Learning Modules - Medical Gross Anatomy Anatomical Orientation - Page 1 of 9

Transcription

1 Anatomical Orientation - Page 1 of 9 In order to accurately describe the human body, a basic set of anatomical terms must be known. To start, there are 3 types of primary or cardinal planes that pass through the body: sagittal, coronal, and transverse. The sagittal plane is named for the sagittal suture, which is a mid-line suture joint of the skull. It is also known as the median or mid-sagittal plane, and it divides the body into right and left halves. Planes passing parallel but not in the mid-line are called parasagittal planes.

2 Anatomical Orientation - Page 2 of 9 A coronal plane, also called a frontal plane, is any plane passing down through the body parallel to the coronal suture of the skull, dividing the body into front and back portions. Coronal planes are therefore perpendicular to sagittal planes and pass through the length of the body. Transverse planes are perpendicular to both sagittal and coronal planes. They pass through the width of the body in a horizontal or transverse direction, similar to the slices of a loaf of bread. Transverse planes divide the body into upper and lower sections, and are also called horizontal or axial planes or cross-sections.

3 Any plane passing through the body not parallel to one of the three primary or cardinal planes is called oblique.

4 Anatomical Orientation - Page 3 of 9 To establish the frame of reference for all of the parts of the body, the body should be thought of as being positioned in an ideal pose called the anatomical position. To assume the anatomical position, stand erect, feet together, head facing forward, upper limbs at the side, with the palms facing forward. By placing or imagining the body in this position, all body parts can then be related to each other through the use of relative terms that describe the location within the body.

5 Anatomical Orientation - Page 4 of 9 Superfical - Deep A superficial structure is closer to the body surface (skin) than a deeper structure. Example: The sternum (breast-bone) is superficial to the more deeply lying heart. Superior - Inferior Superior means toward the top of the head. Inferior means toward the bottom of the feet. Cranial and caudal are often used interchangeably with superior and inferior. Example: The heart is superior to the liver.

6 Anatomical Orientation - Page 5 of 9 Anterior - Posterior / Ventral - Dorsal Anterior or ventral is toward the front of the body surface. Posterior or dorsal is toward the back of the body surface. Example: The vertebral column is dorsal to the more anteriorly placed sternum.

7 Anatomical Orientation - Page 6 of 9 Median - Medial - Intermediate - Lateral Medial means toward the midline of the body, whereas lateral structures lie further away from the midline. Intermediate structures lie between medial and lateral structures, and median structures lie on the midline of the body. Example: The trachea is a median structure. It lies medial to the more laterally placed point or top of the shoulder. The clavicle is intermediate between these two. One could also say that the clavicle is medial to the point of the shoulder, but lateral to the trachea.

8 Anatomical Orientation - Page 7 of 9 Proximal - Distal In referring to structures within the limbs specifically, the term proximal means toward the limb's attachment to the trunk, while distal means away from its attachment. Example: The knee is proximal to the more distally placed ankle. These terms can also be used to describe location along linear structures within the trunk, such as the digestive tract or arteries. Within these structures, the normal direction of flow determines proximal or upstream from distal or downstream. However, in veins and lymphatic vessels, blood or lymph flows distal to proximal. Example: The descending colon is distal to the transverse and ascending colon.

9 Anatomical Orientation - Page 8 of 9 The relative terms for location are often used in combinations, since most structures are not related to each other in only a single dimension. Example: The nipple is superolateral to the umbilicus or belly-button.

10 Anatomical Orientation - Page 9 of 9 In addition to these relative terms, certain body regions are more rigorously defined anatomically. The upper limb, commonly referred to as the "arm", is more precisely defined as the arm extending from shoulder to elbow, the forearm from elbow to wrist, and the hand distal to the wrist. Similarly, the lower limb is made up of the thigh, from hip to knee, the leg which extends from knee to ankle, and the foot distal to the ankle.