Cow diaphragm anatomy is required to understand the extension of the thoracic and abdominal cavities. It is the chief inspiratory muscle and is described under the cow muscle anatomy.
Here, I will help you to learn the different parts, attachments, and relationships of the cow’s diagram to other organs with diagrams.
Quick answer: Cow diaphragm anatomy includes the description of the muscular and aponeurotic parts, attachment to ribs and vertebrae, and relationship with thoracic and abdominal organs.
So, you will learn the practical identification and topographic anatomy of the cow’s diaphragm.
What is the diaphragm of a cow?
The diaphragm of a cow is a dome-shaped musculo aponeurotic structure that separates the thoracic and abdominal cavities. It is the chief muscle of the cow’s inspiration and consists of two identifiable parts: muscular and aponeurotic parts.
Figure 1 shows the dome-shaped schematic diagram sheet of the cow’s diaphragm in between the thoracic and abdominal cavities.
The figure also presents the muscular and aponeurotic parts of the cow’s diaphragm. Some anatomists also expressed the outline of the cow’s diaphragm as a palm-leaf fan appearance (Getty, 1972; Martinello et al.,2023).
Cow diaphragm anatomy
Figure 2 presents the large, broad, and unpaired diaphragm muscle of the cow. It projects into the cow’s thoracic cavity.
Here, the thoracic surface of the cow’s diagram is strongly convex. In contrast, the abdominal surface of the diagram is deeply concave.
The strong convex thoracic part of the cow’s diaphragm is covered by a serous membrane called the pleura. However, the deep concave abdominal part is also covered by another serous membrane called the peritoneum.
Now, to describe the cow’s diaphragm anatomy, you might cover the followings –
- Parts of the cow diaphragm: consists of a peripheral muscular part and a central tendinous/aponeurotic part.
- Attachment of the cow diaphragm: it consists of the costal attachment, the sternal attachment, and the lumbar attachment.
- Crura/pillar of the cow diaphragm: There are right and left crura in the cow’s diaphragm.
- Hiatus/foramina of the cow diaphragm: it consists of three hiatus for the passage of the aorta, esophagus, and vena cava.
- Relationship of the diaphragm with other organs: the cow’s diaphragm is related to different organs/parts of both the thoracic and abdominal cavities.
Figure 3 shows the overview of the cow’s diaphragm that you need to write in your veterinary anatomy examination script.
Parts of the cow diaphragm
Figure 4 shows the schematic diagram/presentation of the fleshy peripheral part of the cow diaphragm. It also presents the center tendinous part of the diaphragm.
Thus, the parts of the cow diaphragm are –
- Muscular part (peripheral fleshy area), and
- Aponeurotic part (central thin tendinous area)
Here, the fleshy peripheral part is called the muscular part of the cow’s diaphragm. It presents the costal, sternal, and lumbar parts on its rim/periphery. In addition, the lumbar part presents two strong tendinous crura/pillars.
However, the center tendinous part of the cow’s diaphragm is also called the aponeurotic part. It is more elongated and partially divided into right and left halves.
The tendinous part of the cow’s diaphragm comprises radiating fibers that interlace in various directions. This special feature is found around the cow’s vena cava hiatus.
However, a strong tendinous laryer extend across below the esophageal hiatus.
Attachments of the cow diaphragm
Figure 5 presents three attachments of the cow diaphragm. Here, the diaphragm is attached dorsally, ventrally, and on two lateral aspects between the cow’s thorax and abdomen.
Thus, the three attachments of the cow’s diaphragm are –
- Costal attachment (laterally),
- Sternal attachment (ventrally), and
- Lumbar attachment (dorsally).
Costal attachment
Here, the costal attachment means that the muscular part of the cow’s diaphragm is attached to the lateral thoracic wall/ribs. However, this attachment extends from the last rib to eight rib of the cow’s thorax.
Actually, the muscle of the diaphragm forms the leaf-like muscle slips that attach to the ribs. These muscle slips are very close to the cow’s abdominal muscle, especially to the transverse abdominis muscle.
You will find different nerves and vessels in between the muscle slips.
In addition, the diaphragm muscle attaches to the ribs (from eight to the last) in a unique arrangement. You will see that the muscles attach higher on the lower ribs, while you will go from eight to thirteen ribs.
All muscle fibers curved toward the center tendinous part of the cow’s diaphragm.
Sternal and lumbar attachments of the cow’s diaphragm
The fleshy/muscular part of the cow’s diaphragm is attached to the dorsal surface of the xiphoid cartilage. This is called the ventral/sternal attachment of the cow’s diaphragm.
The sternal attachment extends from the cartilage of eight rib to the last segment of the sternum/xiphoid cartilage.
Again, the lumbar part of the cow’s diaphragm is attached to the ventral longitudinal ligament of the lumbar vertebrae. The right and left crura are responsible for the lumbar attachment of the diaphragm to different lumbar vertebrae.
Crura/pillars of the cow diaphragm
Figure 6 presents the right and left crura from the cow diaphragm anatomy. Here, the right crus is comparatively larger than the left crus of the cow’s diaphragm.
Thus, the cow diaphragm presents two following crura –
- Larger right crus, and
- Small left crus,
The right crus of the diaphragm is attached to the ventral longitudinal ligament of the first four or five lumbar vertebrae. However, the left crus is attached to the first and second lumbar vertebrae of the cow.
The right crus is about twice as thick as the left and arises from the strong tendon from the lumbar vertebrae. This tendon has a rounded belly and leaves the vertebral column at the last thoracic vertebra.
The fibers of the right crus pass downward and forward and finally join the tendinous part of the cow’s diaphragm.
Again, the left crus of the cow’s diaphragm arises from the thin tendon from the common ligament of the first and second lumbar vertebrae. It also possesses a triangular belly that joins with the central tendinous part of the diaphragm.
Hiatus of the cow diaphragm
Figure 7 shows the three hiatus/openings of the cow diaphragm. These hiatus are designed for passing of the aorta, esophagus, and vena cava (shown in the schematic diagram also).
Thus, these hiatus are named as follows –
- Hiatus aorticus: for the passage of the aorta,
- Hiatus esophagus: for the passage of the esophagus, and
- Foramen vena cavae: for the passage of the caudal vena cava.
Another name for hiatus aorticus is aortic aperature, hiatus esophagus is esophageal aperature, and foramen vena cavae is venacaval aperature.
Here, the hiatus aorticus of the cow’s diaphragm is located between the two crura and below the last/thirteen thoracic vertebra. It also contains the posterior aorta, vena azygos, and cisterna chyli.
The hiatus esophagus perforates the right crus near its junction with the center tendinous part of the cow’s diaphragm. It is located a little to the left of the median plane and six inches below the 8th thoracic vertebra.
This hiatus also passes the vagus nerve and the esophageal branch of the gastric artery along with the esophagus.
Again, the foramen vena cavae is located close to the central tendinous part of the diaphragm. It is just one or two inches right to the median plane of the cow’s body and six inches below the last thoracic vertebra.
However, you will find a good number of small openings in the cow’s diaphragm for small vessels and nerve trunks.
Relationship of the cow’s diagram with other organs
Figure 8 shows the relationship of the cow’s diagram with the different organs of the thoracic and abdominal cavities.
Here, the thoracic surface of the diaphragm is related to the lungs, pericardium, phrenic nerve and vein. This surface is also related to the endothoracic fascia, pleura, and the ribs.
However, the abdominal surface is related to the rumen, reticulum, omasum, abomasum, liver, and spleen. The double fold of the serous membrane connects the liver with the abdominal part of the diaphragm.
FAQ’s on cow’s diaphragm anatomy
The contraction of the cow’s diaphragm tends to flatten the diaphragm. It also forces the abdominal muscle caudally, further into the abdomen. Thus, it increases the volume of the thorax and lowers the intrathoracic pressure, drawing air into the lungs. Thus, the cow’s diaphragm is called the inspiratory muscle.
The phrenic nerve innervates the cow’s diaphragm. Here, the cow’s phrenic nerve arises from its ventral branches of the fourth, fifth, sixth, and seventh cervical spinal nerves.
Conclusion
Thus, the cow diaphragm anatomy describes the two parts along with their attachment to the thoracic wall and vertebrae. Here, the two parts of the cow’s diaphragm are the peripheral fleshy muscular part and the central tendinous aponeurotic part.
There are significant differences in the attachment of the right and left crura of the cow’s diaphragm to the lumbar vertebrae. The three hiatus are also important and feature of the cow’s diaphragm anatomy for the aorta, esophagus, and caudal vena cava. However, the relationship of the diaphragm with different organs of the cow’s thorax and abdomen is important, as they have practical significance.
References
- Solanki et al., Comprehensive anatomy of buffalo diaphragm, Int Jr of Vet Sci & Ani Hus, 2024; 9(2): 780-783.
- Martinello, et al., The dorsal portion of the bovine diaphragm as a useful tissue for producing a 3D muscle scaffold. Journal of Anatomy, 2023; 243, 878–885.
- Fogarty and Sieck, Evolution and Functional Differentiation of the Diaphragm Muscle of Mammals. Comprehensive Physiology, 2019; 9(2), 715–766.
- Ghosh, R. K.: Primary veterinary anatomy, 2nd Edn.Current Books International, Kolkata.
- Getty, R. S&G’sThe anatomy of the Domestic Animals, 5th Edn. W. B. Saynders and Co., Philadelphia (USA).
- Dyce, K. M., W. O. Sack and CSG Wensing: Textbook of Veterinary Anatomy, Lea & Febiger. Philadelphia
- Nickel, R., Schummer, A. and Seiferle, E.: The anatomy of domestic animals, 1st Edn. Verlag Paul Parey, Berlin.
