Physical Examination: Vital Signs and Head-to-Tail Assessment

Why the Physical Examination Matters

The physical examination is the foundation of every patient encounter in veterinary practice. Before any treatment, medication, or procedure begins, the veterinary team must establish a baseline picture of the animal's health. As a veterinary assistant or technician, you will perform or assist with this assessment dozens of times each week. Accuracy is not optional — an undetected abnormality can delay life-saving treatment, while a falsely recorded value can lead to an inappropriate drug dose or missed diagnosis. Your findings feed directly into the SOAP record (Subjective, Objective, Assessment, Plan) that the supervising veterinarian relies on.

The Four Vital Signs: TPR and Weight

Temperature (T) is most commonly measured rectally in dogs and cats. A lubricated digital thermometer is gently inserted into the rectum, taking care not to force it, and held in place until the device signals completion. Normal rectal temperature in the dog is approximately 100.5 °F to 102.5 °F (about 38.1 °C to 39.2 °C). Values outside this range — called hyperthermia or hypothermia — must be flagged immediately and reported to the veterinarian. Always use a fresh disposable sleeve or disinfect the thermometer probe between patients to prevent cross-contamination.

Pulse (P) reflects heart rate and rhythm. The femoral artery, located on the medial (inner) surface of the rear leg at the groin, is the most accessible pulse point in dogs. Press two or three fingertips gently but firmly against the artery. Count beats for a full 60 seconds, or count for 15 seconds and multiply by four for efficiency when the rhythm is regular. Note whether the pulse is strong and regular, weak, bounding, or irregular. Normal resting heart rate in an adult dog is approximately 60 to 140 beats per minute; smaller breeds trend toward the higher end. In cats, normal resting heart rate is approximately 140 to 220 beats per minute. Always auscultate the heart with a stethoscope when possible to confirm rate and detect arrhythmias.

Respiration (R) is the breathing rate, measured by counting chest-wall rises for 60 seconds (or 30 seconds multiplied by two) while the animal is calm and undisturbed. Normal respiratory rate in a resting dog is approximately 10 to 30 breaths per minute; in cats, approximately 20 to 30 breaths per minute. Also note the character of breathing — is it effortless, labored, noisy, or shallow? Panting in a dog inflates the apparent rate; if the dog is panting, note this context and attempt measurement when the animal relaxes.

Weight (W) is recorded at every visit to track trends and calculate drug doses accurately. Place the animal on a calibrated digital scale, read the display, and record in kilograms for clinical calculations. Make sure the scale reads zero before the animal steps on.

Mucous Membrane Color and Capillary Refill Time

The gum tissue (oral mucous membranes) provides a rapid window into cardiovascular and oxygenation status. Lift the upper lip and observe color in good lighting. Normal color in dogs and cats is pink and moist. Pale or white gums suggest poor perfusion or anemia; blue (cyanotic) gums indicate dangerously low oxygen; brick-red gums may signal toxemia or early shock; yellow (icteric) gums point to possible liver disease or hemolysis.

Capillary refill time (CRT) is assessed by pressing a fingertip firmly against the gum for one second, releasing, and counting the seconds until normal pink color returns. Normal CRT is less than two seconds. A CRT of two seconds or longer warrants immediate veterinary attention.

The Head-to-Tail Assessment

Work systematically so nothing is missed. A reliable sequence is:

1. Head and face — Symmetry, eyes (discharge, cloudiness, conjunctival color), ears (odor, discharge, redness), nose (moisture, discharge), and oral cavity (gum color, CRT, tooth condition, tongue).

2. Neck and lymph nodes — Palpate submandibular, prescapular, and other accessible lymph nodes for enlargement or pain.

3. Thorax — Auscultate heart and lungs bilaterally; observe chest-wall movement; palpate ribs.

4. Abdomen — Gently palpate for organ size, masses, pain response, and fluid. Note any tensing or guarding.

5. Spine and musculoskeletal — Run fingers along the spine; observe stance, gait, and limb symmetry.

6. Skin and coat — Check for ectoparasites, lesions, lumps, alopecia, and coat quality.

7. Perineum and tail — Inspect for discharge, swelling, or parasites.

8. Limbs and paws — Palpate joints, check nails, and look between toes.

Documentation and Scope of Practice

Record every finding on the SOAP form using objective, measurable language. Write "HR 58 bpm, irregular" rather than "heart sounds odd." Any value outside the normal reference range must be clearly flagged and brought to the veterinarian's attention without delay — do not normalize, minimize, or fail to report an abnormal finding. Diagnosis and treatment decisions belong to the veterinarian; your role is accurate observation and timely reporting. Never re-record a value to make it look normal. Patient safety depends on honest, precise documentation.