Summary of Comparative Thoracic Limb Vascularization
Comparative Thoracic Limb Vascularization: Arteries & Veins
Introduction
The thoracic limb vascular anatomy describes the major arteries and veins supplying the forelimb for domestic animals. This guide focuses on the main arterial branches, their course, and the muscles and joints they supply. The material is broken into manageable sections with clinical and practical notes to help you retain and apply the information.
Definition: The axillaris artery is the principal continuation of the subclavian artery supplying the thoracic limb; it gives rise to branches that supply shoulder, brachium, and antebrachium structures.
Overview: Major arterial trunks
- A. axillaris (axillary artery): main continuation of a. subclavia, runs on the medial surface of the shoulder region and continues caudally to the collum humeri.
- Main divisions of a. axillaris: a. subscapularis and a. brachialis.
A. axillaris — key branches and targets
- Cervicalis superficialis (in some species) — supplies prescapular region
- Thoracica externa — supplies the pectoral muscles (mm. pectorales) and varies by species in the exact muscular targets
- Suprascapularis (in bovine and equine) — supplies m. supraspinatus, m. subscapularis and the shoulder joint
Definition: A branch is an artery arising from a parent trunk to supply specific muscles, skin regions, or joints.
A. subscapularis (branch of a. axillaris)
- Main branches: a. circumflexa humeri caudalis, a. thoracodorsalis, a. circumflexa scapulae
- Typical supply: muscles of the scapular and proximal brachial region (m. brachialis, heads of m. triceps brachii, m. teres minor, m. latissimus dorsi)
Table: A. subscapularis branches and targets
| Branch | Principal targets | Notes / species differences |
|---|---|---|
| a. circumflexa humeri caudalis | m. brachialis, caput laterale of m. triceps brachii, m. teres minor | Gives off r. proximalis to m. brachialis in sheep; contributes to collaterals |
| a. thoracodorsalis | m. latissimus dorsi, m. teres major, m. subscapularis | May be branch of a. brachialis in some species (bovine) |
| a. circumflexa scapulae | m. supraspinatus, m. infraspinatus, m. deltoideus | Runs around lateral scapula surface |
💡 Did you know?Fun fact: In bovine anatomy the origin and branching pattern of the thoracodorsal artery can vary and sometimes arises as a branch of the brachial artery rather than directly from the subscapular artery.
A. brachialis (continuation/branch of a. axillaris)
- Course: runs on the medial surface of the brachium alongside v. brachialis and n. medianus, on the craniomedial surface of the elbow joint.
- Main branches: a. circumflexa humeri cranialis, a. profunda brachii, a. collateralis ulnaris, a. brachialis superficialis, a. bicipitalis, a. transversa cubiti, a. interossea communis, and species-specific muscular branches.
Important branches and their targets
- a. circumflexa humeri cranialis: supplies m. coracobrachialis, m. biceps brachii, m. teres major and pectoral muscles; its origin may vary among species (from a. axillaris, a. subscapularis, or a. circumflexa humeri caudalis).
- a. profunda brachii: supplies m. triceps brachii (large in horse and carpus-bearing species), anastomoses with a. collateralis ulnaris in some species.
- a. collateralis ulnaris: courses on medial surface of elbow to caudal antebrachium; supplies m. triceps brachii, m. anconeus, flexor muscles including m. flexor carpi ulnaris and deeper digital flexors; anastomoses with interosseous arteries and subscapular contributions.
Table: Selected brachial branches and clinical relevance
| Branch | Muscles supplied | Clinical relevance |
|---|---|---|
| a. circumflexa humeri cranialis | shoulder flexors and pectoral muscles | Variable origin; important in flap surgeries |
| a. profunda brachii | triceps group | Larger in horses—important for intramuscular blood supply |
| a. collateralis ulnaris | caudal antebrachial flexors | Anastomoses important for collateral circ |
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Thoracic Limb Vessels
Klíčová slova: Thoracic Limb Vascular Anatomy, Thoracic limb vasculature
Klíčové pojmy: A. axillaris is the main continuation of a. subclavia supplying the forelimb, A. axillaris divides primarily into a. subscapularis and a. brachialis, A. subscapularis gives off a. circumflexa humeri caudalis, a. thoracodorsalis, a. circumflexa scapulae, A. brachialis runs medially with v. brachialis and n. medianus at the elbow, A. circumflexa humeri cranialis has variable origin across species, A. profunda brachii is large in horses and supplies the triceps, A. collateralis ulnaris supplies caudal antebrachial flexors and anastomoses with interosseous arteries, Anastomoses around shoulder and elbow create important collateral circulation
## Introduction
The thoracic limb vascular anatomy describes the major arteries and veins supplying the forelimb for domestic animals. This guide focuses on the main arterial branches, their course, and the muscles and joints they supply. The material is broken into manageable sections with clinical and practical notes to help you retain and apply the information.
> Definition: The axillaris artery is the principal continuation of the subclavian artery supplying the thoracic limb; it gives rise to branches that supply shoulder, brachium, and antebrachium structures.
## Overview: Major arterial trunks
- **A. axillaris (axillary artery)**: main continuation of **a. subclavia**, runs on the medial surface of the shoulder region and continues caudally to the collum humeri.
- Main divisions of a. axillaris: **a. subscapularis** and **a. brachialis**.
### A. axillaris — key branches and targets
- Cervicalis superficialis (in some species) — supplies prescapular region
- Thoracica externa — supplies the pectoral muscles (mm. pectorales) and varies by species in the exact muscular targets
- Suprascapularis (in bovine and equine) — supplies m. supraspinatus, m. subscapularis and the shoulder joint
> Definition: A branch is an artery arising from a parent trunk to supply specific muscles, skin regions, or joints.
## A. subscapularis (branch of a. axillaris)
- Main branches: **a. circumflexa humeri caudalis**, **a. thoracodorsalis**, **a. circumflexa scapulae**
- Typical supply: muscles of the scapular and proximal brachial region (m. brachialis, heads of m. triceps brachii, m. teres minor, m. latissimus dorsi)
Table: A. subscapularis branches and targets
| Branch | Principal targets | Notes / species differences |
|---|---|---|
| a. circumflexa humeri caudalis | m. brachialis, caput laterale of m. triceps brachii, m. teres minor | Gives off r. proximalis to m. brachialis in sheep; contributes to collaterals |
| a. thoracodorsalis | m. latissimus dorsi, m. teres major, m. subscapularis | May be branch of a. brachialis in some species (bovine) |
| a. circumflexa scapulae | m. supraspinatus, m. infraspinatus, m. deltoideus | Runs around lateral scapula surface |
Fun fact: In bovine anatomy the origin and branching pattern of the thoracodorsal artery can vary and sometimes arises as a branch of the brachial artery rather than directly from the subscapular artery.
## A. brachialis (continuation/branch of a. axillaris)
- Course: runs on the medial surface of the brachium alongside v. brachialis and n. medianus, on the craniomedial surface of the elbow joint.
- Main branches: **a. circumflexa humeri cranialis**, **a. profunda brachii**, **a. collateralis ulnaris**, **a. brachialis superficialis**, **a. bicipitalis**, **a. transversa cubiti**, **a. interossea communis**, and species-specific muscular branches.
### Important branches and their targets
- a. circumflexa humeri cranialis: supplies m. coracobrachialis, m. biceps brachii, m. teres major and pectoral muscles; its origin may vary among species (from a. axillaris, a. subscapularis, or a. circumflexa humeri caudalis).
- a. profunda brachii: supplies m. triceps brachii (large in horse and carpus-bearing species), anastomoses with a. collateralis ulnaris in some species.
- a. collateralis ulnaris: courses on medial surface of elbow to caudal antebrachium; supplies m. triceps brachii, m. anconeus, flexor muscles including m. flexor carpi ulnaris and deeper digital flexors; anastomoses with interosseous arteries and subscapular contributions.
Table: Selected brachial branches and clinical relevance
| Branch | Muscles supplied | Clinical relevance |
|---|---:|---|
| a. circumflexa humeri cranialis | shoulder flexors and pectoral muscles | Variable origin; important in flap surgeries |
| a. profunda brachii | triceps group | Larger in horses—important for intramuscular blood supply |
| a. collateralis ulnaris | caudal antebrachial flexors | Anastomoses important for collateral circ