Anatomical Planes and Directions

Anatomical Position Definition: A reference

position that gives meaning to the directional terms used to describe the body parts and regions

The body is in a standing posture with the arms at the sides, palms turned forward, feet together and pointed forward, and head pointed forward

Midline Definition: A reference

line extending down the middle of the body, encompassing the vertebral column, spinal cord, and naval

Used to cut the body into smaller sections in order to facilitate study of body cavities, organs, systems, etc.

Especially useful in medical imaging studies

Body Planes

Median Plane Definition: The

midline, longitudinal plane dividing the head and torso into equal right and left halves

The middle sagittal plane

Encompasses the vertebral column and spinal cord

Sagittal Plane Definition: The

longitudinal plane dividing the body into left and right parts

Parallel to the median plane and may be applied to the head, torso, and limbs

Not limited to the midline

Frontal (Coronal) Plane Definition: The

longitudinal plane dividing the body into equal or unequal front and back parts

The term “coronal” is used by radiologists in reference to MRIs and CT scans

Transverse Plane Definition: The

horizontal plane that divides the body or body parts into upper and lower segments

A cross section perpendicular to the longitudinal planes

Craft Time!!!!! Construct a plane

model◦ No, not a paper

airplane… A 3-D model of the

body planes, like this:◦ Color-code it and label it

to help you identify the planes

Left Definition: To the left

side of the midline References the

subject’s left, not your left

Example: The stomach is to the left of the liver

Right Definition: To the right

side of the body or structure being studied

Example: The right lung is bigger than the left lung

Lateral Definition: Toward the

side; away from the midline

Example: The eyes are lateral to the nose

Medial Definition: Toward the

midline: away from the side

Example: The eyes are medial to the ears

Anterior Definition: Toward the

front of the body Example: The nose is

on the anterior side of the head

Posterior Definition: Toward the

back of the body Example: A mullet is

long on the posterior side of the body

Superior Definition: Toward the

top of the body Example: The

shoulders are superior to the hips

Inferior Definition: Toward the

bottom of the body Example: The liver is

inferior to the heart

Dorsal Definition: Along (or

toward) the vertebral surface of the body

Example: The SI joints are on the dorsal surface

Ventral Definition: Along

(toward) the belly surface of the body

Example: The naval is on the ventral surface

Caudal Definition: Toward the

tail Example: The neck is

caudal to the skull

Cephalad Definition: Toward the

head Example: The neck is

cephalad to the tail

Proximal Definition: Toward the

trunk Describes relative

position in a limb or other appendage

Example: The joint is proximal to the toenail

Distal Definition: Away from

the trunk or point of attachment

Example: The hand is distal to the elbow

Visceral Definition: Toward an

internal organ; away from the outer wall

Describes positions inside a body cavity

Example: The organ is lined with the visceral layer of the membrane

Parietal Definition: Toward the

wall; away from internal structures

Example: The abdominal cavity is lined with the parietal peritoneal membrane

Deep Definition: Toward the

inside of a part; away from the surface

Example: The thigh muscles are deep to the skin

Superficial Definition: Toward the

surface of a part; away from the inside

Example: The skin is a superficial organ

Medullary Definition: Refers to

an inner region, or medulla

Example: The medullary cavity is where bone marrow is produced

Cortical Definition: Refers to

the outer region, or cortex

Example: Cortical bone covers the external surface of the bone

Intrinsic

Definition: Inherent or insideExample: The lumbricals are intrinsic hand musclesExample: An intrinsic motivation is doing something because it makes you happy

Extrinsic

Definition: Outer or from the outsideExample: The thumb flexor muscle is an extrinsic hand muscleExample: An extrinsic motivation for doing something is monetary compensation

Valgus

Definition: An angulation outward and away from the midline of the body, as exhibited by the distal segment of the bone or jointExample: Someone who is knock-kneed has valgus of the ankles

Varus

Definition: An angulation inward and toward the midline of the body, as exhibited by the distal segment of the bone or jointExample: Someone who is bow-legged has varus of the ankles

Ipsilateral Definition: Situated

on or affecting the same side of the body

Example: The right eye and the right ear are ipsilateral body parts

Contralateral Definition: Situated

on or affecting the opposite side of the body

Example: The eyes are on contralateral sides of the head