Human anatomical terms
Encyclopedia
Human anatomical terms make up a distinct nomenclature to describe areas of the body, to provide orientation when describing parts of human anatomy
Human anatomy
Human anatomy is primarily the scientific study of the morphology of the human body. Anatomy is subdivided into gross anatomy and microscopic anatomy. Gross anatomy is the study of anatomical structures that can be seen by the naked eye...

, and to distinguish different movements of the body. An understanding of these terms is necessary to study the human body in depth. Many of these terms are also applicable in animal anatomy (zootomy).

Anatomical body position

The international standard anatomical position is the position that provides a reference point for describing the structures of the human body. In this position, the body is standing erect with good posture and the face is looking directly forward. The feet are about six inches apart, flat on the floor and the toes pointing forward. The arms are down at the sides with the palms turned forward and thumbs pointing away from the body. When the body is lying face down in the anatomical position, this is called the prone position. When the body is lying face up, this is called the supine position.

Front and back

Anterior and ventral both mean toward the front of the body, while posterior and dorsal mean the back of the body. These terms are almost always used in pairs, with anterior pairing with posterior and ventral pairing with dorsal. The nose is on the anterior surface of the head. The spine is on the posterior (dorsal) side of the body.

However, in the brain (at least the forward part of it), ventral means inferior (towards the jaw) and dorsal means superior (towards the top of the head).

Above and below

The terms superior, cranial, and cephalic all mean toward the head or the upper part of a structure while inferior and caudal refer to the lower part of a structure or away from the head. For example, the shoulder is superior (cranial) to the elbow and the elbow is inferior (caudal) to the shoulder. These terms are also used in their respective pairs: superior with inferior and cranial or cephalic with caudal.

Close to or away from the center of the body

Proximal means closer to the trunk (torso) while distal is away from the trunk. The statement “the knee is proximal to the foot” means the knee is closer to the torso than the foot. Conversely, the foot is distal to the knee.

Near or away from the vertical longitudinal center of the body

Medial describes a structure toward the midline of the body and lateral away from that median plane. Intermediate describes a structure between a medial and a lateral structure. The nose
Human nose
The visible part of the human nose is the protruding part of the face that bears the nostrils. The shape of the nose is determined by the ethmoid bone and the nasal septum, which consists mostly of cartilage and which separates the nostrils...

 is medial to the ear
Ear
The ear is the organ that detects sound. It not only receives sound, but also aids in balance and body position. The ear is part of the auditory system....

s while the ears are lateral to the nose. The cheek
Cheek
Cheeks constitute the area of the face below the eyes and between the nose and the left or right ear. They may also be referred to as jowls. "Buccal" means relating to the cheek. In humans, the region is innervated by the buccal nerve...

s are intermediate between the nose and the ears.

Deep inside or near the surface

Superficial means close to the surface of the body while deep means away from the surface. The brain is deep to the skull while the skull is superficial to the brain.

Planes of the body

Anatomists also divide the body into planes to facilitate discussion. These are the coronal or frontal plane, the sagittal, midsagittal or median sagittal
Sagittal plane
Sagittal plane is a vertical plane which passes from front to rear dividing the body into right and left sections.-Variations:Examples include:...

, and the
transverse or horizontal plane
Transverse plane
The transverse plane is an imaginary plane that divides the body into superior and inferior parts. It is perpendicular to the coronal and sagittal planes....

. These planes are defined using the anatomical position as a reference point. The coronal or frontal section divides the body lengthwise, anterior from posterior. When the body is divided by the coronal plane, the face is separated from the back of the head, the chest from the back, the palms from the back of the hands, the shins from the calves. The sagittal plane bisects the left and right sides of the body longitudinally. This plane runs down the center of the head, torso, and between the legs and the feet. The transverse or horizontal plane runs perpendicularly to the longitudinal axis of the body, dividing it into upper and lower sections.

Body landmarks

Anatomists use specific terms to indicate visible areas of the body. The cephalon or cephalic region refers to the head. This area is further differentiated into the cranium (skull), facies (face), frons (forehead), oculus (eye area), auris (ear), bucca (cheek), nausus (nose), oris (mouth), and mentis (chin). The neck area is called the cervicis or cervical region.

On the trunk of the body, the chest is referred to as the thoracic area. The shoulder in general is the acromial, while the curve of the shoulder is the deltoid. The back as a general area is the dorsum or dorsal area, and the lower back as the lumbus or lumbar region. The shoulderblades are the scapular area and the breastbone is the sternal region. The abdominal area is the region between the chest and the pelvis. The breast is called the mamma or mammary, the armpit as the axilla and axillary, and the navel as the umbilicus and umbilical. The pelvis is the lower torso, between the abdomen and the thighs. The groins, where the thigh joins the trunk, are the inguen and inguinal area.

The entire arm is referred to as the brachium and brachial, the front of the elbow as the antecubitis and antecubital, the back of the elbow as the olecranon or olecranal, the forearm as the antebrachium and antebrachial, the wrist as the carpus and carpal area, the hand as the manus and manual, the palm as the palma and palmar, the thumb as the pollex, and the fingers as the digits, phalanges, and phalangeal. The buttocks are the gluteus or gluteal region and the pubic area is the pubis.

Anatomists divide the lower limb into the thigh (the part of the limb between the hip and the knee) and the leg (which refers only to the area of the limb between the knee and the ankle). The thigh is the femur and the femoral region. The kneecap is the patella and patellar while the back of the knee is the popliteus and popliteal area. The leg (between the knee and the ankle) is the crus and crural area, the lateral aspect of the leg is the peroneal area, and the calf is the sura and sural region. The ankle is the tarsus and tarsal, and the heel is the calcaneus or calcaneal. The foot is the pes and pedal region, and the sole of the foot the planta and plantar. As with the fingers, the toes are also called the digits, phalanges, and phalangeal area. The big toe is referred to as the hallux.

Use of the terms right and left

When anatomists refer to the right and left of the body, it is in reference to the right and left of the subject, not the right and left of the observer. When observing a body in the anatomical position, the left of the body is on the observer’s right, and vice versa.

Regions of the abdomen and pelvis

Anatomists and medical personnel divide the abdomen into smaller regions to facilitate study and discussion. The two most common schemes are division into four quadrants and also into nine areas.

The abdominopelvic quadrants evenly divide the space of the torso below the diaphragm into four. They are referred to simply by location: the right upper quadrant, right lower quadrant, left upper quadrant, and left lower quadrant. The right upper quadrant contains the right portion of the liver, the gallbladder, right kidney, a small portion of the stomach, portions of the ascending and transverse colon and parts of small intestine. The left upper quadrant is the location of the left portion of the liver, the larger portion of the stomach, the pancreas, left kidney, spleen, portions of the transverse and descending colon and parts of the small intestine. In the right lower quadrant sits the cecum, appendix, part of the small intestines, the right reproductive organs, and the right ureter. The left lower quadrant houses the majority of the small intestine, some of the large intestine, the left reproductive organs and the left ureter.

The nine divisions (sometimes also called nine quadrants, though the word 'quadrant' itself means division into four equal parts) of the abdominopelvic region are smaller than the four abdominopelvic quadrants and allow more detailed discussion of the area. These are the right hypochondriac, right lumbar, right inguinal (or right iliac), epigastric, umbilical, hypogastric (or pubic), left hypochondriac, left lumbar, and left inguinal (or left iliac). The right and left hypochondriac regions are the outer and uppermost segments. The epigastric lies between these two. The outer middle sections are the right lumbar and left lumbar regions, with the umbilical region between them. The lowest portions are the right and left iliac region with the hypogastric between these.

The Perineum is considered to be the tenth division.

Body cavities

The body contains two main cavities, dorsal and ventral, that house and protect the internal organ
Organ (anatomy)
In biology, an organ is a collection of tissues joined in structural unit to serve a common function. Usually there is a main tissue and sporadic tissues . The main tissue is the one that is unique for the specific organ. For example, main tissue in the heart is the myocardium, while sporadic are...

s. These cavities are subdivided to further distinguish location.

The dorsal body cavity is the space within the cranium (skull) and the spinal canal
Spinal canal
The spinal canal is the space in vertebrae through which the spinal cord passes. It is a process of the dorsal human body cavity. This canal is enclosed within the vertebral foramen of the vertebrae...

, which is surrounded by the vertebrae. The fluid filled space inside the cranium is called the cranial cavity
Cranial cavity
The cranial cavity, or intracranial space, is the space formed inside the skull. The brain occupies the cranial cavity, which is lined by the meninges and which contains cerebrospinal fluid to cushion blows....

, and it contains the brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...

. The spinal cavity is the space that encloses the spinal cord
Spinal cord
The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain . The brain and spinal cord together make up the central nervous system...

 and extends from the cranial cavity to the base of the spine.

The ventral body cavity contains the organs in the chest and abdomen. It is further divided by the diaphragm
Thoracic diaphragm
In the anatomy of mammals, the thoracic diaphragm, or simply the diaphragm , is a sheet of internal skeletal muscle that extends across the bottom of the rib cage. The diaphragm separates the thoracic cavity from the abdominal cavity and performs an important function in respiration...

 into the superior thoracic cavity
Thoracic cavity
The thoracic cavity is the chamber of the human body that is protected by the thoracic wall ....

 and the inferior abdominopelvic cavity
Abdominopelvic cavity
The abdominopelvic cavity is a body cavity that consists of the abdominal cavity and the pelvic cavity. It contains the stomach, liver, spleen, gallbladder, kidneys, and most of the small and large intestines. It also contains urinary bladder and internal reproductive organs....

.

The thoracic cavity contains the lung
Lung
The lung is the essential respiration organ in many air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located near the backbone on either side of the heart...

s, heart
Heart
The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...

, the lower esophagus
Esophagus
The esophagus is an organ in vertebrates which consists of a muscular tube through which food passes from the pharynx to the stomach. During swallowing, food passes from the mouth through the pharynx into the esophagus and travels via peristalsis to the stomach...

, the thymus
Thymus
The thymus is a specialized organ of the immune system. The thymus produces and "educates" T-lymphocytes , which are critical cells of the adaptive immune system....

 gland, and other organs of the cardiovascular, respiratory, and lymphatic system
Lymphatic system
The lymphoid system is the part of the immune system comprising a network of conduits called lymphatic vessels that carry a clear fluid called lymph unidirectionally toward the heart. Lymphoid tissue is found in many organs, particularly the lymph nodes, and in the lymphoid follicles associated...

s. This cavity is subdivided into the right pleural cavity of the right lung, the left pleural cavity of the left lung, and the mediastinum
Mediastinum
The mediastinum is a non-delineated group of structures in the thorax, surrounded by loose connective tissue. It is the central compartment of the thoracic cavity...

, between the pleural cavities, which houses the trachea
Vertebrate trachea
In tetrapod anatomy the trachea, or windpipe, is a tube that connects the pharynx or larynx to the lungs, allowing the passage of air. It is lined with pseudostratified ciliated columnar epithelium cells with goblet cells that produce mucus...

, esophagus, thymus, heart, and vessels connected to the heart
Coronary circulation
Coronary circulation is the circulation of blood in the blood vessels of the heart muscle . The vessels that deliver oxygen-rich blood to the myocardium are known as coronary arteries...

. The medistinum contains the pericardial cavity
Pericardial cavity
The pericardial cavity is a potential space between the parietal pericardium and visceral layer. It contains a supply of serous fluid. The serous fluid that is found in this space is known as the pericardial fluid....

, which is the area surrounding the heart.

The abdominopelvic cavity is often divided into the superior abdominal and inferior pelvic cavities. The abdominal cavity contains the digestive organs and glands, namely the liver
Liver
The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...

, gallbladder
Gallbladder
In vertebrates the gallbladder is a small organ that aids mainly in fat digestion and concentrates bile produced by the liver. In humans the loss of the gallbladder is usually easily tolerated....

, spleen
Spleen
The spleen is an organ found in virtually all vertebrate animals with important roles in regard to red blood cells and the immune system. In humans, it is located in the left upper quadrant of the abdomen. It removes old red blood cells and holds a reserve of blood in case of hemorrhagic shock...

, kidney
Kidney
The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...

s, pancreas
Pancreas
The pancreas is a gland organ in the digestive and endocrine system of vertebrates. It is both an endocrine gland producing several important hormones, including insulin, glucagon, and somatostatin, as well as a digestive organ, secreting pancreatic juice containing digestive enzymes that assist...

, stomach
Stomach
The stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is...

, small intestine
Small intestine
The small intestine is the part of the gastrointestinal tract following the stomach and followed by the large intestine, and is where much of the digestion and absorption of food takes place. In invertebrates such as worms, the terms "gastrointestinal tract" and "large intestine" are often used to...

 and the majority of the large intestine
Large intestine
The large intestine is the third-to-last part of the digestive system — — in vertebrate animals. Its function is to absorb water from the remaining indigestible food matter, and then to pass useless waste material from the body...

. The pelvic cavity is surrounded by the pelvis and contains the inferior portion of the large intestine, bladder
Urinary bladder
The urinary bladder is the organ that collects urine excreted by the kidneys before disposal by urination. A hollow muscular, and distensible organ, the bladder sits on the pelvic floor...

, uterine tubes
Uterus
The uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species...

, and reproductive organs.

Types of movement

The body has a wide variety of movements available to it, depending on the joint where the movement occurs. Movement occurs when a muscle or muscles contract over joints and is dependent on the joint’s mobility and the location of the muscle in relation to the joint. The different types of movement have specific terms, often in pairs to describe opposite movements.

Flexion occurs in the sagittal plane, when the angle of a joint decreased. It occurs in hinge joints and ball-and-socket joints. When the knee is bent, this is a form of flexion. Conversely, extension occurs when the angle is increased along the same plane. Straightening of the leg is extension. Hyperextension occurs when the extension is beyond 180°. The neck is hyperextended when the chin tilts up toward the ceiling. Some people with flexible ligaments and tendons can hyperextend the elbows and knees, which can cause injury in these joints. Flexion and extension of the ankle are dorsiflexion and plantar flexion, respectively.

Abduction is the movement of a limb away from the median plane of the body. This occurs when someone jumps the arms legs apart, as in jumping jacks, and also when fanning the fingers and toes. Adduction is the reversal of this movement, bringing the limb back to the median plane.

Circumduction is a circular movement of the joint, such as drawing a circle with the arm and wrist straight. It is a combination of abduction, adduction, flexion and extension in a ball-and-socket joint.

A movement of the vertebrae in the coronal plane away from the midline is lateral flexion. The cervical and thoracic regions of the spine are most capable of this movement. It occurs when one moves the ear toward the shoulder with the nose facing forward.

Rotation is movement of a bone around the longitudinal axis of that bone. Lateral (or external) rotation occurs when the anterior aspect rotates outward and medial rotation occurs when it rotates inward. Turning the head to look to the side is lateral rotation, and bringing it back to the center is medial rotation. These movements occur across all ball-and-socket joints. Pronation and supination occur at the elbow to rotate the wrist. Pronation is the turning of the palm from the anatomical position to face backward. Turning the palm forward is supination.

Inversion is a movement of the foot to turn the sole medially while eversion turns it laterally.

Gliding is the motion in any direction of two articulating surfaces sliding past one another. This minimum movement occurs in the carpal bones of the hands and tarsal bones of the feet and also between the clavicles and sternum.

Protraction is movement anteriorly in the transverse plane. Biting the upper lip with the lower teeth is protraction of the jaw, and moving the jaw back to its normal position is retraction.

Elevation is the motion of a limb superiorly, such as lifting the shoulders toward the ears. Depression is the opposite, inferior movement as in opening the mouth.

Opposition is a movement unique to the thumb when it moves toward a finger or the palm to grasp something

Systematic and regional approaches to anatomy

In the systematic approach to the study of anatomy, each system of the body, such as the digestive system, is studied as a thing in itself. The regional approach observes all aspects of a particular region at one time. For example, each muscle, organ, bone, nerve and any other structure in the abdomen is studied together, then the student continues in this fashion with each region. The regional approach better facilitates study with dissection, while the systematic approach is appreciated for its comprehensive look at each system throughout the body.

See also

  • Anatomical terms of location#Planes
  • Anatomical terms of motion
    Anatomical terms of motion
    The movement of body structures is accomplished by the contraction of muscles. Muscles may move parts of the skeleton relatively to each other, or may move parts of internal organs relatively to each other. All such movements are classified by the directions in which the affected structures are moved...

  • Core (anatomy)
    Core (anatomy)
    In anatomy, the core refers, in its most general of definitions, to the body minus the legs and arms. Functional movements are highly dependent on the core, and lack of core development can result in a predisposition to injury...

  • Functional movement
    Functional movement
    Functional movements are movements based on real-world situational biomechanics. They usually involve multi-planar, multi-joint movements which place demand on the body's core musculature and innervation.- Sports-specific :...

  • Human positions
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