Discordant drainage patterns are classified into two main types: and superimposed, while anteposition drainage patterns combine the two. Using a scalpel blade, the scales are scraped at the active border of the lesion, with particular care not to cause pain or bleeding. That is, the subsurface geology has a similar resistance to weathering so there is no apparent control over the direction the tributaries take. The peak incidence of infection is after puberty, although patients may present in the preadolescent period. Several streams develop on both the flanks of the ridges and join the longitudinal synclinal streams at right angle. Unlike tinea corporis, the lesions of granuloma annulare have no scaling or associated vesicles or pustules. The subsequent streams find it easier to erode the concentric, less resistant strata.
Bilateral hilar lymphadenopathy is virtually specific to sarcoidosis. They can sometimes also be found on tops of mountains. Trellised drainage patterns are generally formed in the regions of cuesta topography where hard beds become escarpments and soft beds are eroded to become valleys or lowlands. Spontaneous resolution is less common in these patients than in patients with localized granuloma annulare, and remission in fewer than three to four years is unlikely. With the march of time a network of streams is developed wherein streams follow the lines of weakness joints and fractures.
Antinuclear antibody-keratinocyte interactions in photosensitive cutaneous lupus erythematosus. The courses of the tributaries are straightened because of slope factor and little distance between the ridges and the longitudinal consequents occupying the valleys and thus the tributaries are not allowed to adapt sinuous course and join the longitudinal consequents at acute angles fig. Diagnosis is typically based on clinical appearance and correlation with pathology. Such pattern is generally developed due to river capture fig 17. Tributaries joining a larger stream at acute angle less than 90 degrees. These tributary streams are called as lateral consequent streams. Radial Drainage Pattern : Radial drainage pattern, also known as centrifugal pattern, is formed by the streams which diverge from a central higher point in all directions.
All dermatophytes are aerobic, and they share the ability to assimilate keratin, thus allowing them to penetrate the keratinized layers of the stratum corneum. The drainage basins are young and are still sorting themselves out. Annular Pattern In this drainage pattern, the subsequent streams follow curving or actuate courses prior to joining the consequent stream. For example, rivers like Godavari, Krishna and Kaveri, descending from the Western Ghats and flowing into the Bay of Bengal, are some of the consequent rivers of Peninsular India. First of all the master or trunk consequent stream develops on gently sloping topographic surface. It is believed that erythema annulare centrifugum represents a cutaneous manifestation of a hypersensitivity reaction to a myriad of underlying conditions, including: infection by dermatophytes, bacteria and viruses; malignancy; and immunologic disorders.
Because the lesions follow the skin cleavage lines, they have the characteristic appearance of a Christmas tree. These tributaries enter the main river at approximately 90 degree angles, causing a trellis-like appearance of the drainage system. Though dendritic pattern is independent of structural and lithological controls but almost uniform lithology presence of same type of rocks in extensive area presents most ideal condition for the development of dendritic drainage pattern. In areas of uniform rock, with little distortion by folding or faulting, the rivers develop a random branching network similar to a tree. This type of drainage is called superimposed drainage. Most of the rivers of the Indo-Gangetic Plains are of dendritic type. Drainage divide is usually a ridge or a high platform.
However, other conditions may present with much the same appearance. Sometimes, the joint pattern in the rocks creates a Rectangular drainage. Although these options have been shown to provide symptomatic improvement in some patients, none has a discernible advantage over the others, and there is currently no cure. There are many smaller watersheds within a river basin. This mechanism is associated with urticaria caused by pollens, foods, medications, fungi, molds, Hymenoptera venom and parasitic infections. Laboratory tests are generally of little benefit; however, in patients with generalized granuloma annulare, abnormalities of glucose tolerance are more common. The differential erosion of hard and soft rock beds results in the truncation of the beds which produces ringed belted structure wherein relatively resistant beds project outward whereas the weaker soft beds form circular clefts.
Morcha pahar and Lugu hill of Hazaribagh, Mt. The picture is one of numerous water courses, lakes and marshes; some inter-connected and some in local drainage basins of their own. The lesions are usually found on the hands, feet, wrists and ankles but can potentially occur anywhere on the body. At a much later date tributaries of circular subsequent streams, which join the radial consequents, are also developed and thus the drainage pattern becomes a special case of trellised pattern. Address correspondence to Sylvia Hsu, M.
There are mainly 10 different types of Drainage Pattern: Trellised Drainage Pattern, Dendritic Drainage Pattern, Rectangular Drainage Pattern, Radial Drainage Pattern, Centripetal Drainage Pattern, Annular Drainage Pattern, Barbed Drainage Pattern, Pinnate Drainage Pattern, Herringbone Drainage Pattern, Parallel Drainage Pattern. Trellised Drainage Pattern: Trellised drainage patterns are formed by the network of tributaries and master consequent streams which follow the regional slope and are well adjusted to the geological structures. One or more large erythematous patches may appear anywhere on the skin. This increases the gradient of the stream and therefore, gives the stream more erosive power. Example : Indus, Sutlej, Brahmaputra and other Himalayan rivers that are older than the Himalayas themselves. The small and swift rivers originating in the Western Ghats and discharging their water into the Arabian Sea provide a good example of parallel drainage pattern in India.
They develop where the river channel follows the slope of the terrain. Subacute cutaneous lupus erythematosus can present in an annular form on sunexposed surfaces or in a papulosquamous form. This pattern is more frequently developed on uniformly sloping and dipping rock beds such as cuestas or newly emerged coastal plains. Eventually the system will stabilize. Patients thought to have pityriasis rosea should be screened for syphilis, because the two eruptions often have a similar appearance.
It happens in areas where there has been much geological disruption. A good example of a radial drainage pattern is provided by the rivers originating from the Amarkantak Mountain. An area drained by a single river is called its drainage basin or catchment area. They are the subsequent drainage of the Ganga drainage system. Source: Centripetal The centripetal drainage pattern is just the opposite of the radial as streams flow toward a central depression. The Indus, Satluj, Ganga, Sarju Kali , Arun a tributary of Kosi , Tista and Brahmaputra are some of the important antecedent rivers, originating from beyond the Greater Himalayas. The specimen is transferred to a glass slide, and a coverslip is placed on top to protect the specimen.