Anatomical terminologyDid you hear the saying that learning anatomy is similar to learning a new language? There are thousands of anatomy terms that students need to master in a very short time. The wonderful thing about this language, is that in many cases, the names of anatomy related content are incredibly helpful if you just understand that often the words can be broken down into different parts that have meanings (prefixes and suffixes). However, advancing in anatomy is impossible without conquering the anatomical alphabet first and foremost. This is the foundation onto which further information is built.
What does it consist of? Here’s what you need to know like the back of your hand:
- Anatomical position
- Directions, body planes, and relations
- Types of movements
- Regions of the body
- Surface anatomy
- Body cavities
- Specific anatomical terminology
In this page, we’ll briefly explain all of these aspects, simplifying your future anatomy learning.
Anatomical positionWhen 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:
- Median (mid-sagittal) - vertical plane passing through the centre of the body (midline) that cuts it longitudinally into right and left halves.
- Sagittal - vertical plane passing through the body parallel to the midline, slicing it longitudinally into right and left halves. 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 median plane that divides the body into anterior (front) and posterior (back) portions.
- Transverse (axial) - vertical plane at right angles to the medial and frontal planes, slicing the body into a superior (upper) and inferior (lower) portions. The obtained cuts are transverse or axial views.
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.
|Anterior||In front of or front|
|Posterior||In behind of or behind|
|Ventral||Towards the front of the body|
|Dorsal||Towards the back of the body|
|Distal||Away or farthest away from the trunk or the point of origin of the body part|
|Proximal||Closer or towards the trunk or the point of origin of the body part|
|Median||Midline of the body|
|Medial||Towards the median|
|Lateral||Away from median|
|Superior||Towards the top of the head|
|Inferior||Towards the feet|
|Cranial||Towards the head|
|Caudal||Towards the tail|
|External||Towards the surface, superficial|
|Internal||Away from the surface, deep|
|Superficial||Nearer to the surface|
|Deep||Farther from the surface|
|Palmar||Anterior hand or palm of hand (palmar)|
|Dorsal (of hand)||Posterior surface of hand (dorsum)|
|Plantar||Inferior surface of foot (sole)|
|Dorsal (of foot)||Superior surface of foot (dorsum)|
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 videos and tackle the anatomical terminology quiz to help you cement your knowledge.
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
|Flexion||Decreasing the angle between two structures|
|Extension||Increasing the angle between two structures|
|Plantarflexion||Flexion of the plantar (underside) part of the foot|
|Dorsiflexion||Flexion of the dorsum (top) part of the foot|
|Abduction||Moving away from the midline|
|Adduction||Moving towards the midline|
|Protrusion||Moving straight ahead or forwards (tongue, mandible)|
|Retrusion||Moving backwards (tongue, mandible)|
|Protraction||Moving forwards and laterally simultaneously|
|Retraction||Moving backwards and medially simultaneously|
|Medial (internal) rotation||Spiral movement towards the midline|
|Lateral (external) rotation||Spiral movement away from the midline|
|Rotation (trunk)||Twisting motion towards or away from the midline|
|Flexion (trunk)||Side (lateral flexion) or forward (anterior flexion) bending|
|Extension (trunk)||Bending backwards|
|Pronation||Medial rotation of the radius, resulting in the palm of the hand facing posteriorly (if in anatomical position) or inferiorly (if elbow is flexed)|
|Supination||Lateral rotation of the radius, resulting in the palm of the hand facing anteriorly (if in anatomical position) or superiorly (if elbow is flexed)|
|Circumduction||Combined movement starting with flexion, then abduction, extension, and ending with adduction|
|Deviation||Movement of the wrist joint towards the radial or ulnar sides (radial deviation, ulnar deviation)|
|Opposition||Touching the pad of any one of your fingers with the thumb of the same hand|
|Reposition||Separating the pad of any of your fingers from the thumb of the same hand|
|Inversion||Plantar side of the foot is moved towards the median plane|
|Eversion||Plantar side of the foot is moved away from the median plane|
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!
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. In the upper limb, they are named scapular, axillary, deltoid, brachial (anterior, posterior), cubital (anterior, posterior), antebrachial (anterior, posterior), carpal (anterior, posterior), palmar, and dorsal regions.
The lower limb has the following regions: femoral triangle, gluteal, femoral (anterior, posterior), genicular (anterior, posterior), popliteal, crural (anterior, posterior), lateral retromalleolar, dorsal, plantar, and calcaneal regions.
Memorizing all of these regions can be a challenge, but they are not as hard as they seem. Start learning about them using the videos, articles, and quizzes given below.
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.
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.
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.
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)
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.
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: