Step-by-Step Guide · Ancient Dissection

Ancient Dissection - Re-enacted

Introduction

Step-by-Step Guide

Credits

Other Dissection Material

Legend to the Re-enactment Guide

In the guide below you find the data for each of the steps in the dissection.

Numbers (1, 2, 3…): The anatomical part or areas being dissected.

Letters (1a, 1b…): Particular dissection actions performed, or expected findings.

Instruction: The instruction we wrote and listed in the dissection manual based on our analysis of a particular sentence or passage in Galen’s text.

Translation: An English translation of the respective passage in Galen’s text.

Greek Text: The Greek text of the passage, from the edition of Ivan Garofalo (2000).

Observations: Relevant linguistic points explaining our interpretation; clarifications of anatomical points that Galen took for granted; findings differing from Galen’s descriptions; actions we were unable to achieve.

Step Video Clip: A close-up video of the particular step (when available).

Full Dissection - Step Timecode: A link to the particular step in the video of the entire dissection, providing more context if need (when available).

3D Scan: A 3D scan of the particular part or area (when available).

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1 - Skin

Skin (V.7): 311,18 - 313,15 Garofalo = II.511-513 Kühn

Incision in the middle line from the neck downwards as far as the pubic symphysis.

Strip off skin without tearing underlying tissue

Notice how the skin can be easily separated from the underlying muscles because there is a membrane continuous with the skin that separates it from them.

Pay attention when arriving laterally to the false ribs to not tear a small muscle-like structure that arrives to the axilla.

This structure is formed by fibres that are isolated in their origin over a wide surface, and begin to converge until they form this narrow-fleshy-muscle-like structure that reaches the axilla.

This structure joins and is floating over (ἐποχεπειται) the bodies of the axilla (σώμασιν).

2 - Abdominal muscles

Abdominal muscles 313,17– 315,19 Garofalo = II.513-515 Kühn

Identify linea alba.

2b.i

p. 317, 2) Use somebody else’s hand to pull the (left) rectus muscle laterally by placing their fingers along the linea alba and then pulling laterally (thereby better exposing the tendon and facilitating the cut).

2b.ii

ii. Incise the linea alba superficially (epipolês) from cranial to caudal from the xiphoid cartilage up to the umbilicus area (between the navel and the pubic symphysis).

Observe that the underlying tendon after this initial superficial cut is whiter than its surroundings.

Use your fingers to separate the left rectus muscle from the superficial aponeurosis [aponeurôsesin] of the transversus muscle [i.e. introduce your fingers through the incision to liberate the posterior face of the left rectus abdominis].

Strip the membranous tendons of the oblique muscles from the anterior surface of the left rectus abdomen.

Visualise the lateral border of the muscle.

Incise the lateral tendon of the left rectus muscle at the linea semilunaris superficially, to separate the tendon of the external oblique.

Repeat the procedure more deeply, to separate the tendon of the internal oblique

The largest oblique muscle (external oblique) is henceforth referred to as First.

The deeper oblique with opposite direction [of the fibers] is the Second.

The rectus is the Third.

The transversus abdominis is the Fourth.

2γ

push the (right) rectus muscle laterally with your own one hand and cut with the other.

2δ

Peel the upper surface of the right rectus muscle, i.e. separate the right rectus muscle from the overlying tendons/aponeurosis, trying to distinguish the two layers (i.e. separating the layer of obliquus externus from the internus) . The aim is to lay bare the anterior surface of the rectus abdominis and visualise the lateral edges/borders of the muscle (where the rectus is next to the fibrous part of the external oblique).

2ε

Observe the continuity between each tendon and the corresponding oblique muscle (external and internal).

2λ

Free the rectus muscle from its sheath with the fingers: once the right rectus muscle has been exposed, introduce the fingers through its medial edge to separate it from the underlying tissue (the aponeurosis of the transversus abdominis).

2ζ

Once the tendon of the external oblique (First) is cut from its insertion in the linea alba (from the xiphoid to the umbilicus), stretch the tendon softly upwards in order to facilitate dissection. Dissect the muscle as far as you can towards its origin.

2η

Observe that It is impossible to reach the lateral insertion of the external oblique (First) because it is covered by a thoracic muscle (the serratus).

2ι

Repeat the same procedure with the tendon of the internal oblique muscle (Second), cutting its insertion at the linea alba (from the xiphoid cartilage to the umbilicus), and follow the fibres (inas) to dissect the muscle until its lateral insertion (this one should be visible).

2μ

Note the connection between the aponeurosis of the internal and external abdominal oblique muscles and the transverse abdominis (in the lower end of the abdomen).

3 - Parietal peritoneum

Parietal peritoneum VI. 4 359,25- 361,21 Garofalo = II.551-553 Kühn

Identify the point where the peritoneum is separated from the aponeurosis of the transversus abdominis (it should be close to the navel, away from the tendon of the transversus abdominis (where the peritoneum is adhered to the muscle) and above the lower tendinous junction of the abdominal muscles).

Make a small horizontal incision at this point, and start stripping off the peritoneum. The incision should be enlarged as dissection progresses carefully from left to right (lateral to medial), and from caudal to cranial. Technical note: as the work reaches the tendinous part of the transverse muscle (medially), and the arcuate line (cranially) the peritoneum will be more adhered to the aponeurosis of the transverse muscle and dissection will be likely more difficult.

Strip the peritoneum from the transverse abdominal muscle if possible.

Follow the peritoneum cranially, at the right of the animal, where the transversus muscle inserts in the ribs, and the peritoneum attaches to the diaphragm.

4-Diaphragmatic peritoneum

Diaphragmatic peritoneum 361,21– 363,8 Garofalo = II.553-554 Kühn

Strip the peritoneum from the diaphragm from ventral to dorsal, and from right to left (lateral to medial). Till you reach the spine. It strips easier from the muscular part and is tightly adhered to the centrum tendineum.

Observe the circular shape of the diaphragm with a tendinous centre and a fleshy periphery.

On the right, the dissection of diaphragmatic peritoneum will lead to the hiatus of the vena cava.

On the left, the peritoneum can be stripped to the oesophageal hiatus and is reflected onto the cardia of the stomach where it is thicker.

5 - Visceral peritoneum

Visceral peritoneum 363. 8-26 Garofalo = II. 554-555 Kühn

Strip the peritoneum from the stomach (parietal aspect) until you get to the greater curvature.

Note the difference in thickness between the visceral peritoneum of the stomach, the liver and the spleen.

At the greater curvature you will see the gastrepiploic vein running the length of the stomach with several branches coming off it to supply the greater curvature of the stomach.

Note how the gastroepiploic vessels and the stomach itself are enclosed or wrapped by these two layers of peritoneum. (The double layered peritoneum runs on top of these vessels, thereby covering their anterior side, and in its reflection, it returns to them covering their posterior side).

6 - Greater omentum

Greater omentum VI.5 363,26–365,12 Garofalo = II.555 Kühn

Notice the branches of the gastroepiploic vein running caudally (towards the navel) in the space between two layers of peritoneum (and their similarity to the branches towards the stomach).

Notice the two layers of peritoneum which make up the greater omentum

Omentum is not attached to the intestines except for the duodenal bulb.

Follow the gastroepiploic vein (vein on the greater curvature) left and right

On the right it reaches the first portion of the duodenum (possibly before the gastroepiploic vein joins the gastroduodenal vein).

On the left it will bring you to the hilus of the spleen

Spleen is on the left. Its convex side faces the ribs and body wall, hilus (concave part) faces right

Observe the structures that are in contact with its concavity (apart from the left lobe of the liver).

Observe the left extreme of the gastroepiploic vein, and its connections to the splenic vessels.

Notice the splenic hilial vessels (within the gastro-splenic ligament): they are numerous and small in size (like the gastroepiploic branches to the stomach, see 5c).

The terminal branch of the gastroepiploic vein is the left epiploic vein (accompanied by its corresponding artery), which ‘nourish or generate’ the epiploon. The latter finishes where the vessels finish their progressive branching off. Follow this vessel caudally and visualize the left half of the greater omentum.

6.l

Notice the same about the right epiploic vessels: their origin in the right end of the greater curvature and their trajectory along the epiploon caudally.

7 - Lesser omentum

Lesser omentum 369,5-17 Garofalo = II.558-559 Kühn

Once the superficial fold of the epiploon has been followed from the greater curvature caudally, keep following the deep fold cranially back up to the greater curvature.

Continue tracing the peritoneum in the inferior face of the stomach and further down (in depth) to the lesser curvature. Below it the lesser omentum is found.

Notice the right gastric vein and its branches to the stomach within the hepato-gastric ligament.

Compare gastric branches of the gastric vein with the gastric branches of the gastroepiploic: they are fewer and smaller.

8 - Omental bursa

Experiment to demonstrate the continuity between greater and lesser omentum/omental bursa or lesser sack. 369,17-27 Garofalo = II.559-560 Kühn

Make a small cut in the lesser omentum, parallel and next to the duodenal bulb. Pour water into the hole.

Observe how the water fills the lesser sack, and the continuity between lesser and greater omenta.

Mouth of the omental bursa attached to stomach

Body of omental bursa extends caudally

9 - Removal of the greater omentum

Removal of the greater omentum 369,27–371,9 Garofalo = II.560 Kühn

Cut the the greater omentum at its attachment [through the short vessels] to the greater curvature.

Cut omentum attached to the spleen and (transverse) colon

Notice (sometimes) abnormal adhesion to liver or ribs

10 - Continuity of the larger sack

Continuity of the larger sack. The peritoneum as a large compartment with all the organs inside 371,9–373, 7 Garofalo = II.560-562 Kühn

10a

Strip off the visceral peritoneum in the stomach from the greater curvature at the pylorus or at the start of the small GI (duodenum).

10b

Continue dissecting the lower part of the peritoneum (picking up from where we had interrupted before) from below the arcuate line, as far as the pubic bone.

10c

See peritoneum covering bladder and uterus

10d

Continue dissecting deeper towards the dorsal body wall, and notice the mesenterium

10e

Notice the kidneys

10f

Resume dissection from above dorsally to reach the kidneys from above (thereby demonstrating the continuity of the peritoneum).

10g

Strip the peritoneum of the organs and notice their different thickness: thin in liver and spleen, intermediate in kidneys, thick in stomach, intestines, bladder and uterus.

11 - Mesenterium

Mesenterium 373,7-27 Garofalo = II.562-563 Kühn

11a

Dissect pylorus, first portion of duodenum, jejunum, ilium, and colon.

11b

Notice the mesentery and its relation to the GI, specifically, its mesenteric vs. antimesenteric apects.

11c

Notice the vessels that run in the mesentery to the antimesenteric surface of the GI

11d

To remove the visceral peritoneum of the intestine, make a superficial cut with a sharp knife on the antimesenteric aspect of the intestine (parallel to the direction of the tube) and peel it off from both sides until they meet at the mesenteric side.

11e

This will show how the visceral peritoneum is single layered, whereas the mesentery is double.

11f

Notice the neurovascular bundle to GI covered in peritoneum forming a single structure (lymph nodes will be discussed in next chapter).

11g

Notice the fat in the mesentery. Compare it to the fat in the epiploon.

11h

Observe the fat in other parts of the peritoneum especially in front of the viscera

11i

Notice how the vessels tend to progressively converge like branches into a single origin, which in the case of the veins can be found at the entrance of the liver (vena porta).

11j

Notice that the convergence of the arteries towards a single one (the superior mesenteric artery), which can be followed to the mesenteric root, is less evident. The latter is a fibrous area where all the mesentery has its origin between the diaphragm and the kidney.

11k

This is the location of the cranial mesenteric artery.

11l

Remove intestines and colon but leave the mesentery in the body 373,27–375,11 Garofalo = II.563-564 Kühn

12 - Final remarks

Final remarks on the peritoneum VI.7: Specific organs 379,25–381,12 Garofalo = 567-568 Kühn

12a

Observe the nature of the intestines that have been removed: substance, nature (texture)…

12b

Notice the lymphatic nodes in the mesentery, and their relation to the blood vessels.

12c

Remove stomach (leaving the mesentery intact) and study the organs from all angles and positions

12d

Remove the liver (leaving the mesentery intact) and study the organs from all angles and positions

12e

Remove spleen (leaving the mesentery intact) and study the organs from all angles and positions

12f

Remove kidneys (leaving the mesentery intact) and study the organs from all angles and positions

12g

Remove bladder (leaving the mesentery intact) and study the organs from all angles and positions

12h

Remove uterus (leaving the mesentery intact) and study the organs from all angles and positions

13 - Comments with histological relevance about the organs

Histologic composition of stomach, intestines, bladder and uterus

13a

Once the stomach is removed, cut one of its walls and observe the two strata: an inner layer of straight fibres and an outer layer of circular fibres.

13b

Repeat the same procedure with the intestines, where the same two layers can be found (although the circular fibres are more prominent than the straight ones).

13b

Repeat the same procedure with the the bladder and the uterus. Only one later will be found

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1 - Skin

Step

Instruction

Skin (V.7): 311,18 - 313,15 Garofalo = II.511-513 Kühn

Observations

Translation

I must subsequently explain how dissection can best proceed from here.

Greek Text

Πῶς δ ̓ ἄν τις ἐντεῦθεν ἀρχόμενος ἄριστα χειρουργοίη, λεκτέον ἐφεξῆς,

Images

Step Video Clip

Full Dissection - Step Timcode

3D View

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