The subclavian artery continues as the ruminant axillary artery under the axilla. You will find one axillary artery in each thoracic limb of the cows.
Here, I will show the branches and courses of the cow’s axillary artery with the diagram. The course of a cow’s axillary artery is almost similar to that of a small ruminant like sheep and goat.
Quick overview: The subclavian artery passes under the shoulder joint as the axillary artery. It becomes the brachial artery at the arm and then the median artery at the distal elbow. Finally, the same artery continues as the dorsal metatarsal and supplies the dorsal and palmar aspects of the digits.
I will make the course of the cow’s axillary artery easy for your understanding. Let’s see this artery’s origin, branches, distributions, and main courses from the cow’s thoracic limb.
What is the axillary artery in veterinary anatomy?
The axillary artery in the veterinary anatomy is the main arterial distribution of the animal’s thoracic limb. In animals, the right and left axillary arteries are distributed in their respective right and left forelimbs.
Again, these axillary arteries of animals arise from the subclavian arteries. Here, the diagram shows the origin of the right and left subclavian arteries directly from the brachiocephalic trunk.
The right subclavian artery of most animals arises from the brachiocephalic trunk at the level of the first ribs. However, the animal’s left subclavian artery arises from the brachiocephalic trunk at the level of the second intercostal space.
You may know the details of the heart and brachycephalic trunk from the below-mentioned article –
- Cow heart anatomy – right and left atriums, ventricles, and aorta (brachiocephalic trunk and descending part),
You might know the anatomy of ribs to identify the second intercostal space and first ribs from animals (cows).
Ruminant axillary artery location
The small and large ruminant’s axillary artery is under the axilla (shoulder joint). It arises from the subclavian artery after the origin of the superficial cervical artery.
Again, this axillary artery is continued as the brachial artery at the distal-caudal aspect of the scapula. At this point, the axillary artery gives off the larger subscapular branch to the scapula.
Location and extension of the ox axillary artery: under shoulder joint; superficial cervical artery to the subscapular artery.
Here, the diagram shows the location and extension of the small and large ruminant’s axillary artery. But, I will describe the course of this artery in the different regions of the cow’s thoracic limb.
Ruminant axillary artery course
Learning the course of animal axillary or subclavian arteries from different limb segments will be good. First, I will show you the major course of the animal axillary artery (for example, with the cows). Then, I will enlist the axillary artery branches from their different parts with their distribution.
Let’s describe the short and main course of the left subclavian and axillary artery of the cow –
- Origin: the left subclavian artery of the cow arises from the brachiocephalic trunk at the level of the second intercostal space.
- Axillary artery: after the superficial cervical branch of the subclavian, it becomes the axillary artery under the axilla.
- Brachial artery of the ox: the axillary artery passes through the subscapularis and teres major muscle, giving off the subscapular artery. Now, it continues as the brachial artery at the caudal aspect of the shoulder joint and passes over the brachium.
- Ox or cow’s median artery: the brachial artery courses distally and follows the median nerve at the flexor surface of the elbow. It passes beneath the tendon of biceps brachii and pronator teres (distal to elbow joint). Finally, it gives off the common interosseous artery and continues as the median artery.
- Radial artery of the ox: at the middle of the forearm, the radial artery arises from the median artery. It extends distally along the mediopalamr aspect of the carpus of the cows. Now, the radial artery consists of 3 branches (which will be described in the branch section description).
Summary of the arterial distribution to the cow’s forelimb
Table 1 summarizes the arterial distribution of the cow’s fore limb. Here, I tried to focus on the major branches of the subclavian and axillary artery of the cow.
|Branches of the cow’s axillary artery
|Location of the arteries of cow’s fore limb
|Subclavian artery of a cow
|Just below the clavicle
|Axillary artery of the cow
|Below the axilla or shoulder joint
|Brachial artery of the cow
|Passes through the cow’s brachium
|Common interosseous artery of the cow
|Distal to the cow’s elbow joint
|Median artery of the cow
|Passes through the median groove
|Radial artery of the cow
|In the middle of the forearm of a cow
Branches of the radial artery in the cow’s manus
The radial artery gives off small branches that contribute to forming the dorsal carpal rate. You will find the following arteries in the different segments of the cow’s manus –
Cow’s metacarpal artery: the dorsal carpal branch of the radial artery continues as the dorsal metacarpal artery III. This artery passes through the longitudinal groove of the cow’s metatarsal bone.
Dorsal proper digital arteries: the dorsal metacarpal continues as the dorsal common metacarpal III at the fetlock joint. At the first proximal phalanx, it becomes the dorsal proper digital arteries III and IV.
Palmar metacarpal arteries of the cow: dorsal carpal and deep palmar branches of the radial arteries help to form the palmar metacarpal branch. Here, the dorsal carpal forms the dorsal carpal rate and finally forms the common trunk for the palmar metacarpal III and IV.
Again, the dorsal carpal anastomoses with the palmar carpal branch. The dorsal carpal rate and deep palmar arch communicate with the dorsal metacarpal III.
Palmar proper digital arteries of the cow: from the common palmar metacarpal, the palmar proper digital arteries II and III arise. Again, the palmar proper digital arteries IV and V arise from the deep carpal branches of the radial artery.
Ruminant axillary artery branches
Now, I will show the branches from the ruminant axillary artery in the different segments of the limb. Make sure you know the various segments of the ruminant’s forelimb –
- Shoulder of the animal: formed by the scapula bone,
- Brachium of the animal: formed by the humerus bone,
- Ante-brachium of the animal: formed by the radius and ulna bones and
- Manus of the animal: formed by the carpal, metacarpal, and phalanges,
Again, you might know the different muscles of the ruminant’s (cow) fore limb. The article helps you to know the segments, bones, and muscles from a cow’s forelimb –
Now, let’s see the branches of the subclavian or axillary artery from the cow’s leg –
Chief branches of the cow’s axillary artery
You will find two major branches of the cow’s axillary artery below the shoulder joint –
- External thoracic artery: it is large and gives off the deltoid branch. This artery supplies to the pectoral, biceps brachii, brachiocephalicus, subclavius, omotransversarius, and coracobrachialis muscles.
- Subscapular artery: it is also large and supplies to the supraspinatus, subscapularis, and the cranial aspect of the shoulder joint.
Branches of the cow’s subscapular artery
The subscapular artery of the cow is larger than the brachial artery. It passes caudodorsally between the subscapularis and the major muscles.
This subscapularis artery gives off several collateral branches to the following structures –
- Subscapularis muscle,
- Teres major and tensor fascia antebrachial muscle,
- Long head of the triceps brachii muscle,
- Deltoideus, teres minor, supraspinatus, and infraspinatus muscles, and
- The medial aspect of the shoulder joint,
The major branches of the cow’s subscapular artery are –
- Circumflex scapular artery: gives off the nutrient artery to the cow’s scapula,
- Thoracodorsal artery: it courses along the medial surface of the teres major and latissimus dorsi muscles and
- Caudal circumflex humeral artery: it gives off several collateral arteries. It passes lateral along the flexor aspect of the shoulder joint and divides into proximal and distal parts.
Several collateral arteries supply the teres major, tensor fascia, triceps brachii, and pectoralis profundus muscles. The proximal branch of the caudal circumflex humeral artery passes between the triceps brachii and brachialis muscles.
This branch of the caudal circumflex humeral supplies the deltoid, triceps, teres major, brachialis, and infraspinatus muscles. It also supplies the craniolateral aspect of the cow’s shoulder joint.
The distal branch of the caudal circumflex humeral supply the following structures –
- Triceps, brachialis, anconeus, and extensor carpi radialis muscles, and
- The lateral and caudolateral aspects of the elbow joint,
Branches of the cow’s brachial artery
The cow’s axillary artery gives off the subscapular artery and continues as the brachial artery. This artery of the cow’s brachium courses caudally and follows the median nerve.
This artery passes beneath the tendons of the biceps brachii and pronator teres muscle. Just below the elbow joint, the brachial artery of the co gives off the common interosseous artery and continues as the median artery.
Let’s see the main branches of the cow’s brachial artery in the brachium and proximal part of the ante-brachium –
- Cranial circumflex humeral artery: it is the first branch of the cow’s brachial artery. It supplies to the coracobrachialis, biceps brachii, subclavius, and medial aspect of the shoulder joint.
- Deep brachial artery: it is small and anastomoses with the collateral ulnar artery. This branch of the brachial artery supplies the triceps brachii muscle.
- Collateral ulnar artery: it arises from the caudal aspect of the brachial artery at the level of the olecranon tuber. It supplies to the triceps, anconeus, pectoralis, flexor digital profundus, and caudomedial aspect of the elbow.
- Transverse cubital artery: it arises from the brachial artery at the level of the flexor surface of the elbow joint. It divides into proximal bicipital and distal arteries. They supply to the coracobrachialis, brachialis, brachiocephalicus, and pectoralis muscles.
- Common interosseous artery: this is the last branch of the cow’s brachial artery, just distal to the elbow joint. It supplies to the flexor digitorum profundus and ulnaris lateralis muscles.
Branches of the common interosseous artery
The common interosseous artery of the cow gives off two main branches –
- Cranial interosseous artery, and
- Caudal interosseous artery,
Here, the cranial interosseous artery descends along the craniolateral aspect inside the groove between the radius and ulna. It divides into dorsal and palmar branches at the distal of the forearm of a cow.
The dorsal branch of the cranial interosseous is again divided into deep and superficial branches. Meanwhile, the palmar branch forms the deep palmar arch in the cow.
The cranial interosseous artery also gives off the recurrent interosseous artery. This artery supplies to the adductor digit I longus, extensor digitorum longus, and extensor digitorum communis muscles.
Branches of the cow’s median and radial arteries
After the branches of the common interosseous, the brachial artery continues as the cow’s median artery. It gives off several large muscular branches at the proximal third of the forearm (ante-brachium).
The cow’s radial artery arises from the median artery in the middle of the ante-brachium. Let’s see the three major branches of the cow’s radial artery –
- Dorsal carpal branch: continue as the dorsal metacarpal artery III in a cow,
- Articular branches of the cow’s radial artery and
- Common trunk for the dorsal carpal and deep palmar arteries,
Ultimately, the common trunk for the dorsal carpal and deep palmar arteries supply the digits on their palmar aspects.
So, the ruminant axillary artery arises from the subclavian artery and gives off different branches to the fore limb. The same artery passes through the different forelimb segments as various names.
The subclavian, axillary, brachial, medial, and radial are the major arterial supply to the cow’s forelimb. Now, you might practice the courses of the ruminant axillary artery from the real sample of the cow’s leg.