USET cheat sheet

Skeletal formula: 7 cervical, 18 thoracic, 6 lumbar, 5 sacral (fused), 15-21 caudal vertebrae; 18 ribs (8 sternal, 10 asternal); 36-44 teeth in the adult male.

Forelimb has no bony clavicle; the scapula attaches to the trunk by synsarcosis (muscle sling), so the forelimb is a weight-bearing strut stabilized largely by the serratus ventralis.

Hind limb reciprocal apparatus: the stifle and hock flex and extend together via the peroneus tertius (cranial) and superficial digital flexor (caudal), allowing the standing horse to lock the stifle and rest with minimal muscular effort.

Stay apparatus: pastern joint collateral ligaments, distal sesamoidean ligaments, suspensory ligament, and the superficial/deep digital flexor check ligaments support standing with low energy cost.

Muscle fiber types: Type I slow-twitch oxidative (endurance), Type IIA fast oxidative-glycolytic (intermediate), Type IIX fast glycolytic (sprint); fiber-type proportion varies by breed and training.

Resting adult vital parameters: heart rate 28-44 bpm, respiratory rate 8-16 breaths/min, rectal temperature 37.2-38.5 C (99-101.5 F); gut sounds normally present in all four quadrants.

The hoof wall bears weight at the solear margin; the frog aids proprioception and hemodynamics; the digital cushion and ungual cartilage absorb concussive load.

Cardiovascular: resting cardiac output roughly 30-40 L/min in a 500 kg horse, rising several-fold at maximal exercise; spleen acts as a reservoir releasing red cells during exertion.

Footfall sequences: walk = 4-beat lateral sequence (LH, LF, RH, RF); trot = 2-beat diagonal; canter = 3-beat with a leading leg; gallop = 4-beat transverse.

Stride variables: stride length = distance between successive footfalls of the same limb; stride duration = time for one full cycle; duty factor = stance time / stride time (higher at slower gaits).

Vertical force peaks near mid-stance at roughly 1.0-1.5 times body weight per limb at the walk/trot; peak vertical force rises with speed.

The suspensory apparatus stores and returns elastic energy; tendon strain at gallop can approach or exceed 10% of resting length, a threshold linked to injury risk.

Head and neck movement counteracts vertical oscillation of the trunk; the head acts as a counterbalance and its position affects forelimb loading and stride length.

Lameness is detected by asymmetry: head nod (forelimb, rises when the sound limb is on the ground), pelvic rise (hind limb), and reduced stance time on the affected limb.

Objective gait analysis uses inertial sensors or force plates to quantify asymmetry; a difference of about 3-4 mm in pelvic or head displacement is often used as a threshold for clinical relevance.

Conformation influences loading: a long, sloping pastern increases flexor tendon strain; base-narrow or base-wide limb alignment shifts mediolateral load distribution.

Horses are prey animals with a fight-or-flight response; the primary defense is flight, and the flight zone (personal space) governs handling approach and escape distance.

As a social species with a dominance hierarchy, horses form stable groups; isolation can cause distress and stereotypies such as weaving and crib-biting.

Normal daily time budget: grazing and eating about 16-18 hours, resting/recumbent sleep about 2-3 hours, and the remainder in standing rest and locomotion.

REM sleep requires recumbency; a horse unable to lie down safely may show sleep deprivation signs such as collapse or drowsiness.

Flehmen (lip curl) is a vomeronasal response to pheromones; it is normal and not a sign of pain.

Pain scoring uses composite tools such as the Horse Grimace Scale (facial expression) and composite pain scales (behavior, posture, and locomotion).

Welfare assessment frameworks include the Five Domains (nutrition, environment, health, behavior, and mental state) and the Five Freedoms; both inform management decisions.

Signs of stress during handling include elevated heart rate, sweating, defecation, head elevation, and increased muscle tension; these guide low-stress handling choices.

Water intake is roughly 5-10 L per 100 kg body weight per day; a 500 kg horse typically drinks 25-50 L/day, increasing with heat and exercise.

Dry matter intake target is about 1.5-2.5% of body weight per day; forage should make up the majority (at least 1% of body weight as long-stem forage).

Body condition score (BCS) uses a 1-9 scale (Henneke); 4-5 is ideal for most horses; a cresty neck score (0-5) adds metabolic risk information.

Energy requirements rise with work: light work roughly 1.2x maintenance, moderate 1.4x, heavy 1.6-1.8x, and very heavy up to about 2x maintenance.

Protein: adult maintenance needs about 8-10% crude protein in the total diet; growing, pregnant, and lactating horses need higher levels (12-16%).

Electrolytes: sweat is rich in sodium, potassium, chloride, and calcium; a working horse can lose 5-15 L of sweat per hour, so electrolyte replacement matters in hot conditions.

Conditioning principle: progressive overload with adequate recovery; adapt tendons and bone more slowly than muscle, so increase workload gradually (roughly 10% per week is a common guide).

A fitness test such as tracking heart rate recovery after a standardized exercise (e.g., heart rate at 5 and 10 minutes post-exercise) helps assess conditioning progress.

Lameness grading uses the AAEP 0-5 scale: 0 = sound, 1 = inconsistent at trot, 2 = consistent at trot, 3 = consistent at trot and visible at walk or with weight shifting, 4 = obvious at walk, 5 = non-weight-bearing.

Common causes: navicular syndrome, suspensory desmitis, superficial digital flexor tendinitis, osteoarthritis, and hoof abscess; forelimb lameness is more common than hind.

Flexion tests (distal limb, carpal, hock) are provocative and non-specific; a positive response supports but does not confirm a diagnosis.

Diagnostic analgesia (nerve and joint blocks) localizes pain; results must be interpreted with a re-evaluation of gait after each block.

Imaging: radiography for bone, ultrasonography for soft tissue, and MRI or CT for complex or ambiguous cases.

Tendon healing passes through inflammation, proliferation, and remodeling; controlled loading during remodeling improves collagen alignment, while complete rest weakens the repair.

Rehabilitation progression: restore range of motion, then strength, then controlled exercise; monitor for heat, swelling, and increased lameness as signs of overload.

Return-to-work criteria include symmetry at trot, no heat or swelling, and progressive tolerance of increasing work without recurrence.

Manual therapy includes massage, myofascial release, joint mobilization, and stretching; it aims to improve tissue extensibility and reduce pain and muscle hypertonicity.

Cryotherapy reduces tissue temperature, blood flow, and pain; typical application is 15-20 minutes, and skin should be checked for cold injury.

Therapeutic ultrasound uses high-frequency sound waves for deep heating; it is avoided over growth plates, the eye, tumors, and areas of acute inflammation.

Electrical stimulation (TENS/NMES) targets pain gating or muscle recruitment; contraindications include pacemakers and application over the heart or gravid abdomen.

Laser therapy (photobiomodulation) doses in joules per square centimeter; protective eyewear is required, and it is avoided over neoplasia or the thyroid.

Hydrotherapy and swimming reduce weight-bearing load, useful for early rehabilitation; pool or treadmill use must be supervised and matched to the injury.

Kinesiology taping and bandaging can support proprioception and circulation; bandages must be applied with even tension to avoid pressure sores or bandage bows.

All modalities require a diagnosis, a treatment plan, and documentation of parameters, response, and any adverse effects.

Baseline assessment: signalment, history, vital parameters, body condition score, and a full physical exam before any treatment.

Lameness exam sequence: observation at rest, in-hand walk and trot, flexion tests, lunging on hard and soft surfaces, and ridden evaluation when appropriate.

Palpation findings to record: heat, swelling, effusion, pain on pressure, muscle tone, and symmetry between limbs.

SOAP note format: Subjective, Objective, Assessment, Plan; each treatment session gets its own entry with date, provider, and parameters.

Objective measures include joint range of motion (goniometry), stride length, heart rate recovery, and lameness grade; repeat measures support progress tracking.

Treatment plan components: diagnosis or working problem list, goals, modality and dose, frequency and duration, and re-evaluation dates.

Documentation must record informed consent, owner communication, adverse events, and referral decisions; records are legal and professional documents.

Reassessment criteria: change in lameness grade, tissue response, function, and owner-reported outcome; adjust the plan when goals are not met.

Approach a horse from the shoulder or neck, speak to announce presence, and stay out of the kick zone (directly behind) and the strike zone (directly in front).

Use a properly fitted halter and lead rope; never wrap the lead around the hand or body, and keep a safe distance from the handler's body.

Tie with a quick-release knot at about head height; never tie to an unsecured object or with a fixed knot the horse can panic against.

Handling aids: a stud chain over the nose or under the chin for control; a lip chain is a last resort and requires experience.

Facility checks: secure fencing and gates, non-slip flooring, adequate lighting, fire extinguishers, and clear evacuation routes.

Emergency preparedness: a written fire and evacuation plan, accessible water for firefighting, and a list of emergency contacts posted in the barn.

Personal protective equipment: helmet when riding or lunging, gloves, and sturdy boots; proper lifting technique protects the handler's back.

Horse and handler communication: use pressure and release, and keep the horse's attention; sudden movements and loud noise increase startle risk.

Scope of practice: the equine therapist works within their training and certification, and does not diagnose, prescribe, or perform surgery.

Veterinary referral and consent: obtain a veterinarian's diagnosis and clearance before treating a medical or lameness condition; work under the veterinarian's direction.

Informed consent: explain the proposed intervention, expected benefits, risks, alternatives, and costs, and document the owner's agreement.

Confidentiality: protect client and patient information and share it only with consent or as required by law.

Conflict of interest: disclose financial or personal interests that could influence recommendations; avoid endorsing products without evidence.

Continuing education and competence: maintain current knowledge and refer out when a case exceeds one's competence.

Professional boundaries: do not make medical claims beyond the evidence, and do not contradict the veterinarian's treatment plan without discussion.

Documentation ethics: record accurately and contemporaneously; never alter records retroactively or omit adverse events.