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Introduction

The location of body parts and associated pathology can be difficult to describe without specific anatomical terminology. The universal descriptions allow for a standardised reference point for referring to structures, which provides precision and reduces room for medical error or ambiguity.1,2

This article will cover the anatomical position and describe key anatomical terms.


Anatomical position

The anatomical position is the starting point for any description of the human body.

The anatomical position is facing forwards, with mouth closed and facial expression neutral.1, 3 Eyes focused on the distance. Arms should be straight and by the sides with palms facing forward. The penis is erect. Legs are straight with feet flat on the ground and toes facing forwards.3

The anatomical position
Figure 1. The anatomical position.4

Regional and directional terms

Anatomical terms can be grouped into regional and directional terms.

Regional terms refer to precise regions of the human body.2 For example, ‘arm’ and ‘forearm’ are more specific terms than ‘upper limb’. Similarly, ‘thigh’ and ‘leg’ are more specific terms than ‘lower limb’, as well as ‘sacrum’ and ‘lumbar’ are more specific than ‘lower back’.

Directional terms refer to the relative locations of different body structures.2 Essentially, they explain how close or far away different structures are from one another. 

Anterior and posterior

Anterior and posterior are terms used to describe whether a structure is in front of or behind another. The more anterior a structure is, the closer it is to the front of the body.

Anterior and posterior
Figure 2. Anterior and posterior.5

Superior and inferior

Superior and inferior are terms used to describe how close structures are to the head or the feet in relation to one another. Structures which are more superior will be closer to the head (to remember that Superior means closer to the Head, think about how you use your Head to drink Soup).

Superior and inferior
Figure 3. Superior and inferior.5

Medial and lateral

Medial and lateral refer to how close structures are to the body’s midline. More medial structures will be closer to the midline (think Medial is closer to the Midline).

Medial and lateral
Figure 4. Medial and lateral.5

Proximal and distal

Proximal and distal refer to how close a structure is to the trunk (normally in reference to limbs) or how close a structure is to its origin (Distal structures are more Disant from the main structure).

In Figure six, the liver can be described as proximal to the stomach but distal to the anus.

Contralateral and ipsilateral 

As the human body is mostly symmetrical, it is important to differentiate between sides when describing separate structures.

The terms contralateral and ipsilateral refer to the relationship between two structures and whether they are on the same side of the midline. Contralateral refers to structures on opposite sides, whereas ipsilateral structures are on the same side.

In Figure 7, the pink arm is ipsilateral to the blue leg but contralateral to the red leg (ipSilateral structures are on the Same side).

Contralateral and ipsilateral
Figure 7. Contralateral and ipsilateral.5

Superficial and deep

Internal structures can be described based on how close they are to the skin’s surface.

Superficial structures are closer to the skin, whereas deep structures are further from the skin’s surface. These descriptions are best visualised in a sagittal plane rather than a frontal plane used for other terms.

Superficial and deep
Figure 8. Superficial and deep.7

Anatomical terms can also be combined to enable even more specificity in descriptions (e.g. anterolateral).


Anatomical planes

There are three commonly used anatomical planes: coronal (frontal), transverse, and sagittal. To describe normal or pathological structures imaged within these planes, it is important to utilise anatomical terminology correctly.

Anatomical planes
Figure 9. Anatomical planes.8

Supine and prone

Although not a description of anatomical location, if a person is lying down, it is important to know whether they are supine or prone, as this can influence how different structures appear both in person and on imaging.

 Supine and prone
Figure 10. Supine and prone.9

Clinical relevance

There are three main areas of clinical relevance for anatomical terminology.

Handover

When providing a patient handover, it is important to describe the exact location of any injuries, lesions, or abnormalities identified. This is particularly relevant when referring a patient over the phone, as you cannot use imaging or reference using your own body.

This allows the receiving clinician to get a precise picture of the location of pathology, as well as identify if any changes occur or new abnormalities develop.

Injury

When dealing with injuries (whether internal or external), it is important to describe and document exactly where the injury is. This helps others caring for the patient to monitor progress. It can also help surgical teams pinpoint the exact site of any intervention required.

Imaging

When reviewing imaging, it is important to be able to identify and describe anatomical structures within the image, as well as any potential pathology. When asked to request imaging, it is essential to understand the anatomical terms used to describe the requested area.

Order of anatomical descriptions

When describing a specific area of the body, it is important to order the terms used correctly. Starting with the term applying to the largest region on the body and gradually becoming more specific.

Example of anatomical descriptions

Examples of lesions and markings
Figure 11. Examples of lesions and markings.5

In the example (Figure 11):

  • Red marking: on the right thigh, anterolateral surface, superior to the patella
  • Blue marking: on the right forearm, anteromedial surface, inferior to the antecubital fossa
  • Yellow marking: on the left side of the lower abdomen, superior and lateral to the umbilicus
  • Green marking: on the left anterior chest, inferior to the clavicle, lateral to the manubrium

Summary table

Table 1. Summary of anatomical terms1,2,3

Term Definition Example
Anterior In front of another structure The lips are anterior to the tongue
Posterior Behind another structure The kidneys are posterior to the intestines
Superior Above another structure The ears are superior to the neck
Inferior Below another structure The foot is inferior to the patella
Medial Closer to frontal midline The left eye is medial to the left ear
Lateral Further from frontal midline The appendix is lateral to the bladder
Proximal Closer to trunk/origin The humeral head is proximal to the clavicle
Distal Further from trunk/origin The patella is distal to the femoral head
Contralateral Opposite side to structure The left elbow is contralateral to the right clavicle
Ipsilateral Same side as structure The right foot is ipsilateral to the right hand
Superficial Closer to skin surface The fingernail is superficial to the skin
Deep Further from skin surface The lungs are deep to the ribs

Key points

  • Anatomical terminology is a universal method of describing parts of the human body accurately and helps avoid medical errors
  • The anatomical position is the starting point for any anatomical description
  • When reviewing imaging, it is important to understand both the anatomical terms as well as anatomical planes to be able to describe any relevant pathology
  • Accurately describing lesions and injuries can help improve efficiency and co-ordination between medical teams
  • Structuring the descriptions appropriately makes it clear which area is being described

Editor

Dr Chris Jefferies


References

  1. Mitchell, A. Wayne Vogl, Richard Drake, A.Gray’s Anatomy for Students. 2020. Available from: ClinicalKey Student, (4th Edition), Elsevier Health Sciences (US).
  2. OpenStax. Anatomy and Physiology. 2017. Available from: [LINK]
  3. Stephens, Samuel Hall, J. Crash Course Anatomy and Physiology. 2019. Available from: ClinicalKey Student, (5th Edition). Elsevier Health Sciences (US).
  4. Connexions. The anatomical position. Licence: [CC BY 3.0]
  5. Another-anon-artist-234. Adapted by Emily Tiffney. Outline of anatomical position. Licence: [Public domain] 
  6. Blausen.com staff (2014). Gastrointestinal system. Licence: [CC BY 3.0
  7. Henry Vandyke Carter. Sagittal section of thorax. Licence: [Public domain] 
  8. OpenStax. Anatomical Planes. Licence: [CC BY 4.0
  9. Jmarchn, Supine and prone. Licence: [CC BY-SA 3.0]

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