Lippincott Q&A Chapter 1

During an exercise program, a physical therapist instructs her patient to fl ex his elbow. Which of the following terms describes the muscles that perform that desired action? (A) Agonists (B) Antagonists (C) Fixators (D) Proprioceptors (E) Synergists

A: Agonists. Muscles work in antagonistic pairings, that is, in opposition to one another. A muscle that performs a desired action is an agonist (prime mover). In this case, the muscles that act to fl ex the elbow are the agonists.

Which of the following medical imaging techniques utilizes a beam of X-rays to transilluminate the body? (A) Computerized tomography (CT) (B) Magnetic resonance imaging (MRI) (C) Positron emission tomography (PET) (D) Ultrasonography (E) X-ray glasses

A: Computerized tomography (CT). CT scans are produced by rotating a beam of X-rays in an arc or a circle around the body, measuring the energy absorptions of the beam in different tissues in a computer, and converting the differential energy absorptions into images. CT scans are very similar to plain film radiographs in that both use X-rays to image levels of radiodensity. However, CT images show radiographs that reconstruct horizontal sections of the body.

In endochondral ossifi cation, bone replaces most of an initial cartilage model. Which of the following refers to the part of a bone ossified from the primary ossification center? (A) Diaphysis (B) Epiphysis (C) Metaphysis (D) Epiphyseal plate (E) Condyle

A: Diaphysis. The diaphysis of a bone is the region that ossifi es from the primary ossifi cation center. This area typically corresponds to the main body of the bone model, which develops from the periosteal bud. In long bones, the diaphysis forms the shaft of the bone.

A physician discovers that his 72-year-old patient is leaking blood from a vessel that normally carries oxygen depleted blood. Which of the following vessels is most likely damaged? (A) Pulmonary trunk (B) Pulmonary veins (C) Abdominal aorta (D) Coronary arteries (E) Common carotid arteries

A: Pulmonary trunk. The right side of the heart receives oxygen-depleted blood from the systemic and coronary veins. The pulmonary trunk is the large artery that drains the right ventricle and sends that blood to the lungs for aeration. Remember, the critical difference between arteries and veins is that arteries carry blood away from the heart, whereas veins carry blood toward the heart. In the systemic vessels, arterial blood is typically oxygen-rich and venous blood oxygen-poor. However, in the pulmonary circuit, that oxygenation relationship is reversed.

Under normal conditions, lymphatic vessels periodically contain elevated amounts of fat droplets (chyle). The highest concentration of chyle is found in the lymphatics that drain which of the following organs? (A) Small intestine (B) Brain (C) Heart (D) Long bones (E) Spleen

A: Small intestine. Lymphatic capillaries (lacteals) collect the lipids and lipid-soluble vitamins absorbed by the gut and send that chyle through larger lymphatic vessels to the thoracic duct. Thus, the greatest concentration of chyle is found in the intestinal lymphatics (e.g., those draining the small intestine) following meals.

Synovial joints allow free movement between their bony elements. They are classifi ed into multiple subtypes according to the shape of the articulating surfaces and/or the degree of movement allowed. Which of the following synovial joint types permits multiaxial movement? (A) Pivot (B) Ball and socket (C) Condyloid (D) Saddle (E) Hinge

B: Ball and socket. Multiaxial movement occurs through several (more than two) axes or planes. In ball and socket joints, the rounded head of one bone moves in the concave socket of the other bone, such as the hip and shoulder (glenohumeral) joints. These highly mobile joints permit fl exion- extension, abduction-adduction, medial and lateral rotation, and other more subtle motions

A radiologist orders a posteroanterior (PA) plain fi lm of the chest. This image should provide the greatest resolution of which of the following structures? (A) Transverse processes of vertebrae (B) Heart (C) Esophagus (D) Primary bronchi (E) Descending aorta

B: Heart. The PA plain fi lm is the standard radiographic view of the thorax, and probably the most commonly obtained medical image. In basic terminology, a PA radiograph is one in which the X-ray beam penetrates from the patient's posterior side to the anterior side, as shown in the given illustration. The X-ray projector is located posterior to the patient, and the X-ray fi lm is positioned anterior. The part of the body under study should be as close as possible to the X-ray fi lm in order to optimize the resolution of that part and minimize magnification artifacts. Thus, in the PA orientation, the heart is closest to the X-ray fi lm and appears sharper than the other structures in question.

A 17-year-old boy engages in an intensive weight-lifting program to build muscle strength. The growth of his muscles is the result of which of the following processes? (A) Atrophy (B) Hypertrophy (C) Hyperplasia (D) Tonus (E) Shunting

B: Hypertrophy. Postnatal growth in size of skeletal muscles in response to exercise is the result of increased size (hypertrophy) of existing muscle fi bers rather than the addition of new muscle fi bers. Hypertrophy increases the number and size of myofi brils within individual muscle fibers. This growth increases the cross-sectional area of each fiber, thus each muscle, resulting in added muscle force production (strength).

A man exhibits anhydrosis (lack of sweating) and erythema (fl ushing) on his chest due to loss of sympathetic innervation. A thorough neurological analysis reveals dysfunction of presynaptic (preganglionic) sympathetic nerve cell bodies. Which of the following sites is most likely damaged in this patient? (A) Brainstem (B) Lateral gray horn of the spinal cord (C) Sympathetic chain ganglia (D) Prevertebral ganglia (E) Dorsal root ganglia

B: Lateral gray horn of the spinal cord. Presynaptic sympathetic neurons originate in the pronounced lateral gray horn of the spinal cord, from spinal segments T1-L2 (or L3). Thus, the sympathetic division is described as having a thoracolumbar outflow. It is the sympathetic nerve fibers that are damaged in this patient, leading to the anhydrosis and erythema.

Bones are often classifi ed according to their shape and/or developmental pattern. Which of the following choices is an example of a flat bone? (A) Humerus (B) Sternum (C) Hamate (D) Maxilla (E) Patella

B: Sternum. The sternum (breastbone) and the bones that form the cranial roof, or calvaria, are fl at bones. These bones are typically located subcutaneously and are easily accessible. The sternum is a notable fl at bone because it is relatively thick for this type of bone, and it is commonly used for collecting bone marrow.

Which of the following is true of the anatomical position? (A) The humerus is proximal to the scapula. (B) The radius is medial to the ulna. (C) The vertebral arch is ventral to the vertebral body. (D) The femur is superior to the fibula. (E) The phalanges of the foot are cranial to the metatarsals.

(D) The femur is superior to the fibula. In the anatomical position, a person is standing erect, facing anterior (forward), with the upper limbs by the sides, the palms facing anterior, the lower limbs placed together with the soles on the ground, and the toes pointing anterior. In this position, the thigh is superior to (above) the lower leg. Thus, the femur is superior to both the tibia and fibula.

Which of the following is a characteristic feature of the venous system? (A) The direction of blood fl ow in veins is away from the heart (B) Veins in the limbs tend to be double or multiple vessels (C) Veins are less abundant than arteries (D) The walls of veins are thicker than those of their companion arteries (E) Veins tend to spurt blood when cut

B: Veins in the limbs tend to be double or multiple vessels. The veins in the limbs tend to occur as two or more smaller vessels tightly surrounding their accompanying artery. This feature is especially true of the deep vessels, where the veins are denoted as accompanying veins (venae comitantes). This arrangement works as a physiological countercurrent heat exchange mechanism, in which outfl owing warmer arterial blood warms the in flowing cooler venous blood.

Which of the following statements is true regarding the resultant imagery in standard CT (computerized tomography) films? (A) Air appears white (B) Muscle appears black (C) Bone appears white (D) Fluids appear black (E) Fat appears white

C: Bone appears white. Both plain fi lm radiographs and CT scans utilize X-ray beams to penetrate the body and measure different levels of radiodensity. Thus, both techniques produce similar images. More radio dense tissue (e.g., compact bone) appears white, whereas less radiodense substances (e.g., air) appear black. Tissues of intermediate degrees of radiodensity appear as varying shades of gray.

In examining a radiograph of the right shoulder of a 32-year-old male car accident victim, the radiologist identifies the head of the humerus located below the coracoid process of the scapula in a subcoracoid position. Which of the following terms best describes the condition of the humerus? (A) Avulsed (B) Comminuted (C) Dislocated (D) Reduced (E) Subluxated

C: Dislocated. The head of the humerus normally articulates with the glenoid fossa of the scapula to form the glenohumeral (shoulder) joint. Therefore, the subcoracoid position is abnormal. A dislocation is a complete displacement of the bones at a joint. In this case, the head of the humerus is completely removed from its normal position. Repositioning of the humerus may require anesthesia and/or muscle relaxants administered to the patient.

A radiologist wishes to image the body in a plane parallel to both scapulae. Which of the following choices best describes the desired sectioning? (A) Horizontal section (B) Transverse section (C) Frontal section (D) Sagittal section (E) Oblique section

C: Frontal section. The scapulae (shoulder blades) lie across the back. An imaging plane passing parallel to both these bones divides the body into anterior (front) and posterior (back) parts. A frontal (coronal) section divides the body into anterior (front) and posterior (back) portions. It runs perpendicular to the median and horizontal planes.

Which of the following is an example of a cartilaginous joint? (A) Humeroulnar joint (B) Middle radioulnar joint (C) Intervertebral disc joint (D) Cranial sutural joint (E) Tibiotalar joint

C: Intervertebral disc joint. Three major classes of joints exist, based on the nature of the articulation: (1) Synovial, (2) Fibrous, and (3) Cartilaginous. In cartilaginous joints, the articulating bones are joined together by hyaline cartilage or fi brocartilage. The intervertebral discs are pads of largely fi brocartilage that bind together the bodies of adjacent vertebrae. Other examples include the pubic symphysis, the mental symphysis, and all epiphyseal plates.

A 65-year-old woman develops blood clots in her lower limbs. If one of these were to break loose and fl ow through the venous system, it would embed in capillaries in which of the following locations? (A) Brain (B) Kidneys (C) Lungs (D) Liver (E) Heart

C: Lungs. Vascular drainage of the lower limbs is through the systemic veins and into the right side of the heart. The right heart sends blood to the lungs, where the fi rst capillary beds are encountered. Thus, the clot (thrombus) would lodge in the capillary beds of the lungs, producing a thromboembolism.

A research scientist at a pharmaceutical company discovers a new drug that selectively blocks the release of norepinephrine from nerve endings. At which of the following sites would this drug have the greatest effect on normal synaptic transmission? (A) Somatic neuron motor end plates (B) Postsynaptic parasympathetic nerve terminals (C) Postsynaptic sympathetic nerve terminals (D) Synapses between presynaptic and postsynaptic parasympathetic neurons (E) Synapses between presynaptic and postsynaptic sympathetic neurons

C: Postsynaptic sympathetic nerve terminals. Postsynaptic sympathetic neurons typically release the neurotransmitter norepinephrine/noradrenaline from their endings, so the sympathetic division is described as a noradrenergic system. Blocking the release of norepinephrine would disrupt normal neurotransmission at these terminal sites. An important exception to this rule is that the postsynaptic sympathetic neurons supplying sweat glands typically release acetylcholine from their endings.

A surgeon mistakenly lacerates the thoracic duct during lung surgery. Which of the following would be the immediate consequence of this iatrogenic action? (A) High blood pressure (B) Low blood pressure (C) Decreased immunity (D) Chylothorax (E) Lymphedema

D: Chylothorax. Because it is thin walled and often appears colorless, the thoracic duct may be diffi cult to recognize and is subject to accidental injury. If lacerated, lymph and chyle drain into the pleural cavity, creating a condition termed "chylothorax." If the thoracic duct requires ligation, lymph enters the venous system via alternative lymphatic vessels.

If the body were sectioned along a ___ plane, it would be divided into ___ portions. (A) sagittal...anterior and posterior (B) sagittal...superior and inferior (C) coronal...superior and inferior (D) coronal...right and left (E) horizontal...superior and inferior

E: horizontal...superior and inferior. A horizontal plane lies perpendicular to both the median and coronal (frontal) planes. It divides the body into superior (upper) and inferior (lower) portions.

A physician delivers an intramuscular injection into the lateral aspect of the shoulder. Which of the following sequences describes the correct order of tissue layers pierced by the needle, passing from superfi cial to deep? (A) Epidermis, dermis, superfi cial fascia, epimysium, deep fascia (B) Dermis, epidermis, superfi cial fascia, deep fascia, epimysium (C) Dermis, epidermis, superfi cial fascia, epimysium, deep fascia (D) Epidermis, dermis, superfi cial fascia, deep fascia, epimysium (E) Epidermis, superfi cial fascia, dermis, deep fascia, epimysium

D: Epidermis, dermis, superficial fascia, deep fascia, epimysium. The epidermis is the superfi cial cellular layer of the skin. The dermis is the deeper, dense connective tissue layer of the skin. The superficial fascia (subcutaneous tissue) is the fatty loose connective tissue layer that underlies the skin. The deep fascia is the relatively dense, fat-free connective tissue layer that lies deep to the skin and superficial fascia. The epimysium is a deep extension of the deep fascia that tightly invests the surface of individual muscles.

Which of the following is true of a median plane of the hand? (A) It becomes a horizontal plane when the hand is medially rotated 90 degrees. (B) It becomes a coronal plane when the brachium (upper arm) is laterally rotated 90 degrees and abducted 90 degrees. (C) It is the same as a frontal plane. (D) It remains a median plane regardless of limb or body position. (E) It is oriented mediolaterally.

D: It remains a median plane regardless of limb or body position. All anatomical descriptions are relative to the anatomical position. Thus, no matter how the body is moved or postured, the observer must transpose the body into the anatomical position in order to make accurate, uniform descriptions.

A 16-year-old boy crashes his mountain bike and suffers a fractured tibia. Which of the following damaged structures would most likely produce the acute pain emanating from the fractured tibia? (A) Nerves in compact bone (B) Nerves in trabecular bone (C) Surrounding muscle and tendon receptors (D) Periosteal nerves (E) Vascular nerves

D: Periosteal nerves. The periosteum contains a dense population of pain fi bers and is very sensitive to tearing, tension, or torsion. Thus, the severe pain associated with bone injury emanates mainly from trauma to the periosteum.

A teenage boy breaks a pane of glass with his fist and receives a laceration to the posterior aspect of his wrist. He notices the tendons that cross his wrist lift out of place (or bowstring) when he extends his wrist. Which of the following structures was most likely cut by the broken glass? (A) Investing deep fascia (B) Intermuscular septum (C) Bursa (D) Retinaculum (E) Synovial tendon sheath

D: Retinaculum. A retinaculum is a thickened band of deep fascia that serves to hold tendons in place where they cross joints, as shown in the illustration. The presence of a retinaculum is important in muscle mechanics because it prevents tendons from lifting up out of place and bowstringing across the shortened joint angle created when the muscles crossing that joint contract. Because the tendons of the wrist lift out of place when the teenager extends his wrist, the retinaculum was damaged by the broken glass

A 20-year-old college student on spring break suffers a first degree sunburn on her back and upper limbs. Which of the following integumentary structures/functions is most likely affected? (A) Hair follicles (B) Subcutaneous fat (C) Vitamin A production (D) Parasympathetic nerve endings (E) General sensory nerve endings

E: General sensory nerve endings. Burns are classified in increasing order of severity, according to the depth of damage to the skin. First-degree burns are superfi cial depth injuries (e.g., most sunburns) that damage only the epidermis. Second-degree burns are partial-thickness injuries that affect the epidermis and superficial part of the dermis. Third degree burns are full-thickness injuries that damage the entire depth of the skin and may include deeper structures as well. General sensory (General Somatic Afferent; GSA) nerves are the general sensory nerves that register pain and other generalsensations in the body wall and limbs, including the skin. While most of these nerve endings are in the dermis, many do penetrate into the epidermis. Collectively, the general sensory fibers convey the pain derived from the sunburn.

Which of the following structures are innervated by somatic motor neurons? (A) Meissner corpuscles (B) Arrector pili muscles of hair follicles (C) Myocardium of the left ventricle (D) Wall of the axillary artery (E) Semispinalis muscle

E: Semispinalis muscle. The system of identifying functional components of nerves is used to organize neuron types according to their anatomical distribution, functional properties, and developmental patterns. Five defined functional components exist, including general sensory, visceral sensory, visceral motor, somatic motor, and special sensory. Somatic motor (General Somatic Efferent; GSE) neurons are motor neurons that supply skeletal muscles derived from embryonic myotomes, such as the semispinalis muscle in the back

A young boy uses his right hand to screw-in a new light bulb. Which of the following terms best describes the screw-home movement of his forearm? (A) Flexion (B) Abduction (C) Pronation (D) Adduction (E) Supination

E: Supination. The screw-home movement is the clockwise motion that drives a screw into its receptacle, in this case the bulb into the socket. When using the right hand, the palm and forearm turn laterally and the palm moves from facing posterior to facing anterior, which is supination.

A 55-year-old woman presents with ulceration and pain in the skin around and including her right nipple. Her physician correctly identifies the affected area as that of the T4 dermatome. The pain this woman is suffering could be related to which of the following spinal segmental levels? (A) T3 only (B) T4 only (C) T3 and T4 (D) T4 and T5 (E) T3, T4, and T5

E: T3, T4, and T5. A dermatome is the area of skin innervated by sensory fi bers (i.e., by the dorsal root) from a single spinal segment. The classic anatomical dermatome map shown in the illustration indicates a barber-pole-like distribution of discrete bands of cutaneous territories. However, this standard map is somewhat deceiving in that there is actually considerable overlap between the dermatomes supplied by adjacent spinal cord segments. Thus, any one dermatome is actually supplied by three spinal segments: one major supplying segment plus two smaller supplying adjacent segments that overlap with the main segment.