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Dermatomic area

 
Dermatomic Area

 
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Dermatomic area
 
 
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A Dermatome is an area of skin
Skin

The skin is the outer covering of the body, also known as the epidermis. It is the largest organ of the integumentary system made up of multiple layers of epithelial biological tissue, and guards the underlying muscles, bones, ligaments and organ s....
 associated with a pair of dorsal root
Dorsal root

In anatomy and neurology, the dorsal root is the afferent nervesomatosensory system root of a spinal nerve.At the distal end of the dorsal root is the dorsal root ganglion, which contains the neuron cell bodies of the nerve fibres conveyed by the root....
s from the spine. The significance of dermatomic regions is important, as pain in a dermatomic area may indicate spinal damage or neurological stenosis
Stenosis

A stenosis is an abnormal narrowing in a blood vessel or other tubular Organ or structure.It is also sometimes called a "stricture" .The term "coarctation" is synonymous, but is commonly used only in the context of aortic coarctation....
. A compressed spinal nerve
Nerve

A nerve is an enclosed, cable-like bundle of Peripheral nervous system axons . A nerve provides a common pathway for the electrochemical nerve impulses that are transmitted along each of the axons....
 may show as pain elsewhere on the body, according to the dermatomic area covered by the compressed nerve. A similar area innervated by peripheral nerves is called a peripheral nerve field
Peripheral nerve field

Peripheral nerve field refers to an area of skin innervate by a single peripheral nerve. A peripheral nerve field can also be described as cutaneous nerve distribution....
.

The body can be divided into regions that are mainly supplied by a single spinal nerve
Spinal nerve

The term spinal nerve generally refers to the mixed spinal nerve, which is formed from the dorsal and ventral roots that come out of the spinal cord....
s.






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A Dermatome is an area of skin
Skin

The skin is the outer covering of the body, also known as the epidermis. It is the largest organ of the integumentary system made up of multiple layers of epithelial biological tissue, and guards the underlying muscles, bones, ligaments and organ s....
 associated with a pair of dorsal root
Dorsal root

In anatomy and neurology, the dorsal root is the afferent nervesomatosensory system root of a spinal nerve.At the distal end of the dorsal root is the dorsal root ganglion, which contains the neuron cell bodies of the nerve fibres conveyed by the root....
s from the spine. The significance of dermatomic regions is important, as pain in a dermatomic area may indicate spinal damage or neurological stenosis
Stenosis

A stenosis is an abnormal narrowing in a blood vessel or other tubular Organ or structure.It is also sometimes called a "stricture" .The term "coarctation" is synonymous, but is commonly used only in the context of aortic coarctation....
. A compressed spinal nerve
Nerve

A nerve is an enclosed, cable-like bundle of Peripheral nervous system axons . A nerve provides a common pathway for the electrochemical nerve impulses that are transmitted along each of the axons....
 may show as pain elsewhere on the body, according to the dermatomic area covered by the compressed nerve. A similar area innervated by peripheral nerves is called a peripheral nerve field
Peripheral nerve field

Peripheral nerve field refers to an area of skin innervate by a single peripheral nerve. A peripheral nerve field can also be described as cutaneous nerve distribution....
.

The body can be divided into regions that are mainly supplied by a single spinal nerve
Spinal nerve

The term spinal nerve generally refers to the mixed spinal nerve, which is formed from the dorsal and ventral roots that come out of the spinal cord....
s. There are eight cervical (one for the head, and one for each cervical vertebra
Vertebra

A vertebra is an individual bone in the flexible column that defines vertebrate animals. The vertebral column encases and protects the spinal cord, which runs from the base of the cranium down the dorsal side of the animal until reaching the pelvis....
), twelve thoracic, five lumbar and five sacral spinal nerves.

This innervates the body in a patterned form. Along the thorax
Thorax

The thorax is a division of an animal's body that lies between the head and the abdomen.In mammals, the thorax is the region of the body formed by the sternum, the thoracic vertebrae and the ribs....
 and abdomen
Abdomen

In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity....
 it is simply like a stack of discs forming a human, each supplied by a different spinal nerve.

Along the arms and the legs, the pattern is different: the dermatomes run longitudinally along the limbs.

Clinical significance

Dermatomes are useful in neurology
Neurology

Neurology is a medical specialty dealing with disorders of the nervous system. Specifically, it deals with the diagnosis and treatment of all categories of disease involving the Central nervous system, Peripheral nervous system, and autonomic nervous systems, including their coverings, blood vessels, and...
 for finding the site of damage to the spine. Viruses that infect spinal nerves such as Herpes zoster
Herpes zoster

Herpes zoster , commonly known as shingles, is a viral disease characterized by a painful skin rash with blisters in a limited area on one side of the body, often in a stripe....
 infections (shingles), can reveal their origin by showing up as a painful dermatomic area. Herpes zoster, a virus that is dormant in the dorsal root ganglion
Dorsal root ganglion

In anatomy and neurology, the dorsal root ganglion is a nodule on a dorsal root that contains cell bodies of neurons in afferent nerve spinal nerves....
, migrates along the spinal nerve to affect only the area of skin served by that nerve. Symptoms are usually unilateral but in the immune suppressed, they are more likely to become bilateral and symmetrical, meaning that the virus is present in both ganglia of a dorsal root ganglion pair.

Important dermatomes and anatomical landmarks

  • C2 - posterior half of the skull cap
  • C3 - area correlating to a high turtle neck shirt
  • C4 - area correlating to a low-collar shirt
  • C6 - (radial nerve]]) 1st digit (thumb
    Thumb

    The thumb is the Human_anatomical_terms#Anatomical_directions-most finger of the hand. The English adjective for thumb is pollical....
    )
  • C7 - (median nerve) 2nd and 3rd digit
  • C8 - (ulnar nerve
    Ulnar nerve

    In human anatomy, the ulnar nerve is a nerve which runs near the ulna bone. The ulnar nerve is the largest unprotected nerve in the human body , and the only unprotected nerve that does not serve a purely sensory function ....
    ) 4th and 5th digit, also the funny bone
  • T4 - nipple
    Nipple

    In its most general form, a nipple is a structure from which a fluid emanates. More specifically, it is the projection on the breasts of a mammal by which breast milk is delivered to a mother's young....
    s.
  • T5 - Inframammary fold
    Inframammary fold

    Inframammary fold , inframammary crease or inframammary line is the feature of human anatomy which is a natural boundary of a breast from below, the place where the breast and the chest meet....
    .
  • T6/T7 - xiphoid process
    Xiphoid process

    The xiphoid Process , also known as the xiphisternum is a small Cartilage extension to the lower part of the sternum which is usually Ossification in the adult human....
    .
  • T10 - umbilicus
    Umbilicus

    Umbilicus may refer to:*Umbilicus , a feature of gastropod, Nautilus and Ammonite shell anatomy*Navel, a synonym for the navel or belly button....
     (important for early appendicitis pain)
  • T12 - pubic bone area.
  • L1 - inguinal ligament
  • L4 - includes the knee caps


Additional images



See also

  • Cutaneous innervation
    Cutaneous innervation

    Cutaneous innervation refers to the area of the skin which is supplied by a specific nerve, that is, by a cutaneous nerve.Dermatome s are similar; however, a dermatome only specifies the area served by a spinal nerve....
  • Myotome
    Myotome

    In vertebrate embryonic development, a myotome is a group of tissues formed from somites that develop into the body wall muscle.Each myotome divides into a Dorsum epaxial part and a ventral hypaxial part....


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