1, 2 & 3. Approaches to studying, terminology and variations in anatomy

Question 1

List the three approaches to studying anatomy and define each

Answer 1

1. Regional anatomy considers the body as organized into segments or parts.
2. Systemic anatomy sees the body as organized into organ systems.
3. Clinical anatomy emphasizes application of anatomical knowledge to the practice of medicine

Question 2

In what position is the body when the anatomical position is described?

Answer 2

The head, gaze (eyes), and toes directed anteriorly (forward),
The arms adjacent to the sides with the palms facing anteriorly, and
The lower limbs close together with the feet parallel.

Question 3

Define the median plane

Answer 3

The median plane is the vertical plane passing longitudinally through the body, divides the body into right and left halves.

Question 4

Define the sagittal and paramedian plane

Answer 4

Sagittal planes are vertical planes passing through the body parallel to the median plane. A plane parallel and near to the median plane may be referred to as a paramedian plane.

Question 5

Define the coronal (frontal) plane

Answer 5

Frontal (coronal) planes are vertical planes passing through the body at right angles to the median plane, dividing the body into anterior and posterior parts.

Question 6

Define the transverse plane

Answer 6

Transverse planes are horizontal planes passing through the body at right angles to the median and frontal planes, dividing the body into superior (upper) and inferior (lower) parts. Radiologists refer to transverse planes as transaxial, which is commonly shortened to axial planes.

Question 7

Define the term superior

Answer 7

Superior refers to a structure that is nearer the vertex, the topmost point of the cranium.

Question 8

Define the term cranial

Answer 8

Cranial relates to the cranium and is a useful directional term, meaning toward the head or cranium.

Question 9

Inferior

Answer 9

Inferior refers to a structure that is situated nearer the sole of the foot.

Question 10

Caudal

Answer 10

Caudal (L. cauda, tail) is a useful directional term that means toward the feet or tail region, represented in humans by the coccyx (tail bone), the small bone at the inferior (caudal) end of the vertebral column.

Question 11

Define the term posterior (dorsal)

Answer 11

Posterior (dorsal) denotes the back surface of the body or nearer to the back.

Question 12

Define the term anterior (ventral) and differentiate it from rosteral.

Answer 12

Anterior (ventral) denotes the front surface of the body.
Rostral is often used instead of anterior when describing parts of the brain; it means toward the rostrum (L. for beak); however, in humans it denotes nearer the anterior part of the head (e.g., the frontal lobe of the brain is rostral to the cerebellum).

Question 13

Define the term medial

Answer 13

Medial is used to indicate that a structure is nearer to the median plane of the body whereas lateral stipulates that a structure is farther away from the median plane. The 1st digit of the hand (thumb) is lateral to the other digits.

Question 14

Define the term dorsum

Answer 14

Dorsum usually refers to the superior aspect of any part that protrudes anteriorly from the body, such as the dorsum of the tongue, nose, penis, or foot. It is also used to describe the posterior surface of the hand, opposite the palm. Because the term dorsum may refer to both superior and posterior surfaces in humans, the term is easier to understand if one thinks of a quadripedal plantigrade animal that walks on its palms and soles, such as a bear.

The sole is the inferior aspect or bottom of the foot, opposite the dorsum, much of which is in contact with the ground when standing barefoot.

Question 15

What do the terms superficial, intermediate and deep describe?

Answer 15

Superficial, intermediate, and deep describe the position of structures relative to the surface of the body or the relationship of one structure to another underlying or overlying structure.

Question 16

Define the term external

Answer 16

External means outside of or farther from the center of an organ or cavity, while internal means inside or closer to the center, independent of direction.

Question 17

When are the terms proximal and distal used?

Answer 17

Proximal and distal are used when contrasting positions nearer to or farther from the attachment of a limb or the central aspect of a linear structure, respectively.

Question 18

In terms of laterality, discuss the terms bilateral, unilateral, ipsilateral and contralateral.

Answer 18

Paired structures having right and left members (e.g., the kidneys) are bilateral, whereas those occurring on one side only (e.g., the spleen) are unilateral.
Something occurring on the same side of the body as another structure is ipsilateral whereas contralateral means occurring on the opposite side of the body relative to another structure.

Question 19

In terms of movement, describe flexion and extension.

Answer 19

Flexion indicates bending or decreasing the angle between the bones or parts of the body and for most joints (e.g., elbow), flexion involves movement in an anterior direction whereas extension indicates straightening or increasing the angle between the bones or parts of the body. Extension usually occurs in a posterior direction.

Question 20

In terms of movement, describe dorsiflexion and plantarflexion.

Answer 20

Dorsiflexion describes flexion at the ankle joint, as occurs when walking uphill or lifting the front of the foot and toes off the ground whereas plantarflexion bends the foot and toes toward the ground, as when standing on your toes.

Question 21

In terms of movement, describe hyperextension, abduction and adduction.

Answer 21

Hyperextension is the extension of a limb or part beyond the normal limit
Except for the digits, abduction means moving away from the median plane and adduction means moving toward it. In abduction of the digits (fingers or toes), the term means spreading them apart—moving the other fingers away from the neutrally positioned 3rd (middle) finger or moving the other toes away from the neutrally positioned 2nd toe. The 3rd finger and 2nd toe medially or laterally abduct away from the neutral position. Adduction of the digits is the opposite—bringing the spread fingers or toes together, toward the neutrally positioned 3rd finger or 2nd toe.

Question 22

In terms of movement, describe circumduction

Answer 22

Circumduction is a circular movement that involves sequential flexion, abduction, extension, and adduction (or in the opposite order) in such a way that the distal end of the part moves in a circle.

Question 23

In terms of movement, describe rotation

Answer 23

Rotation involves turning or revolving a part of the body around its longitudinal axis, such as turning one’s head to face sideways. Medial rotation (internal rotation) brings the anterior surface of a limb closer to the median plane, whereas lateral rotation (external rotation) takes the anterior surface away from the median plane.

Question 24

In terms of movement, describe pronation and supination

Answer 24

Pronation rotates the radius medially so that the palm of the hand faces posteriorly and its dorsum faces anteriorly. Supination is the opposite rotational movement, rotating the radius laterally and uncrossing it from the ulna, returning the pronated forearm to the anatomical position. When the elbow joint is flexed, supination moves the hand so that the palm faces superiorly.

Question 25

In terms of movement, describe inversion and eversion.

Answer 25

Eversion moves the sole of the foot away from the median plane, turning the sole laterally. When the foot is fully everted it is also dorsiflexed.

Inversion moves the sole of the foot toward the median plane (facing the sole medially). When the foot is fully inverted it is also plantarflexed. Pronation of the foot actually refers to a combination of eversion and abduction that results in lowering of the medial margin of the foot (the feet of an individual with flat feet are pronated), and supination of the foot generally implies movements resulting in raising the medial margin of the foot, a combination of inversion and adduction.

Question 26

In terms of movement, describe opposition and reposition

Answer 26

Opposition is the movement by which the pad of the 1st digit (thumb) is brought to another digit pad.

Reposition describes the movement of the 1st digit from the position of opposition back to its anatomical position.

Question 27

In terms of movement, describe protrusion and retrusion

Answer 27

Protrusion is a movement anteriorly (forward) as in protruding the mandible (chin), lips, or tongue.

Retrusion is a movement posteriorly (backward), as in retruding the mandible, lips, or tongue.

Question 28

In terms of movement, describe elevation and depression

Answer 28

Elevation raises or moves a part superiorly, as in elevating the shoulders when shrugging, the upper eyelid when opening the eye, or the tongue when pushing it up
against the palate (roof of mouth).

Depression lowers or moves a part inferiorly, as in depressing the shoulders when standing at ease, the upper eyelid when closing the eye, or pulling the tongue away from the palate.

Question 29

Discuss the concept of anatomical variations

Answer 29

Anatomical variations are common and it is important to know how such variations may influence physical examinations, diagnosis, and treatment.

A wide variation is found in the size, shape, and form of the attachments of muscles. Similarly, considerable variation exists in the patterns of branching of veins, arteries, and nerves. Veins vary the most and nerves the least.