Anatomical terminology

Anatomical position

When describing any orientation, location, movement, and direction, the reference is the anatomical position. In this universally accepted reference, the person is considered to be standing upright, with the arms hanging by the side, palms facing forward, and thumbs pointing away from the body. The feet are slightly parallel, and toes oriented to the front.

The anatomical position has no real meaning on its own since it is a reference for position. It has to be placed in the same context as other anatomical terms, such as body planes, directions, and relations. Regarding anatomical planes, these are imaginary planes that intersect the body, creating various cuts or slices of various organs and structures. There are four major planes of the body:

• Mid-sagittal/median - vertical plane passing through the centre of the body (midline) that cuts it longitudinally into right and left halves.
• Sagittal - arbitrary vertical plane passing through the body parallel to the midline, slicing it longitudinally into right and left parts. To aid your understanding, imagine that you are slicing an apple - each slide is a sagittal plane. 
• Frontal (coronal) - vertical plane at right angle to the sagittal plane that divides the body into anterior (front) and posterior (back) portions.
• Transverse (axial) - horizontal plane at right angles to the sagittal and frontal planes, slicing the body into a superior (upper) and inferior (lower) portions. The obtained cuts are transverse or axial views.

Directional terms

We’ve seen how the sections and views included in a typical anatomical atlas are obtained, but how can we describe the position and relation between various structures? By using anatomy directional terms. These adjectives compare the position of two structures relative to one another in the anatomical position. They are in pairs of opposites, so if the nose is superior to the mouth, it is automatically inferred that the mouth is inferior to the nose.

There are quite a lot of them, right? Unfortunately, they are essential and you need to know them like the dorsum of your hand. Here’s a human body diagram that provides you with an overview:

Do you want to learn more about body planes and sections, as well as anatomical directions? Check out the following study unit to help you cement your knowledge. If you want to challenge yourself even further, try out our customizable quiz about the anatomical terminology! 

Types of movements

Now that we’ve looked at planes and relations, let’s learn the anatomy terms that describe movements. As you know, joints are the junction of two or more bones and allow movements to take place in various directions and degrees of motion. Non-skeletal structures like the lips, tongue and eyelids also move, but their associated movement terms are specific.

When describing joint movements, two factors are included:

• Axis, or fulcrum, around which the specific part moves
• Plane of the movement

All of these movements can be very confusing without seeing them in action. If you want to simplify your learning about movement terms, take a look below!

Anatomical regions

The human body is divided into regions. The main ones in the human body are the head, neck, thorax, abdomen, pelvis, together with the upper and lower extremities. The upper limb is divided into shoulder, arm, elbow, forearm, wrist, and hand. The lower limb consists of the hip, gluteal, thigh, knee, leg, ankle, and foot. All of the anatomical regions are defined by precise landmarks making them universally accepted terms that every healthcare professional instantly recognizes and understands. Generally speaking, these landmarks are provided by evident structures that are easily palpable or visible. This is known as surface anatomy.

On the trunk (thorax and abdomen) there are several lines and surface landmarks, as follows: anterior/posterior median lines, sternal line, parasternal line, midclavicular line, anterior/middle/posterior axillary lines, paravertebral line, scapular line, ribs, sternum, vertebral spinous processes, clavicle, and pectoral muscles. These imaginary lines intersect at various points, creating particular regions between them. These are named:

• Presternal region
• Infraclavicular fossa
• Clavipectoral triangle
• Deltoid region
• Axillary region
• Pectoral region
• Inframammary region
• Vertebral region
• Suprascapular region
• Scapular region
• Interscapular region
• Lateral pectoral region
• Infrascapular region
• Lumbar triangle
• Sacral region
• Gluteal region
• Anal region

The head and neck also consist of regions. They are not formed by precise planes, but they are named according to the anatomical structures contained within them. Therefore, the terms are easy to understand: frontal, orbital, infraorbital, nasal, oral, mental, sternocleidomastoid, lateral cervical, posterocervical, buccal, parotideomasseteric, infratemporal, zygomatic, temporal, occipital, and parietal regions. In addition, there are submandibular, submental, carotid, and muscular triangles, supraclavicular, jugular, and retromandibular fossae. 

Similar to the head and neck, the extremities are divided into regions according to their anatomical contents. Regions in the upper limb are named scapular, axillary, deltoid, brachial (anterior, posterior), cubital (anterior, posterior), antebrachial (anterior, posterior), carpal (anterior, posterior), palmar, and dorsal regions.

The regions of the lower limb are the following: femoral triangle, gluteal, femoral (anterior, posterior), genicular (anterior, posterior), popliteal, crural (anterior, posterior), lateral retromalleolar, dorsal, plantar, and calcaneal regions.

Solidify your knowledge about the main regions of the body with the following quiz!

Abdominopelvic regions

Regarding the abdominal regions, we’ll look at them separately because they are a favourite exam question and crucial clinical topic. Two approaches are used in medical practice. The simpler one takes advantage of a horizontal and vertical axis crossing at right angles directly on the umbilicus. This results in the formation of four abdominal quadrants called right upper (RQQ), left upper (LUQ), right lower (RLQ), and left lower (LLQ) quadrants. 

The second one involves four planes: two vertical lines running through the middle of the clavicles and middle of the inguinal ligaments, and two horizontal axes. One of which passes directly subcostally, while the second traverses the iliac tubercles. The intersection of these planes forms 9 abdominal regions; the right hypochondriac, epigastric, left hypochondriac, left lumbar, umbilical, right lumbar, right iliac, hypogastric, and left iliac regions.

Are you curious to find out more about these regions and what organs or structures they include? We’ve got your back - you just need to click below.

Body cavities

Many anatomical structures are housed inside open fluid filled spaces, or cavities, located throughout the body. The most important ones are located axially, meaning inside the skull, vertebral column, thorax, and abdomen. What’s the importance of such spaces? Cavities compartmentalise the body, they also protect and lubricate organs; reducing friction during organ movement.

The human body has two cavitary groups - anterior and posterior. The latter is composed of two cavities called the cranial cavity and vertebral canal, which are continuous with each other and contain the central nervous system (brain plus spinal cord). It is filled with cerebrospinal fluid which bathes the central nervous system.

The larger anterior cavitary group is composed of several smaller cavities called the thoracic and abdominopelvic cavities. The former is composed out of the superior, anterior, middle, and posterior mediastinal cavities, as well as the two pleural cavities. The latter is subdivided into the abdominal and pelvic cavities. The thoracic and abdominal cavities are separated by the diaphragm. Each of these spaces is home to the typical neurovasculature structures and organs specific to each respective region. The pericardial cavity, sitting within the mediastinum, deserves a special mention because it contains the heart.

Fortify your knowledge about the cavities of the body with this content we have prepared for you.

Synovial joint

Do you remember when we talked about all the different anatomical terms representing movements? One set of structures making these actions a daily reality are joints, which are the union of two or more bones. There are many types of joints classified according to many criteria, one example being synovial joints. Also known as diarthrosis, a synovial joint is a potential space containing synovial fluid that separates two bones. It is the most flexible out of all types, allowing a great degree of motion and joint movements. The bone ends are covered with cartilage. There are six main types of synovial joints:

• Pivot joint
• Ball and socket joint
• Condyloid joint
• Saddle joint
• Hinge joint
• Plane joint

Almost every major joint in the human body is synovial in nature, including the shoulder, elbow, hip, knee, and ankle joints. If you want to learn more about this specific joint type, tackle the following resources.

Brain anatomy

Housed within the cranium, more specifically the cranial cavity, the brain consists of folds (gyri), grooves (sulci), and clefts (fissures). It is composed of several parts, such as:

• Cerebral hemispheres (cerebral cortex)
• Diencephalon
• Brainstem
• Cerebellum
• Ventricles

Several lobes of the brain (parietal, occipital, temporal, frontal, and insular) form the cerebral hemispheres, each one having several distinct roles. For example, the frontal lobe function includes motor function, problem solving, memory, language, judgement, and many more. The brainstem is the vegetative and most primitive part, consisting of the midbrain, pons, and medulla oblongata. Here’s a brain diagram illustrating its various parts:

What about the cerebellum function? This structure is unique in terms of structure and roles, being involved in balance and movement coordination, to name a few. The ventricles are part of an entire system called the ventricular system of the brain that is involved in the production and drainage of the cerebrospinal fluid within the central nervous system. 

In terms of directional terms, axes, and planes, the brain is quite special. It has neuraxes which are different than the normal body axes. There are two in total called rostral/caudal and ventral/dorsal neuraxes. As you can see, the previous four relation terms are preferred in the brain, but they can change to the normal terms used in other parts of the human body when referring to structures above or below the midbrain.

Test your knowledge of the anatomy of the brain with the quiz below!

If you want to master the parts of the brain and their anatomy, as well as the complicated orientation within the brain, take a sneak peek below:

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Articles within this topic:

• 8 steps to create your own anatomy flashcards
• Anatomical and Medical Prefixes and Suffixes
• Anatomical spaces of the pectoral region
• Anatomical spaces of the pelvic cavity
• Applied and clinical anatomy
• Articular capsule
• Axillary region
• Basic anatomy and terminology
• Basic medical terminology 101: Learn with quizzes
• Body regions: Learn with quizzes and labeled diagrams
• Brain orientation difficulties
• Bursa
• Central
• Clavipectoral fascia
• Clinical case: Sister Mary Joseph nodule
• Coronal plane
• Deep
• Directional terms and body planes
• Distal
• Dorsal body cavity
• Endosteum
• Fascia
• Gluteal region
• Human anatomy
• Inferior
• Infracolic compartment
• Intergluteal cleft
• Internal
• Lateral
• Learn anatomy while playing games
• Linea alba
• Lobes of the brain
• Lumen
• Median plane
• Medical terminology course
• Midclavicular line
• Nuchal region
• Parts of the brain: Learn with diagrams and quizzes
• Peripheral
• Plane joint
• Pleural cavity
• Proximal
• Regions of the abdomen
• Regions of the lower limb
• Regions of the upper limb
• Right upper quadrant of the abdomen
• Sacral region
• Saddle joint
• Superficial
• Superior
• Supracolic compartment
• Terminologia Anatomica
• Types of joints: Arthrology
• Types of movements in the human body