Anatomical Terms Of Location Directions General Usage

Animals typically have one end with a head and mouth, with the opposite end often having the anus and tail. The head end is the cranial end; the tail end is the caudal end. Within the head itself, rostral refers to the direction toward the end of the nose, and caudal is still used to refer to the tail direction.

The surface or side of the body normally oriented upwards, away from the pull of gravity, is the dorsal side; the opposite side, typically the one closest to the ground when walking on all legs, swimming or flying, is the ventral side. For example: in vertebrates, the spine or nerve chord is located on the dorsal side of the organism. A cow's udder is on the ventral side. A dolphin's dorsal fin is, unsurprisingly, on the dorsal side.

The right and left side (sometimes in Latin: dexter - right, and sinister - left) are given as viewed from the animal that is described.

1.2 Usage in human anatomy

In human anatomy, the body and its parts are always described using the assumption that the body is in anatomical position, i.e. standing upright.

Portions of the body which are closer to the head end are "superior" ("upper"); those which are farther away are "inferior" ("lower") -- superior corresponds to cranial, and inferior to caudal. Objects near the front are "anterior"; those near the rear are "posterior" -- these correspond respectively to "ventral" and "dorsal". On the limbs, an object closer to the main body is "proximal"; an object farther away is "distal".

The terms "anterior" and "posterior" should not be used when referring to most animals however, and are particularly incorrect for quadrupeds.

2 Planes

2.1 General usage

Three basic reference planes are used in zoological anatomy. The sagittal plane divides the body into left and right halves. A coronal plane divides the body into dorsal and ventral halves. A transverse plane divides the body into cranial and caudal halves.

2.2 Usage in human anatomy

Sometimes the orientation of certain planes need to be distinguished, for instance in medical imaging techniques such as CT scans, MRI scans or PET scans. One imagines a human in anatomical position (standing, arms hanging down with palms to the front) and an X-Y-Z coordinate systemCartesian means relating to the French mathematician and philosopher Descartes, who, among other things, worked to merge algebra and Euclidean geometry. This work was influential to the development of analytic geometry, calculus, and cartography. The idea with the X-Y plane parallel to the ground, the X-axis going from left to right, the Y-axis passing from front to back, and the Z-axis going up and down.

3 Relative directions

Structures near the midline are called medial and those near the sides of animals are called lateral. Therefore, medial structures are closer to the midsagittal plane, lateral structures are further from the midsagittal plane. Structures in the midline of the body are median. For example, your cheeks are lateral to your nose and the tip of the nose is in the median line.

Structures that are close to the center of the body are proximal or central, while ones far removed are distal or peripheral. For example, the hands are at the distal end of the arms, while the shoulders are at the proximal ends. These terms can also be used relatively to organs, for example the proximal end of the urethraIn anatomy, the urethra is a tube which connects the urinary bladder to the outside of the body. The urethra has an excretory function in both sexes, to pass urine to the outside, and also a reproductive function in the male, as a passage for sperm. The e is attached to the bladderIn the anatomy of mammals, the urinary bladder is the organ that collects urine excreted by the kidneys prior to disposal by urination. Urine enters the bladder via the ureters and exits via the urethra. Anatomy The urinary bladder is a hollow, muscular a.

Structures on or closer to the body´s surface are superficial (or external) and those further inside are profound or deep (or internal).

When speaking of inner organs, visceral means close to or attached to the organ, while parietal is more distant. For example, the visceral pleuraIn anatomy, the pleural cavity is the potential space between the lungs and the chest wall. It has virtually nothing in it in the normal non-diseased state, except a small amount of pleural fluid . The cavity is lined by specialized epithelium called pleu is attached to the lung and the parietal pleura is attached to the chest wall.

3.1 Relative directions in the limbs

In the limbs, the terms cranial and caudal are used in the regions proximal to the carpus (the wristIn human anatomy, the wrist is the flexible and narrower connection between the forearm and the hand. The wrist-joint Articulatio Radiocarpea is a condyloid articulation. The parts forming it are the lower end of the radius and under surface of the articu, in the forelimb) and the tarsus (the ankleIn anatomy, the ankle is the part of the lower limb that is located between the foot and the leg. It comprises two joints: the talocrural joint connecting the distal ends of the tibia and fibula with the proximal end of the talus, and the subtalar joint c in the hindlimb). Objects and surfaces closer to or facing towards the head are cranial; those facing away or further from the head are caudal.

Distal to the carpal joint, the term dorsal replaces cranial and palmar replaces caudal. Similarly, distal to the tarsal joint the term dorsal replaces cranial and plantar replaces caudal. For example, the top of a dogThis article discusses the domestic dog. For other members of the dog family, see Canidae. The dog is a canine omnivorous mammal that has been domesticated for somewhere between 14,000 and 150,000 years. In those millennia, the dog has developed into hund's paw is its dorsal surface; the underside, either the palmar (on the forelimb) or the plantar (on the hindlimb) surface.

The sides of the forearm are named after its bones: Structures closer to the radius are radial, and structures closer to the ulna are ulnar. Similarly, in the lower leg, structures near the tibia (shinbone) are tibial and structures near the fibula are fibular (or peroneal).

4 Relative motions

Flexion means approximating adjacent parts of the body (usually at a joint) and extension means separating them. For example, the legs are flexed at the knee joints when sitting down, and extended when standing up. Generally, flexion produces an acute angle between adjacent parts, with its vertex at the joint, and extension produces an obtuse angle. One exception to this rule is in the ankle joint where moving the foot such that the toes move upwards is dorsiflexion and moving the foot such that the toes move downwards is plantar flexion .

Adduction means moving a part of the body toward or past its median line or toward the long axis of a limb. Abduction means moving a part of the body away from its median line or away from the long axis of a limb. For example, adducting the thighs brings the legs together, and abducting the thighs spreads the legs apart. Similarly, adducting the fingers brings them into contact with one another, and abducting the fingers spreads them apart.

Rotation means moving a part about its long axis, for example, in turning the neck. Supination means rotation of the forearm such that the palm of the hand faces forward or upward, and pronation means rotation of the forearm such that the palm of the hand faces backward or downward; the forearm with the hand is supinated or pronated at the elbow. Similar movements may be accomplished at the ankle, where supination results in the foot tipping inward relative to its long axis, and pronation results in the foot tipping outward; overpronation may contribute to the condition flatfoot.

An anterograde motion is in the normal direction of flow, while retrograde means reversed flow. For example, passage of food from the mouth to the stomach is in an anterograde direction, and gastric reflux is in a retrograde direction.

Home > Anatomical terms of location

1 Directions

1.1 General usage