Re: INE - SDN Course Bundle [Compressed]
Cinty Bolner
The piriformis syndrome is considered as a subgroup of the deep gluteal syndrome (15), which occurs due to several conditions: Asymmetrical hypertrophy of the piriformis muscle with anterior displacement of the sciatic nerve; dynamic sciatic nerve entrapment by the piriformis muscle; and variants in the course of the sciatic nerve related to the piriformis muscle.
In another plane, the origins and the organization pattern of the pudendal nerve, the sacrospinous ligament, the coccygeus muscle and the perineal course of the internal pudendal neurovascular bundle were dissected and separated from the surrounding anatomical elements.
As regards the general anatomical layout, the left half of the pelvic floor is clearly visible. Due to its central location, the sacrospinous ligament and the coccygeus muscle separate the lateral pelvic wall into three zones: i) The posterior-superior zone corresponds to the greater sciatic notch and its content. In a deep plane, the piriformis muscle attaches to the sacrum, with its origins slightly separated by the roots of the sciatic nerve. The anterior divisions of the S2, S3 and S4 spinal nerves give rise to the pudendal nerve. The dissection image clearly shows that these roots can be compressed during the contraction of the piriformis muscle. This nerve, together with the internal pudendal artery, are closely associated with the rigid superior border of the sacrospinous ligament, actually passing between the piriformis muscle and the sacrospinous ligament and then between the ligament and the upper border of the sciatic spine. The elements of the internal pudendal neurovascular bundle follow their extrapelvic course surrounding the ischial spine in the deep gluteal region in order to reenter the pelvis through the lesser sciatic notch. ii) The middle zone is dominated by the attachments of the sacrospinous ligament and coccygeus muscle onto the ischial spine, forming a rigid osteo-fibro-muscular structure. iii) The anterior-inferior zone contains the contents of the lesser ischial notch. In order to reach the internal pudendal neurovascular bundle, the levator ani muscle was reflected medially, thus obtaining favorable access towards the ischiorectal fossa. On the lateral wall of this fossa, the pudendal canal (Alcock canal) was opened, and the fibrous remnants of the fascia were removed in order to emphasize the neurovascular content of the canal. In close association with the osseous plane, the fascicles of the internal obturator muscle unite in a common body that passes below the inferior border of the ischial spine in its course towards the femoral attachment.
The image is centered on the emerging sciatic nerve (no. 9) under the inferior border of the piriformis muscle (no. 1), in the infrapiriform space. In the medial end of this space, the internal pudendal neurovascular bundle (no. 11) exits the pelvis, surrounds the ischial spine and reenters the pelvis along the lateral wall of the ischiorectal fossa, in the Alcock canal, which was removed on dissection.
In the ischiorectal fossa, the inferior rectal branches of the internal pudendal neurovascular bundle lying lateral to the anococcygeal ligament (no. 5) and the external anal sphincter (no. 14) may be clearly seen.
The internal pudendal neurovascular bundle travels through a critical zone between the piriformis muscle and the sacrospinous ligament, in contact with the superior margin of the ischial spine, where compression may occur. When this bundle reenters the pelvis, it may traverse a compression zone between the internal obturator muscle, the gemellus superior muscle and the inferior border of the ischial spine.
Several aspects are important for the imaging evaluation of the nerve tracts, such as identifying the piriformis muscle in the greater sciatic notch, identifying the internal obturator muscle in its course below the ischial spine, evaluation of the upper and lower borders of the ischial spine, and sequential evaluation of the course of the neurovascular bundles.
The difficulty of the evaluation using MRI lies with the oblique orientation of the sacrum and the piriformis muscle, the curving tendency of the internal obturator muscle and the combined intra- and extrapelvic course of the internal pudendal bundle.
The sciatic nerve can be compressed along its course in the following locations. Its roots can be compressed intrapelvically by the origins of the piriformis muscle; its trunk can be compressed in the infrapiriform space between the inferior border of the piriformis muscle and the upper border of the ischial spine.
The internal pudendal nerve can be compressed along its course in several locations: In its intrapelvic course, it may be compressed in the anterior-inferior part of the piriformis muscle and in the superior border of the sacrospinous ligament. In this part, there are also rare cases of pudendal nerve syndrome entrapment associated with ganglion cysts (19).
In its extrapelvic course, the internal pudendal nerve runs in the medial part of the infrapiriform space. In the infrapiriform space, the bundle runs the following course: Upon entering this space, the internal pudendal bundle is actually located between the inferior border of the piriformis muscle and the tip of the ischial spine. Next, the bundle surrounds the lateral aspect of the sciatic spine (Fig. 2) and then reenters the pelvis through the lesser sciatic notch, in contact with the inferior border of the ischial spine passing between the spine, the superior gemellus and internal obturator muscles.
In its intraperineal course, the bundle travels along the internal aspect of the internal obturator muscle, inside the Alcock canal. In this part, the nerve is unlikely to be compressed by extrinsic structures.
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Everyone has one of those friends that just can't make good judgement calls. All of my friends happen to be like that, except for me, of course (I'm perfect). So that's why I'm never surprised when they bring back a 24-pack of warm beers, after explicitly being told to make sure to get cold ones.
Put on your gloves and use the drill to make a small hole in the container where you will place the compressed air straw in to. Place the beers inside the plastic container and wrap it up with duct tape (securely). Place the air straw inside the container hole and squeeze the bottle for about a minute.
When unloadAllLoadedObjects is false, compressed file data for assets inside the bundle will be unloaded, but any actual objects already loaded from this bundle will be kept intact. Of course you won't be able to load any more objects from this bundle.
When unloadAllLoadedObjects is true, all objects that were loaded from this bundle will be destroyed as well. If there are game objects in your scene referencing those assets, the references to them will become missing.
The costoclavicular passage is one of three passages that consitute the thoracic outlet; the others are the superior thoracic outlet and the costoscalene hiatus.[1] The costo-clavicular passage is formed by the clavicle antero-laterally, the first rib medially, and the scapula posteriorly.[2] The brachial nerve plexus, subclavian artery and subclavian vein run within the costoclavicular space between the first rib and the clavicle. The neurovascular bundle is vulnerable to compression in this space.[2]
The costoclavicular syndrome was first described in soldiers with loaded knapsacks, who developed pain, numbness, and fatigueability of the arms as they stood at attention.The mechanisms of compression involved downward movement of the clavicle against the first rib with a resultant tendency to shearing of the neurovascular bundle.[3]
Mercurial 4.1 ships with the python-zstandard bindings. Two Mercurial4.1 peers talking to each other will exchange Zstandard compresseddata instead of zlib. For a Firefox repository clone, transfer size isreduced from 1184 MB (zlib level 6) to 1052 MB (zstd level 3) in thedefault Mercurial configuration while using 60% of the CPU that zlibrequired on the compressor end. When cloning from hg.mozilla.org, thepre-generated zstd clone bundle hosted on a CDN using maximumcompression is 707 MB - 60% the size of zlib! And, work is ongoingfor Mercurial to support Zstandard for on-disk storage, which shouldbring considerable performance wins over zlib for local operations.
Being at least 27 years old, DEFLATE is getting a bit long in thetooth. Computers are completely different today than they were in 1990.The Pentium microprocessor debuted in 1993. If memory serves (punintended), it used PC66 DRAM, which had a transfer rate of 533 MB/s.For comparison, a modern NVMe M.2 SSD (like the Samsung 960 PRO)can read at 3000+ MB/s and write at 2000+ MB/s. In other words,persistent storage today is faster than the RAM from the era whenDEFLATE was invented. And of course CPU and network speeds haveincreased as well. We also have completely different instructionsets on CPUs for well-designed algorithms and software to takeadvantage of. What I'm trying to say is the market is ripe forDEFLATE and zlib to be dethroned by algorithms and software thattake into account the realities of modern computers.
Since Mercurial is the driver for my work in Zstandard, the data andnumbers I report in this post are mostly Mercurial data. Specifically,I'll be referring to data in themozilla-unified Firefox repository.This repository contains over 300,000 commits spanning almost 10 years.The data within is a good mix of text (mostly C++, JavaScript, Python,HTML, and CSS source code and other free-form text) and binary (likePNGs). The Mercurial layer adds some binary structures to e.g. representmetadata for deltas, diffs, and patching. There are two Mercurial-specificpieces of data I will use. One is a Mercurial bundle. This is essentiallya representation of all data in a repository. It stores a mix of raw,fulltext data and deltas on that data. For the mozilla-unified repo, anuncompressed bundle (produced via hg bundle -t none-v2 -a) is 4457 MB.The other piece of data is revlog chunks. This is a mix of fulltextand delta data for a specific item tracked in version control. Ifrequently use the changelog corpus, which is the fulltext datadescribing changesets or commits to Firefox. The numbers quoted andused for charts in this postare available in a Google Sheet.
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