are small, have holes in their transverse processes, and a split spinous process. Lumbar vertebrae are large, blocklike vertebrae with a blunt spinous process that projects directly back. They have a large body and no foramina in their transverse processes.

How does the shape of a newborn baby's spine differ from that of an adult?

At birth the newborn's spine is an arc (C-shaped), whereas an adult's spine has two additional curvatures and is S-shaped.

Why do bone injuries heal much more rapidly than injuries to cartilage?

Because bone tissue is well vascularized (good blood supply) while cartilage is not.

Fibrous joints

Bones joined by fibrous tissue; no joint cavity is present.

Cartilaginous joints

Bones united by cartilage; no joint cavity is present.

If osteoclasts in a long bone are more active than osteobalsts, what change in bone mass is likely to occur?

Bones will become thinner and weaker because osteoclasts are bone-destroying cells.

At what stage of life do the lower limbs attain the same height as the head and trunk? a. At birth b. By 10 years of age c. At puberty d. When the epiphyseal plates fuse e. Never

By 10 years of age.

Where are the carpals found, and what type (long, short, irregular, or flat) of bone are they?

Carpals are the short bones found in the wrist.

How does the structure of compact bone differ from the structure of spongy bone when viewed with the naked eye?

Compact bones appear solid and very dense with few holes. Spongy bone areas look like the cross-beams of a house with lots of space between the bone spicules.

Johnny was vigorously exercising the only joints in the skull that are freely movable. What would you guess he was doing?

Eating or talking.

Which bone has the cribriform plate and crista galli?

Ethmoid bone.

Name the bones of the lower limbs from superior to inferior.

Femur, patella, tibia, and fibula.

Name two ways in which the fetal skull differs from the adult skull.

Fetal skull is 1/4 body length compared to adult skull, which is 1/8 body length. The fetal skull has fibrous membranes connecting the cranial bones called fontanels (or soft spots).

What bone class do the ribs and skull bones fall into to?

Flat bones.

Bo's longitudinal and medial arches have suffered a collapse. What is the name of Bo's condition?

Flat feet.

Coxal (hip) bone:

Formed by 2 coxal (ossa coxae) bones. Composed of three pairs of fused bones: 1) Ilium 2) Ischium 3) Pubis Pelvic girdle = 2 coxal bones, sacrum Bony pelvis = 2 coxal bones, sacrum, coccyx

Synovial joints

Freely movable joints exhibiting a joint cavity enclosed by a fibrous capsule lined with synovial membrane.

Which bones are connected by the coronal suture? By the sagittal suture?

Frontal joins with the parietals at the coronal suture. Parietals join one another at the sagittal suture.

List two factors that can keep bones healthy. List two factors that can cause bones to become soft or to atrophy.

Getting enough calcium and vitamin D can help keep bones healthy. Two factors that can make bones soft: 1) is vitamin D deficiency which could lead to Rickets; 2) diseases like Osteoporosis.

What is the function of the intervertebral discs? What is a slipped disc?

Intervertebral discs cushion the vertebrae and absorb shocks while allowing the spine flexibility. Drying of the disc, along with a weakening of the ligaments of the vertebral column, predisposes older people to herniated (slipped) discs.

What are the functions of joints?

Joints connect bones together while allowing flexibility of the body.

Where is the synovial membrane found, and what is its role?

Lining a synovial joint capsule to provide a source of lubricating fluid in the joint.

Which two regions of the skeleton grow most rapidly during childhood?

Lower limbs and facial skeleton grow most rapidly during childhood.

Which of the following would you expect to be prominent in osteoclasts? a. Golgi apparatus b. Microfilaments c. Lysosomes d. Exocytosis

Lysosomes.

Which skull bone(s) form the "keystone of the face"?

Maxillae.

Bones don't begin as bones. What do they begin as?

Membranes or cartilage.

Where are most long bones found in the body?

Most long bones are found in the limbs.

What is the relationship between muscle function and bones?

Muscles use bones as levers to bring about body movements.

Compare and contrast the role of PTH (hormone) and mechanical forces acting on the skeleton in bone remodeling.

PTH determines if calcium is put into or taken from the bones. Mechanical stress determines the location in the body where the calcium is deposited or taken away.

Which bones of the upper limb have a styloid process?

Radius and ulna.

What is the anatomical name for the shaft of a long bone? For its ends?

Shaft = diaphysis; Bone ends = epiphyses.

90-year-old Mrs. Pelky is groaning in pain. Her grandson has just picked her up and given her a bear hug. What do you think might have just happened to her spine, and what bone condition may she be suffering from?

She got a compression fracture and she is probably suffering from osteoporosis.

What are the three main parts of the axial skeleton?

Skull, vertebral column, and bony thorax.

Bone pain behind the external acoustic meatus probably involves the: a. Maxilla b. Ethmoid c. Sphenoid d. Temporal e. Lacrimal

Temporal.

Contrast the general function of the axial skeleton to that of the appendicular skeleton.

The axial skeleton forms the body axis and protects the brain and viscera. The appendicular skeleton allows for mobility and manipulation of the external environment.

Which humeral process articulates with the radius? a. Trochlea b. Greater tubercle c. Lesser tubercle d. Capitulum e. Olecranon fossa

The capitulum.

What is the single point of attachment of the shoulder girdle to the axial skeleton?

The clavicle attaches medially to the sternum.

In what ways does the bony pelvis of a woman differ from that of a man?

The female pelvis is broader, lighter, has a less acute pubic angle, a wider inlet and outlet, and shorter ischial spines.

Which bone of the lower limb has an intertrochanteric line and crest and an intercondylar fossa?

The femur has these markings.

Which fracture types are most common in older people? Why are greenstick fractures more common in children?

The fracture types most common in older people are comminuted and compression fractures. Greenstick fractures are more common in children because their bones are more flexible than those of adults.

Name the functions of the skeletal system.

The functions of the skeletal system are: 1) Support; 2) Protection; 3) Movement; 4) Storage; 5) Blood cell formation.

Which stimulus--PTH (a hormone) or mechanical forces acting on the skeleton--is more important in maintaining blood calcium levels than in maintaining bone strength?

The hormonal stimulus (PTH) maintains blood calcium homeostasis.

What bone forms the skeleton of the arm?

The humerus forms the skeleton of the arm.

Which bone of the arm corresponds to the femur of the leg? a. Ulna b. Humerus c. Radius d. Tibia e. Fibula

The humerus.

What three bones form the coxal (hip) bone? What two bones form each pectoral girdle?

The ileum, ischium, and pubis form the coxal (hip) bone. Each pectoral girdle is formed by the scapula and the clavicle.

What is yellow marrow? How do spongy and compact bone look different?

The inner bony surface of the shaft is covered by endosteum, a delicate connective tissue lining. In adults, the cavity of the shaft is primarily a storage area for adipose (fat) tissue. It is called the yellow marrow, or medullary, cavity. Compact bone is dense and looks smooth and homogeneous. Spongy bone is composed of small, needlelike pieces of bone and lots of open space.

With one exception, all skull bones are joined by sutures. What is the exception?

The mandible.

What is the major difference between a fibrous joint and a cartilaginous joint?

The material between the articulating bone ends, which is connective tissue fibers in fibrous joints and cartilage in cartilaginous joints.

Which of the following bones or bone parts articulate with the femur? a. Ischial tuberosity b. Pubis c. Patella d. Fibula e. Tibia

The pubis, patella, and tibia.

Name the bones of the shoulder girdle.

The shoulder (or pectoral) girdle consists of two bones, the clavicle and the scapula.

What two joints of the body are ball-and-socket joints? What is the best example of a saddle joint?

The shoulder and hip joints are ball-and-socket joints. The carpometacarpal joint of the thumb is a saddle joint.

Which spinal curvatures are present at birth?

The thoracic and sacral curvatures are present.

Which parts of the thoracic vertebrae articulate with the ribs? a. Spinous process b. Transverse process c. Superior articulation processes d. Body e. Pedicles

The transverse process and the body.

Name all the bones with which the ulna articulates.

The ulna is a medial bone in the anatomical position. Proximal end articulation: The coronoid process and olecranon articulate with the humerus.

Which of the following are correctly matched? a. Short bone - wrist b. Long bone - leg c. Irregular bone - sternum d. Flat bone - cranium

The wrist is a short bone, the leg is a long bone, and the cranium is a flat bone.

List the facial bones.

There are 14 facial bones. All are paired except for the single mandible and vomer. 1-2. Maxillae 3-4. Zygomatics 5-6. Palatines 7-8. Nasals 9-10. Lacrimals 11-12. Inferior nasal conchae 13. Mandible 14. Vomer

How many vertebrae are there in each of the three superior regions of the vertebral column?

There are 24 single vertebral bones are separated by intervertebral discs: There are 7 cervical vertebrae are in the neck; 12 thoracic vertebrae are in the chest region; and 5 lumbar vertebrae are associated with the lower back.

What is the importance of canaliculi?

They carry nutrients to the bone cells.

What two bones form the skeleton of the leg?

Tibia and fibula form the skeleton of the leg.

What are the two functions of a bone's marrow cavities?

To provide a site for hematopoiesis and storage site for fat.

Besides the ribs and the sternum, there is a third group of bones forming the thoracic cage. What is it?

Vertebrae.