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Foot & Ankle International May 2019Despite evidence that instability of the first ray (first metatarsal and medial cuneiform) alters the loading mechanics of the foot, surprisingly few studies have linked... (Review)
Review
Despite evidence that instability of the first ray (first metatarsal and medial cuneiform) alters the loading mechanics of the foot, surprisingly few studies have linked the condition with disorders of the foot. A factor limiting this research is the difficulty associated with measuring first ray mobility (FRM). To quantify dorsal FRM, clinicians and researchers have devised a variety of methods that impose a dorsally directed load, and record displacement. The methods include manual examination, radiographs, mechanical devices, and handheld rulers. Since different methods yield different results; each of these methods is worthy of scrutiny. This article reviews the methods used to quantify dorsal FRM and offers commentary on how the testing procedures could be standardized. The measurement of dorsal FRM informs surgical decisions, orthotic prescriptions, and research design strategies mostly as it pertains to the identification and treatment of first ray hypermobility. This review found sufficient support to recommend continued use of radiographs and mechanical devices for quantifying dorsal displacement, whereas measurements acquired with handheld rulers are prone to the same subjective error attributed to manual examination procedures. Since measures made with radiographs and existing mechanical devices have their own drawbacks, the commentary recommends ideas for standardizing the testing procedure and calls for the development of a next-generation device to measure dorsal FRM. This future device could be modeled after arthrometers that exist and are used to quantify stability at the knee and ankle. Level of Evidence: Level V, expert opinion.
Topics: Equipment Design; Humans; Joint Instability; Metatarsophalangeal Joint; Orthopedic Equipment; Radiography; Range of Motion, Articular; Tarsal Bones; Tarsal Joints
PubMed: 30902026
DOI: 10.1177/1071100719839692 -
Handbook of Clinical Neurology 2015The language-relevant brain regions, Brodmann's area in the inferior frontal cortex and Wernicke's area in the superior temporal cortex, are connected via long-range... (Review)
Review
The language-relevant brain regions, Brodmann's area in the inferior frontal cortex and Wernicke's area in the superior temporal cortex, are connected via long-range fiber bundles, which are located dorsally and ventrally to the sylvian fissure. These dorsal and ventral pathways consist of a number of partly parallel-running fiber tracts, which can be differentiated by their termination regions and by the particular language functions of these termination regions. Dorsally, there are two major fiber tracts connecting the posterior temporal cortex with the frontal cortex: one terminating in the premotor cortex that subserves sensory-to-motor mapping and one terminating in posterior Broca's area, the pars opercularis, that supports the processing of complex syntactic structures. Ventrally, two language-related fiber tracts are discussed: one connects the inferior frontal cortex, i.e., the pars triangularis and orbitalis, with Wernicke's area and supports semantic processes and another one connects the most ventral portions of the inferior frontal cortex, including the frontal operculum, with the anterior temporal cortex. This latter ventral tract is suggested to subserve elementary combinatorial processes in language. Together these fiber tracts guarantee the transmission of information between different brain regions within the neural language network.
Topics: Brain Mapping; Humans; Language; Neural Pathways; Speech; White Matter
PubMed: 25726269
DOI: 10.1016/B978-0-444-62630-1.00010-X -
Journal of Wrist Surgery Mar 2016Background Treating chronic scapholunate ligament injuries without the presence of arthritis remains an unsolved clinical problem facing wrist surgeons. This article...
Background Treating chronic scapholunate ligament injuries without the presence of arthritis remains an unsolved clinical problem facing wrist surgeons. This article highlights a technique for reconstructing the scapholunate ligament using novel fixation, the ScaphoLunate Axis Method (SLAM). Materials and Methods In a preliminary review of the early experience of this technique, 13 patients were evaluated following scapholunate ligament reconstruction utilizing the SLAM technique. Description of Techinque The scapholunate interval is reconstructed utilizing a palmaris longus autograft passed between the scaphoid and lunate along the axis of rotation in the sagittal plane. It is secured in the lunate using a graft anchor and in the scaphoid utilizing an interference screw. The remaining graft is passed dorsally to reconstruct the dorsal scapholunate ligament. Results At an average follow-up of 11 months, the mean postoperative scapholunate gap was 2.1 mm. The mean postoperative scapholunate angle was 59 degrees. The mean postoperative wrist flexion and extension was 45 and 56 degrees, respectively. The mean grip strength was 24.9 kg, or 62% of the contralateral side. The mean pain score (VAS) was 1.7. There was 1 failure with recurrence of the pathologic scapholunate gap and the onset of pain. Conclusion While chronic scapholunate ligament instability remains an unsolved problem facing wrist surgeons, newer techniques are directed toward restoring the normal relationships of the scaphoid and lunate in both the coronal and sagittal planes. The SLAM technique has demonstrated promise in preliminary clinical studies.
PubMed: 26855838
DOI: 10.1055/s-0035-1570744 -
JBJS Essential Surgical Techniques 2023The all-dorsal scapholunate reconstruction technique is indicated for the treatment of scapholunate injuries in cases in which the carpus is reducible and there is no...
BACKGROUND
The all-dorsal scapholunate reconstruction technique is indicated for the treatment of scapholunate injuries in cases in which the carpus is reducible and there is no arthrosis present. The goal of this procedure is to reconstruct the torn dorsal portion of the scapholunate ligament in order to stabilize the scaphoid and lunate.
DESCRIPTION
A standard dorsal approach to the wrist, extending from the third metacarpal distally to the distal radioulnar joint, is utilized. The extensor pollicis longus is transposed and retracted radially, and the second and fourth extensor compartments are retracted ulnarly. A Berger ligament-sparing capsulotomy is utilized to visualize the carpus. Volarly, an extended open carpal tunnel release is also utilized to relieve any median nerve compression and to aid in reduction. The contents of the carpal tunnel can be retracted radially, allowing for visualization of the carpal bones. Joystick pins are placed in order to reduce the scaphoid and lunate. Reduction is held provisionally by clamping the pins until 4 pins can be placed across the carpal bones. For scapholunate reconstruction, 3 holes are made: in the lunate, proximal scaphoid, and distal scaphoid. Suture tape is then utilized to hold the scaphoid and lunate in their proper position. The dorsal wrist capsule and extensor retinaculum are repaired during closure. The pins are cut near the skin and are removed in 8 to 12 weeks.
ALTERNATIVES
Several other methods of scapholunate reconstruction have been described, including capsulodesis, tenodesis, and bone-tissue-bone repairs. Additionally, in patients who are poor candidates for scapholunate reconstruction, wrist-salvage procedures can be utilized as the primary treatment.
RATIONALE
Scapholunate reconstruction has the advantage of preserving the native physiologic motion of the wrist, in contrast to the many different wrist-salvage procedures that include arthrodesis or arthroplasty. Avoiding arthrodesis is specifically advantageous in patients who have not yet developed arthrosis of the wrist bones.
EXPECTED OUTCOMES
Outcomes of scapholunate reconstruction vary widely; however, there is a nearly universal decrease in range of motion and strength of the wrist. Wrist range of motion is typically 55% to 75% of the contralateral side, and grip strength is typically approximately 65% of the contralateral side. In a prior study, 50% to 60% of patients whose work involved physical labor were able to return to their same level of full-time work. Disabilities of the Arm, Shoulder and Hand scores average between 24 and 30. Specific patients at risk for inferior outcomes are those with delayed surgical treatment, poor carpal alignment following reduction, or open injuries.
IMPORTANT TIPS
Patients are counseled preoperatively regarding the likelihood of permanent wrist stiffness and the possibility of scapholunate diastasis even in the setting of technically successful repair.Traction and dorsally directed pressure on the lunate through an extended carpal tunnel incision can aid in reduction of the lunate.The joystick pin position in the dorsal scaphoid is angulated from distal to proximal and that in the lunate is angulated from proximal to distal in order to help correct flexion of the scaphoid and extension of the lunate by clamping together the Kirschner wires. Modifying the distance of the clamp from the carpus can allow precision in the degree of scapholunate angle fixation.Intercarpal Kirschner wire fixation of the scapholunate, lunotriquetral, and midcarpal joints (scaphocapitate and triquetrohamate) is best performed with 0.062-in (1.6-mm) Kirschner wires. The insertion angle is best visualized when the Kirschner wire is introduced from inside the incision through the skin, "inside out," in order to best envision the trajectory on the dorsal carpus and define the starting point on the bone. The Kirschner wire is then advanced through the carpus from outside-in at a slightly more volarly translated (but not angulated) position. The Kirschner wires are then cut beneath the skin at a depth that will allow them to be retrieved but will not cause them to become exposed once swelling decreases.The wrist is generally immobilized until the pins are removed at 3 months postoperatively.
ACRONYMS AND ABBREVIATIONS
ROM = range of motionK-wire = Kirschner wireDASH = Disabilities of the Arm, Shoulder and HandDISI = dorsal intercarpal ligament instability.
PubMed: 38357468
DOI: 10.2106/JBJS.ST.23.00031 -
Journal of Morphology Jun 2022The classic view of the vertebrate dorsal root ganglion is that it arises from trunk neural crest cells that migrate to positions lateral to the spinal cord, sending...
The classic view of the vertebrate dorsal root ganglion is that it arises from trunk neural crest cells that migrate to positions lateral to the spinal cord, sending axons dorsally into the spinal cord and dendrites ventrally to meet with motor axons in the ventral root to form spinal nerves. As a result, the ganglion ends up lying in the dorsal root of the spinal nerve. Serial histological sections of parts of the trunk of juveniles of different snake species revealed that the ganglia lie distal to the junction of dorsal and ventral roots of spinal nerves and outside the neural canal. The anatomical position of spinal ganglia in snakes suggests that regulation of trunk neural crest migration in snakes differs from that in the model endotherms in which it has been most thoroughly explored. Dorsal roots have no distinct rootlets and the span of root entry to the spinal cord is short compared to that of ventral rootlets in the same segment. Comparing early developmental stages to juvenile spinal cords shows an increased separation of spinal nerve root sites and ventral migration of the ganglion in later development. Dorsal rami of the spinal nerves leave directly from the dorsal edge of the ganglion, and the ventral ramus leaves from the ventral tip of the ganglion. How these features relate to the developmental regulation of ganglion form and position and the extraordinary locomotor capabilities of the snake trunk are unclear.
Topics: Animals; Ganglia, Spinal; Neural Crest; Snakes; Spinal Cord; Spinal Nerve Roots
PubMed: 35510680
DOI: 10.1002/jmor.21481 -
Current Biology : CB Nov 2023The elephant trunk operates as a muscular hydrostat and is actuated by the most complex musculature known in animals. Because the number of trunk muscles is unclear, we...
The elephant trunk operates as a muscular hydrostat and is actuated by the most complex musculature known in animals. Because the number of trunk muscles is unclear, we performed dense reconstructions of trunk muscle fascicles, elementary muscle units, from microCT scans of an Asian baby elephant trunk. Muscle architecture changes markedly across the trunk. Trunk tip and finger consist of about 8,000 extraordinarily filigree fascicles. The dexterous finger consists exclusively of microscopic radial fascicles pointing to a role of muscle miniaturization in elephant dexterity. Radial fascicles also predominate (at 82% volume) the remainder of the trunk tip, and we wonder if radial muscle fascicles are of particular significance for fine motor control of the dexterous trunk tip. By volume, trunk-shaft muscles comprise one-third of the numerous, small radial muscle fascicles; two-thirds of the three subtypes of large longitudinal fascicles (dorsal longitudinals, ventral outer obliques, and ventral inner obliques); and a small fraction of transversal fascicles. Shaft musculature is laterally, but not radially, symmetric. A predominance of dorsal over ventral radial muscles and of ventral over dorsal longitudinal muscles may result in a larger ability of the shaft to extend dorsally than ventrally and to bend inward rather than outward. There are around 90,000 trunk muscle fascicles. While primate hand control is based on fine control of contraction by the convergence of many motor neurons on a small set of relatively large muscles, evolution of elephant grasping has led to thousands of microscopic fascicles, which probably outnumber facial motor neurons.
Topics: Animals; Elephants; Muscle, Skeletal; Motor Neurons
PubMed: 37757829
DOI: 10.1016/j.cub.2023.09.007 -
Veterinary Surgery : VS Feb 2023To investigate the feasibility and describe the clinical experience of performing laryngeal tie-forward (LTF) in standing horses unaffected (experimental) and affected...
OBJECTIVES
To investigate the feasibility and describe the clinical experience of performing laryngeal tie-forward (LTF) in standing horses unaffected (experimental) and affected (clinical) by intermittent dorsal displacement of the soft palate (iDDSP).
STUDY DESIGN
Experimental study and case series.
ANIMALS
Five normal experimental controls and five client owned horses affected by iDDSP.
METHODS
Standing LTF was performed and evaluated in five experimental horses and five clinical cases diagnosed with iDDSP. Standing LTF was performed under endoscopic guidance with horses sedated and the surgical site desensitized with local anesthetic solution. Short term outcome was assessed using radiography, resting and (in clinical cases) dynamic upper respiratory tract (URT) endoscopy.
RESULTS
Standing LTF was well tolerated and completed in all horses. Radiographic assessment demonstrated that compared to preoperatively, the basihyoid bone and thyrohyoid-thyroid articulation were positioned dorsally (9.6 mm, p = .006 and 20.4 mm, p = .007, respectively) at 2 days postoperatively. During repeat dynamic URT endoscopy at 48 hours postoperatively, 3/5 horses showed resolution of iDDSP and 2/5 marked improvement. One horse experienced brief iDDSP associated with neck flexion which corrected after swallowing. The second achieved a greater speed and total distance prior to iDDSP.
CONCLUSIONS
Standing LTF did not incur any major peri- or postoperative complications. The laryngohyoid apparatus was repositioned dorsally and in a small case series had a similar surgical effect on laryngeal position.
CLINICAL SIGNIFICANCE
Standing LTF is feasible, mitigates the risk of general anesthesia related complications and reduces cost.
Topics: Horses; Animals; Larynx; Palate, Soft; Endoscopy; Nose; Radiography; Horse Diseases
PubMed: 36448601
DOI: 10.1111/vsu.13920 -
Movement Disorders : Official Journal... Feb 2021The aim of this study is to identify anatomical regions related to stimulation-induced dyskinesia (SID) after pallidal deep brain stimulation (DBS) in Parkinson's...
OBJECTIVES
The aim of this study is to identify anatomical regions related to stimulation-induced dyskinesia (SID) after pallidal deep brain stimulation (DBS) in Parkinson's disease (PD) patients and to analyze connectivity associated with SID.
METHODS
This retrospective study analyzed the clinical and imaging data of PD patients who experienced SID during the monopolar review after pallidal DBS. We analyzed structural and functional connectivity using normative connectivity data with the volume of tissue activated (VTA) modeling. Each contact was assigned to either that producing SID (SID VTA) or that without SID (non-SID VTA). Structural and functional connectivity was compared between SID and non-SID VTAs. "Optimized VTAs" were also estimated using the DBS settings at 6 months after implantation.
RESULTS
Of the 68 consecutive PD patients who underwent pallidal implantation, 20 patients (29%) experienced SID. SID VTAs were located more dorsally and anteriorly compared with non-SID and optimized VTAs and were primarily in the dorsal globus pallidus internus (GPi) and dorsal globus pallidus externus (GPe). SID VTAs showed significantly higher structural connectivity than non-SID VTAs to the associative cortex and supplementary motor area/premotor cortex (P < 0.0001). Simultaneously, non-SID VTAs showed greater connectivity to the primary sensory cortex, cerebellum, subthalamic nucleus, and motor thalamus (all P < 0.0004). Functional connectivity analysis showed significant differences between SID and non-SID VTAs in multiple regions, including the primary motor, premotor, and prefrontal cortices and cerebellum.
CONCLUSION
SID VTAs were primarily in the dorsal GPi/GPe. The connectivity difference between the motor-related cortices and subcortical regions may explain the presence and absence of SID. © 2020 International Parkinson and Movement Disorder Society.
Topics: Deep Brain Stimulation; Dyskinesias; Globus Pallidus; Humans; Parkinson Disease; Retrospective Studies
PubMed: 33002233
DOI: 10.1002/mds.28324 -
Biology Open Sep 2021The tracheal basal cells (BCs) function as stem cells to maintain the epithelium in steady state and repair it after injury. The airway is surrounded by cartilage...
The tracheal basal cells (BCs) function as stem cells to maintain the epithelium in steady state and repair it after injury. The airway is surrounded by cartilage ventrolaterally and smooth muscle dorsally. Lineage tracing using Krt5-CreER shows dorsal BCs produce more, larger, clones than ventral BCs. Large clones were found between cartilage and smooth muscle where subpopulation of dorsal BCs exists. Three-dimensional organoid culture of BCs demonstrated that dorsal BCs show higher colony forming efficacy to ventral BCs. Gene ontology analysis revealed that genes expressed in dorsal BCs are enriched in wound healing while ventral BCs are enriched in response to external stimulus and immune response. Significantly, ventral BCs express Myostatin, which inhibits the growth of smooth muscle cells, and HGF, which facilitates cartilage repair. The results support the hypothesis that BCs from the dorso-ventral airways have intrinsic molecular and behavioural differences relevant to their in vivo function.
Topics: Cell Differentiation; Epithelial Cells; Gene Ontology; Genetic Heterogeneity; Humans; Stem Cells; Trachea
PubMed: 34396394
DOI: 10.1242/bio.058676 -
Cells Nov 2021The heart, also referred to as the dorsal vessel, pumps the insect blood, the hemolymph. The bilateral heart primordia develop from the most dorsally located mesodermal... (Review)
Review
The heart, also referred to as the dorsal vessel, pumps the insect blood, the hemolymph. The bilateral heart primordia develop from the most dorsally located mesodermal cells, migrate coordinately, and fuse to form the cardiac tube. Though much simpler, the fruit fly heart displays several developmental and functional similarities to the vertebrate heart and, as we discuss here, represents an attractive model system for dissecting mechanisms of cardiac aging and heart failure and identifying genes causing congenital heart diseases. Fast imaging technologies allow for the characterization of heartbeat parameters in the adult fly and there is growing evidence that cardiac dysfunction in human diseases could be reproduced and analyzed in , as discussed here for heart defects associated with the myotonic dystrophy type 1. Overall, the power of genetics and unsuspected conservation of genes and pathways puts at the heart of fundamental and applied cardiac research.
Topics: Aging; Animals; Disease Models, Animal; Drosophila; Gene Expression Regulation, Developmental; Heart; Heart Diseases; Humans
PubMed: 34831301
DOI: 10.3390/cells10113078