Fishes have adapted a number of different behaviors to move out of the water, but none have been described as being able to walk on land with a tetrapod-like gait. Here we show that the blind cavefish Cryptotora thamicola walks and climbs waterfalls with a salamander-like diagonal-couplets lateral sequence gait and has evolved a robust pelvic girdle that shares morphological features associated with terrestrial vertebrates. In all other fishes, the pelvic bones are suspended in a muscular sling or loosely attached to the pectoral girdle anteriorly. In contrast, the pelvic girdle of Cryptotora is a large, broad puboischiadic plate that is joined to the iliac process of a hypertrophied sacral rib; fusion of these bones in tetrapods creates an acetabulum. The vertebral column in the sacral area has large anterior and posterior zygapophyses, transverse processes, and broad neural spines, all of which are associated with terrestrial organisms. The diagonal-couplet lateral sequence gait was accomplished by rotation of the pectoral and pelvic girdles creating a standing wave of the axial body. These findings are significant because they represent the first example of behavioural and morphological adaptation in an extant fish that converges on the tetrapodal walking behaviour and morphology.
Impact of a three-dimensional “hands-on” anatomic teaching module on acetabular fracture pattern recognition by orthopaedic residents
- The Journal of bone and joint surgery. American volume
- Published almost 8 years ago
Much of the difficulty in understanding acetabular fracture patterns is due to the complex three-dimensional relationship of the acetabulum to the greater pelvis. We hypothesized that combining three-dimensional “hands-on” anatomic models with two-dimensional informational teaching sheets would improve the ability of orthopaedic residents to accurately classify acetabular fracture patterns and aid in preoperative surgical approach selection.
- European journal of obstetrics, gynecology, and reproductive biology
- Published almost 8 years ago
OBJECTIVE: It is important to understand the underlying mechanisms of the physiological framework of the pelvic organ support system to develop more effective interventions. Developing more successful interventions for restoration of defects of the pelvic floor will lead to symptomatic improvement of pelvic floor prolapse and stress incontinence disorders. The purpose of the current study was to investigate the physiological framework related to the pelvic organ support system and propose the underlying mechanisms of pelvic organ support based on the anatomical findings. STUDY DESIGN: Ten female soft embalmed cadavers were dissected after a colorectal hands-on workshop to visualize components of the pelvic organ support system. RESULTS: The puborectalis attached at the superior pubic ramus above the arcus tendineus fasciae pelvis. The anterior half of the iliococcygeus originated at the level of the arcus tendineus fasciae pelvis but descended from the arcus tendineus fasciae pelvis before it reached the ischial spine. The fibrous visceral sheath of the endopelvic fascia covered both the bladder and the upper vagina and bound these structures together. The levator ani muscle was separated into a horizontal and a vertical part at the medial attachment of the fibrous visceral sheath. A well-circumscribed adipose cushion pillow, in the ischioanal fossa and its anterior recess, supported the horizontal part of the levator ani muscle and pressed the vertical part against the pelvic viscera. Perivascular sheaths and pelvic nerve plexuses were reinforced by condensed endopelvic fascia, they suspended the pelvic organs posterolaterally. CONCLUSION: The pelvic organ support framework consists of two mechanical structures: (1) the supporting system of the levator ani muscle, the arcus tendineus fasciae pelvis and the adipose cushion pillow, and (2) the suspension system of the neurovascular structures and the associated endopelvic fascia condensation.
Developmental dysplasia of the hip (DDH) and acetabular retroversion represent distinct acetabular pathomorphologies. Both are associated with alterations in pelvic morphology. In cases where direct radiographic assessment of the acetabulum is difficult or impossible or in mixed cases of DDH and retroversion, additional indirect pelvimetric parameters would help identify the major underlying structural abnormality.
Cup positioning is an important variable for short and long term function, stability, and durability of total hip arthroplasty (THA). This novel method utilizes internal and external bony landmarks, and the transverse acetabular ligament for positioning the acetabular component. The cup is placed parallel and superior to the transverse ligament and inside the anterior wall notch of the true acetabulum, then adjusted for femoral version and pelvic tilt and obliquity based on weight bearing radiographs. In 78 consecutive THAs, the mean functional anteversion and abduction angles were 17.9°±4.7° and 41.7°±3.8°, respectively. 96% of the functional anteversion measurements and 100% of the functional abduction angles were within the safe zone. This technique is an easy, reproducible, and accurate method for functional cup placement.
The most frequent causes of chronic instability of the pubic symphysis are sports-related continual overload and traumatic symphyseal injuries. Acute injury of the pubic symphysis may be the result of external forces acting on the anterior pelvic ring or the result of internal forces, such as those arising during parturition. The postpartum form of instability following a complication-free birth is reversible and usually returns to normal within a few months through strengthening of the pelvic floor muscles. Residual instability of the pubis symphysis is on the whole a rare complication. Although established therapy options for acute symphyseal separation can be found in the literature, there are only a few case reports on chronic symphyseal instability. There are no guidelines on standardized therapy options. This review article examines the etiology, clinical findings, diagnostic techniques and management options for patients suffering from chronic symphyseal instability.
Pelvic ring injuries are associated with significant morbidity and mortality. Understanding the anatomy of the pelvic ring is essential for accurate diagnosis and treatment. A systematic approach taking into account the mechanism of injury, physical examination, and radiographic assessment is important to quickly identify unstable pelvic disruptions and associated injuries. Because the pelvis is a ring structure, isolated pubic rami fractures on plain radiographs are unusual and should warrant careful evaluation for posterior pelvic disruption with computed tomography. Hemorrhagic shock can occur in about 10% of pelvic ring injuries. Immediate recognition and treatment of this life-threatening condition is critical in emergency management. In addition to fluid resuscitation and blood transfusion, circumferential wrapping, angiographic embolization, laparotomy with pelvic packing, and external fixation can be important life-saving adjuncts in the setting of hemodynamic instability.
Sport-related pubalgia is often a diagnostic challenge in elite athletes. While scientific attention has focused on adults, there is little data on adolescents. Cadaveric and imaging studies identify a secondary ossification centre located along the anteromedial corner of pubis beneath the insertions of symphysial joint capsule and adductor longus tendon. Little is known about this apophysis and its response to chronic stress.
The Neanderthal remains from Shanidar Cave, excavated between 1951 and 1960, have played a central role in debates concerning diverse aspects of Neanderthal morphology and behavior. In 2015 and 2016, renewed excavations at the site uncovered hominin remains from the immediate area where the partial skeleton of Shanidar 5 was found in 1960. Shanidar 5 was a robust adult male estimated to have been aged over 40 years at the time of death. Comparisons of photographs from the previous and recent excavations indicate that the old and new remains were directly adjacent to one another, while the disturbed arrangement and partial crushing of the new fossils is consistent with descriptions and photographs of the older discoveries. The newly discovered bones include fragments of several vertebrae, a left hamate, part of the proximal left femur, a heavily crushed partial pelvis, and the distal half of the right tibia and fibula and associated talus and navicular. All these elements were previously missing from Shanidar 5, and morphological and metric data are consistent with the new elements belonging to this individual. A newly discovered partial left pubic symphysis indicates an age at death of 40-50 years, also consistent with the age of Shanidar 5 estimated previously. Thus, the combined evidence strongly suggests that the new finds can be attributed to Shanidar 5. Ongoing analyses of associated samples, including for sediment morphology, palynology, and dating, will therefore offer new evidence as to how this individual was deposited in the cave and permit new analyses of the skeleton itself and broader discussion of Neanderthal morphology and variation.
The shift to habitual bipedalism 4-6 million years ago in the hominin lineage created a morphologically and functionally different human pelvis compared to our closest living relatives, the chimpanzees. Evolutionary changes to the shape of the pelvis were necessary for the transition to habitual bipedalism in humans. These changes in the bony anatomy resulted in an altered role of muscle function, influencing bipedal gait. Additionally, there are normal sex-specific variations in the pelvis as well as abnormal variations in the acetabulum. During gait, the pelvis moves in the three planes to produce smooth and efficient motion. Subtle sex-specific differences in these motions may facilitate economical gait despite differences in pelvic structure. The motions of the pelvis and hip may also be altered in the presence of abnormal acetabular structure, especially with acetabular dysplasia. Anat Rec, 300:633-642, 2017. © 2017 Wiley Periodicals, Inc.