# Dorsal Recumbency: Definition and Clinical Use Dorsal recumbency is the body position in which an animal lies on its back, with the dorsal (upper) surface against the support surface and the ventral (lower) surface, including the sternum and abdomen, facing upward. It is one of four standard recumbency positions used in [veterinary medicine](/blog/careers/veterinary-medicine-careers-from-clinical-practice-to-public-health), alongside sternal, left lateral, and right lateral recumbency. Understanding when to place an animal in dorsal recumbency, and when not to, is a practical skill that affects image quality, surgical access, airway safety, and patient survival. A radiograph taken in the wrong position can hide a lesion. A brachycephalic dog restrained on its back can obstruct its airway within seconds. A horse placed in dorsal recumbency for more than a short procedure can develop severe ventilation-perfusion mismatch. This article defines the position precisely, compares it with the other recumbencies, explains its clinical indications, and flags the pitfalls that every clinician and technician should recognize. ## What Is Dorsal Recumbency? Dorsal recumbency is defined by the orientation of the patient's body axis relative to gravity. The animal lies supine, meaning the spine is horizontal and the ventral body wall faces upward. The limbs may be extended or flexed depending on the procedure. In dogs and cats, the forelimbs are often pulled cranially or tied loosely to the table, and the hindlimbs are extended caudally for abdominal radiography. In reptiles and birds, the same principle applies: the coelomic cavity faces up. The term comes from the Latin *dorsum* (back) and *recumbere* (to lie down). Dorsal recumbency literally means lying on the back. It is not the same as dorsal positioning, which in radiographic terminology refers to the direction of the x-ray beam (a dorsoventral or DV view). A DV radiograph can be taken with the patient in sternal recumbency, for example, because the beam enters the dorsum and exits the ventrum. The recumbency describes the patient. The view describes the beam. ### Dorsal Recumbency vs. Ventral Recumbency Ventral recumbency is synonymous with sternal recumbency: the animal lies on its sternum, ventral surface down. Some older texts use ventral recumbency and sternal recumbency interchangeably. Modern veterinary usage favors sternal recumbency because it specifies the contact point (the sternum) and avoids confusion with ventral positioning of the x-ray beam. ### Dorsal Recumbency vs. Supine Position Supine is the human medical term for lying face up. In veterinary medicine, dorsal recumbency is the preferred term because it specifies the animal's anatomical orientation without implying a human posture. The two terms describe the same physical position, but [veterinary radiography](/knowledge/diagnostics/imaging/veterinary-radiography) and surgery use dorsal recumbency for consistency across species. ## The Four Standard Recumbency Positions Veterinary patients are positioned in one of four recumbencies for examination, imaging, or surgery. Each position changes the relationship between abdominal organs, the diaphragm, and the spine, which affects both what you can see and what can go wrong. ### Sternal Recumbency The animal lies on its sternum with the ventral thorax and abdomen against the table. The forelimbs are typically flexed or extended forward. Sternal recumbency is the most physiologically neutral position for most species because it minimizes compression of the diaphragm and allows the lungs to expand symmetrically. It is the default position for thoracic radiography, echocardiography in cats, and recovery from anesthesia. A study of 102 hospitalized cats found that left atrial measurements obtained by focused cardiac ultrasound in sternal recumbency were not significantly different from those obtained in right lateral recumbency, supporting the use of sternal positioning when lateral restraint is poorly tolerated [1]. ### Left and Right Lateral Recumbency The animal lies on one side, with the dependent (down) side named. Right lateral recumbency means the right side is against the table. Left lateral recumbency means the left side is down. Lateral recumbency is the standard position for most echocardiographic examinations, for many orthopedic radiographs, and for procedures requiring access to one side of the body. In horses, lateral recumbency is used for myelography, though a retrospective study of seven horses found that seizures and cortical blindness occurred contralateral to the side of recumbency after iohexol myelography, with seizure onset localized to the right parietal cortex and blindness to the right occipital cortex in affected horses [2]. ### Dorsal Recumbency The animal lies on its back. This position is used when the clinician needs ventral access, a symmetric view of paired structures, or a specific radiographic projection that cannot be obtained in another position. It is the least physiologically neutral of the four positions for most mammals because the weight of the abdominal organs presses against the diaphragm, reducing functional residual capacity and impairing venous return in large patients. ## Comparison Table of Recumbency Positions | Position | Contact surface | Typical indications | Key risks | |--|--|--|--| | Sternal | Sternum, ventral thorax | Thoracic radiography, echocardiography in cats, anesthesia recovery, neonatal calf adaptation | Minimal for most patients | | Left lateral | Left side | Echocardiography, left-sided orthopedic views, myelography in horses | Dependent lung atelectasis, contralateral seizure risk in horses after myelography [2] | | Right lateral | Right side | Echocardiography, right-sided orthopedic views, arterial blood sampling | Same as left lateral | | Dorsal | Dorsum, spine | Abdominal radiography (VD view), ventral coelioscopy, some orthopedic procedures, CPR | Respiratory compromise, regurgitation and aspiration, venous return reduction, poor tolerance in horses and cattle | ## Clinical Uses of Dorsal Recumbency ### Abdominal Radiography The ventrodorsal (VD) abdominal radiograph is the classic indication for dorsal recumbency. In a VD view, the x-ray beam enters the ventrum and exits the dorsum, producing a symmetric image of the abdomen. This view is essential for evaluating the kidneys, ureters, bladder, and reproductive tract because it separates left and right structures that overlap in a lateral view. A study of Syrian hamsters using survey radiography and in situ anatomy found that on VD views, the left kidney was generally visible, whereas the right kidney was identified in only 28% of animals, illustrating how species anatomy affects what dorsal recumbency can reveal [3]. The VD view also provides a complementary perspective to the lateral view for detecting radiopaque uroliths, evaluating intestinal position, and assessing organ displacement. In dogs and cats, the patient is placed in dorsal recumbency with the hindlimbs extended and the forelimbs pulled cranially or tied to the table. Sandbags or foam wedges are used to maintain symmetry. Even slight rotation can obscure the kidneys or create a false impression of organ displacement. ### Orthopedic Procedures and Radiography Dorsal recumbency is used for certain orthopedic procedures and radiographic views. The caudocranial view of the femur, for example, can be obtained with the patient in sternal recumbency, but dorsal recumbency is sometimes used for ventral approaches to the pelvis or for procedures requiring access to the ventral aspect of the limb. A study comparing caudocranial femoral radiographs to CT reconstructions found that radiographs overestimated the anatomic lateral distal femoral angle by an average of 1.8 degrees compared to CT, with a 95% limit of agreement range of 15.4 degrees [4]. This finding underscores that positioning and projection geometry affect measurement accuracy, regardless of recumbency. In minimally invasive spinal surgery, cadavers positioned in sternal recumbency or at a 30 to 60 degree angle were used for integrated endoscopic thoracolumbar mini-hemilaminectomy and lateral corpectomy, with successful access to disc spaces from T11-12 through L3-4 [5]. Dorsal recumbency is not the standard position for thoracolumbar spine surgery because it requires a ventral approach, but it may be used for ventral slot procedures in the cervical spine or for ventral abdominal approaches. ### Ultrasound of Certain Organs Ultrasound examination of the urinary bladder, prostate, and reproductive tract is often performed in dorsal recumbency because the organs float upward toward the transducer. In female dogs and cats, dorsal recumbency facilitates imaging of the ovaries and uterus. In male dogs, it provides access to the prostate and testes. The position also allows the sonographer to use gravity to displace gas-filled bowel loops away from the target organ. For cardiac ultrasound, dorsal recumbency is rarely used because the heart sits against the sternum and the ribs obscure the acoustic window. Lateral or sternal recumbency is preferred. A study of healthy French Bulldogs found that echocardiographic measurements in lateral recumbency differed from those in standing position, and that brachycephalic dogs sometimes cannot tolerate lateral recumbency without dyspnea or cyanosis [6]. The Cambridge classification for brachycephalic obstructive airway syndrome alone was not predictive of whether a dog could tolerate lateral recumbency for echocardiography, but temperament score and the combination of temperament and Cambridge classification were predictive [7]. This has implications for any recumbency position, including dorsal, in flat-faced breeds. ### Cardiopulmonary Resuscitation (CPR) During CPR, the patient is placed in dorsal recumbency to allow chest compressions over the sternum. The theoretical advantage is that the heart lies between the sternum and the spine, so compressions directly compress the ventricles. In practice, the evidence for dorsal versus lateral recumbency during CPR in animals is limited, and the choice often depends on the patient's size, the presence of equipment, and the clinician's training. The RECOVER guidelines (Reassessment Campaign on Veterinary Resuscitation) recommend chest compressions in lateral recumbency for most dogs and cats, with dorsal recumbency reserved for specific circumstances such as ventral chest wall access or concurrent procedures. The key point is that dorsal recumbency during CPR requires the same airway management and monitoring as any other position. ### Ventral Coelioscopy and Endoscopy Dorsal recumbency provides ventral access to the coelom in reptiles and birds. A study comparing ventral and left lateral approaches to coelioscopy in bearded dragons found that the ventral approach, performed with the animal in dorsal recumbency, was faster than the left lateral approach and provided good to excellent visualization of the heart, lungs, liver, stomach, intestines, pancreas, gallbladder, left kidney, gonads, and fat body [8]. The left kidney, testis, and vas deferens were easier to see with the left lateral approach, while the pancreas in females and gallbladder in both sexes were easier to see with the ventral approach. This illustrates that the choice of recumbency for endoscopy depends on which organs need to be examined. ## Species Differences in Dorsal Recumbency Tolerance ### Dogs and Cats Small animals tolerate dorsal recumbency well for short procedures. The main concerns are airway obstruction in brachycephalic breeds and regurgitation in patients with full stomachs. French Bulldogs and other flat-faced breeds may develop dyspnea, stertor, stridor, or cyanosis when restrained in lateral recumbency, and the same risks apply to dorsal recumbency [6][7]. Pre-oxygenation, rapid intubation, and minimal restraint time are essential. ### Horses Horses tolerate dorsal recumbency poorly. The weight of the abdominal organs compresses the diaphragm and reduces functional residual capacity, leading to hypoxemia and hypercapnia. A study of anesthetized horses found that transdiaphragmatic pressure and oxygen saturation were decreased in the Trendelenburg position compared to dorsal recumbency, and that gastric expiratory pressure was decreased in the standing position compared to dorsal recumbency [9]. These findings highlight that even among recumbent positions, dorsal recumbency has distinct effects on respiratory mechanics. Horses also risk myopathy and neuropathy from prolonged recumbency, and they may develop gastric rupture if not properly positioned. Dorsal recumbency in horses is reserved for short procedures such as castration or for specific surgical approaches, and it requires careful padding, monitoring, and often mechanical ventilation. ### Cattle Adult cattle tolerate dorsal recumbency poorly for the same reasons as horses: the rumen and abdominal organs compress the diaphragm, and the weight of the viscera impairs venous return. Dorsal recumbency in cattle is used for procedures such as rumenotomy, cesarean section, and claw trimming, but it is typically limited to 30 to 60 minutes. A study of newborn calves delivered by cesarean section found that placing calves in sternal recumbency or suspending them by the hind legs immediately after delivery improved respiratory and metabolic adaptation to extrauterine life compared to lateral recumbency [10]. This finding underscores that even in the neonatal period, body position affects physiology, and dorsal recumbency is not the default for compromised patients. ### Reptiles and Birds Reptiles and birds have unique respiratory anatomy. Snakes have a single lung or a vestigial second lung, and their lungs are thin and sac-like. A study of ball pythons found that CT evaluation of the lungs was feasible in curled recumbency, with lung parenchyma thickness and attenuation declining from cranial to caudal [11]. Dorsal recumbency in snakes is used for ventral coelioscopy and for radiographic views of the coelom. In birds, dorsal recumbency is used for coelioscopy and for some orthopedic procedures, but the air sacs and lungs are highly efficient, and the patient must be monitored for respiratory compromise. A study of chicken cadavers in lateral recumbency for ultrasound-guided nerve blocks found that the sciatic and femoral nerves could be visualized in the same acoustic window, but this was a lateral approach, not dorsal [12]. ## Pitfalls and Safety Considerations ### Respiratory Compromise Dorsal recumbency reduces functional residual capacity in mammals because the abdominal organs press against the diaphragm. In large patients, this can cause hypoxemia and hypercapnia. In brachycephalic patients, the upper airway may obstruct when the patient is on its back, especially if the head is not elevated. Pre-oxygenation, intubation, and mechanical ventilation may be necessary for prolonged procedures. In horses, dorsal recumbency is associated with decreased transdiaphragmatic pressure and oxygen saturation compared to other positions, and the Trendelenburg position further impairs respiratory function [9]. ### Regurgitation and Aspiration Risk Dorsal recumbency increases the risk of passive regurgitation and aspiration because gravity no longer keeps gastric contents below the gastroesophageal sphincter. Patients with full stomachs, gastrointestinal obstruction, or gastroesophageal reflux disease are at highest risk. Fasting before anesthesia reduces but does not eliminate the risk. Rapid intubation with a cuffed endotracheal tube is the standard preventive measure. In horses, the risk of gastric rupture is a concern during prolonged dorsal recumbency, and the stomach should be decompressed with a nasogastric tube before positioning. ### Padding and Monitoring Dorsal recumbency requires careful padding to prevent pressure sores and nerve compression. The spine, ribs, and pelvic bones are the main contact points. Foam pads, gel cushions, and vacuum-positioning bags are used to distribute pressure. The patient's limbs should be supported in a neutral position to avoid stretching the brachial plexus or sciatic nerve. Monitoring includes pulse oximetry, capnography, blood pressure, and temperature. In horses, creatine kinase and other muscle enzymes are monitored to detect myopathy. ### Venous Return and Cardiovascular Effects Dorsal recumbency can impair venous return because the weight of the abdominal organs compresses the caudal vena cava. This is most pronounced in large patients and in those with hypovolemia. Fluid therapy, vasopressors, and careful positioning can mitigate the effect. In horses, dorsal recumbency is associated with decreased arterial pressures in some positions, and the reverse Trendelenburg position increases heart rate [9]. ## How Dorsal Recumbency Is Tested and Observed in Practice Veterinary students learn recumbency positions through anatomy labs, radiology rotations, and surgery practice. The ability to position a patient correctly is assessed in practical exams, where students must identify the recumbency, explain the indications, and demonstrate safe restraint. In clinical practice, the choice of recumbency is documented in the medical record and on radiograph labels. A VD radiograph is labeled as such, and the recumbency is noted in the imaging report. In surgery, the recumbency is part of the surgical preparation checklist, and the patient is positioned before the surgical site is clipped and prepped. ## Common Misconceptions ### Dorsal Recumbency and DV View Are the Same They are not. Dorsal recumbency describes the patient's position. DV describes the direction of the x-ray beam. A DV view can be obtained with the patient in sternal recumbency (beam enters the dorsum, exits the ventrum). A VD view is obtained with the patient in dorsal recumbency (beam enters the ventrum, exits the dorsum). The two are complementary and are often taken together. ### Dorsal Recumbency Is Always the Best Position for Abdominal Ultrasound It is useful for some organs, but not all. The liver, spleen, and kidneys are often imaged in lateral recumbency because the ribs and gas-filled bowel loops interfere less. Dorsal recumbency is best for the bladder, prostate, and reproductive tract. ### Horses Can Be Safely Placed in Dorsal Recumbency for Long Procedures Horses tolerate dorsal recumbency poorly. Prolonged dorsal recumbency causes hypoxemia, hypercapnia, myopathy, and neuropathy. It is reserved for short procedures and requires mechanical ventilation and careful monitoring. ### Brachycephalic Dogs Can Be Restrained in Any Position Brachycephalic dogs may develop dyspnea, cyanosis, or airway obstruction in lateral or dorsal recumbency. Temperament and BOAS severity both affect tolerance, and the Cambridge classification alone does not predict which dogs will tolerate lateral recumbency [7]. Pre-oxygenation and rapid intubation are essential. ## Quick Review 1. Dorsal recumbency means the animal lies on its back with the ventral surface up. 2. It is one of four standard recumbencies: sternal, left lateral, right lateral, and dorsal. 3. The VD radiograph is the classic indication for dorsal recumbency in abdominal imaging. 4. Dorsal recumbency is used for ventral coelioscopy, some orthopedic procedures, ultrasound of pelvic organs, and CPR. 5. The main risks are respiratory compromise, regurgitation and aspiration, and impaired venous return. 6. Horses and cattle tolerate dorsal recumbency poorly and require short procedure times and intensive monitoring. 7. Brachycephalic breeds are at high risk for airway obstruction in any recumbency, including dorsal. This article is educational and is not a substitute for veterinary diagnosis or treatment. ## Clinical Relevance, Limitations and Common Mistakes Dorsal recumbency is a tool, not a default. The clinician must weigh the diagnostic or surgical benefit against the physiologic cost. In small animals, the cost is usually low for short procedures, but brachycephalic breeds and patients with full stomachs require extra precautions. In horses and cattle, the cost is high, and dorsal recumbency is reserved for procedures that cannot be performed in another position. The most common mistakes are failing to pad pressure points, failing to monitor oxygenation, and failing to recognize that a patient is struggling to breathe. In radiography, the most common mistake is poor symmetry, which can obscure lesions or create false positives. In surgery, the most common mistake is inadequate restraint, which can lead to patient movement and surgical error. Individual cases require a veterinarian's judgment, and the information here is a guide, not a protocol. ## Frequently Asked Questions ### What is dorsal recumbency? Dorsal recumbency is the position in which an animal lies on its back with its ventral surface facing upward. It is used for abdominal radiography, some surgeries, ultrasound of pelvic organs, and CPR. ### How does dorsal recumbency differ from lateral recumbency? In dorsal recumbency, the animal is on its back. In lateral recumbency, the animal is on its side, with the dependent side named (left or right). Lateral recumbency is the standard position for echocardiography and many orthopedic views. ### Why is dorsal recumbency risky for horses? Horses tolerate dorsal recumbency poorly because the weight of the abdominal organs compresses the diaphragm, reducing lung capacity and impairing oxygenation. Prolonged dorsal recumbency can also cause muscle damage and nerve compression. ### Can brachycephalic dogs be placed in dorsal recumbency? Brachycephalic dogs can be placed in dorsal recumbency for short procedures, but they are at high risk for airway obstruction and respiratory distress. Pre-oxygenation, rapid intubation, and minimal restraint time are essential. ### What is the difference between dorsal recumbency and a DV view? Dorsal recumbency is the patient's position (on the back). A DV view describes the x-ray beam direction (dorsal to ventral). A DV view can be taken with the patient in sternal recumbency, and a VD view is taken with the patient in dorsal recumbency. ### Is dorsal recumbency used in CPR? Dorsal recumbency is sometimes used during CPR to allow chest compressions over the sternum, but lateral recumbency is more commonly recommended for most dogs and cats. The choice depends on the patient and the clinical situation. ## Related Articles - [Surgical Approaches to the Spine: Dorsal and Ventral Exposure](/knowledge/veterinary-medicine/veterinary-surgery/surgical-approaches-spine-dorsal-ventral) - [Clinical Chemistry Analyzer Maintenance and Troubleshooting](/knowledge/diagnostics/clinical-pathology/clinical-chemistry-analyzer-maintenance-and-troubleshooting) - [Reference Intervals in Veterinary Clinical Pathology: Establishment and Use](/knowledge/veterinary-medicine/clinical-pathology/reference-intervals-veterinary-clinical-pathology) - [Circulating Tumor DNA: Biology, Detection, and Clinical Use](/knowledge/molecular-biology/circulating-tumor-dna) - [Digital Pathology Scanners: A Buyer's Guide for Clinical and Research Use](/knowledge/bioinformatics/digital-pathology-scanners-a-buyer-s-guide-for-clinical-and-research-use) - [Avian Enrofloxacin: Pharmacology, Clinical Use, and Resistance in Poultry](/knowledge/bacteria/avian-bacteria/avian-enrofloxacin) - [Ischial Spines: Anatomy, Landmarks, and Clinical Use](/knowledge/veterinary-medicine/veterinary-anatomy-physiology/ischial-spines-anatomy-landmarks-and-clinical-use) ## Sources 1. 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