Anatomical Planes of the Body

Second, you will consider the planes of the body. Understanding these will facilitate learning terms related to position of structures relative to each other and movement of various parts of the body.

FRONTAL (or coronal) separates the body into Anterior and Posterior parts
MEDIAN (or midsagittal) separates body into Right and Left parts
HORIZONTAL separates the body into Superior and Inferior parts
SAGITTAL any plane parallel to the median plane
anatomical planes
After taking a look at the Anatomical Planes, you can then view some of the terms related to the planes. These are listed in the following tables. You will notice that most of these are in pairs of opposites.

Terms of relation or position

superior (closer to the head) inferior (closer to the feet) reference point -- horizontal plane
posterior (dorsal) closer to the posterior surface of the body anterior (ventral) closer to the anterior surface of the body reference point -- frontal or coronal plane
medial (lying closer to the midline) lateral (lying further away from the midline) reference point -- sagittal plane
proximal closer to the origin of a structure distal further away from the origin of a structure reference point -- the origin of a structure
superficial deep reference point -- surface of body or organ 
median reference point -- along the midsagittal or median plane 
intermediate between two other structures 
external internal refers to a hollow structure (external being outside and internal being inside) 
supine prone face or palm up when lying on back, face or palm down when lying on anterior surface of body
cephalad caudad toward the head, toward the tail (feet) 

Terms of movement

flexion extension increasing angle with frontal plane
decreasing angle with frontal plane 
abduction adduction moving away from or toward the sagittal plane 
protraction retraction moving forward or backward along a surface 
elevation depression raising or lowering a structure 
medial rotation lateral rotation movement around an axis of a bone 
pronation supination placing palm backward or forward (in anatomical position) 
circumduction combined movements of flexion,
extension, abduction, adduction
medial and lateral rotation
circumscribe a cone 
opposition bringing tips of fingers and thumb together
as in picking something up

Table of Frequently Used Terms in Anatomy

Aditus an entrance or opening
Ala a wing-like process
Alveolus a deep narrow pit, such as a tooth-socket
Ampulla used to describe the dilated part of a duct.
Ansa a loop, usually referring to a nerve
Antrum a cavity
Aponeurosis a glistening sheet of fibrous connective tissue from which muscle fibers arise or into which they run
Artery a blood vessel which conducts blood from the heart
Bone a special form of connective tissue in which calcium salts are deposited and which provides a framework, or skeleton, for the other tissues of the body.
Bursa a membranous sac containing a small amount of viscous fluid. A bursa is usually found in tissues where friction develops, such as where a tendon crosses a bony prominence. A bursa may form synovial sheaths to surround tendons as they cross other tendons or bone.
Canal a tubular and relatively narrow channel, or tunnel, often through a bone. A canaliculus is a smaller canal.
Capsule a fibrous or membranous envelope surrounding an organ. An articular capsule surrounds each synovial joint, being attached to the bones just beyond the limits of the joint cavity.
Cartilage a firm white tissue, from which most parts of the bony skeleton are formed and which persists to protect the surfaces of bones and joints.
Caruncle a small fleshy eminence
Cauda tail
Cavity a hollow space (or potential space) within the body or its organs.
Cervix means neck and is applied to the neck like portion of an organ (e.g. cervix of uterus)
Chiasma a crossing of fibers in the form of an X. Used primarily to describe nerve fibers.
Commissure a band of fibers which join corresponding right and left parts of a structure across the median plane.
Corpus means body
Cortex outer part, or rind, or some organs as distinguished from their inner part, or core usually called a medulla.
Crest a projecting ridge, especially one which on a bone
Crus means a leg and is applied to a structure that resembles a leg or stalk
Decussation same as a chiasma. A crossing of fibers in the form of an X.
Digitation a finger like process of a muscle
Disc a flat round structure usually applied to plates of cartilage in joints.
Duct a tube for the passage of fluid, especially secretions of glands. A ductule is a small duct.
Epithelium a layer of cells which forms the external surface of the skin, or which lines the cavities of the digestive, respiratory and urogenital organs, serous cavities, inner coats of blood and lymphatic vessels, gland and cavities within the brain. The epithelium of the skin is the epidermis. The epithelium of the digestive, respiratory and urogenital organs is moistened by a film of mucus and is known as the mucous coat. The epithelium lining bloods vessels is known as the endothelium. Serous cavities are lined by epithelium called mesothelium.
Fascia tissue which lies immediately deep to the skin known as subcutaneous tissue. It usually consists of a layer of connective tissue which contains fat, and of a deep and more fibrous layer which adheres to the surface of the underlying muscle and vessels. These layers are known as superficial and deep fascia respectively. Fascia surrounds every muscle, organ, vessel and nerve in the body.
Fasciculus a small bundle. A term that is usually applied to collections of nerve fibers.
Filum literally mean a "thread". This name is given to several thread-like structures such as the filum terminale, the lower extension of the pia mater of the spinal cord.
Fold a ridge formed where a membrane doubles back on itself
Folium mean leaf. The plural "folia" is applied to the folds of the cortex of the cerebellum.
Foramen a hole, often in a bone or between adjacent bones.
Fossa a "ditch", usually referring to a shallow depression or cavity.
Fovea a small pit or fossa
Frenulum a small fold of the mucous coat which limits the movement of the structure to which it is attached
Fundus used to denote the widest part of a hollow organ
Ganglion a swelling on the course of a nerve. Usually corresponds to a collection of nerve cells.
Genu mean knee. Geniculum is sometimes applied to a bent part of a structure.
Gyrus a fold or convolution of the cerebral cortex.
Hilum a depression or notch where blood vessels enter or leave an organ.
Humor applied to fluids of the eye
Infundibulum a funnel-shaped passage
Interdigitate an interlocking of structures by finger-like processes, as when the fingers of the two hands are interposed.
Invaginate a process when part of a wall of a structure is pushed inwards to that the structure which invaginates the membrane becomes partly ensheathed by it.
Isthmus a narrow part of a duct or other passage, or a narrow strip of tissue connecting two wider parts of an organ
Joints

places where bones meet each other (articulate). Where bones are connected by fibrous tissue, the joint is known as a fibrous joint (i.e. suture of skull). Where bones are united by cartilaginous tissue, the joint is known as a cartilaginous joint (i.e. symphysis pubis). Where a space intervenes between the articulating ends of bones, the joint is called a synovial joint (i.e. most of the joints of the body). In these joints, there is an articular capsule the encloses the joint. This capsule is lined by a synovial membrane which secretes a lubricating fluid.


Labium lip
Lamina A thin plate of bone or cartilage or a thin layer of softer tissues. A stratum is also used to denote a layer
Ligament a band of fibrous connective tissue by which bones are connected to each other. Sometimes bands of connective tissue which support the viscera or the thorax or abdomen are also known as ligaments.
Lobe a part of an organ, often separated from the rest by a fissure. A lobule is a small lobe
Meatus a passage or opening
Muscle these structures vary in shape and size, but always consist of masses of special contractile cells which are under nervous control. It is usual to describe a muscle as possessing an origin and insertion, in the sense that when the muscle contracts, the insertion moves toward the origin. It is probably more useful to regard a muscle as possessing attachments which are approximated when the whole muscle contracts. The original of a muscle is sometimes called the head and the contractile part the belly.
Nerves
the nerves of the body can be divided into twelve pairs of cranial nerves, which arise from the brain and brainstem, 31-33 pairs of spinal nerves which arise from the spinal cord in segmental series (8 cervical, 12 thoracic, 5 lumbar, 5 sacral and 1-3 coccygeal). The spinal nerves emerge from the intervertebral foramina which lie along side of adjacent vertebrae. The pass laterally into the neck or trunk.
A typical spinal nerve is formed by the union of a dorsal root, which arises from the dorsal aspect of the spinal cord and a ventral root which arises from the ventral aspect of the spinal cord. The dorsal root consists of sensory (afferent) fibers and contains a swelling called the dorsal root ganglion. This ganglion contains the cells bodies of the sensory nerve fibers. The ventral root consists of motor (efferent) nerve fibers.
The nerve trunk formed by the mergence of the two roots splits immediately into a dorsal ramus and a ventral ramus. The dorsal ramus supplies the deeper muscles of the back the their overlying skin. The ventral ramus supplies muscles and skin on the lateral and ventral aspects of the body. The nerve supply of the limbs is derived entirely from the ventral rami of the spinal nerves.
Sympathetic nerves Just at the point where the 12 thoracic and first 2 lumbar spinal nerve trunks split into a dorsal and ventral ramus, two branches leave the trunk that connect to the sympathetic chain ganglia, and these are called the communicating rami. The gray communicating ramus usually comes off first and connects to the ganglion in the sympathetic chain. It carries post ganglionic neurons from the ganglion back to the spinal nerve trunk and thence to its branches. The white communicating ramus arises a little more distal than the gray one and also connects to the sympathetic chain and its ganglia. This connection carries pre ganglionic neurons from the spinal cord to the sympathetic chain where synapses may occur at that level or past the sympathetic ganglia into other sympathetic ganglia.
Neuron The neuron or nerve cell is the functional unit of the nervous system. Each is composed of a cell body (perikaryon) where the nucleus of the cell is located, and one or more processes. One of the processes, called the axon, is different from the others, which are called dendrites. The dendrites and body are the receiving part of the neuron and the axon is the distribution part of the neuron.
Node a swelling or protuberance. A nodule is a small node.
Notch an indentation or depression, usually on the border of a bone.
Nucleus literally means a kernel or nut. In anatomy, nucleus is most often used to describe an aggregation or cluster of nerve cells.
Papilla a small nipple-shaped elevation
Periosteum the fibrous covering of a bone.
Plexus a network of nerve or vessel processes
Pouch pockets of peritoneum in the abdomen
Process an appendage or projection from the main part of a bone or organ
Punctum a minute opening
Ramus a branch, which, when translated, is used to describe smaller arteries, veins and nerves arising from their parent vessels or nerves.
Raphe a seam where two similar sheets of tissue unite.
Rete a network, used to describe plexuses of small canals, nerves or vessels
Retinaculum a band of connective tissue, usually connected at both ends to bone, which keeps tendons or other structures in place
Rima a cleft or fissure that refers to a narrow oval or oblong opening
Root the part of a nerve or organ which arises from another structure
Sac a bag-like cavity or pouch
Septum a dividing wall or partition
Sinus a recess, a cavity or hollow space, a dilated channel for venous blood or a small tunnel
Space a clearly demarcated segment of tissue or potential cavity
Spine a small, sharp-pointed projection from a bone
Stria a streak or stripe, sometimes slightly elevated
Stroma supporting fibrous framework of tissue
Substantia means substance or matter
Sulcus a groove
Taenia a flat band or tape, applied to a narrow strip of muscle
Tegmen roof
Tela means a web and describes a thin web-like membrane. Loosely translated, it can mean tissue
Tendon a cord of connective tissue into which muscles fibers end by which a muscle is attached to bone or other structures
Trabecula means a beam or bar.
Tract a bundle of fibers, often nerve fibers, having similar origins and terminations
Trigonum a triangular space or area
Trochlea pulley
Tuber an enlargement or swelling
Tubercle an eminence on a bone, usually smoother than a tuberosity
Tuberosity a rough eminence on a bone
Tunica a covering or coat around muscle or hollow viscera
Uvula means little grape, usually referring to the small fleshy appendage that hangs from the soft palate.
Vallecula a wide depression, furrow or valley
Valve a fold in an artery, vein or duct which prevents reflux of its contents
Vas a tubular structure
Velum means a veil or curtain.
Veins vessels that return blood from capillaries to the heart
Viscus any organ of the digestive, respiratory or urogenital systems, or ductless gland. Viscera is the plural.

Anatomical Position Anatomical Word Derivatives

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