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| ===Ascending colon=== | | ===Ascending colon=== |
| *The ascending colon is very large and takes up most of the ventral abdomen. | | *The ascending colon is very large and takes up most of the ventral abdomen. |
− | *It is the shape of a double "U", where one U is on top of the other. | + | *It is the shape of a double "U", where one "U" is on top of the other. |
− | *There are four limbs that lie parallel to each other, and three flexures that change the direction of the limbs. | + | *There are four limbs that lie parallel to each other, and three flexures that change these direction of the limbs. |
| *Sequence of the limbs and flexures of the ascending colon: | | *Sequence of the limbs and flexures of the ascending colon: |
| **Right Ventral Colon ''(for those with an RVC bias remember, "the RVC comes first!")'' | | **Right Ventral Colon ''(for those with an RVC bias remember, "the RVC comes first!")'' |
− | **Sternal Flexure | + | ***Passes out of the caecocolic orifice on the right side of the abdomen and continues cranially to the xiphoid region. |
| + | **''Sternal Flexure'' |
| + | ***Passes across the midline from right to left. |
| **Left Ventral Colon | | **Left Ventral Colon |
− | **Pelvic Flexure | + | ***Runs caudally on the left ventral abdominal floor. |
| + | **''Pelvic Flexure'' |
| + | ***Turns dorsally just cranial to the pelvic inlet and then runs cranially to the diaphragm. |
| **Left Dorsal Colon | | **Left Dorsal Colon |
− | **Diaphragmatic Flexure | + | ***Runs cranially, parallel and dorsal to the left ventral colon. |
| + | **''Diaphragmatic Flexure'' |
| + | ***Turns caudally at the diaphragm. |
| **Right Dorsal Colon | | **Right Dorsal Colon |
− | ***The right ventral colon passes out of the caecocolic orifice and continues cranially to the xiphoid region. | + | ***Continues caudally on the right. It is the shortest limb of the ascending colon. |
− | ***The sternal flexure passes across the midline.
| + | *The '''transverse colon''' continues on from the right dorsal colon as the right dorsal colon turns medially. |
− | ***The left ventral colon runs caudally on the ventral abdominal floor.
| + | *The right dorsal colon is attached by a mesentry to the dorsal abdominal wall, the base of the caecum, the root of the mesentry and the pancreas. |
− | ***Cranial to the pelvic inlet it turns dorsally and then cranially as the pelvic flexure.
| + | **This anatomical arrangement of mesentry allows the left ascending colon to twist and is a common cause of colic (colonic torsion). |
− | ***The left dorsal colon runs cranially, parallel and dorsal to the left ventral colon.
| + | *The ventral parts of the ascending colon are attached to the dorsal parts by a short mesocolon. |
− | ***At the diaphragm it turns caudally as the diaphragmatic flexure. | + | **The mesocolon houses the blood vessels, nerves and lymphatics. |
− | ***The right dorsal colon continues caudally. It is the shortest limb of the ascending colon.
| |
− | *The transverse colon continues as the right dorsal colon turns medially. | |
| *In the ventral colon many important digestive and absorptive functions take place, whilst the dorsal colon is mainly responsible for transportation of ingesta. | | *In the ventral colon many important digestive and absorptive functions take place, whilst the dorsal colon is mainly responsible for transportation of ingesta. |
− | *The right dorsal colon is attached by a mesenteric attachment to the dorsal abdominal wall, the base of the caecum, the root of the mesentry and the pancreas.
| |
− | **This anatomical arrangement of mesentry allows the left ascending colon to twist and is a common cause of colic.
| |
− | *
| |
| *Taenia are present. | | *Taenia are present. |
| **Different parts of the colon can be distinguished by the number of taenia present: | | **Different parts of the colon can be distinguished by the number of taenia present: |
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| ***The left dorsal colon and pelvic flexure have '''one''' taenia. | | ***The left dorsal colon and pelvic flexure have '''one''' taenia. |
| ***The right dorsal colon and diaphragmatic flexure have '''three''' taenia. | | ***The right dorsal colon and diaphragmatic flexure have '''three''' taenia. |
− | ***The descending colon has '''two''' taenia. | + | |
| + | ===Transverse Colon=== |
| + | *Short |
| + | *Passes from across the midline from right to left. It passes cranial to the root of the mesentry |
| + | *The transverse colon has '''two''' taenia. |
| + | *Turns caudally to become the descending colon at the level of the left kidney. |
| + | |
| + | ===Descending Colon=== |
| + | *Between 2-4m long. |
| + | *Suspended by a long mesentry; ''mesocolon descendens''. |
| + | *The descending colon has '''two''' taenia. |
| + | **Between the two taenia are distinct sacculations that house the faecal balls. |
| | | |
| ==Rectal Palpation== | | ==Rectal Palpation== |