Happy International Day of Radiology!
Create a Pelvis 3D Model Using STL Files
For the better part of history, human anatomy has been taught by using human cadavers. While the practice has become much more ethical over the past century (grave-robbing is a rarity), there has been a push among the medical community to transition from human cadavers to 3D-printed anatomical models. Recently, the Anatomical Sciences Education released a report that may be of interest to those in the medical community: The Production of Anatomical Teaching Resources Using Three-Dimensional (3D) Printing Technology. This report details how 3D printing can provide the most important aspects of the prosection experience for medical students, yet without the ethical or hygienic issues often associated with using cadavers.
Since Charles W. Hull first described the concept of 3D printing back in 1986, the field has now grown to encompass nearly every aspect of society — everything from do-it-yourself toys to life-saving implants, and even a pelvis 3D model as is the case in this week's featured article. Many of these uses would likely even be somewhat of a surprise to Mr. Hull.
The embodi3D® community is helping the medical field to become less reliant on human cadavers while also creating opportunities to share 3D-printed anatomical models via STL files — something that is especially useful for medical students wishing to practice procedures in the treatment of rare conditions. Medical 3D printing offers a range of opportunities for medical students to study the bones, tissues, and muscles of the human anatomy. 3D printing also helps create understanding between physician and patient; patients are more apt to agree to a medical procedure when the condition can be seen as a lifelike 3D-printed model.
In this week's hip, spine, and pelvis-themed post, embodi3D® will share with you some of the best 3D pelvis models. Many of these are available in ready-to-print STL format. You can create your own 3D printer-ready STL files by using embodi3D® software to convert CT scans. To get started, all you have to do is register with embodi3D®. It's quick, easy, and costs absolutely nothing to join.
#1. An Anatomically Precise 3D-Printed Spine and Pelvis (Available for Free in STL Format)
Embodi3D uploaded this excellent example of the pelvis anatomy. The pelvis is a complex structure composed of an osseous ring formed by the ischia, ilii, and sacrum, with numerous muscles and fascial condensations attached for support of the pelvis viscera and to enable ambulation. Within the pelvis reside the organs of reproduction, urination, and evacuation, in addition to major blood vessels, lymphatics, and nerves.
#2. An Incredible 3D Model of an Acetabular Fracture of the Pelvis
valchanov upload an incredible 3D model showing us acetabular fracture of the pelvis.
Acute pelvic injuries can be divided into three major categories: Disruptions of the pelvic ring, fractures of the acetabulum, and isolated pelvic fractures which do not involve the acetabulum or disrupt the pelvic ring. Radiologists should be able to categorize the injury into one of these patterns based on an AP radiograph of the pelvis obtained as part of the routine trauma evaluation. Additional views, or more often today, CT scans, are used to further categorize the injury pattern and direct treatment.
Hip injuries can be divided into two major categories: Dislocations and fractures. Fractures are further subdivided into femoral head, femoral neck, intertrochanteric, subtrochanteric, or isolated trochanteric fractures. Dislocations are most commonly posterior, but may be anterior or central. Sports injuries of the pelvis can be divided into intraarticular injuries, impingement syndromes, bursitis, fatigue fractures, and muscle/tendon injuries.
The older population may present with insufficiency fractures of the pelvis, bursitis, or tendinopathy and tears of the pelvic musculature.
• Fracture involving articular surface of acetabulum.
• Anterior column: Portion of innominate bone extending from anterior superior iliac spine to pubic symphysis and inferior pubic ramus.
○ Delimited on radiographs by iliopubic (a.k.a. iliopectineal) line.
• Posterior column: Portion of innominate bone extending from posterior superior iliac spine to inferior pubic ramus.
○ Delimited on radiographs by ilioischial line.
• Anterior, posterior walls: Create cup surrounding superior portion of femoral head.
• Sciatic buttress: Bony continuity from sacroiliac junction (SIJ) to acetabulum.
○ Lost in both-column fracture, preserved in other types.
• High-energy trauma most common.
• Fall in elderly osteoporotic patient..
• 5 simple fracture types: Anterior column, posterior column, posterior wall, anterior wall, transverse
• 5 associated fracture types: Transverse with posterior wall, posterior column with posterior wall, T-shaped, both column, anterior column with posterior hemi-transverse.
#3. A Anatomical 3D-Printed Pelvis Bone (Available in STL Format)
Dr. Mike makes this 3D model of the pelvis bone showing the bony pelvis. This forms a ring which can be conceptually subdivided in several ways. In the adult, it is formed of three bones and three articulations. The sacrum articulates via the paired sacroiliac joints with the innominate bones on either side, which articulate with each other via the pubic symphysis.
The sacroiliac joints and pubic symphysis are synovial joints, but allow very limited motion. The bony pelvis can also be divided into the anterior portion of the ring, including the innominate bones from the ischial spine to the pubic symphysis, and the posterior ring, including the sacrum and
the posterior portion of the innominate bones. Alternatively, the pelvis can be divided into the false pelvis above the iliopectineal line and part of the abdominal cavity, and the true pelvis which lies between the iliopectineal line and the ischial tuberosities.
#4. A Muscle Model STL File Converted from a CT Scan
This 3D printable of the pelvis was generated from real CT scan data and is thus anatomically accurate as it comes from a real person. It shows the detailed anatomy of the muscles.
• Hip adductors
○ Pectineus, adductors brevis, longus and magnus, obturator externus, quadratus femoris.
• Hip flexors
○ Iliopsoas, rectus femoris, sartorius.
• Hip abductors
○ Gluteus medius, gluteus minimus, tensor fascia lata, sartorius, tensor fascia lata.
• Hip external rotators
○ Piriformis, gemelli, quadratus femoris, obturator internus, obturator externus
• Hip internal rotators
○ Piriformis (when hip flexed)
• Hip extensors
○ Gluteus maximus, long head biceps femoris, semimembranosus, semitendinosus.
#5. 3D-Printable Model of the Bony Pelvis (from a CT Scan)
3D printed bone anatomy facilitate pelvis education, especially in assisting structure recognition, compared with cadaveric pelvis and atlas. Other advantages over cadavers relate to ethics, cost, hygiene and repaired fragile structures.
#6. A 3D-Printable Medical File of the Bony Pelvis (Converted from a CT Scan DICOM)
Anatomic Spaces in Pelvis
• Horizontal division into true and false pelvis
• False pelvis: Iliac crest to pelvic brim
○ Part of abdominal cavity.
• True pelvis: Pelvic brim to ischial tuberosity
• Greater sciatic notch
○ Concavity along inferior border of ilium between posteroinferior margin of ilium and ischial spine .
○ Sacrospinous ligament along inferior border of notch converts notch to greater sciatic foramen.
○ Much of foramen is occupied by piriformis muscle.
○ Superior to piriformis muscle: Superior gluteal vessels and nerve.
○ Inferior to piriformis muscle: Inferior gluteal vessels, internal pudendal vessels, sciatic nerve, posterior femoral cutaneous nerve, nerve to obturator internus, nerve to quadratus femoris muscle.
• Lesser sciatic notch
○ Small notch anterior to ischial spine.
○ Sacrospinous and sacrotuberous ligaments convert notch to lesser sciatic foramen.
○ Contains obturator internus, nerve to obturator internus, internal pudendal vessels and nerve.
• Obturator ring/foramen
○ Bony ring formed from pubic body, superior and inferior pubic rami, and ischium.
○ Majority of foramen is covered by obturator membrane.
○ Superior portion of foramen not covered by obturator membrane.
– Designated obturator canal
– Obturator artery, vein, and nerve pass out of pelvis through obturator canal.
○ Obturator internus muscle arises from internal margin of obturator ring and obturator membrane.
○ Obturator externus muscle arises from external margin of obturator ring and obturator membrane.
#7. 3D Pelvis Model from 62-Year-Old Patient with OA and Fracture (from CT Scan Data)
An incredible 3D model showing degeneratives changes and fracture of the pelvis.
○ OA pathogenesis not fully understood; heterogeneous risk factors
○ Microtrauma applied to cartilage with biochemical changes of aging
– ↓ water content, ↓ proteoglycans, ↓ number of chondrocytes
□ Leads to brittle or soft cartilage, at risk for fissuring, ulceration, and delamination
– Acetabular or femoral head fracture, generally related to hip dislocation
– Abnormal weight bearing due to trauma or degenerative change in other joints
□ Limb-length discrepancy with pelvic tilt
□ Scoliosis with pelvic tilt
□ Knee arthritis with malalignment and relative limb shortening
○ Developmental abnormalities
– Legg-Calvé-Perthes (ON in childhood)
– Slipped capital femoral epiphysis
○ Abnormal morphology (developmental)
□ Acetabular dysplasia (most common)
□ Rotational malalignment of femoral neck
– Femoral acetabular impingement morphology
□ Cam type: Anterolateral femoral neck bump
□ Pincer type: Overcoverage of head by acetabulum
□ Cam and pincer types often coexist
□ Several etiologies for each of these types
○ Abnormal morphology (congenital)
– Epiphyseal abnormalities, such as spondyloepiphyseal dysplasia
○ Low levels of estrogen have been associated with ↑ risk of OA
○ Twin and familial studies suggest OA is multigenic trait
#8. Free Downloadable 3D Printing Model of the Pelvis and its relation with vascular vessels
This incredible 3d model uploaded by vishnuk shows the pelvis and its relation with vascular vessels with great detail.
#9. 3D model of the pelvis showing ureter passing down along the sides of the pelvis and get inside the bladder
This excellent example was uploaded by Siewerts showing us the urinary pelvic organs and the relations with the pelvis bones.
#10. Skin model STL file from converted CT scan
This 57 years old female pelvis shows the shape and surface of this anatomical region, also you can access to all the series including bone, muscle and ct.