Blood Supply to the Thoracic Limb: Arteries & Veins

What aspect are the main arterial branches found?

Caudomedial aspect of the limb

Where do long bones receive their blood supply?

Mid-shaft through nutrient foramen

Where do joint capsules receive their rich blood supply?

Perarticular region where the joint capsule attaches to the periosteum

Do anastomoses occur in the thoracic limb?

YES, especially in the manus

Describe the superficial set of veins

Do not accompany arteries; anastomose with the deeper set of veins at certain points

Why is the anastomosis of vessels important?

Allows blood to drain through alternate route if certain vessels are blocked or compressed

Where are the proximal superficial set of veins found in the thoracic limb?

Cranial and lateral

What are the superficial set of veins involved in and what are they useful for?

Thermoregulation; intravenous sampling/injection

What is the main artery entering the thoracic limb?

Axillary artery

What is the axillary artery the continuation of?

Subclavian artery

What branch of the subclavian artery supplies the shoulder region and protractors of the thoracic limb?

Superficial cervical artery

Describe the course of the axillary artery

1. Emerges from the cranial border of the first rib

2. Crosses the axillary space

3. Enters thoracic limb

What structures are supplied by the axillary artery?

Shoulder region

What are the four branches of the subclavian artery?

1. External thoracic artery

2. Lateral thoracic artery

3. Subscapular artery

4. Cranial circumflex humeral artery

What do the external and lateral thoracic arteries supply?

Pectoral muscles

What specific muscles does the external thoracic artery supply?

Superficial pectorals (descending and transverse)

What specific muscles does the lateral thoracic artery supply?

Deep pectorals (ascending) and cutaneous trunci

Describe the course of the subscapular artery

Runs caudal to the shoulder joint

What structures are supplied by the subscapular artery?

1. Flexors of the shoulder joint

2. Extensors of the elbow joint

3. Flexors of the elbow joint

What are the three branches of the subscapular artery

1. Thoracodorsal artery

2. Caudal circumflex humeral artery

3. Collateral radial arteries

What structure does the thoracodorsal artery supply?

Latissimus Doris

What structures does the caudal circumflex humeral artery supply?

Deltoideus, brachialis, triceps brachii

What structure does the cranial circumflex humeral artery anastomose with?

Caudal circumflex humeral branch of the subscapular artery

What structures does the cranial circumflex humeral artery supply?

Brachialis and part of triceps

What is the continuation of the axillary artery after it gives off the cranial circumflex humeral artery?

Brachial artery

What region does the brachial artery supply?

Brachial region

Describe the path of the brachial artery

1. Medial aspect of the humerus

2. Between the musculocutaneous and the median nerves

What is clinically significant regarding the brachial artery?

Location for taking a pulse (medial aspect of the brachium)

What are the six main branches of the brachial artery?

1. Deep brachial artery

2. Bicipital artery

3. Superficial brachial artery

4. Collateral ulnar artery

5. Transverse/median cubital artery

6. Common interosseus artery

What are the general structures that the branches of the brachial artery supply?

Muscles, skin, and bone of the brachial and antebrachial regions

What does the deep brachial branch of the brachial artery supply?

Triceps brachii muscles

What does the bicipital branch of the brachial artery supply?

Biceps brachii muscle

What is the course of the superficial brachial branch of the brachial artery?

Runs distally over the antebrachium; medial and lateral branches run distal to the carpus to the manus

What structures do the superficial brachial artery branches supply?

Skin on dorsal aspect of the antebrachium, manus, and digits

What structures does the collateral ulnar branch of the brachial artery supply?

Elbow joint and caudomedial muscles of the antebrachium

What structures does the transverse/median cubital artery supply?

Carpal and digital extensors

Where is the common interosseus branch of the brachial artery located?

Within the interosseus muscle between the radius and ulna

What are the three branches of the common interosseus branch of the brachial artery?

1. Ulnar artery

2. Cranial interosseus artery

3. Caudal interosseus artery

Describe the course of the ulnar artery of the common interosseus branch

Distally on the lateral aspect of the flexor carpi ulnaris

What are the contributions of the ulnar artery to other vessels?

1. Recurrent branch to the collateral ulnar artery

2. Contributes to the dorsal carpal rete

3. Anastomose with the caudal interosseus artery in the carpal canal

Describe the course of the caudal interosseus artery?

1. Runs between the interosseus membrane and the pronator quadratus

2. Runs through the carpal canal

What does the caudal interosseus artery contribute to at the level of the carpus?

Dorsal carpal rete

What vessel does the branch of the caudal interosseus artery anastomose with in the carpal canal?

Ulnar artery

What two structures does the caudal interosseus artery supply after the carpal canal?

Superficial and deep palmar arches

After giving off the common interosseus artery, what does the brachial artery continue as?

Median artery

What is the largest artery to the distal thoracic limb?

Median artery

Describe the median artery in terms of structures it supplies

Main artery to the antebrachium and manus

Describe the course of the median artery

1. Deep aspect of the flexor carpi ulnaris in the antebrachial region

2. Passes through the carpal canal

What are the two main branches the median artery gives off in the antebrachial region?

1. Deep antebrachial artery

2. Radial artery

What structures does the deep antebrachial artery supply?

Carpal and digital flexors

What is the course of the radial artery?

Medial aspect of the radius

What is the radial artery used for in humans but rarely in dogs?

Taking a pulse

What two structures does the radial artery contribute to at the level of the carpus?

1. Dorsal carpal rete

2. Deep palmar arch

What is the branch of the radial artery to the deep palmar arch termed?

Palmar branch of the radial artery

What other artery helps to form the deep palmar arch?

Caudal interosseous artery

What structure does the median artery form after passing through the carpal canal?

Superficial palmar arch

What arteries supply the manus below the carpus on the dorsal aspect?

1. Superficial set - superficial brachial artery

2. Deep set - dorsal carpal rete

The blood supply to which aspect of the manus below the level of the carpus is richer?

The palmar blood supply

What are the main arteries involved in supplying the manus below the level of the carpus?

1. Superficial brachial artery

2. Caudal interosseous artery (common interosseous artery)

3. Ulnar artery (common interosseous artery)

4. Median artery

What structure do the branches of the superficial brachial artery supply in the manus?

Superficial structures

What is main branch from the superficial brachial artery on the dorsal aspect of the manus?

Dorsal common digital arteries

Where are the dorsal common digital arteries located in the manus?

Along the metacarpals

What branches arise from the dorsal common digital arteries?

1. Dorsal axial proper digital arteries (I-V)

2. Dorsal abaxial proper digital arteries (I-V)

Where do the proper digital arteries course?

Across the axial and abaxial surfaces of each digit

What structures are supplied by the dorsal carpal rete of the deep dorsal manus arterial supply?

Tendons and bones of the manus

What arteries form the dorsal carpal rete?

Branches of the radial, caudal interosseous, and ulnar arteries

What arteries are derived from the dorsal carpal rete on the manus?

Dorsal metacarpal arteries (I-IV)

What structure do the dorsal metacarpal arteries anastomose with?

Dorsal common digital arteries from the superficial antebrachial artery

What arteries supply the manus below the carpus on the palmar aspect?

1. Superficial palmar arch

2. Deep palmar arch

Where are the superficial and deep palmar arches located within the manus?

Proximal end of the metacarpus on the palmar aspect

Where is the superficial palmar arch specifically located?

Between the superficial digital flexor and deep digital flexor

What arteries form the superficial palmar arch?

1. Median artery (main)

2. Caudal interosseous artery from the common interosseous artery (small contribution)

What does main branches does the superficial palmar arch split into?

Palmar common digital arteries

What course do the palmar common digital arteries follow?

Follow the split flexor tendons for each digit

What branches do the palmar common digital arteries split into?

1. Palmar axial proper digital arteries (I-V)

2. Palmar abaxial proper digital arteries (I-V)

What structures are supplied by the superficial palmar arch and its branches?

Pads and dermis of claws

Where is the deep palmar arch located within the palmar aspect of the manus?

Deep to the interosseus muscles

What arteries form the deep palmar arch?

1. Palmar branch of the radial artery

2. Caudal interosseous artery of the common interosseous artery

3. Ulnar artery of the common interosseous artery

How does the ulnar artery contribute to the formation of the deep palmar arch?

It fuses with the caudal interosseous artery in the carpal canal

What branches does the deep palmar arch give rise to?

Palmar metacarpal arteries (I-IV)

Are there anastomoses between the palmar and dorsal arteries of the manus?

YES

What is clinically significant about the arrangement of the manus arterial supply?

1. Rich palmar blood supply leads to considerable bleeding when cut

2. Superficial palmar arch and branch arrangement aids in diffusion of concussion and thermoregulation

How many sets of veins compose the major veins of the thoracic limb?

Two; superficial set and deep set

Which set of veins follows the major arterial supply of the thoracic limb?

The deep set

What are the superficial set of veins of the thoracic limb used for?

Thermoregulation

What is the main superficial vein of the thoracic limb?

Cephalic vein

What is the location of the cephalic vein?

Cranial aspect of the antebrachium

What is most clinically significant about this structure?

Common site for intravenous sampling and injection

What muscle does the cephalic vein run deep to on the proximal thoracic limb?

Brachiocephalicus

What major vein does the cephalic vein join at the proximal limb?

External jugular vein

What branch from the cephalic vein runs superficial to the shoulder joint?

Omobrachial vein

What specific boney structure does the omobrachial vein pass over?

Greater tubercle of the humerus

What muscles does the omobrachial vein pass between?

Brachiocephalicus and omotransversarius

What major vessel does the omobrachial vein join with after passing proximally over the shoulder joint?

External jugular vein

What vessel joins with the cephalic vein distally?

Accessory cephalic vein

Which direction does the cephalic vein continue at the point where its is joined by the accessory cephalic vein?

Medially towards digit I

What are the two point where the superficial veins and deep veins of the thoracic limb anastomose?

1. Transverse/Median cubital vein

2. Axillo-brachial vein

What two vessels connect at the transverse/median cubital vein?

1. Cephalic vein

2. Median vein

Where is the transverse/median cubital vein located?

Flexor aspect of the elbow

What two vessels connect at the axillo-brachial vein?

1. Cephalic vein

2. Axillary vein