Royal College of Veterinary Surgeons Membership Exam (RCVS) Equine Medicine and Surgery Flashcards

24 sample cards from the Equine Medicine and Surgery deck

Sampled from the end of the deck, so these are different cards from the ones shown on the syllabus page.

1. What is a suspensory ligament desmitis, and how is proximal suspensory desmitis (PSD) typically blocked?

   Inflammation/injury of the suspensory ligament (interosseous muscle). Proximal suspensory desmitis affects the origin at the proximal palmar/plantar cannon. Localised by a lateral palmar/deep branch lateral plantar nerve block (or local infiltration); hindlimb PSD has a guarded prognosis.

2. What is the 'check ligament' (accessory ligament of the DDFT) and the consequence of its desmitis?

   The accessory ligament of the deep digital flexor tendon (inferior check ligament) connects palmar carpus to the DDFT. Desmitis causes localised swelling in the proximal-mid metacarpus and lameness; generally good prognosis with rest.

3. In diagnostic imaging of lameness, what modality is best for soft tissue (tendon/ligament) versus bone?

   Ultrasonography is the first-line modality for soft tissue (tendons, ligaments, joint capsules). Radiography is best for bone (fractures, osteoarthritis, OCD). MRI images both bone and soft tissue (ideal for foot pain); scintigraphy detects active bone remodelling ('hot spots').

4. What is nuclear scintigraphy (bone scan) used for in equine lameness?

   Scintigraphy uses technetium-99m-labelled bisphosphonate (Tc-99m MDP) that concentrates in areas of active bone turnover/inflammation, producing 'hot spots'. Useful for localising occult/multilimb lameness, stress fractures, and bone pathology not visible on radiographs.

5. Why is MRI considered the gold standard for investigating chronic foot pain in the horse?

   MRI images both soft tissue and bone simultaneously, revealing lesions invisible to radiographs — e.g. DDFT lesions within the hoof capsule, collateral ligament injury of the DIP joint, navicular bone oedema/marrow change, and subchondral bone injury.

6. Name three key risks of general anaesthesia in the horse compared with small animals.

   1) High mortality (~1% in healthy horses, much higher in colic) — far greater than small animals. 2) Myopathy/neuropathy from prolonged recumbency and poor perfusion (compartment pressure). 3) Hazards of recovery (fractures/injury during the violent standing phase). Also hypoventilation and V/Q mismatch/hypoxaemia in dorsal recumbency.

7. Describe a standard triple-drip (TIVA) for field/short equine anaesthesia.

   'Triple drip' = Guaifenesin (GGE, muscle relaxant) + Ketamine (dissociative anaesthetic) + an alpha-2 agonist (xylazine/detomidine), given as a constant-rate infusion after induction. Provides short-term total intravenous anaesthesia with reasonable cardiovascular stability.

8. What is the typical sedation/induction protocol for equine anaesthesia?

   Premedication/sedation with an alpha-2 agonist (xylazine, detomidine, or romifidine) +/- an opioid (butorphanol). Induction commonly with ketamine combined with a benzodiazepine (diazepam/midazolam) or guaifenesin; maintenance with inhalant (isoflurane/sevoflurane) or TIVA.

9. Why is hypoxaemia common in the anaesthetised horse in dorsal recumbency, and how is it managed?

   Large abdominal viscera compress the diaphragm causing atelectasis and ventilation-perfusion (V/Q) mismatch with right-to-left shunting. Managed with intermittent positive pressure ventilation (IPPV), high inspired oxygen, and sometimes recruitment manoeuvres or beta-2 agonists (e.g. salbutamol).

10. What is post-anaesthetic myopathy and how is it prevented?

    Muscle damage from poor perfusion/compartment pressure during prolonged recumbency, causing pain, hard swollen muscles, myoglobinuria and reluctance/inability to stand on recovery. Prevented by good padding, maintaining mean arterial pressure (>70 mmHg), avoiding hypotension and limiting anaesthesia duration.

11. What is a standing surgery in the horse, and name a procedure commonly done standing under sedation and local block.

    Standing surgery avoids general anaesthesia risks by using heavy sedation (alpha-2 +/- opioid CRI) plus local/regional anaesthesia. Examples: castration, sinus surgery/trephination, laparoscopic ovariectomy/cryptorchidectomy, dental extractions, and some fracture repairs.

12. Describe the difference between open, closed and half-closed castration techniques.

    Open: vaginal tunic incised, emasculator applied directly to vessels/ductus within an open tunic. Closed: tunic NOT opened, emasculator applied across the whole cord including tunic (reduces eventration risk). Half-closed: tunic incised distally but cord crushed/ligated with tunic intact proximally. Closed/ligated techniques reduce evisceration risk and are preferred in older/standing horses.

13. What are the two most serious complications of equine castration?

    1) Evisceration (herniation of intestine/omentum through the inguinal canal/vaginal ring) — a surgical emergency. 2) Haemorrhage from the testicular artery. Other complications: scrotal/sheath swelling, infection (septic funiculitis/'scirrhous cord'), and hydrocele.

14. What is a cryptorchid ('rig'), and why must surgical removal be confirmed?

    A cryptorchid is a horse with one or both testes not descended into the scrotum (retained abdominal or inguinal). The retained testis must be removed (often laparoscopically) because it still produces testosterone causing stallion-like behaviour; an hCG stimulation test or anti-Mullerian hormone (AMH) confirms presence of retained testicular tissue.

15. What is the average gestation length of the mare, and the typical oestrous cycle length?

    Mean gestation is approximately 340 days (range ~320-360). The oestrous cycle averages 21 days (oestrus ~5-7 days, dioestrus ~14-15 days). Mares are seasonally polyoestrous, cycling in the long days of spring/summer (long-day breeders).

16. What is the optimal time to breed a mare relative to ovulation, and why?

    Mares should be bred close to ovulation (within ~24-48 hours before, or shortly after) because equine sperm survive ~48 hours in the reproductive tract but the ovum is fertilisable for only a short period (~6-12 hours). Ovulation is monitored by transrectal ultrasound and induced with hCG or deslorelin.

17. What is a Caslick's procedure and its indication?

    A Caslick's vulvoplasty is suturing of the upper vulval lips to close the dorsal vulval cleft. Indicated for poor perineal conformation (sunken/tipped vulva) that allows pneumovagina/faecal contamination causing ascending placentitis and infertility; the vulva must be opened ('episiotomy') before foaling.

18. What is the 'red bag' (premature placental separation) emergency at foaling?

    The red velvety chorioallantois (rather than the normal translucent amnion) appears at the vulva, indicating premature separation of the placenta from the endometrium. The foal is being deprived of oxygen — the membrane must be cut immediately and the foal delivered urgently.

19. What is the normal IgG status check for a neonatal foal and the cut-off for failure of passive transfer?

    Foals are born agammaglobulinaemic and depend on colostral antibody. Serum IgG is measured at 18-24 hours; adequate transfer is IgG >8 g/L (>800 mg/dL). Failure of passive transfer (FPT) is IgG <4 g/L (<400 mg/dL); partial 4-8 g/L. Treat with plasma transfusion if low and gut closure has occurred.

20. What is the dental formula of the adult male horse?

    Adult male horse permanent dentition: $2(I\,\tfrac{3}{3}\;C\,\tfrac{1}{1}\;P\,\tfrac{3\text{-}4}{3}\;M\,\tfrac{3}{3}) = 40\text{-}42$ teeth. Mares often lack canines giving 36-40. The first premolar ('wolf tooth') is variable and often absent.

21. Why do horses develop sharp enamel points, and what routine procedure corrects them?

    Horses have hypsodont (continuously erupting) teeth and anisognathic jaws (upper arcade wider than lower), so the teeth wear unevenly leaving sharp enamel overgrowths on the buccal (cheek) edge of upper molars and lingual edge of lower molars. Corrected by routine floating/rasping (odontoplasty).

22. What is the approximate age relevance of 'Galvayne's groove' in equine ageing?

    Galvayne's groove is a longitudinal groove on the labial surface of the upper corner incisor. It appears at the gum margin around 10 years, reaches halfway down by ~15 years, extends the full length by ~20 years, and recedes from the top by ~25-30 years — used as a rough age guide.

23. What is an EOTRH (Equine Odontoclastic Tooth Resorption and Hypercementosis) and its typical signalment?

    A painful progressive disease of older horses (>15 years) affecting incisors and canines, with resorption of tooth substance and bulbous hypercementosis, gingival recession and bulb-like swellings. Causes pain on biting; definitive treatment is extraction of affected teeth.

24. What core vaccinations and routine preventive care are recommended for horses in the UK?

    Core vaccines: tetanus (toxoid) and equine influenza (often a combined 'flu/tet'); EHV-1/4 for at-risk/pregnant mares. Routine care: targeted strategic anthelmintic worming based on faecal egg counts, annual dental checks, and regular farriery (every 6-8 weeks).

What this deck covers

Equine Medicine and Surgery flashcards FAQ