Cow neck muscles

Cow neck muscles are well-developed to support and provide greater flexibility to the head. It presents the most complex arrangement among the different regions of cow muscle anatomy.

Here, I will identify and present the cow’s neck muscles in a very easy way with schematic diagrams and real pictures.

Quick answer: Cow neck muscles are arranged into two groups, the ventral group and the dorsolateral group of cervical muscles.

Thus, you will learn how to identify these two groups of muscles from the neck layer by layer.

Cow neck muscles

Figure 1 shows a schematic diagram/presentation of the cow’s neck muscles from the ventral and ventrolateral aspects. The muscles included in this group are known as the ventral cervical muscles of the cow’s neck.

Thus, you will find the following muscles in the ventral cervical/neck group –

• Brachiocephalicus muscle: It consists of cleido occipitalis and the cleidomastoid parts.
• Omotransversarius muscle: It runs along the deep face of the brachiocephalicus muscle.
• Sternocephalicus muscle: It consists of sternomandibularis and sternomastoideus parts.
• Sternothyrohyoideus muscle: This muscle consists of sternothyroideus and sternohyoideus parts.
• Omohyoideus muscle: Practically, it lies deep to the sternomastoideus muscle.
• Scaleneus muscle: It consists of the dorsalis and ventralis parts.
• Longus capitis muscle: Practically, it lies below the splenius muscle.
• Longus colli muscle: It resembles a V-shaped form on the lateral surface of the bodies of cervical vertebrae.  
• Intertransversales colli muscle: These are six segmental muscles in the neck.

Again, Figure 2 shows the schematic diagram/presentation of the dorsolateral cervical muscles of the cow.

Here, the dorsolateral muscles of the cow’s neck are arranged in four layers –

• First layer: It consists of the trapezius and brachicephalicus muscles.
• Second layer: It consists of rhomboideus and omotransversarius muscles.
• Third layer: It consists of a large serratus cervicis muscle.
• Fourth layer: It consists of splenius, longissimus capitis, semispinalis capitis, and multifidus capitis muscles.

Now, you need to identify all these muscles from the ventral and dorsolateral aspects of the cow’s neck practically.

Identification of the cow’s ventral neck muscles

To identify the cow’s ventral neck muscles from a real sample, you may use the schematic diagram (Figures 1 and 2). Again, I will follow similar identifying strategies that were also followed in the identification of the cow’s abdominal muscle and forelimb muscles.

Thus, you need to know the exact fiber directions of these neck muscles and their position. However, you might also know the bony structure of the cow’s neck.

Here, Figure 3 shows all the superficial muscles from the ventral aspect of the cow’s neck.

But I will help you to identify these cows’ neck muscles individually.

What is the brachiocephalicus in a cow?

The brachiocephalicus is a thin and first ventrolateral muscle in a cow’s neck. Here, Figure 4 shows that it extends from the cow’s head to the arm segment of the forelimb. 

It lies just beneath the skin and the cutaneous colli muscle in the cow. So, after removing the skin, the first layer of ventrolateral muscle of the cow’s neck is the brachicephalicus muscle.

However, this muscle is divided into two divisions: dorsal and ventral. The dorsal division of the cow’s brachicephalicus is cleido occipitalis muscles. In contrast, the ventral division is the cleidomastoid muscle.

When the head and neck are fixed, the brachicephalicus muscle pulls up the forelimb cranially. However, when the cow’s forelimbs are fixed, it depresses the head.

Thus, the unilateral contraction of the brachicephalicus muscle flexes the neck to the contracting side.

Omotransversarius muscle in a cow

Figure 5 shows a flat, long muscle that extends from the wing of a cow’s atlas to the shoulder. Practically, it runs along the deep face of the brachicephalicus muscle.

However, the caudal part of this muscle lies between the cow’s brachicephalicus and trapezius muscles.

Thus, this is the omotransversarius muscle of the cow.

If the cow’s shoulder becomes fixed, this muscle moves the neck laterally. Again, if the neck is fixed, it draws the shoulder and the forelimb cranially.

Cow’s sternocephalicus muscle identification

Here, Figure 6 shows a long and narrow muscle just below the cleidomastoideus part of the cow’s brachiocephalicus muscle. It extends along the ventral and lateral aspect of the cow’s trachea from the sternum to the angle of the mandible.

It forms the ventral boundary of the cow’s jugular furrow and clearly divides into two divisions: superficial and deep. Here, the superficial division of this muscle is called the sternomandibularis (Figure 6).

Again, the deep division of the cow’s sternocephalicus is known as the sternomastoideus muscle.

Thus, it is the sternocephalicus muscle of the cow. Both the right and left sternocephalicus muscles lie close to each other in the lower two-thirds of the cow’s neck.

Finally, they diverge from each other and cover the lateral aspect of the cow’s trachea.

Both the cow’s right and left sternocephalicus muscles flex the head and neck ventrally. It also causes the turning of the cow’s head to one side. However, this muscle assists in opening the cow’s mouth by depressing the mandible.  

What is the sternothyrohyoideus muscle in a cow?

The sternothyrohyoideus is a long, slender, digastric muscle of the ventrolateral aspect of the cow’s neck. Here, Figure 7 shows that it lies on the ventral surface of the cow’s trachea.

Thus, to identify the sternothyrohyoideus muscle from the cow’s neck, you might identify the trachea first.

The figure also shows that the cow’s sternothyrohyoideus muscle divides into two parts: sternothyroideus and sternohyoideus. But, they can be easily identified only when they reach near the base of the cow’s head.

Both the right and left sternothyroideus muscles lie close together ventrally and laterally. Thus, it covers the cow’s trachea completely ventrally and laterally except the cranial aspect.

This muscle retracts the cow’s hyoid bone, tongue, and larynx and assists in deglutition.

Identification of the Omohyoideus muscle of a cow

There is a thin, ribbon-like muscle, almost entirely fleshy muscle in the cow’s neck (Figure 8). Superficially, it was covered by the cow’s sternocephalicus and brachicephalicus muscles.

This is the omohyoideus muscle of a cow, and practically it covers the trachea very obliquely. Again, for easy visualization and identification of the cow’s omohyoideus muscle, you might remove the sternocephalicus and brachicephalic muscles from the neck of a cow.

The omohyoideus muscle of a cow extends from the ventrolateral aspect of the cow’s neck to the basihyoid bone. It depresses and retracts the cow’s hyoid bone and root of the tongue.

How to identify scaleneus muscle in a cow?

The cow’s scalaneus muscle is located on the side of the posterior part of its neck. Thus, to identify the scalaneus muscle from the cow, you might remove the forelimb bones and muscles.

Figure 9 shows the cow’s scalaneus muscle that is located partly in the caudal part of the neck and craniolateral part of the thorax. It also shows two distinct divisions: ventral and dorsal.

Here, the dorsal division is the scalaneus dorsalis, whereas the ventral division is the scalaneus ventralis muscles. The root of the cow’s brachial plexus emerges between these two divisions of the scalaneus muscle.

When both right and left scalaneus muscles act, the cow’s neck becomes flexed. If the unilateral scaleneus muscle acts, it inclines the neck on the corresponding side.

However, if the neck is flexed, this cow’s scalaneus muscle performs the respiratory function by pulling the ribs cranially (Getty, 1972).

Cow’s longus capitis muscle identification

There are different straight capitis muscle in the deep layer of the cow’s neck on its caudal aspect (Figure 10). To identify these straight capitis muscles from the cow’s neck, you need to remove all the superficial muscles.

Here, the capitis ventralis is a long, flat muscle in the cow’s neck. It extends from the sixth cervical vertebrae to the base of the cranium/skull.

However, it lies along the ventrolateral aspect of the cow’s second to sixth cervical vertebrae. It continues with the longus colli muscle that comes from the thoracic part of the vertebral column.

It also connects the entire ventral surface of the cervical vertebrae to the base of the cow’s skull. This muscle is also known as the longus capitis, and it flexes and inclines the cow’s head.

There is a small but strong fleshy muscle that lies dorsolateral to the cow’s longus capitis muscle. It crosses the lateral part of the ventral surface of the cow’s atlantooccipital articulation. This muscle is known as the straight capitis ventralis minor, which assists the longus capitis in flexion of the cow’s head.

However, there is a small, slender muscle that runs from the ventral arch of the atlas to the jugular process of the cow’s occipital bone. It is known as the straight capitis lateralis muscle of the cow’s neck.

Longus colli muscle of a cow

Figure 11 shows the long, slender, and strong muscle lies on the ventral surfaces of the cervical and first six thoracic vertebrae. Thus, this muscle has cervical and thoracic parts.

This is the longus colli muscle of a cow. To identify this muscle, you might remove all the ventrolateral muscles from the cow’s neck.

However, this muscle form V-shaped appearance on the ventral surface of the cervical and thoracic vertebrae. It helps to flex the cow’s neck ventrally.

Cow’s intertransversales colli muscle

These are the six segmental muscles that occupy the lateral aspect of vertebrae and transverse and articular processes. Thus, to identify these intertransversales colli muscles from the cow’s neck, you might remove all other superficial muscles.

Each muscle of the intertransversals has two bundles: dorsal and ventral. The dorsal bundle arise from the transverse process of the vertebra and runs forward and upward. Finally, it gets attached to the articular process of the preceding vertebra.

Again, the ventral bundle occupy the intertransversales space and is attached to the adjacent transverse process.

The muscle bundles from the sixth to the second cervical vertebrae form the common mass. It connects with the tendon and inserts into the wing of the cow’s atlas bone.

Identification of dorsolateral neck muscles of the cow

The arrangement of the different muscles in the dorsolateral aspect of the cow’s neck is complex. However, these dorsolateral muscles of the neck are arranged in four layers.

I will try to show these dorsolateral muscles from the cow’s neck in an easy way with schematic diagrams (shown in Figure 2). I will also use the cow muscle samples to identify these dorsolateral muscles from their neck (in Figure 12).

Some of the larger muscles from this aspect of cow’s neck are also included in the shoulder and thorax muscles group. Thus, I will only focus on the important dorsolateral muscles from the cow’s neck.

Figure 12 shows the different muscles of the four layers of the dorsolateral aspect of the cow’s neck.

Cow’s trapezius and brachiocephalicus muscle (first layer)

There is a flat, wide, and triangular muscle at the uppermost part of the forelimb (Figure 13). Though it is considered the forelimb muscles, it also covers the caudo-dorsal part of cow’s neck.

This muscle extends along the nuchal ligament in the cervical part, and the supraspinous ligament in the thoracic part. It lies ventrally and covers part of the cow’s shoulder.

This is the trapezius muscle of the cow, which is very extensive and has two parts –

• Cervical part: It is known as trapezius cervicis.
• Thoracic part: It is known as trapezius thoracis.

But there is no practical separation between these two parts of the cow’s trapezius muscle. Here, the part of this muscle cover the cervical region is the cervical part. Whereas, the part cover the thoracic region is known as the thoracic part.

The cervical part of the cow’s trapezius muscle pulls the scapula’s dorsal and cranial aspect. Again, the thoracic part draws the cow’s scapula caudal and dorsal aspects.

However, the cow’s brachicephalicus muscle was identified previously in the ventrolateral muscles of the neck (in Figure 4).

Rhomboideus and omotransversarius muscles of the cow (second layer)

After removing the cow’s trapezius, you will see an extensive and triangular muscle (Figure 14). It extends from the funicular part of ligamentum nuchae to the supraspinous ligament at the level of the ninth thoracic vertebra.

This is the rhomboideus muscle of the cow and presents two parts: cervical and thoracic. There is no clear demarcation between the cervical and thoracic parts of the cow’s rhomboideus muscle.

Here, the cervical part of the cow’s rhomboideus is thick and wide at its cranial part. In contrast, the thoracic part is thin, irregular, and quadrilateral.

Here, the cervical part draws the cow’s shoulder cranially, and the thoracic part draws it dorsally.

The omotransversarius, which is the muscle of the ventrolateral aspect of the neck, also extends to the dorolateral aspect (in Figure 5).  

Serratus cervicis muscle of a cow (third layer)

The cow’s serratus cervicis muscle partly covers the neck and partly covers the thorax (Figure 15). The first and second layer muscles should be removed from the dorsolateral muscles of the cow’s neck to identify this muscle.

The cow’s serratus cervicis extends from the level of the second cervical vertebra to the first rib. Again, the caudal part of this muscle is covered by the cow’s serratus thoracis muscle.

The thoracic part of the cow’s serratus muscle shows clear serration in the ventral direction.

Splenius and capitis muscle of the cow (fourth layer)

The fourth layer of muscle from the dorsolateral aspect of the cow’s neck presents more complex muscles (Figure 16). It presents a thin, flat, triangular muscle just under the cow’s rhomboideus muscle.

This is the splenius muscle of the cow that lies on the dorsal surface of the neck.

There is a long and thick strip of muscle placed between the splenius and semispinalis capitis. It is known as the longissimus capitis, which extends from the level of the first thoracic vertebra to the head.

However, this muscle also presents two divisions: the superior is the longissimus capitis, and the inferior is the longissimus atlantis. Here, the largest muscle that lies on the dorsal surface of the cow’s cervical vertebrae is the semispinalis capitis muscle (Figure 17).

This is a very complex muscle that is covered by the splenius and longissimus capitis muscles. It lies lateral to the ligamentum nuchae and arises from the transverse process of the ninth cervical vertebra.

It gradually increases in size and become wide muscle till it reaches the level of the seventh cervical vertebra. Both right and left semispinalis capitis muscles extend the cow’s head and neck.

FAQ’s on cow’s neck muscles

Conclusion

The skeletal muscles of the neck region of a cow are arranged into two groups – ventrolateral and dorsolateral groups. Here, the brachicephalicus, sternocephalicus, sternothyroihyoideus, and scalaneus are the major muscles from the ventrolateral aspect of the cow’s neck.

However, the dorsolateral group of the cow’s neck muscle presents in four different layers. The trapezius, rhomboideus, serratus, and splenius are the major muscles from the dorsolateral aspect of the cow’s neck.

References

• Mansour et al., The Head, Neck, and Vertebral Column. In Guide to Ruminant Anatomy, 2017; (eds M. Mansour, R. Wilhite and J. Rowe). https://doi.org/10.1002/9781119379157.ch1 
• Karima et al., Muscle and bone distribution in mature normal and double muscled cows, Livestock Production Science, Volume 28, Issue 4, 1991, Pages 291-303, ISSN 0301-6226, https://doi.org/10.1016/0301-6226(91)90011-E. 
• Ghosh, R. K.: Primary veterinary anatomy, 2nd Edn.Current Books International, Kolkata.
• Getty, R. S. & G.’s The anatomy of the domestic animals, 5th Edn. W. B. Saynders and Co., Philadelphia (USA).
• Nickel, R., Schummer, A. and Seiferle, E.: The anatomy of domestic animals, 1st Edn. Verlag Paul Parey, Berlin.
• Mcleod, W. N.: Bovine anatomy, 2nd Edn. Burgess Publishing Co., Minneapolis.
• Dyce, K. M., W. O. Sack and CSG Wensing: Textbook of Veterinary Anatomy, Lea & Febiger. Philadelphia