Clinical pelvimetry is taught badly when students measure the outside of the pelvis and believe they have measured the birth canal, so a model that lets an instructor reveal the inside is worth more than one that only looks realistic. BIX-F22 is an adult female model with flexible joints throughout, described by the supplier as having clear anatomical landmarks for positioning, a transparent window in the lower abdomen so the intrapelvic measurement can be observed from outside, and support for both intrapelvic and extrapelvic measurement. This comparison explains the difference between the two sets of measurements, how to teach each on the model, and what the evidence allows you to claim.
| Item | Detail |
|---|---|
| Model | BIX-F22 |
| Type | Pelvic measurement model, adult female |
| Joints | Flexible throughout, to allow different positions |
| Landmarks | Described as obvious for manipulation and positioning |
| Key feature | Transparent lower-abdominal window to observe the intrapelvic measurement |
| Measurements | Intrapelvic and extrapelvic |
| Main use | Midwifery and obstetric skills teaching, clinical pelvimetry drills |
| Price | Quoted per order |
| Certification | ISO 9001, ISO 14001 and ISO 45001 (as listed) |
The four external diameters. Intercristal, interspinous, intertrochanteric and the external conjugate are the standard external measurements. They describe the bony envelope, and they are quick to teach and quick to examine.
They do not measure the inlet. This is the misconception the model should break: an external conjugate of normal length does not exclude a narrow obstetric conjugate, because the measurement passes around the sacrum rather than through the pelvis. Students who learn this on a model with a transparent window remember it.
Landmarks are the examinable part. The supplier describes the landmarks as obvious for manipulation. Use that: ask the student to find the iliac crests, the anterior superior iliac spines, the pubic tubercles and the sacral promontory by palpation before any caliper or tape appears.
Observation before correction. In a normal classroom, an instructor cannot see what a student's fingers are doing inside a manikin. The transparent window turns an invisible skill into a visible one, which shortens the feedback loop dramatically.
Position changes are teachable. Flexible joints allow the lithotomy and lateral positions to be set, so students practise the examination in the positions used in labour rather than in one fixed pose.
It supports the honest answer about evidence. Routine X-ray or CT pelvimetry is not recommended for deciding mode of delivery in cephalic presentations at term, because the evidence does not show benefit [1]. What remains valuable is the clinical assessment skill — recognising a contracted inlet or a prominent ischial spine — and that skill is what the model trains. WHO intrapartum care guidance frames assessment around the progress of labour and the individual woman rather than around a set of bony diameters [2], and later work on intrapartum care measures keeps the focus on processes that change outcomes [3].
| Criterion | Why it matters |
|---|---|
| Transparent window | Without it, intrapelvic technique cannot be observed or corrected |
| Joint mobility | Fixed models cannot teach position-dependent examination |
| Fetal head inclusion | Measurement teaching is stronger when the fetal head can be related to the diameters |
| Landmark clarity | Palpation practice depends on being able to find crests and spines reliably |
| Spare parts | Pelvic models are handled heavily; confirm replacement availability |
If a competing model lacks the window or the joints, it is a demonstration pelvis rather than a measurement trainer, and the price difference should be judged on that basis.
Documentation and quotation. Specification, accessory list and current pricing for BIX-F22 are available from adanursing@adaanatomy.com.
Q1. What does BIX-F22 allow students to practise? Intrapelvic and extrapelvic pelvic measurement on an adult female model with flexible joints and a transparent lower-abdominal window.
Q2. Why does the transparent window matter? It lets the instructor see where the examining fingers are during intrapelvic measurement, so technique can be corrected rather than assumed.
Q3. Does it include a fetal head? A fetal head is not listed in the product description; ask the supplier whether it can be supplied as an accessory.
Q4. Is clinical pelvimetry still recommended? Routine X-ray or CT pelvimetry is not supported for deciding mode of delivery at term; clinical assessment of pelvic shape and landmarks remains a taught skill.
Q5. What positions can the model be placed in? The joints are flexible throughout, so the model can be set in the positions used for examination during labour.
Q6. What is the price and minimum order? Quoted per order, depending on quantity and destination.
For a quotation on BIX-F22, including any fetal-head accessory and a measurement worksheet, write to adanursing@adaanatomy.com with your programme level and class size.