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Anatomical position

Image:Anatpos.png The anatomical position is a schematic convention for describing the relative morphologyof the human body. All terms in the study of anatomy refer to when the body is in this position.
The person is oriented

in an erect standing position
eyes and head facing forward
feet forward and perpendicular to the body
arms close to the sides and palms of the hands facing forward with fingers extended.

It should be noted that this is not the normal position that arms rest in.

Inhaltsverzeichnis

1 Median and sagittal plane
2 Coronal plane
3 Transverse plane
4 Movement terms
5 Special cases
- 5.1 Foot and hand
- 5.2 Others
6 See also

Median and sagittal plane

The body in anatomical position may be divided conceptually by planes. The median plane passes from the top to the bottom of the body and separates the left and the right sides of the body in equal halves.
Positions toward the median plane are called medial, and positions away from the median plane are called lateral. Hence ipsilateral refers to things on the same side, contralateral to something on the opposite side and bilateral to both sides.
A sagittal plane is any plane parallel to the median and hence the median plane is also called the midsagittal plane. A sagittal slice or section that is not on the median plane is also referred to as a parasagittal section.

Coronal plane

The frontal or coronal plane essentially separates the body into the forward half and the back half. This plane is perpendicular to the median and also passes from the top to the bottom along the long axis of the body. The term posterior refers to objects on the back half of the body, behind the coronal plane and the term anterior refers to objects in front of this plane.

Transverse plane

The horizontal or transverse plane is perpendicular to both of these planes and is the plane which divides the body into an upper and a lower half. Positions above the transverse plane are called superior, and positions below the transverse plane are called inferior. In comparative anatomy, superior may be called the rostral(beak) or cranial(head) end. Inferior may be referred to as the caudalor (tail) ends.

Planes in between these three are known as oblique planes.

Movement terms

All acts of movement are considered to be a mixture or a single contribution of the following movement terms:

Flexion - where there is a reduction in the angle between bones or parts of the body. This term applies only to movement along the sagittal or median plane. An example of arms flexing is lifting a dinner plate. When applied to the trunk of the body, this term means bowing forwards.
Extension - is the opposite of flexion, and there is an increase in the angle. This term applies only to movement along the sagittal or median plane. With the trunk of the body, this movement is bowing backwards.

Adduction - where there is a reduction in the angle between bones or parts of the body. This only applies to movement along the coronal plane. An example of this is where extending arms outwards as if to fly.
Abduction - the exact opposite, with an increase in the angle. Also only applies to movement along the coronal plane.

Rotation - is rotation of an entire limb clockwise (laterally) or anticlockwise (medially).

Pronation - this is the rotation of the hand so that the palm faces posteriorly. This is not medial rotation as this must be performed when the arm is half flexed. Prone means the hand is facing posteriorly.
Supination - the roation of the hand so that the palm faces anteriorly. The hand is supine (facing anteriorly) in the anatomical position.

Protrusion - is the anterior movement of an object. This term is often applied to the jaw.
Retrusion - the opposite of protrusion.

Elevation - superior movement. This term is often applied to the shoulders (eg shrugging shoulders is elevation)
Depression - inferior movement, opposite of elevation.

Circumduction - is a special case of movement involving adduction, flexion, extension and abduction. The resulting movement creates a circular path of movement.

Special cases

There are several cases where the meaning of these planes are slightly different. Hence new definitions for movement applies. This is apparent in the foot, the tongue, the hand, the penis, the brain and sometimes and the perineum(often by professionals).

Foot and hand

Since the footis discontiguous with the coronal plane, it is described by analogyand with embryological considerations, with the hand.

The palm (adj palmar) of the hand corresponds to the sole (adj plantar) of the foot, and the dorsum (back) of the hand corresponds to the dorsum (top) of the foot.

From this, the term dorsiflexion means to flex upwards (true flexion) and the term plantarflexion, meaning to extend downwards (true extension) are derived.

The term volar, used mainly in orthopaedics, is synonymous with palmar and plantar.

The foot is also capable of movement along another axis due to the flexibility of the anklejoint. These movements are

Eversion - the movement of the sole of the foot away from the median plane.
Inversion - the movement of the sole towards the median plane. (same as when an ankle is twisted).

The position of the hand in anatomical position is considered supine, such that rotation of the hand so that the palm faces backwards is called pronation and the reverse action, supination.

Others

In the anatomical position, the penisis considered to be erect and pointing upwards, i.e. the dorsal side of the penis is what one would normally call its top side.

The tonguehas a dorsal side which is facing upwards (the side that tastes and licks).

The perineumis a special place for obstetricians and gynecologists. The professions regard the perineal bodyin the perinuem to be the center of everything and an important landmark. A lot of anatomy is based on relations to this body and so the terminology is affected.

Note that the reclining body may be viewed correctly in terms of the anatomical position. Standing behind and at the head of a body, you will observe that the body's right arm with respect to your right arm is in the anatomically correct position. Likewise, the same with the body's left arm. This continues down the scope of the viewed body. Standing at the feet position when viewing the body, does not reveal the proper anatomical correct position.