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Anatomy of the Upper Fist Chute

 

ID: 010303301

Science Topic

Anatomy of the Upper Fist Chute

Anatomical Insights for Deep Fisting

Education Center | Course ID: 010303301

Publication Details

Author: Finn Vortex

Published: 19 October 2024

Updated: 19 October 2024

Duration: 20 Minutes

Executive Summary

Gross anatomical review of the upper fist chute, including the sigmoid colon, descending colon, and transverse colon. Recommendations for preventing injuries per segment are provided.

Upper Fist Chute

The fist chute can be divided into two parts: the upper fist chute, which is used primarily for depth play, and the lower fist chute, which is used for elementary play, punch play, and width/girth play. The accessible sections of the upper fist chute include the sigmoid and descending colons, as well as a very small segment of the transverse colon. The lower fist chute includes the rectum and anus.

Anatomical Considerations

In the anatomical study of the lower fist chute, it makes sense to focus on the lumen, the bony framework, and supporting tissues of the fist chute. In the upper fist chute, such a focus makes less sense because of the lack of bony framework and the decreased variation in supporting tissues. Instead, a focus on the following items is more helpful:

  • lumen structure (morphology) | the physical characteristics of the upper fist chute, including sphincters and muscle organization.
  • spatial relationships | the position and orientation of chute segments relative to the stomach and groin (abdominal and pelvic cavities), the gut sack (peritoneum), the abdominal organs, and other segments of the colon.
  • supporting infrastructure | the firm and the flexible anchor points that affect penetration, continued passage, and deeper play.
Vocabulary

Lumen

  1. Noun the central cavity of a tubular or other hollow structure in an organism.

Morphology

  1. Noun the study of the structure, form, and arrangement of organ and tissue systems in organisms, focusing on shape, size, and anatomical and physiological relationships within the body.
Navigable Areas of Fist Chute
Figure 1.1: Segments of the Upper Fist Chute

The upper fist chute, consisting of the sigmoid and descending colon, can vary in length from 50 - 75 centimeters (20 - 30 inches). In some individuals, the first 5 centimeters (2 inches) of the transverse colon is accessible.

Depth play requires gradual conditioning.

Without surgery or genetic abnormalities, the process of dislodgement and depth development takes years to accomplish. In the heat of the moment, it is tempting to push limits for rapid gain. This can result in perforation.

Lumen Schematics

There are two major differences between the upper and lower fist chute that are experienced after passing through the second hole. The first is an organizational/structural change in the lumen (fist channel). The second is a reduction of navigational landmarks that help fisters understand current insertive positions and next steps in depth exploration.

Tissue Structure (Histology)

The tissue structure (histology) of the lumen wall affects the intensity and limits of play, particularly depth play. The lower fist chute has very thick walls with high stretch capacity. The upper fist chute has more delicate walls that are easier to perforate.

VOCABULARY

Histology

  1. Noun The study of the microscopic and macroscopic nature of tissues.

The lumen has several distinct layers of tissue, but for the sake of simplicity and relevance, they can be consolidated into two groups:

  • Inner wall | Absorptive and smooth muscle tissues that create the soft, velvety lining of the fist chute.
  • Outer wall | Smooth muscle tissues and protective wrappings that control stretch capacity and mobility of intestinal contents.

In outer wall, there are two layers of muscle tissue. A circular layer helps squeeze the contents of the lumen, a longitudinal layer helps churn and propel the contents of the colon toward the rectum and anus.

In the rectum, this longitudinal layer is uniform in thickness and coverage. In the remaining segments of the colon, a majority of the outer longitudinal layer bands together to create three ribbons that run the length of the upper fist chute. These ribbons are known as taenia coli. The concentration/grouping of these longitudinal muscle fibers in the taeniae coli decreases the overall thickness and durability of the longitudinal layer, making perforation more likely in this section of the fist chute.

Lumen Layers
1.2: Layers of the Fist Chute Wall

The exterior wall of the lumen has two muscle layers that control mobility within the fist chute.

Interiror View of Taeniae Coli
Exterior View of Taeniae Coli
1.3: Interior and Exterior Views of Taeniea Coli

Three ribbons (spaced about 120˚ from one another) form the taeniae coli. Despite their prominence, they are not recognizable to the touch.

Form and Structure (Morphology)

Morphologically, relevant items of interest include:

  • Haustral Segments | The sack-like enclosures spanning all parts of the upper fist chute.
  • Rectosigmoid Junction | The second hole and passage between the upper and lower fist chute.
  • Splenic Flexure | The third hole and terminal limit for further fist penetration.

Haustral Segmentation

The banding of the muscle fibers in the taeniae coli results in ribbons that are shorter than the lumen of the upper fist chute. The difference in length causes the lumen to bunch up into small pouches. These pouches, known as haustra, churn and remove water from undigested food. They also provide living accommodations for the natural flora in your colon.

If a haustrum (a single haustra) has never been accessed by a finger or fist, the constriction may feel like a ring. Many novice depth tops often misinterpret haustral constrictions as the third hole. Constrictions open up with minimal effort. In contrast, the third hole has limited ability to stretch open.

Frequently accessed haustra can become elongated and lose segmented appearance.

Haustral Segments
1.4: Segmental Haustral Pouches

The taeniae coli are responsible for shortening the colon by creating haustra.

Junctions and Flexures (Holes)

There are only two holes in the upper fist chute: the rectosigmoid junction and the splenic flexure. Neither of these holes are sphincters, rather they are soft, flexible, cartilage-like rings that can stretch with regular conditioning.

Fisters refer to the rectosigmoid junction as the second hole or second ring. A sharp, 90˚ bend marks the connection between the rectum and sigmoid colon. At this ring, the thick, longitudinal muscle layer that covers the entire rectum divides into the three taenia coli that span the length of the upper fist chute. In depth fisters, the bend may be absent, and the ring may be less rigid but still recognizable to the touch.

The splenic flexure, referred to as the third hole, is a hairpin turn (< 75˚ ) where the descending and transverse colons meet near the far end of the spleen. Anatomically, this hole (and the second hole) lacks the specific musculature to qualify as a sphincter. Hensing's ligament (phrenicocolic ligament), which attaches the colon to the diaphragm, creates a semi-lunar, and very prominent ring. Due to anchor points and the anatomy of the hand, it is very rare that this hole is accessed. When it is, typically only a few fingers can penetrate it.

  Second Hole Third Hole
Name Rectosigmoid Junction Splenic Flexure
Minimum Depth 16.5 cm (6.5 inches) 52 cm (20 inches)
Angle 90˚ < 75˚
Composition Fibrous Connective Tissue Phrenicocolic Ligament
Mobility Floating (Intraperitoneal) Fixed (Retroperitoneal)
Haustral Segments
1.5: Upper Fist Chute Rings/Holes

The rectosigmoid junction is formed by a natural bend in the colon whereas the splenic flexure is caused by ligaments.

Sigmoid Colon

The sigmoid colon is the primary play space in depth fisting. It can be anatomically divided into the pelvic and iliac colons; however, fisters cannot distinguish the two components from one another. Some texts consider the iliac colon to be part of both the sigmoid and descending colons. In general, Fist Theory treats the pelvic and iliac colons as a single segment (sigmoid) of the fist chute.

For additional information on the sigmoid, including landmarks, misconceptions, tips, and techniques to maximize pleasure, please refer to the associated quick reference topics.

Vocabulary

Iliac

  1. Adjective relating to the ilium (hip bone) or the nearby regions of the lower body.
Sigmoid Lumen (Fist Channel) | Structural Details
Length: 25-40 centimeters (10-16 inches)
Max Stretch Capacity:* Length: Varies
Circumference: 30 - 35 centimeters (12-14 inches)
Diameter: 9.5 - 11 centimeters (3.5-4.5 inches)
Primary Components: Rectosigmoid Junction, Haustral Segments
Secondary Components: Taeniae Coli

*Varies based on genetics, experience level, and training/conditioning.

Pelvic and Iliac Colons
2.1: Named Sections of Sigmoid Colon

The sigmoid colon is divided into two named sections. The iliac colon crosses the iliac crest and connects to the lower portion of the descending colon.[ 1 ]

Spatial Relationships

The position of the sigmoid varies based on genetics and conditioning. It begins at the second hole (known as the recto-sigmoid junction). It terminates at the descending colon just above the top of the hip bone (iliac crest). Between the rectum and the descending colon, it bends and curves frequently. This tortuous portion has very high mobility and can be pushed deep into the abdominal cavity.

Vocabulary

Tortuosity

  1. Noun the quality of being twisted, winding, bended, or crooked.
Mobility of Pelvis
2.2: Mobility of Sigmoid Colon

Most of the sigmoid colon floats freely in the upper pelvis and can be pushed into the abdominal cavity.

Classical Configuration

In the classical configuration, the sigmoid joins the rectum just below the pelvic inlet at approximately the third vertebra of the sacrum.[ 2 ] In less technical terms, the first few inches (several centimeters) of the sigmoid are squished into the grapefruit-sized space just inside the first hole alongside the bladder, rectum and anus. The remaining portion of the sigmoid rests on the flat wing of the hip bone (the left iliac fossa). It joins the descending colon just above the iliac crest.

This configuration is more common in women, non-fisters, and novice fisters.

In novice fisters, insertion of the full fist may be difficult with this configuration. Due to space limitations, the rectum may not fully accommodate the hand. The anal canal is under extreme duress because the hand is unable to pass completely through it.

These fisters are known to have a shallow garage or a short hole. These holes are also known as \-holes (slash holes) because the fold in the lesser pelvis requires the top to search for the second hole at the front side of the body instead of the back side of the body.

Lesser Pelvis
2.3: Lesser Pelvis and Sacral Promontory

Novice fisters may have a classical configuration where the first few inches of the sigmoid colon are compressed within the lesser pelvis.

Long Configuration

In the long configuration, the sigmoid is said to be supra-pelvic, meaning it joins the rectum in the greater pelvis at the top of the sacrum.[ 3 ]

This configuration is common in established fisters that have restructured their intestines with repetitive fisting or toy play. Some individuals are born with a long configuration.

Regardless or natural or restructured origin, with long configuration, the second hole is often pushed deeper and is not completely penetrated until the full hand passes the sacral promontory.

  Classical Configuration Long Configuration
Bone Relations Begins Mid Sacrum Begins Above Sacral Promontory
Organ Relations Shares Space with Bladder, Reproductive Glands None
Second Hole Position Shallow (< 20.5 cm [8 inches]) Low - Mid Forearm (>20.5 cm [8 inches])
Table 2.2: Sigmoid Colon Configuration Comparisons

The differences between Classical and Long Configurations demonstrate how the second hole position affects adjacent relationships and external depth measurements.

Greater Pelvis
2.4: Greater Pelvis and Iliac Crest

Long configuration sigmoid colons join the rectum in the greater pelvis before crossing into the abdomen and joining the descending colon.

Supporting Infrastructure

The sigmoid colon is the least constrained segment of the entire fist chute. It is completely intraperitoneal, meaning it is contained within the sack that envelops the abdomen. This allows it to float and move with relative ease.

Some additional fascia offers some support near the second hole and at the transition point to descending colon. Surgeons and anatomists believe the support is very limited.

Vocabulary

Intraperitoneal

  1. Adjective Within the peritoneum, the thin membrane lining the abdominal cavity.

The sigmoid mesocolon attaches the sigmoid to the posterior (backside) muscles, bones, and ligaments of abdomen. It has a wedge-, fan-, or sail-like appearance. Extreme range of movement is due to:

  • Stretch Capacity | The mesocolon can stretch and grow through regular training/conditioning.
  • Anchor Points | The mesocolon may have an extensive anchoring system (broad) or it may have reduced anchoring (narrow). Narrow anchoring allows for greater twists (with longer sigmoids) that can result in a condition known as volvulus sigmoid.
  • Disruption | The integrity of mesocolon may be compromised surgically or by aggressive play.
  • Natural Elongation | Elongated mesocolon due to genetic traits is unrestrictive and is essentially a longer leash than shorter mesocolon.
Vocabulary

Sigmoid Volvulus

  1. Noun Phrase A condition of the sigmoid that occurs when the last part of the colon twists on itself causing obstruction and compromising the blood supply to the colon.
Sigmoid Mesocolon
2.5: Intraperitoneal Mesocolon

The size and flexibility of the mesocolon that envelops the sigmoid and most of the transverse colons allows for a wide range of movement.

Injury Prevention

The following practices can help reduce fisting-related injuries involving the sigmoid.

Lubrication

When using alphabet lubes, inject or pour lube into the hole to prevent lube loss from the squeegee effect. Ensure the sigmoid is lubricated by pressing forward and then retracting to spread the lube consistently.

When using solid lubes such as Crisco, make sure the lube has transitioned from solid to liquid forms by manual manipulation in the lower fist chute.

Do not assume more lube is the answer to getting deeper. It isn't. Gentle massage and gradual conditioning over time opens the hole.

If injecting lube, make sure the injection tool is soft enough to bend in the colon instead of poke through and perforate it.

Physical Conditioning

Regular depth play with tapered toys will improve the responsiveness of the second hole.

Near daily conditioning is analogous to gym attendance. If you don't go, you won't see any change.

Also analogous to workouts is gradual increase. In the gym, you don't do rapid jumps in weights and sets. In your hole, you shouldn't do rapid jumps either. Work up from a small toy to an extra-large hand.

The second hole must be assessed to determine if a hand will pass through without stress on the hole. It should be massaged in order to relax. It may take several sessions for it to relax enough to allow passage.

Psychological Conditioning

Practicing meditation and rhythmic breathing decreases body resistance from the autonomic and enteric nervous systems.

Build trust between partners in order to remove psychological triggers for defensive actions (such as closing one's hole).

Communication

Discuss previous depth experience with one another prior to play. Gather a history of successful experiences, past injuries, typical warmup time required, experience levels, and hand size.

The data exchanged helps tailor depth routines. It also sets a precedent that both partners are willing to speak up if something feels off or out of the ordinary.

Tops should pay close attention to body language and facial grimaces and pull back when the bottom is consistently feeling pain.

Toys

Colon tubes and colon snakes are helpful in expanding areas that have not previously been accessed.

Never put multiple depth toys (20.5 cm / 8 inches or greater) in your hole simultaneously. They stretch the colon, making it taut. The colon will often rip before a toy bends. Likewise, avoid using arms and toys simultaneously.

Avoid using firm toys, especially when pistoning inside your hole. They catch the sigmoid wall and can easily rip it. Firm toys may help straighten your hole but should never be forced in or rode aggressively.

Do not let Tops insert depth toys into your hole, especially when compromised chemically. With their arm, they can tell when the hand is blocked. With a toy, they cannot tell when it is blocked or caught in a crevice that will perforate.

Acknowledge Limitations

Rome wasn't built in a day. Taking your first elbow without injuries and tears will take multiple sessions over several months. Don't push it to impress others. Accept when your body says, "No more!" or "I'm done!".

Do not use chems to short circuit the process. Do not slip into memory holes where you are unable to recognized what you are experiencing in your sigmoid colon.

Descending Colon

The name of the descending colon reflects its anatomical position and orientation in the body, indicating that it descends from third hole to the sigmoid colon.

Anatomy textbooks describe the descending as fixed and retroperitoneal; however, a recent study shows some variation in mobility that indicates that a portion of the descending may be intraperitoneal. Nearly 33% of males express this expanded mobility which may allow deeper penetration of the transverse colon beyond a few centimeters.[ 4 ]

Vocabulary

Extra-, Retro-, and Intra- Peritoneal

  1. Noun - the three locations of abdominal organs. Intra is within the peritoneal cavity. Extra and retro refer to outside and behind the peritoneal cavity.
Descending Colon
3.1: Width of Descending Colon

Since the descending colon does not store fecal material, it may have less capacity to stretch than the sigmoid.

Passage into and through the descending colon can be tricky as a fister approaches the fixed component, especially if the sigmoid is long with excessive mesocolon that allows it to stretch and move freely.

Flexible colon tubes or colon snakes can reposition the colon and pass through with relative ease. Firmer toys and solid objects have more difficulty.

To reach the third hole, the top must either tug the sigmoid down or reposition his body, hand, and arm in awkward, inverted angles to gain entry into the descending to proceed deeper. Either methodology can be slightly painful and alarming to the bottom.

Descending Lumen (Fist Channel) | Structural Details
Length: 10 - 25 centimeters (4 - 10 inches)
Max Stretch Capacity:* Length: Varies
Circumference: 30 - 35 centimeters (12-14 inches)
Diameter: 9.5 - 11 centimeters (3.5-4.5 inches)
Primary Components: Haustral Segments, Splenic Flexure
Secondary Components: Taeniae Coli

*Varies based genetics, mobility (partially intraperitoneal, and conditioning. Stretch capacity is likely smaller than the sigmoid.

Spatial Relationships

The descending colon starts just above the iliac crest; however, passing the crest does not indicate passage into the descending. The rectum can be stretched lengthwise and the sigmoid can be pushed above the crest. The lack of specific structures within the lumen or nearby bony landmarks may prevent a top from ascertaining his position. The descending colon ends in the lower rib cage, near the spleen.

While the kidneys and small intestines are close, neither is palpable within the lumen.

Supporting Infrastructure

Two intestinal components support the descending colon: the splenic flexure (third hole) and the mesentery.

Splenic Flexure [ Third Hole ]

The descending and transverse join together at the third hole, technically known as the splenic flexure or left colic flexure. Position of the flexure in the body varies based on differing anatomies. In some cases, it may be elevated when compared to the transverse colon and hepatic (or right colic) flexure. In other cases, it may be positioned horizontally with the transverse colon.

There is no sphincter at this flexure. Instead, the degree of the angle at the point of the bend creates the appearance of a ring. A 90° curve will have a less prominent 'ring' when compared a flexure with a smaller angle.

Mild Angle Splenic Flexure
Extreme Angle Splenic Flexure
3.2 [ A - B ]: Two Presentations of the Splenic Flexure

The angle of the splenic flexure may be [ A ] mild (about 90˚) or [ B ] extreme (< 90˚).

Mesentery/Left Mesocolon

The left mesocolon covers at least three sides of the descending colon. The side without covering is attached to the muscles and ligaments of the back. A three-sided configuration limits mobility and stretch capacity of the descending colon.

In 33% of the population, the left mesocolon completely encircles the lower portion of the descending colon, allowing it some level of mobility. As the descending colon approaches the third hole, the surrounding envelope dissipates and covers only a portion of the descending colon.

QUICK REFERENCE
Sigmoid Mesocolon Configuration
3.3: Retro- and Intraperitoneal Mesocolon

The image on the left demonstrates a descending colon that is mobile and intraperitoneal. The image on the right depicts a retroperitoneal descending colon with limited mobility and stretch capacity.

Injury Prevention

The following practices can help reduce fisting-related injuries involving the descending colon.

Entrance Techniques

Recognize that the wall strength in the descending colon is even less than that of the sigmoid. Also take note that the descending is much narrower than the sigmoid. Proceed slowly with extreme caution.

Transverse Colon

The transverse colon spans the width of the body. Its ends are retroperitoneal, and its middle section is intraperitoneal. It has limited mobility because of the retroperitoneal ends that anchor it within the abdomen.

Access to this portion of the colon is limited to genetically unique individuals or those who have had some type of abdominal surgery near the spleen or liver that severed the tissue holding the right and left colic flexures in place. Even with surgery, access is limited to a few centimeters and Fist Theory does not cover this portion of the colon.

Content Development

The following material is under consideration in the development of this topic:

Objectives

Upon completing this course, the student will be able to:

  • List the three segments of the upper fist chute.
  • Provide the techical names for the second and third hole and mark on a diagram where they are located in the body.
  • Explain the difference between a classical and long configurations of the sigmoid colon.
  • Identify three practices that decrease injury to the sigmoid colon and one pracitice that decrease injury in the descending colon.
  • Explain why the simultaneous use of multiple toys or toys coupled with hands can lead to injury in the sigmoid colon.
  • List four reasons why the sigmoid mesocolon permits great motility of the sigmoid colon.
  • Identify where to look for passage into the sigmoid colon in a new or inexperienced bottom.
  • Define extra-, intra-, and retroperitoneal and explain how positioning affects accessibility.
  • Rank the three segments of the upper fist chute in order of likelihood of injury and explain why.

Note: Objectives should follow instructional design standards and be easily measurable with little ambiguity.

Supplemental Content

Blog Articles

  • Coming Out as a Non-Transverse Fister
  • Selected Toys for Advanced Depth Bottoms from Hankey's Toys

F2 Promotional Materials

  • Thursday Erotica/neurotica: None
  • Skills: None
  • Protocols: None
  • FWOTD:
    • Haustra / Haustral Segments
    • Left Colic Flexure
    • \-hole (slash hole)
    • Genu
    • Splenic Flexure
    • Sacral Promontory

Outline (Proposed)

  • Upper Fist Chute
  • Anatomical Segments
  • Lumen Schematics
  • Components
  • Tissue Structure (Histology)
  • Form and Function (Morphology)
  • Sigmoid Colon
  • Spatial Relationships
  • Classical Configuration
  • Long Configuration
  • Supportive Infrastructure
  • Injury Prevention
  • Descending Colon
  • Spatial Relationships
  • Supportive Infrastructure
  • Splenic Flexure
  • Messentery/Left Mesocolon
  • Injury Prevention
  • Transverse Colon

F2 Resources

These individuals have indicated they continue fisting with this condition:

  • Not Applicable

Brain Dump - Staging Area

        

Version History

  • 18 Oct 2024: Initial Draft Completed and Published

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