Complete Guide to Vaginal Speculums: Cusco vs Graves vs Sims

In 1845, working on a makeshift table with a bent pewter spoon, James Marion Sims fashioned the first practical instrument for opening and inspecting the vaginal canal. That improvised spoon became the duck-bill Sims speculum, and it changed gynecology overnight. A generation earlier, the French physician Joseph Récamier had already revived the bivalve principle from antiquity, and by the mid-1800s the Parisian instrument maker Édouard-Gabriel Cusco had refined a hinged, self-retaining design that still carries his name. Add T.W. Graves’ later refinement to that lineage, and you have the three instruments that sit in nearly every gynecology tray today.

At Fizza Surgical, we forge all three. The questions clinicians and distributors send us are almost always the same: which type for which procedure, what blade length, what steel, and how it holds up to repeat autoclaving. This guide answers those questions the way our engineering and finishing teams answer them on the shop floor.

The Three Families of Vaginal Speculum

Despite dozens of named patterns, every vaginal speculum descends from one of three working principles.

The bivalve self-retaining group covers the Cusco, Graves, and Pederson. Two hinged blades open like a duck-bill and lock in place, freeing both of the examiner’s hands. This is the workhorse for routine pelvic exams, Pap smears, IUD insertion, and colposcopy.

The single-blade retractor group is the Sims. It is not self-retaining. One blade retracts a single vaginal wall while an assistant, a weight, or a second instrument handles the rest. It dominates the operating theatre.

The weighted group, exemplified by the Auvard, is a Sims-type posterior blade with a heavy ball or fluid-channel weight that holds itself open against the perineum under gravity. It earns its place in vaginal surgery where an assistant’s hands are scarce.

Understand those three principles and the rest is sizing and finish.

The Cusco Bivalve: The Self-Retaining Standard

The Cusco is what most people picture when they hear “speculum.” Two blades hinge at a central pivot. A spring-loaded thumb lever opens the anterior blade, and a thumbscrew lock threaded along the upper handle fixes the gap so the instrument stays open without a hand on it. Loosen the screw and the spring closes the blades for withdrawal.

That thumbscrew is the detail that separates a good Cusco from a frustrating one. The thread must run smoothly under wet, gloved fingers and hold position without creep once set. We machine ours from a single billet so the screw seat does not loosen across hundreds of sterilization cycles. Some patterns substitute a notched ratchet bar for the screw; the screw lock gives finer, infinitely variable control of the opening, which clinicians tend to prefer for IUD work and colposcopy where a precise window matters.

Cusco blade lengths run roughly 75 to 115 mm. The four sizes we supply most often:

• Virgin / extra-small — about 75 mm long, 17 mm wide, for the narrowest canal.
• Small — about 76 mm long, 32 mm wide.
• Medium — about 86 mm long, 35 mm wide, the default adult size.
• Large — about 102 mm long, 35 mm wide, for the parous or deeper vaginal vault.

The standard reference Cusco is often quoted at roughly 80 mm long and 22 mm broad, but in practice the four-size range above is what a stocked clinic actually needs. Blade tips are rounded and the leading edges deburred so insertion is atraumatic; a rough edge anywhere on the blade is a finishing defect, not a design feature.

The bivalve’s strength is that it visualizes the cervix while holding both walls apart. Its limitation is the same anatomy: the blades cover most of the vaginal wall, so a small lateral lesion can hide behind a blade. When wall inspection matters, clinicians reach for a Sims.

Graves vs Pederson: Choosing the Right Bivalve

Within the bivalve family, the two patterns that matter clinically are the Graves and the Pederson. They share the same hinge, spring, and thumbscrew lock. The difference is entirely in the blades.

The Graves has wider, often slightly longer blades with a pronounced curve. That width seats well in the parous vagina and the post-hysterectomy vault, where the walls are lax and a narrow blade would let them collapse inward. The wider opening also gives a generous working window for cervical sampling and IUD work. The Graves is the default adult pattern in most clinics.

The Pederson runs narrow and flat, with blades of similar length but markedly less width. It is the instrument of choice for nulliparous and adolescent patients, for postmenopausal women with vaginal atrophy, and for anyone where the wider Graves causes discomfort or simply will not pass. A correctly chosen Pederson is the single biggest comfort improvement an examiner can offer.

A practical rule from our customers: stock Graves in medium and large, Pederson in small and medium, and a virgin-size bivalve for the exceptional case. That covers the overwhelming majority of clinic encounters. For a deeper look at the bivalve in routine practice, see our guide to the Cusco vaginal speculum in gynecological exams.

The Sims Speculum: The Surgeon’s Retractor

The Sims is a different animal. It is a single curved blade — or two blades of different sizes on a double-ended shaft — shaped like an elongated S. It does not lock open and it is not self-retaining. The examiner or an assistant holds it.

What it gives up in convenience it returns in access. Inserted to retract the posterior wall, the Sims exposes far more of the vaginal walls and the cervix than any bivalve, and it can be slid and rotated to inspect each quadrant in turn. A shallow groove along the blade channels blood and secretions away from the field, keeping the area dry during a procedure. That is why the Sims, not the Cusco, lives in the gynecological surgery tray.

Two configurations are standard:

• Single-ended Sims — one working blade with a flat handle, common sizes roughly 64 mm (small), 76 mm (medium), and larger, with blade widths around 27 to 35 mm.
• Double-ended Sims — a small blade on one end and a large blade on the other, so one instrument covers two anatomies. Efficient for clinics that want fewer SKUs on the tray.

The Sims pairs naturally with an anterior vaginal wall retractor and, in the operating room, with a weighted Auvard speculum. The Auvard is essentially a Sims posterior blade carrying a heavy weight; placed in the posterior fornix, it holds itself down by gravity and retracts the perineum without an assistant, freeing the surgical team’s hands for examinations under anaesthesia, dilatation and curettage, colporrhaphy, and vaginal hysterectomy. For more on Sims selection and care, see our dedicated page on Sims speculum uses, sizes, and sterilization.

Specifications and Selection at a Glance

The table below is the quick-reference our own sales engineers use when matching an instrument to a procedure.

Read it from the right-hand column inward: start with the procedure, and the design follows.

Materials, Finish, and Why They Matter

A reusable speculum is only as good as the steel under the polish. We forge our reusable specula from austenitic stainless — AISI 304 for general patterns and AISI 316 where added molybdenum buys extra corrosion resistance against repeated steam and chemical exposure. Both grades fall within the alloy chemistry specified by ISO 7153-1, the international standard for the metallic materials used in surgical instruments. Fizza Surgical manufactures under an ISO 13485 quality system and supplies CE marked product.

Steel grade alone does not make a durable instrument. Two finishing steps decide service life:

• Passivation — a controlled acid treatment that strengthens the chromium-oxide layer so the surface resists pitting and crevice corrosion at the hinge and screw seat, exactly where moisture collects.
• Surface finish — a bright mirror polish sheds water and biological debris and is easiest to clean, while a satin or matte finish cuts glare under bright theatre lamps. We supply both; the choice is the clinician’s preference, not a quality difference.

Disposable single-use specula exist and have their place in high-throughput screening and infection-sensitive settings; they are typically moulded polymer or light-gauge steel. They trade the lifetime economy and rigidity of a forged reusable instrument for the convenience of no reprocessing. We make reusable instruments to last; where a customer needs single-use, we are clear about the trade-off rather than blurring it.

Common Sizing and Selection Mistakes

Most of the complaints we field from clinics are not about the instrument at all. They are about the wrong instrument being reached for. Four mistakes account for nearly all of them.

Defaulting to a medium Graves for every patient. A medium Graves is a sensible average, but an average fits no one perfectly. Used on a nulliparous or postmenopausal patient it causes pain and a guarded, uncooperative exam; used on a deep parous vault it lets the lateral walls collapse over the cervix. Stocking a Pederson alongside the Graves solves both at trivial cost.

Confusing blade length with blade width. Length determines how far the speculum reaches toward the cervix; width determines how far the walls are held apart. A short, wide blade and a long, narrow blade are completely different tools. A patient with a posterior or deep cervix needs length, not width — reaching for a wider blade only adds discomfort without improving the view.

Over-tightening the thumbscrew. The lock is there to hold a set position, not to force the canal wider than it wants to open. Cranking the screw past the point of comfortable opening is the single most common cause of examination pain and, over time, of stripped screw threads on the instrument itself. Open to the view you need and stop.

Treating a stained blade as a cosmetic issue. Brown or blue staining at the hinge is the early warning of pitting corrosion, usually from biological soil baked on during autoclaving or from chloride residue left after a poor rinse. Caught early it polishes out; ignored, it becomes a pit that harbours soil and fails decontamination. A stained speculum is a maintenance signal, not a blemish to overlook.

None of these require a bigger budget. They require the right four or five sizes on the shelf and a moment’s thought before the instrument is opened.

Sterilization and Care

Reusable specula are designed for steam sterilization. The standard cycle is a 134°C autoclave at appropriate pressure and hold time, and 304/316 stainless tolerates it cycle after cycle when the instrument is cleaned and dried properly first.

The failure points are never the blade. They are the hinge and the thumbscrew. Practical care:

• Open the blades fully before cleaning so the hinge and thread are exposed to detergent and rinse water.
• Remove all biological soil before autoclaving — baked-on protein under steam is what starts staining and corrosion.
• Dry thoroughly, especially around the screw seat, before storage.
• Lubricate the hinge periodically with an instrument-grade, steam-permeable lubricant.
• Inspect the thumbscrew for smooth travel; a screw that creeps under load is a sign the instrument needs servicing or retirement.

Treated this way, a forged stainless Cusco or Sims will outlast many of the disposables it replaces, several times over.

Matching Instrument to Patient and Procedure

Pulling it together, the selection logic our engineering team recommends is short.

For a routine examination or screening, reach for a bivalve. Graves medium for the average parous patient, Pederson for the nulliparous, adolescent, postmenopausal, or anxious patient, and a virgin-size bivalve for the narrowest anatomy. The self-retaining lock keeps both hands free for sampling.

For vaginal wall inspection or any procedure needing wide exposure, choose a Sims and pair it with an anterior wall retractor. The single blade sweeps the field a bivalve would hide.

For vaginal surgery, the weighted Auvard does the posterior retraction by gravity while the team works. Size the blade to the depth of the vault.

And whatever the pattern, size to the patient, not to the tray. The right size chosen first is the difference between a comfortable exam and a difficult one. To browse our full range of forged stainless gynecology and general surgical instruments, visit our surgical instruments catalogue.