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==Introduction==

==Introduction==

The physical examination involves observation of the snake, taking measurements and a thorough methodical area by area examination. Many techniques are similar to other animals, but before examining the snake ask the owner if it is accustomed to being handled.  [[Snake Handling and Restraint|See here]] for information on handling and restraint of snakes.  A veterinarian who is inexperienced with reptiles may be likely to focus on the presenting signs but then can end up treating exclusively the secondary problems.  Stomatitis and rectal prolapse are secondary conditions where a full examination with husbandry review, including [[Snake Housing|housing]] and [[Snake feeding|nutrition]], is vital in determining the principal problem.

The physical examination involves observation of the snake, taking measurements and a thorough methodical area by area examination. Many techniques are similar to other animals, but before examining the snake ask the owner if it is accustomed to being handled.  [[Snake Handling and Restraint|See here]] for information on handling and restraint of snakes.  A veterinarian who is inexperienced with reptiles may be likely to focus on the presenting signs but then can end up treating exclusively the secondary problems.  Stomatitis and rectal prolapse are secondary conditions where a full examination with husbandry review, including [[Snake Housing|housing]] and [[Snake feeding|nutrition]], is vital in determining the principal problem.

===Observation===

==Observation==

Snakes should have active tongues that are sampling scent particles in the atmosphere.  Normal movement should be observed although allowances must be made for any chilling effect in transit since this will reduce the patient's metabolism and give a misleading impression of lethargy and lack of strength.  The righting reflex should be tested since poor reactions can be a result of weakness and not necessarily neurological disease.  Respiration, including rib movements and any sounds produced.  Be aware of hissing noises arising from agitation that are not a result of respiratory infection.

Snakes should have active tongues that are sampling scent particles in the atmosphere.  Normal movement should be observed although allowances must be made for any chilling effect in transit since this will reduce the patient's metabolism and give a misleading impression of lethargy and lack of strength.  A healthy snake will have adequate muscle tone and grip the clinician's hands.  There will be a level of activity befitting the particular species.  A sick snake usually remains limp.  The righting reflex should be tested since poor reactions can be a result of weakness and not necessarily neurological disease.  Neurological function can be assessed by checking head position, body posture, cloacal tone and righting reflexes.  Respiration, including rib movements and any sounds produced should be noted.

===Body condition===

==Organ positions==

Weight of the snake should be taken at every examination, as should snout-vent lengths.  Obese snakes have increased fat deposition on the last third of the body before the cloaca.  Cachectic snakes with significant loss of muscle mass show a prominant dorsal spine and ribs, and the body shape looks more triangular in cross section.

The organisation of internal structures varies between snake families and genera.  However it is important to know the approximate position of the organs during a physical examination.  The following is a generalisation if the snake's body is divided into thirds from snout to vent:

*'''Cranial third''' - contains the trachea, oesophagus and heart

*'''Middle third''' - contains the liver, lung and stomach

*'''Caudal third''' - contains the small intestine, the triad of pancreas, spleen and gallbladder, the adrenal glands, large intestine, gonads, reproductive tract, kidneys, fat body and cloaca.  Behind the vent are the musk and, if the snake is a male, the hemipenes.

==Skin==

==Skin==

[[Image:0051_BLISTER_DISEASE_PYTHON_ed.jpg|250px|thumb|right|'''Blisters on skin''' ©RVC and its licensors, Peer Zwart and Fredric Frye. All rights reserved]]

[[Image:0051_BLISTER_DISEASE_PYTHON_ed.jpg|250px|thumb|right|'''Blisters on skin''' ©RVC and its licensors, Peer Zwart and Fredric Frye. All rights reserved]]

Examine under a bright light and with a hand lens if necessary.

Check the general appearance of the skin.  The skin should be bright and shiny. Assess elasticity and skin tenting. Dehydrated snakes show outwardly directed folds of skin and dysecdysis.  Examine the skin both dorsally and ventrally for retained shed, blisters, pustules, burns, discharges, erythema, pettechi, ulcers, loss of scales, lacerations ad swellings.  Examine for ectoparasites, especially mites that tend to hde under scales of the skin. Brushing the body of the snake over a white sheet may be helpful in checking for mites. The snake's body can be palpated by simply moving the hand, both dorsally and ventrally, down its length.  Identify any masses and swellings under the skin.  Subcutaneous lumps are usually due to abscesses but neoplasia and the second-stage cysts of cestodes can also be encountered in snakes.

 

 

*Dysecdysis - retained skin is often dry and brown while normal ecdysis occurring in a piecemeal fashion is flexible and transparent. Retained skin is a focus for infection and acts as a tourniquet on the tail tip and digits leading to ischaemic necrosis

*Examine the scales for loss, scabs, blisters and haemorrhages, ensuring the ventral scales are inspected

*Assess for abnormal masses, swellings or bruised areas

*Skin folding indicates dehydration, cachexia. Assessment of dehydration in reptiles is analogous to mammals. With 5-8% dehydration there is loss of skin elasticity with a wrinkled appearance. With more severe dehydration (10-15%) the eyes are sunken and the mucous membranes become dry and sticky (consider that the oral cavity of most reptiles is relatively dry compared with mammals).

Find out more about [[Snake Skin|snake skin]]

Find out more about [[Snake Skin|snake skin]]

Ecdysis (shedding) generally takes place every 14 days although this is dependent on many variables such as environment, age and size of snake.  Snakes shed their entire skin in one piece, including the spectacles, although large snakes greater than 3m in length may shed their skin in incomplete sections.  Prior to ecdydsis, a snake will become anorectic and handling may be hazardous to the animal at this time if the underlying epidermis is damaged.

Ecdysis (shedding) generally takes place every 14 days although this is dependent on many variables such as environment, age and size of snake.  Snakes shed their entire skin in one piece, including the spectacles, although large snakes greater than 3m in length may shed their skin in incomplete sections.  Prior to ecdydsis, a snake will become anorectic and handling may be hazardous to the animal at this time if the underlying epidermis is damaged.

==Head==

==Head==

Initially check that the snake moves and supports its head normally and that it investigates its surroundings with an active flicking tonge.  Examine the rostrum for abrasions that may indicate an unsuitable cage.  Check the nares for patency and discharge.  Examine the heat-sensing pits, the crevice around the spectacle and the skin between the scales for ectoparasites or retained skin.  Palpate the jaws for any abnormal swellings.

The nares should be clear and free of discharge and retained shed.

===Eyes===

===Eyes===

The eyes are usually considered as a barometer of general health and environmental conditions; therefore a full ophthalmologic examination should be performed in all cases.  

The eyes are usually considered as a barometer of general health and environmental conditions; therefore a full ophthalmologic examination should be performed in all cases. Observe the movement and general position of the eye within the socket.  The optic nerve and other cranial nerves associated with eye function are assessed by observing the snake's reaction to movement and by normal and co-ordinated eye movements.  Strabismus may indicated dysfunction.  Bulging eyes may result from retrobulbar or periocular cellulitis, absecesses or neoplasia.  Inspect the spectacles. They should be clear, not wrinkled, distended or discoloured although they are normally bluish-white prior to shedding. The subspectacular space should be clear.  Check for any signs of conjunctivitis.  Remember that the mydriatics are not useful and that there is no consensual light reflex.  

 

* Other diagnostic tools, such as tonometry (measurement of the intraocular pressure), stains, cytology, bacteriology, histopathology and electron microscopy, in addition to routine diagnostic tools (haemotology, biochemistry, radiology and ultrasound) can also be used to detect an ocular disease or underlying problem in snakes.  

* Following a general assessment of the eye, a more detailed examination should be performed using a form of focal illumination and a magnification system.

* Examination of the ocular fundus to assess the retina (fundoscopy) can be carried out using a direct or indirect ophthalmoscope.

* Mydriasis can be attempted either through general anaesthesia or intracameral injection of neuromuscular blocking agents such as curare or d-tubocurarine. These agents can also be applied topically; however their effectiveness may be affected by the variable corneal penetration of the drugs.  

* Other diagnostic tools, such as tonometry (measurement of the intraocular pressure), stains, cytology, bacteriology, histopathology and electron microscopy, in addition to routine diagnostic tools (haemotology, biochemistry, radiology and ultrasound) can also be used to detect an ocular disease or underlying problem in snakes.

*Retained spectacles are a concern.  They should be clear with no signs of subspectacluar disease.  

[[Image:Boa_stomatitis_ed.jpg|200px|thumb|right|'''Ulcerative stomatitis''' ©RVC and its licensors, Peer Zwart and Fredric Frye. All rights reserved]]

[[Image:Boa_stomatitis_ed.jpg|200px|thumb|right|'''Ulcerative stomatitis''' ©RVC and its licensors, Peer Zwart and Fredric Frye. All rights reserved]]

===Oral cavity===

===Oral cavity===

*The oral cavity should be opened using a soft, pliable speculum

The oral cavity is fairly easy to evaluate once the mouth is open.  Use an object to gently open the mouth without damaging the delicate gingiva and teeth.  Do not use any cotton since it snags on the caudally curving teeth.  The normally pale and pinkish-white gingiva should be glistening and moist with no petecchiation, excess salivation or oedema.  Excessive saliva in the oral cavity suggests pneumonia or gastrointestinal upset.  Mouth rot when present varies from mild erythema to a generalised stomatitis with pus necrotic tissue.  The tongue and its sheath should be examined.  Check the glottis for any discharge.  Check the patency of the internal nares.

*Mucous membranes should be pale to pink and free of thick ropey mucous

*Evaluate the tongue for movement

Assess the bulk and tone of the muscles first.  The body should be rounded.  With emaciation it becomes triangular and the spine and ribs more prominent.  Then assess locomotion on a rough surface.  Normal posture and coordination should be evident.  Check the righting reflex.  A defect in the vestibular system or hypothiaminosis may result in rolling and an inability to right.  The spine and ribcage should then be palpated for swellings that may be associated with abscesses or fractures.

*The glottis should be gree of discharge

*Examine the teeth for fractures

In colubrids and boids the heart is located in the cranial third of the body and the lung is in the middle third.  The use of a moistened gauze sponge over the stethoscope will help to eliminated the grating noise against the scales.  Special attention should be paid to abnormal sounds and symmetry.  Sometimes the presence of mucous can be detected.  Defensive hissing must be differentiated from pathologic respiration.

 

Examination of the coelomic cavity is possible in most small snakes by palpating ventrally between the ends of the ribs.  Large snakes are difficult to palpate because of their musculature.  There should be no palpable swellings and if they do occur their position can indicate the organ involved.  The heart can be palpated in the cranial third and the liver lies at a distance caudally in boids and colubrids because of their caudal lung.  Caudal to the liver the gall bladder can be palpated on the ventral midline.  It is possible to palpate the ingesta in healthy snakes while anorexic individuals will feel empty of doughy.

The cloaca can be examined very simply by using a otoscope or endoscope.  Check for oedema, erythema, discharge and swellings.  Check the vent for any soiling which may be due to parasitic infection of the large intestine.  Make a faecal smear if possible.  Examine the tail for retained sloughed skin, lumps and other deformities.

==References==

==References==

Fowler, M.E. and Miller, R.E. (2003). Zoo and Wild Animal Medicine. Saunders, 5th Edition. pp. 84. ISBN 0-7216-9499-3  

Fowler, M.E. and Miller, R.E. (2003). Zoo and Wild Animal Medicine. Saunders, 5th Edition. pp. 84. ISBN 0-7216-9499-3  

[[Category:Snake_Examination]]

[[Category:Snake_Examination]]