Figure 1 - uploaded by Ashraf Youssef Nasr
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Photographs of human cadaveric specimens showing in Panel a a closed dural sac within the spinal canal after resection of the vertebral laminae with the spinal nerves originating from its sides. Its termination (DST) is seen at the level of middle third of second sacral vertebra (S2M). In Panel b the opened dural sac shows the method of measuring the linear distance (line A) between the caudal termination of conus medullaris (CMT) and dural sac (DST). The dural sac contains the cauda equina and filum terminale. In Panel c the sagittal section at the lumbosacral area shows the position of dural sac within the vertebral canal, the method of measuring the linear distance (line B) between the vertebral level of sacral hiatus apex (SHA) and DST (DST-SHA), the linear distance between SHA and the coccyx (SCM-L) that represents the length of sacrococcygeal membrane (SCM) and the method of division of the vertebra into three thirds and the following disc into a consequence manner (1, 2, 3, 4). In Panel d the sagittal section of lumbosacral area shows the linear distance between DST and SHA (line B) and the linear distance between SHA and coccyx (line C) that represent the length of SCM; L5 — fifth lumbar vertebra; S1 — first sacral vertebra; SH — sacral hiatus.
Source publication
Background: Anatomical orientation of the caudal space and termination level of conus medullaris (CMT) and dural sac (DST) has great significance for anaesthetists and neurosurgeons. This study aimed to explore the anatomical landmarks important to perform save spinal anaesthesia, lumber puncture and caudal analgesia through the correlation between...
Context in source publication
Context 1
... of the dural sac was done throughout the exposed part. The dural sac was also traced down to its termination. The vertebral levels of CMT, DST and SHA were determined. The linear distance between the vertebral level of CMT, DST and SHA as well as the length and thickness of SCM were measured by using a digital Vernier calliper (0.01 mm accuracy) (Fig. ...
Citations
... Studies have focused on determining the vertebral level and variations in the conus medullaris and dural sac position to enhance clinical relevance and procedural safety [18,19]. While the anatomy, extent and variations of some species' conus medullaris and dural sacs, such as those of cats [20] and dogs [18, 21,22], are well documented, information speci c to sheep is limited. ...
This study aimed to provide information about the conus medullaris (CM) and dural sac (DS) termination points in sheep. Thirteen adult Merino-mixed sheep were anaesthetised and underwent lumbosacral computed tomography (CT) myelography. A spinal injection was administered using a Tuohy needle while the sheep were in sternal recumbency. After confirming the presence of cerebrospinal fluid, 0.4 ml kg-1 iodinated contrast media was injected, and a CT scan was conducted. The analysis focused on determining the vertebrae at which the CM and DS ended. The results showed that in eight cases, the conus ended at the first sacral vertebra, while in five sheep, the termination point was identified at the level of the second sacral vertebra. DS termination occurred in the 3rd sacral vertebra in one animal, the 4th sacral vertebra in another sheep, the 1st caudal vertebra in six cases, and the 2nd caudal vertebra in five cases. The findings highlight the need for caution during lumbosacral injections in sheep, as the CM concludes caudally to this space. It is also essential to be aware that the DS persists caudal to the sacrococcygeal space for safe epidural injections in this region.
... This point was defined considering twelve in-vivo magnetic resonance imaging studies that reported the occurrence count of the termination level in relation to the upper, middle, or lower third of the respective vertebral body or to the respective intervertebral disc (bins), with a total of 4797 subjects (Demiryürek et al., 2002;Karabulut et al., 2016;Kim et al., 2003;Kwon et al., 2016;Liu et al., 2017;Moon et al., 2019;Moussallem et al., 2014;Nasr, 2016;Preeti and Chaturvedi, 2016;Rostamzadeh et al., 2015;Saifuddin et al., 1998;Sevinc et al., 2006). We constructed a distribution of occurrence counts from the data set of each study by normalizing the occurrence counts per bin to the total number of counts. ...
Epidural electrical stimulation of the spinal cord is an emergent strategy for the neurological recovery of lower-extremity motor function. Motoneuron pools are thought to be recruited by stimulation of posterior roots. Here, we linked electromyographic data of epidurally evoked lower-extremity responses of 34 individuals with upper motoneuron disorders to a population model of the spinal cord constructed using anatomical parameters of thousands of individuals. We identified a relationship between segmental stimulation sites and activated spinal cord segments, which made spinal motor mapping from epidural space possible despite the complex anatomical interface imposed by the posterior roots. Our statistical approach provided evidence for low-threshold sites of posterior roots and effects of monopolar and bipolar stimulation previously predicted by computer modeling and allowed us to test the impact of different upper motoneuron disorders on the evoked responses. Finally, we revealed a statistical association between intraoperative and postoperative mapping of the spinal cord.
... Las explicaciones propuestas indican que en el género femenino los cuerpos vertebrales disminuyen en altura con la edad y, por otra parte, en los estudios de autopsia, cambios como el rigor mortis pueden modificar la altura de CM. Al comparar el presente estudio con ocho de los reportes más recientes 3,16,19,[20][21][22][23][24] del 2009 al 2017 (Tabla 2), llama la atención que cinco de ellos son de Medio Oriente, y tres orientales (India y Corea); en todos ellos, incluyendo el presente, la localización del CM presenta una curva de distribución normal, con variación entre el 1/3 superior de T12 al espacio intervertebral L2-L3. En cuanto al sitio más frecuente de localización de CM, se observa variación según el estudio consultado, desde el tercio superior de L1 (un reporte), tercio medio de L1 (tres reportes); tercio inferior de L1 (tres reportes) y espacio intervertebral L1-L2 (dos reportes), específicamente en mujeres; en el presente estudio, la localización más frecuente del CM fue la mitad inferior de L1, siguiéndole el espacio L1-L2, concordando con siete de los estudios confrontados. ...
Introducción:
Existen varios estudios tanto de imagenología como en autopsias sobre la variación de la altura del cono medular.
Objetivo:
Determinar la altura del cono medular en adultos en una población mexicana.
Material y métodos:
Medición de la altura del cono medular en una muestra de 500 adultos mayores de 18 años, con resonancia magnética.
Resultados:
En muestra de 500 pacientes, 238 femeninos (47.6%) y 262 masculinos (52.4%), con edad promedio de 46 años (rango de 18 a 72), se observó variación de la altura del cono medular desde la mitad inferior de T1 al espacio L2-L3, con predominio de localización de la mitad inferior de L1 (n = 164), 45.8%, y del espacio L1-L2 (n = 152), 30.3%, sin diferencias en relación a edad ni género. Cuando el cono medular se localizó inferior al espacio L1-L2, se observó diferencia estadísticamente significativa (p de 0.05 y 0.03) a favor del género femenino.
Conclusiones:
El cono medular se localizó a la altura de la mitad inferior de L1 y el espacio L1-L2 en 76% de los casos, sin diferencia entre géneros ni edad, siendo predominante su localización inferior a estos niveles en el género femenino de la muestra estudiada.
... Las explicaciones propuestas indican que en el género femenino los cuerpos vertebrales disminuyen en altura con la edad y, por otra parte, en los estudios de autopsia, cambios como el rigor mortis pueden modificar la altura de CM. Al comparar el presente estudio con ocho de los reportes más recientes 3,16,19,[20][21][22][23][24] del 2009 al 2017 (Tabla 2), llama la atención que cinco de ellos son de Medio Oriente, y tres orientales (India y Corea); en todos ellos, incluyendo el presente, la localización del CM presenta una curva de distribución normal, con variación entre el 1/3 superior de T12 al espacio intervertebral L2-L3. En cuanto al sitio más frecuente de localización de CM, se observa variación según el estudio consultado, desde el tercio superior de L1 (un reporte), tercio medio de L1 (tres reportes); tercio inferior de L1 (tres reportes) y espacio intervertebral L1-L2 (dos reportes), específicamente en mujeres; en el presente estudio, la localización más frecuente del CM fue la mitad inferior de L1, siguiéndole el espacio L1-L2, concordando con siete de los estudios confrontados. ...
There are several studies of imaging and autopsies of medullary cone height variation, although not in Mexican population. Medullary cone was located at the lower half of L1 and the L1-L2 space in 76% of the cases with no difference between genders or age, their predominance being below these levels in female gender at the studied sample.
The spinal column is a complex mechanical structure and protects the spinal cord and nerve roots. It performs multidirectional movements, including flexion, extension, rotation, and lateral bending. MR imaging is well established to evaluate the adult and pediatric spine for many conditions, including degenerative, traumatic, neoplastic, and congenital diseases. Here, we will review some basic anatomy of the spine, focusing on MRI.
