Exam 2

A bimalleolar fracture is a common sports injury that affects the lateral malleolus and the medial malleolus. Which of the following does this fracture impact?

A bimalleolar fracture is a break in the distal ends of both the tibia and fibula. The medial malleolus of the tibia bone is the medial bulge of the ankle. The lateral malleolus of the fibula is the lateral ankle bulge. The femur is the thigh bone. The patella is the kneecap.

Correctly match the bone type with its example: Short bone.

A carpal of the wrist is an example of a short bone. Short bones are roughly cube shaped. The bones of the wrist and ankle are examples. Sesamoid bones ("shaped like a sesame seed") are a special type of short bone that form in a tendon (for example, the patella). They vary in size and number in different individuals. Some sesamoid bones act to alter the direction of pull of a tendon. The function of others is not known. The femur of the leg is a long bone because it is longer than it is wide. The sternum (breast bone) is a flat bone because it is thin and flattened. A carpal is a short bone because it is cube-shaped. A vertebra of the spinal column is an irregular bone because it has a complicated shape that does not fit the other classification classes.

Correctly match the definition and disorder: Dorsally exaggerated thoracic curvature, or "hunch back."

A dorsally exaggerated thoracic curvature, or "hunch back," is known as kyphosis. There are several types of abnormal spinal curvatures (figure below). Some are congenital (present at birth); others result from disease, poor posture, or unequal muscle pull on the spine. Scoliosis (sko"le-o'sis), literally, "twisted disease," is an abnormal rotation of the spine that results in a lateral curvature, most often in the thoracic region. It is quite common during late childhood, particularly in girls. Other, more severe cases result from abnormal vertebral structure, lower limbs of unequal length, or muscle paralysis. If muscles on one side of the body are nonfunctional, those of the opposite side exert an unopposed pull on the spine and force it out of alignment. Scoliosis is treated (with body braces or surgically) before growth ends to prevent permanent deformity and breathing difficulties due to a compressed lung. Kyphosis (ki-fo'sis), or hunchback, is a dorsally exaggerated thoracic curvature. It is particularly common in elderly people because of osteoporosis, but may also reflect tuberculosis of the spine, rickets, or osteomalacia. Lordosis, or swayback, is an accentuated lumbar curvature. It, too, can result from spinal tuberculosis or osteomalacia. Temporary lordosis is common in those carrying a large load up front, such as men with "potbellies" and pregnant women. In an attempt to maintain their center of gravity, these individuals automatically throw back their shoulders, accentuating their lumbar curvature.

A motor unit consists of

A motor unit consists of one motor neuron and all of the muscle fibers it supplies. Each muscle is served by at least one motor nerve, and each motor nerve contains axons (fibrous extensions) of up to hundreds of motor neurons. As an axon enters a muscle, it branches into a number of endings, each of which forms a neuromuscular junction with a single muscle fiber. A motor unit consists of one motor neuron and all the muscle fibers it innervates, or supplies. When a motor neuron fires (transmits an action potential), all the muscle fibers it innervates contract. The number of muscle fibers per motor unit may be as high as several hundred or as few as four. Muscles that exert fine control (such as those controlling the fingers and eyes) have small motor units. By contrast, large, weight-bearing muscles, whose movements are less precise (such as the hip muscles), have large motor units. The muscle fibers in a single motor unit are not clustered together but are spread throughout the muscle. As a result, stimulation of a single motor unit causes a weak contraction of the entire muscle. A fascicle is a bundle of muscle fibers within a muscle.

Identify the part of a rib and thoracic vertebra indicated by...A,B,C,D,E

A) transverse costal facetB) superior costal facetC) neck of ribD) head of ribE) shaft rib

Identify the type of movement at the neck indicated by "A." Identify the type of movement at the neck indicated by "C."

A- Hyperextension C- Flexion

Identify the part of a generalized synovial joint indicated by "A." Identify the part of a generalized synovial joint indicated by "D." Identify the part of a generalized synovial joint indicated by "C." Identify the part of a generalized synovial joint indicated by "B."

A- Ligament D- Fibrous layer C- Articular (hyaline) cartilage B- Joint (articular) cavity E- Synovial membrane

Match the following description of muscle contraction with the correct term: Contraction of muscle during which the tension continues to increase but the muscle neither shortens nor lengthens.

An isometric contraction is a contraction of muscle during which the tension continues to increase but the muscle neither shortens nor lengthens. In isometric contractions, tension may build to the muscle's peak tension-producing capacity, but the muscle neither shortens nor lengthens. Isometric contractions occur when a muscle attempts to move a load that is greater than the force (tension) the muscle is able to develop—think of trying to lift a piano single-handedly. Muscles contract isometrically when they act primarily to maintain upright posture or to hold joints stationary while movements occur at other joints. Isotonic contractions come in two "flavors"—concentric and eccentric. Concentric contractions are those in which the muscle shortens and does work, such as picking up a book or kicking a ball. Concentric contractions are probably more familiar, but eccentric contractions, in which the muscle generates force as it lengthens, are equally important for coordination and purposeful movements. Eccentric contractions occur in your anterior thigh muscles, for example, as you walk down a steep hill. Eccentric contractions are about 50% more forceful than concentric ones at the same load and more often cause delayed-onset muscle soreness. (Consider how your thigh muscles feel the day after hiking that hill.) The muscle stretching that occurs during eccentric contractions causes microtrauma in the muscles that results in soreness.

Identify the type of movement of the upper limb at the shoulder as indicated by "B."

B- Adduction C- Circumduction

Identify the type of synovial joint indicated by "B." Identify the type of synovial joint indicated by "F." Identify the type of synovial joint indicated by "E." Identify the type of synovial joint indicated by "C." Identify the type of synovial joint indicated by "D." Identify the type of synovial joint indicated by "A."

B- Saddle joint F- Pivot joint C- Hinge joint The type of synovial joint indicated by "C" is a ball-and-socket joint. Letter A is a condylar joint. Letter B is a saddle joint. Letter C is a ball-and-socket joint. Letter D is a plane joint. Letter E is a hinge joint. Letter F is a pivot joint. The type of synovial joint indicated by "D" is the plane joint. Letter A is a condylar joint. Letter B is a saddle joint. Letter C is a ball-and-socket joint. Letter D is a plane joint. Letter E is a hinge joint. Letter F is a pivot joint. The type of synovial joint indicated by "A" is a condylar joint. Letter A is a condylar joint. Letter B is a saddle joint. Letter C is a ball-and-socket joint. Letter D is a plane joint. Letter E is a hinge joint. Letter F is a pivot joint.

Bone-forming cells originate from __________.

Bone-forming cells originate from osteoprogenitor cells. Osteoprogenitor cells, also called osteogenic cells, are mitotically active stem cells found in the membranous periosteum and endosteum. In growing bones they are flattened or squamous cells. When stimulated, these cells differentiate into bone-forming cells called osteoblasts, while others persist as osteoprogenitor cells. Osteoblasts become osteocytes when they surround themselves with bone matrix. Osteoclasts develop separately from a white blood cell lineage.

Identify the friction-reducing structure associated with synovial joints indicated by "C." Identify the friction-reducing structure associated with synovial joints indicated by "A."

C-Joint cavity containing synovial fluid A- Subacromial bursa

Identify the part of a typical vertebra indicated by "C." Identify the part of a typical vertebra indicated by "B."

C. Lamina B. Transverse process

Identify the region of the vertebral column indicated by "E."

Coccyx

Identify the part of the thoracic cage indicated by "D." Identify the part of the thoracic cage indicated by "A."

D- False rib A- True ribs

Which of the following is true?

Despite the environmental factors that influence bone density, genetics still plays the major role in determining bone density, is true. In children and adolescents, bone formation exceeds bone resorption. In young adults, these processes are in balance, and in old age, resorption predominates. Despite the environmental factors that influence bone density, genetics still plays the major role in determining how much a person's bone density will change over a lifetime. A single gene that codes for vitamin D's cellular docking site helps determine both the tendency to accumulate bone mass during early life and a person's risk of osteoporosis later in life. Beginning in the fourth decade, bone mass decreases with age. The only exception appears to be in bones of the skull. Among young adults, skeletal mass is generally greater in males than in females. Age-related bone loss is faster in white people than in black people (who have greater bone density to begin with) and faster in females than in males.

Match the following with the type of muscle action: Activity best suited for slow-oxidative fibers.

Endurance-type activities such as running a marathon are activities best suited for slow-oxidative fibers. Slow oxidative fibers in the first column of the table below. Contracts slowly because its myosin ATPases are slow (a criterion) Depends on oxygen delivery and aerobic pathways (its major pathways for forming ATP give it high oxidative capacity—a criterion) Resists fatigue and has high endurance (typical of fibers that depend on aerobic metabolism) Is thin (a large amount of cytoplasm impedes diffusion of O2 and nutrients from the blood) Has relatively little power (a thin cell can contain only a limited number of myofibrils) Has many mitochondria (actual sites of oxygen use) Has a rich capillary supply (the better to deliver bloodborne O2) Is red (its color stems from an abundant supply of myoglobin, muscle's oxygen-binding pigment that stores O2 reserves in the cell and helps O2 diffuse through the cell)

Which of the following statements is true?

Hypocalcemia leads to hyperexcitability, is true. Minute changes from the homeostatic range for blood calcium can lead to severe neuromuscular problems. For example, hypocalcemia (hi"po-kal-se'me-ah; low blood Ca2+ levels) causes hyperexcitability. In contrast, hypercalcemia (hi"per-kalse' me-ah; high blood Ca2+ levels) causes nonresponsiveness and inability to function. In addition, sustained high blood levels of Ca2+ can lead to the formation of kidney stones or undesirable deposits of calcium salts in other organs, which may hamper their function.

If a breastfeeding mother becomes vitamin D deficient, what disease is most likely to develop in the nursing infant?

If a breastfeeding mother becomes vitamin D deficient, rickets is likely to develop in the nursing infant. Osteomalacia ("soft bones") includes a number of disorders in which the bones are poorly mineralized. Osteoid is produced, but calcium salts are not adequately deposited, so bones are soft and weak. The main symptom is pain when weight is put on the affected bones. Rickets is the analogous disease in children. Because young bones are still growing rapidly, rickets is much more severe than adult osteomalacia. Bowed legs and deformities of the pelvis, skull, and rib cage are common. Because the epiphyseal plates cannot calcify, they continue to widen, and the ends of long bones become visibly enlarged and abnormally long. Osteomalacia and rickets are caused by insufficient calcium in the diet or by a vitamin D deficiency. Increasing vitamin D intake and exposing the skin to sunlight (which spurs the body to form vitamin D) usually cure these disorders. Although the seeming elimination of rickets in the United States has been heralded as a public health success, rickets still rears its head in isolated situations. For example, if a mother who breastfeeds her infant becomes vitamin D deficient because of sun-deprivation or dreary winter weather, the infant too will be vitamin D deficient and will develop rickets. Dwarfism could be caused by a lack of growth hormone from the anterior pituitary gland. Dwarfism is not related to vitamin D. Osteoporosis refers to a group of diseases in which bone resorption outpaces bone deposit. Paget's disease is characterized by excessive and haphazard bone deposit and resorption. Neither of these diseases would likely occur in an infant of a breastfeeding mother with vitamin D deficiency.

What would occur if a muscle became totally depleted of ATP?

If a muscle became totally depleted of ATP, the muscle cells would die and rigor mortis would occur. Vigorous muscle activity cannot continue indefinitely. Muscle fatigue is a state of physiological inability to contract even though the muscle is still receiving stimuli. You might think that running out of ATP is the critical event that causes muscle fatigue. In fact, ATP levels inside muscle cells do drop, but muscle fatigue serves to prevent complete depletion of ATP in muscle, which would result in death of muscle cells and rigor mortis. Rigor mortis (death rigor) illustrates the fact that cross bridge detachment is ATP driven. Most muscles begin to stiffen 3 to 4 hours after death. Peak rigidity occurs at 12 hours and then gradually dissipates over the next 48 to 60 hours. Dying cells are unable to exclude calcium (which is in higher concentration in the extracellular fluid), and the calcium influx into muscle cells promotes formation of myosin cross bridges. Shortly after breathing stops, ATP synthesis ceases, but ATP continues to be consumed and cross bridge detachment is impossible. Actin and myosin become irreversibly cross-linked, producing the stiffness of rigor mortis, which gradually disappears as muscle proteins break down after death.

In smooth muscle, neurotransmitter is released from ____________.

In smooth muscle, neurotransmitter is released from varicosities. Smooth muscle has varicosities instead of neuromuscular junctions. The innervating nerve fibers of the autonomic (involuntary) nervous system have numerous bulbous swellings, called varicosities. Unlike the highly structured neuromuscular junctions of skeletal muscle, varicosities form diffuse junctions that have wide synaptic clefts. The varicosities simply "sprinkle" neurotransmitter in the general area of the smooth muscle cells. Comparing the neural input to skeletal and smooth muscles, you could say that skeletal muscle gets high-speed internet while smooth muscle gets slow-speed dial-up. Smooth muscle fibers have less elaborate SR and no T tubules. The sarcoplasmic reticulum of smooth muscle fibers has no terminal cisterns and lacks a specific pattern relative to the myofilaments. Although the SR does release some of the Ca2+ that triggers contraction, most Ca2+ enters through calcium channels directly from the extracellular space. The sarcolemma has multiple caveolae ("little caves"), pouchlike infoldings containing large numbers of Ca2+ channels. These calcium channels are the major source of Ca2+ for smooth muscle contraction. This situation is quite different from what we see in skeletal muscle, which does not depend on extracellular Ca2+ for excitation-contraction coupling.

Identify the general class of bone indicated by "B."

Irregular bone

To what percent of its length can a ligament be stretched and not snap?

Ligaments can stretch to 6% before they snap. The capsules and ligaments of synovial joints unite the bones and prevent excessive or undesirable motion. As a rule, the more ligaments a joint has, the stronger it is. However, when other stabilizing factors are inadequate, undue tension is placed on the ligaments and they stretch. Stretched ligaments stay stretched, like taffy, and a ligament can stretch only about 6% of its length before it snaps. Thus, when ligaments are the major means of bracing a joint, the joint is not very stable.

Lyme disease is an inflammatory disease caused by __________.

Lyme disease is an inflammatory disease caused by bacteria transmitted by tick bites. Lyme disease often results in joint pain and arthritis, especially in the knees, and is characterized by a skin rash, flu-like symptoms, and foggy thinking. If untreated, neurological disorders and irregular heartbeat may ensue. Because symptoms vary from person to person, the disease is hard to diagnose. Antibiotic therapy is the usual treatment, and works best when initiated soon after the initial infection. Osteoarthritis is a degenerative joint disorder. Rhematoid arthritis is an autoimmune disease involving chronic inflammation. Gouty arthritis involves a buildup of uric acid in the blood.

Correctly match the following term: Markings include glenoid cavity and acromion

Markings on the scapula include glenoid cavity and acromion. The scapulae, or shoulder blades, are thin, triangular flat bones. Interestingly, their name derives from a word meaning "spade" or "shovel," for ancient cultures made spades from the shoulder blades of animals. The scapulae lie on the dorsal surface of the rib cage, between ribs 2 and 7. Each scapula has three borders. The superior border is the shortest, sharpest border. The medial, or vertebral, border parallels the vertebral column. The thick lateral, or axillary, border is next to the armpit and ends superiorly in a small, shallow fossa, the glenoid cavity (gle'noid; "pit-shaped"). This cavity articulates with the humerus of the arm, forming the shoulder joint. The anterior, or costal, surface of the scapula is concave and relatively featureless. Its posterior surface bears a prominent spine that is easily felt through the skin. The spine ends laterally in an enlarged, roughened triangular projection called the acromion (ah-kro'me-on; "point of the shoulder"). The acromion articulates with the acromial end of the clavicle, forming the acromioclavicular joint.

Correctly match the synovial joint to its range of motion: Multiaxial.

Multiaxial joints have a range of motion in three planes. Range of motion allowed by synovial joints varies from nonaxial movement (slipping movements only) to uniaxial movement (movement in one plane, such as gliding movement) to biaxial movement (movement in two planes) to multiaxial movement (movement in or around all three planes of space and axes). Range of motion varies greatly. In some people, such as trained gymnasts or acrobats, range of joint movement may be extraordinary. The ranges of motion at the major joints are given in the far right column of the table below.

Graded muscle contractions are smooth and varying in strength as different needs are placed on them. How can muscle contractions be graded?

Muscle contractions can be graded in two ways: temporal summation and recruitment. Muscle twitches—like those single, jerky contractions provoked in a laboratory—may result from certain neuromuscular problems, but this is not the way our muscles normally operate. Instead, healthy muscle contractions are relatively smooth and vary in strength as different demands are placed on them. These variations, needed for proper control of skeletal movement, are referred to as graded muscle responses. In general, muscle contraction can be graded in two ways: by changing the frequency of stimulation, and by changing the strength of stimulation. An increase in the frequency of stimulation causes temporal summation. The higher the frequency, the greater the strength of contraction of a given motor unit. Temporal summation contributes to contractile force, but its primary function is to produce smooth, continuous muscle contractions by rapidly stimulating a specific number of muscle cells. An increase in the strength of stimulation causes recruitment. The stronger the stimulation, the more motor units are activated, and the stronger the contraction. Recruitment, also called multiple motor unit summation, controls the force of contraction more precisely. previous

Which of the following bone disorders is not treatable with increased calcium and vitamin D?

Paget's disease is not treatable with increased calcium and vitamin D. Paget's disease is characterized by excessive and haphazard bone deposit and resorption. The newly formed bone, called pagetic bone, is hastily made and has an abnormally high ratio of spongy bone to compact bone. This, along with reduced mineralization, causes a spotty weakening of the bones. Late in the disease, osteoclast activity wanes, but osteoblasts continue to work, often forming irregular bone thickenings or filling the marrow cavity with pagetic bone. Drug therapies include bisphosphonates and calcitonin, which have shown success in preventing bone breakdown. Osteoporosis refers to a group of diseases in which bone resorption outpaces bone deposit. Osteoporosis is treated with weight-bearing exercise and by ensuring that calcium and vitamin D intake is adequate. Osteomalacia ("soft bones") includes a number of disorders in which the bones are poorly mineralized. Rickets is the analogous disorder in children. Osteomalacia and rickets are caused by insufficient calcium in the diet or by a vitamin D deficiency. Increasing vitamin D intake and exposing the skin to sunlight (which spurs the body to form vitamin D) usually cure these disorders.

The hormonal control of bone remodeling primarily involves which of the following?

Parathyroid hormone

Identify the part of a typical vertebra indicated by "D."

Pedicle

Identify the step in the phases leading to muscle fiber contraction indicated by "E."

SR releases Ca2+; Ca2+ binds to troponin; myosin-binding sites (active sites) on actin exposed

Identify the part of the sacrum or coccyx indicated by "C."

Sacral foramina D: Coccyx A: Sacral canal B: Body

Match the following with the type of muscle action: Activity best-suited for fast-oxidative fibers.

Sprinting and walking are activities best-suited for fast-oxidative fibers. The less common intermediate muscle fiber types, called fast oxidative fibers (table below, middle column). They have many characteristics intermediate between the other two types (fiber diameter and power, for example). Like fast glycolytic fibers, they contract quickly, but like slow oxidative fibers, they are oxygen dependent and have a rich supply of myoglobin and capillaries.

Correctly match the definition and disorder: Common in those carrying a "large load up front," such as men with "potbellies" and pregnant women.

Temporary lordosis

Correctly match the term and definition: Bone that contains the infraorbital foramen.

The bone that contains the infraorbital foramen is the maxilla. Just below the eye socket on each side is an infraorbital foramen that allows the infraorbital nerve (a continuation of the maxillary nerve) and artery to reach the face.

Correctly match the following term: Bones that form the palms of the hands.

The bones that form the palms of the hands are the metacarpals. Five metacarpals radiate from the wrist like spokes to form the metacarpus or palm of the hand (meta = beyond). These small long bones are not named, but instead are numbered I to V from thumb to little finger. The bases of the metacarpals articulate with the carpals proximally and each other medially and laterally. Their bulbous heads articulate with the proximal phalanges of the fingers. When you clench your fist, the heads of the metacarpals become prominent as your knuckles. Metacarpal I, associated with the thumb, is the shortest and most mobile. It occupies a more anterior position than the other metacarpals. Consequently, the joint between metacarpal I and the trapezium is a unique saddle joint that allows opposition, the action of touching your thumb to the tips of your other fingers. The carpals form the bones of the wrist. The phalanges are the bones of the fingers and the toes. The tarsals form the posterior part of the foot. The metatarsals extend from the tarsals to the phalanges of the foot.

Correctly match the bone of the upper limb with its description: Forms the wrist joint with the radius and ulna.

The carpals forms the wrist joint with the radius and ulna. A "wrist" watch is actually worn on the distal forearm (over the lower ends of the radius and ulna), not on the wrist at all. The true wrist, or carpus, is the proximal part of the structure we generally call our "hand." The carpus consists of eight marblesize short bones, or carpals (kar'palz), closely united by ligaments. Because gliding movements occur between these bones, the carpus as a whole is quite flexible. The carpals are arranged in two irregular rows of four bones each (figure below). In the proximal row (lateral to medial) are the scaphoid (skaf'oid; "boat-shaped"), lunate (lu'nāt; "moonlike"), triquetrum (tri-kwet'rum; "triangular"), and pisiform (pi'sĭ-form; "pea-shaped"). Of these, all but the pisiform participate in forming the wrist joint. The carpals of the distal row (lateral to medial) are the trapezium (trah-pe'ze-um; "little table"), trapezoid (tra˘'peh-zoid; "four-sided"), capitate ("headshaped"), and hamate (ham'āt; "hooked"). There are numerous memory-jogging phrases to help you recall the carpals in the order given above, such as: "Sally left the party to take Cindy home." The humerus is the arm bone, located proximal to the forearm bones, the radius and ulna. Located distal to the carpals are the metacarpals and phalanges of the hand.

Correctly match the following term: Coronoid process.

The coronoid process is found on the ulna. The ulna (ul'nah; "elbow") is slightly longer than the radius. It has the main responsibility for forming the elbow joint with the humerus. Its proximal end looks like the adjustable end of a monkey wrench: It bears two prominent processes, the olecranon (elbow) and the coronoid process, separated by a deep concavity, the trochlear notch. Together, these two processes grip the trochlea of the humerus, forming a hinge joint that allows the forearm to be bent upon the arm (flexed), then straightened again (extended). When the forearm is fully extended, the olecranon "locks" into the olecranon fossa, keeping the forearm from hyperextending (moving posteriorly beyond the elbow joint). The posterior olecranon forms the angle of the elbow when the forearm is flexed and is the bony part that rests on the table when you lean on your elbows. On the lateral side of the coronoid process is a small depression, the radial notch, where the ulna articulates with the head of the radius. Distally the ulnar shaft narrows and ends in a knoblike head. Medial to the head is the ulnar styloid process, from which a ligament runs to the wrist. The ulnar head is separated from the bones of the wrist by a disc of fibrocartilage and plays little or no role in hand movements. The femur is the thigh bone. The tibia and fibula are the leg bones. The humerus is the arm bone. The radius and ulna are the forearm bones. The coxal bones are the hip bones.

The interphalangeal joint is a hinge joint.

The interphalangeal joints are between bones of the fingers or toes. In a hinge joint, the cylinder part of one bone fits into the trough part of another bone. This joint allows for uniaxial movement, flexion, and extension.

Select the correct sequence of fracture repair steps.

The correct sequence of steps for the healing of a bone fracture is: hematoma forms, fibrocartilaginous callus forms, bony callus forms, and bone remodeling occurs. Repair in a simple fracture involves four major stages: A hematoma forms. When a bone breaks, blood vessels in the bone and periosteum (and perhaps in surrounding tissues) are torn. The hemorrhaged blood clots, forming a hematoma at the fracture site. Fibrocartilaginous callus forms. Within a few days, new blood vessels grow into the clot. Fibroblasts and chondroblasts invade the fracture site from the nearby periosteum and endosteum. The fibroblasts produce collagen fibers that span the break and connect the broken bone ends. The chondroblasts secrete a cartilaginous matrix that bulges externally and later calcifies, forming a fibrocartilaginous callus that spans the break and connects the broken bone ends. Bony callus forms. Within this mass of repair tissue, osteoblasts begin forming spongy bone. Within a week, osteoblasts begin to lay down trabeculae of new bone around and within the fibrocartilaginous callus. These trabeculae span the width of the callus and unite the two fragments of broken bone. Gradually the fibrocartilaginous callus is replaced by immature bone, converting it to a bony (hard) callus. Bone remodeling occurs. Beginning during bony callus formation and continuing for several months after, the bony callus is remodeled. The excess material on the diaphysis exterior and within the medullary cavity is removed. Compact bone is laid down to reconstruct the shaft walls.

The female pelvis __________.

The female pelvis is tilted anteriorly (forward) compared to a male pelvis. The deep, basinlike structure formed by the hip bones, sacrum, and coccyx is called the pelvis or the bony pelvis. The differences between the male and female pelves are striking. The female pelvis is modified for childbearing: It tends to be wider, shallower, lighter, and rounder than that of a male. The female pelvis not only accommodates a growing fetus, but it must be large enough to allow the infant's relatively large head to exit at birth. The major differences between the typical male and female pelves are summarized and illustrated in the table below.

Correctly match the following term: Articulates with both the acetabulum and the tibia.

The femur articulates with both the acetabulum and the tibia.

Which of the following have bone markings called trochanters?

The femur is the only bone that has bone markings called trochanters. At the junction of the shaft and neck are the lateral greater trochanter and posteromedial lesser trochanter. These projections serve as sites of attachment for thigh and buttock muscles. The two trochanters are connected by the intertrochanteric line anteriorly and by the prominent intertrochanteric crest posteriorly.

Correctly match the ligaments to their function: Prevent lateral or medial rotation when the knee is extended.

The fibular and tibial collateral ligaments prevent lateral or medial rotation when the knee is extended. The extracapsular fibular and tibial collateral ligaments are critical in preventing lateral or medial rotation when the knee is extended. The oblique popliteal ligament is actually part of the tendon of the semimembranosus muscle that fuses with the joint capsule and helps stabilize the posterior aspect of the knee joint. The arcuate popliteal ligament arcs superiorly from the head of the fibula over the popliteus muscle and reinforces the joint capsule posteriorly. The knee's intracapsular ligaments are called cruciate ligaments because they cross each other, forming an X in the notch between the femoral condyles. They act as restraining straps to help prevent anterior-posterior displacement of the articular surfaces and to secure the articulating bones when we stand. The anterior cruciate ligament prevents forward sliding of the tibia on the femur and checks hyperextension of the knee. It is somewhat lax when the knee is flexed, and taut when the knee is extended. The stronger posterior cruciate ligament prevents backward displacement of the tibia or forward sliding of the femur.

Identify the friction-reducing structure associated with synovial joints indicated by "A."

The friction-reducing structure associated with synovial joints indicated by "A" is the subacromial bursa. Bursae and tendon sheaths are not strictly part of synovial joints, but they are often found closely associated with them. Essentially bags of lubricant, they act as "ball bearings" to reduce friction between adjacent structures during joint activity. Bursae are flattened fibrous sacs lined with synovial membrane and containing a thin film of synovial fluid. They occur where ligaments, muscles, skin, tendons, or bones rub together. (The subacromial bursa indicated by letter A). A tendon sheath (indicated by letter B) is essentially an elongated bursa that wraps completely around a tendon subjected to friction, like a bun around a hot dog. The joint (articular) cavity (indicated by letter C) is the innermost space within a synovial joint. It contains a small amount of lubricating synovial fluid. The synovial membrane produces synovial fluid. This is the innermost layer of the joint capsule.

Correctly match the following bone marking to its bone: Greater trochanter.

The greater trochanter is a bone marking found on the femur.

Select the bone that does not articulate directly with another bone.

The hyoid bone does not directly articulate with another bone. Though not directly connected to the skull, the hyoid bone ("U shaped") is considered to be part of the skull. It lies in the anterior neck just inferior to the mandible, and looks like a miniature version of it (see figure below). The hyoid bone is unique in that it is the only bone of the body that does not articulate directly with any other bone.

Correctly match the following joint: Interphalangeal joint.

The interphalangeal joint is a hinge joint. The interphalangeal joints are between bones of the fingers or toes. In a hinge joint, the cylinder part of one bone fits into the trough part of another bone. This joint allows for uniaxial movement, flexion, and extension.

Correctly match the following bones: Facial bone.

The maxillary bone is a facial bone. The facial skeleton is made up of 14 bones (see figures below), of which only the mandible and the vomer are unpaired. The maxillae, zygomatics, nasals, lacrimals, palatines, and inferior nasal conchae are paired bones. The eight cranial bones are the paired parietal and temporal bones and the unpaired frontal, occipital, sphenoid, and ethmoid bones.

The occipital bone articulates with which of the following bones?

The occipital bone articulates with the atlas, the first cervical vertebra. The atlas (C1) has no body and no spinous process. Essentially, it is a ring of bone consisting of anterior and posterior arches and a lateral mass on each side. Each lateral mass has articular facets on both its superior and inferior surfaces. The superior articular facets receive the occipital condyles of the skull—they "carry" the skull, just as Atlas supported the heavens in Greek mythology. These joints allow you to nod your head "yes." The inferior articular facets form joints with the axis (C2) below. Ribs extend from the thoracic vertebrae. The coccyx is the tailbone. The sacrum articulates with the hip bones to form the pelvic girdle.

Which of the following is the bony part that rests on the table when you lean on your elbows?

The olecranon is the bony part that rests on the table when you lean on your elbows. The ulna (ul'nah; "elbow") is slightly longer than the radius. It has the main responsibility for forming the elbow joint with the humerus. Its proximal end looks like the adjustable end of a monkey wrench: It bears two prominent processes, the olecranon (elbow) and the coronoid process, separated by a deep concavity, the trochlear notch. Together, these two processes grip the trochlea of the humerus, forming a hinge joint that allows the forearm to be bent upon the arm (flexed), then straightened again (extended). When the forearm is fully extended, the olecranon "locks" into the olecranon fossa, keeping the forearm from hyperextending (moving posteriorly beyond the elbow joint). The posterior olecranon forms the angle of the elbow when the forearm is flexed and is the bony part that rests on the table when you lean on your elbows. On the lateral side of the coronoid process is a small depression, the radial notch, where the ulna articulates with the head of the radius. Distally the ulnar shaft narrows and ends in a knoblike head. Medial to the head is the ulnar styloid process, from which a ligament runs to the wrist. The ulnar head is separated from the bones of the wrist by a disc of fibrocartilage and plays little or no role in hand movements.

Identify the part of the sacrum or coccyx indicated by "A."

The part of the sacrum or coccyx indicated by "A" is the sacral canal. Letter A indicates the sacral canal of the sacrum. Letter B indicates the body of the sacrum. Letter C indicates one of the posterior sacral foramina. Letter D indicates the coccyx.

The pectoral girdle does not quite satisfy the features of a true girdle because

The pectoral girdle does not quite satisfy the features of a true girdle because posteriorly the medial ends of the scapulae do not join each other. The pectoral girdle, or shoulder girdle, consists of the clavicle (klav′ĭ-kl) anteriorly and the scapula (skap′u-lah) posteriorly. The paired pectoral girdles and their associated muscles form your shoulders. Although the term girdle usually signifies a beltlike structure encircling the body, a single pectoral girdle, or even the pair, does not quite satisfy this description. Anteriorly, the medial end of each clavicle joins the sternum; the distal ends of the clavicles meet the scapulae laterally. However, the scapulae fail to complete the ring posteriorly, because their medial borders do not join each other or the axial skeleton. Instead, the scapulae are attached to the thorax and vertebral column only by the muscles that clothe their surfaces.

Correctly match the following term: Articulates with the capitulum of the humerus.

The radius articulates with the capitulum of the humerus. At the distal end of the humerus are two condyles: a medial trochlea ("pulley"), which looks like an hourglass tipped on its side, and the lateral ball-like capitulum. These condyles articulate with the ulna and the radius, respectively. The carpals make up the wrist and the tarsals form the posterior aspect of the foot. The femur is the thigh bone.

Correctly match the bone and location: Radius.

The radius is the bone of the lateral forearm. In anatomical position, the ulna is the bone of the medial forearm. The humerus is the arm bone. The carpals make up the wrist.

The rotator cuff is part of what joint?

The rotator cuff is part of the shoulder joint. Four other tendons (and the associated muscles) make up the rotator cuff. This cuff encircles the shoulder (glenohumeral) joint and blends with the articular capsule. The muscles include the subscapularis, supraspinatus, infraspinatus, and teres minor. The rotator cuff can be severely stretched when the arm is vigorously circumducted; this is a common injury of baseball pitchers. Shoulder dislocations are fairly common. Because the shoulder's reinforcements are weakest anteriorly and inferiorly, the humerus tends to dislocate in the forward and downward direction.

Match the following: Sphenoid bone.

The sphenoid bone encloses the pituitary. The bat-shaped sphenoid bone (sfe'noid; sphen = wedge) spans the width of the middle cranial fossa. The sphenoid is considered the keystone of the cranium because it forms a central wedge that articulates with all other cranial bones. It is a challenging bone to study because of its complex shape. As shown in the figure below, it consists of a central body and three pairs of processes: the greater wings, lesser wings, and pterygoid processes (ter'ĭ-goid). Within the body of the sphenoid are the paired sphenoidal sinuses. The superior surface of the body bears a saddle-shaped prominence, the sella turcica (sel'ah ter'sĭ-kah), meaning "Turk's saddle." The seat of this saddle, called the hypophyseal fossa, forms a snug enclosure for the pituitary gland (hypophysis). The bony part of the nasal septum consists of the vomer inferiorly and the perpendicular plate of the ethmoid bone superiorly. The external acoustic meatus of the temporal bone surrounds the external ear canal. The frontal bone forms the anterior cranium. The parietal bones form most of the superior and lateral aspects of the skull, as such, they form the bulk of the cranial ceiling. The occipital bone forms most of the skull's posterior wall and base.

Identify structure indicated by "B" in this photomicrograph of a cross section of part of a skeletal muscle.

The structure indicate by "B" is the perimysium. The epimysium (letter A) ("outside the muscle") is an "overcoat" of dense irregular connective tissue that surrounds the whole muscle. Sometimes it blends with the deep fascia that lies between neighboring muscles or the superficial fascia deep to the skin. Perimysium (letter B). Within each skeletal muscle, the muscle fibers are grouped into fascicles ("bundles") that resemble bundles of sticks. Surrounding each fascicle is a layer of dense irregular connective tissue called perimysium ("around the muscle"). The endomysium (letter C). ("within the muscle") is a wispy sheath of connective tissue that surrounds each individual muscle fiber (cell). It consists of fine areolar connective tissue.

Identify the structure indicated by "A" in this photomicrograph of a cross section of part of a skeletal muscle.

The structure indicated by "A" is the epimysium. The epimysium (letter A) ("outside the muscle") is an "overcoat" of dense irregular connective tissue that surrounds the whole muscle. Sometimes it blends with the deep fascia that lies between neighboring muscles or the superficial fascia deep to the skin. Perimysium (letter B). Within each skeletal muscle, the muscle fibers are grouped into fascicles ("bundles") that resemble bundles of sticks. Surrounding each fascicle is a layer of dense irregular connective tissue called perimysium ("around the muscle"). The endomysium (letter C). ("within the muscle") is a wispy sheath of connective tissue that surrounds each individual muscle fiber (cell). It consists of fine areolar connective tissue.

Correctly match the bone and location: Ulna.

The ulna is the bone of the medial forearm. In anatomical position, the radius is the bone of the lateral forearm. The humerus is the arm bone. The carpals make up the wrist.

Which of the following is a facial bone?

The vomer is a facial bone. The slender, plow-shaped vomer (vo'mer; "plow") lies in the nasal cavity, where it forms part of the nasal septum. The facial skeleton is made up of 14 bones (see figures below), of which only the mandible and the vomer are unpaired. The maxillae, zygomatics, nasals, lacrimals, palatines, and inferior nasal conchae are paired bones. The eight cranial bones are the paired parietal and temporal bones and the unpaired frontal, occipital, sphenoid, and ethmoid bones.

Bone is broken down by __________.

osteoclasts

Chewing involves the __________ joint.

temporomandibular

Rickets can be caused by a deficiency of

vitamin D