INVITED REVIEW

A Clinically Oriented Comprehensive Pictorial Review of Canine

Elbow Anatomy

GHEORGHE M. CONSTANTINESCU, DVM, PhD, mult Dr h c and ILEANA A. CONSTANTINESCU, DVM, MS

The clinically oriented canine elbow anatomy in its complexity earned a high importance in surgeryespecially after multiple imaging modalities have been used in the benefit of diagnosis and treatment ofcanine elbow disorders. The bony, joint, and muscular structures, the arteries, the veins and the nervessupplying the elbow are described and illustrated in textbooks and atlases in the context of thecomparative anatomy. Nevertheless, there is no publication focused on all of these structuresdescribed together from the skin to the bones in a systematic and topographic order, nor throughcross and/or sagittal and coronal sections. The figures used in this article are original and drawn afterdissection, cross, sagittal, and coronal sections of the elbow structures. The sections are correlated tothe multiple imaging modalities shown in the next article.r Copyright 2009 by The American College of Veterinary Surgeons

Keywords: clinical comprehensive anatomy, elbow, canine

INTRODUCTION

THE ANATOMY of the canine elbow has been fullypresented in a number of texts,1–7 but with one ex-

ception,4 illustration and description from a diagnosticand therapeutic perspective is not readily available.We provide a comprehensive review of the anatomyof the canine elbow for clinical reference. Presentationof anatomic features of the canine elbow is presented sothat it can be readily correlated to diagnostic imag-ing, used for understanding disease mechanisms, and ap-plied to current and novel treatment strategies. A com-prehensive review is provided covering all tissues fromsuperficial to deep, cross-sectional anatomy to corre-spond to diagnostic imaging, and functional relationshipsto address disease mechanisms and treatment strategies,which are the topics of the subsequent articles in thisissue.

CANINE ELBOW ANATOMY

Fasciae, Cutaneous Blood Vessels, and Cutaneous Nerves

Just beneath the skin, a subcutaneous olecranon bursamay be present to facilitate the smooth gliding of the skinover the olecranon. The elbow is entirely surrounded bythe brachial and antebrachial fasciae and on the medialaspect, the superficial antebrachial fascia is added.

The arteries are cutaneous branches of the caudal cir-cumflex humeral A. (cranially), thoracodorsal A. (caudo-laterally and caudomedially), and superficial brachial A.(craniolaterally and craniomedially). Cutaneous branchesof the recurrent interosseous A. reach the elbow caudo-ventrally.

The superficial veins are branches of the collateral ul-nar V. (caudally), cephalic V. (cranially), median cubitalV. (medially), and branches of the collateral radial and

Address reprint requests to Dr. Gheorghe Contantinescu, DVM, PhD, mult Dr h c, Department of Biomedical Sciences, College of

Veterinary Medicine, University of Missouri, 1600 E. Rollins, Columbia, MO 65211-5120. E-mail: constantinescug@missouri.edu.

Submitted April 2008; Accepted September 2008

From the Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, MO.

r Copyright 2009 by The American College of Veterinary Surgeons

0161-3499/09

doi:10.1111/j.1532-950X.2008.00480.x

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middle collateral Vv. (laterally). The recurrent interosse-ous V. may also supply the elbow.

The cranial cutaneous antebrachial N. (branch of theaxillary N.) runs on the cranial aspect of the elbow, infront of, and close to, the lateral cutaneous antebrachialN. (from the superficial branch of the radial N.); the lat-ter splits into a lateral branch for the craniolateral aspectof the elbow, and a medial branch for the craniomedialaspect of the elbow. The medial cutaneous antebrachialN. (from the musculocutaneous N.) supplies the cranio-medial aspect of the elbow, caudal to, and close to, the

medial branch of the lateral cutaneous antebrachial N.The proximal branch of the caudal cutaneous ante-brachial N. (from the ulnar N.) supplies the caudolateraland caudomedial aspects of the elbow. Branches of theintercostobrachial N., and lateral cutaneous branches ofthe intercostal N. II can also be found on the laterocaudalextent of the elbow.

The arteries and nerves of the elbow, superficial anddeep, in topographic relationship with the muscles areshown in Fig 1 (lateral aspect), Fig 2 (medial aspects),and Fig 3 (cranial aspect).

Fig 2. Muscles, arteries, nerves—medial elbow of a dog.

Fig 1. Muscles, arteries, nerves—lateral elbow of a dog.

136 CANINE ELBOW ANATOMY

Muscles

The muscles surrounding the elbow belong to the bra-chial and antebrachial groups of muscles. From the bra-chial group, the biceps brachii and brachialis Mm. run onthe cranial aspect, the long and lateral heads of the tricepsbrachii M., and the anconeus M. cover the lateral aspectof the elbow, and the medial head of triceps runs on themedial aspect of elbow accompanied by the tensor fasciaeantebrachii M. (Figs 1–3). A subtendinous bursa (of thetriceps brachii M.) is located between the tendon of this

Fig 3. Muscles and nerves—cranial elbow of a dog.

Fig 4. Tricipital bursa of a dog—lateral elbow.

Fig 5. Bicipitoradial bursa of a dog—medial elbow.

Fig 6. Elbow joint of a dog—lateral aspect.

Fig 7. Elbow joint of a dog—medial aspect.

137CONSTANTINESCU AND CONSTANTINESCU

muscle and the olecranon (Fig 4). Another subtendinous(bicipitoradial) bursa is located between the radius andthe insertion of the biceps brachii M. (Fig 5).

From the antebrachial group, starting on the cranialaspect and continuing laterally, caudally and medially,the muscles around the elbow are the brachioradialis M.,the extensor carpi radialis M., the common digital ex-tensor M., the lateral digital extensor M., the extensorcarpi ulnaris M., the ulnar head of the deep digital flexorM., the ulnar and the humeral heads of the flexor carpiulnaris M., the superficial digital flexor M., the humeralhead of the deep digital flexor M., the flexor carpi radialisM., and the 2 deep muscles: the pronator teres M. and thesupinator M. (Figs 1–3). Within the tendon of origin ofthe supinator M. an inconstant sesamoid bone can befound and is outlined as an interrupted circle in Fig 3.

The insertions of the triceps brachii M. and its olecr-anon bursa, as well as the insertions of the biceps brachiiand brachialis Mm. are shown in Figs 4 and 5.

Blood Vessels (Figs 1–3)

The arteries supplying structures of the elbow accom-panied by veins are the brachial A.V.; collateral radialA.V.; middle collateral A.V. forming an articular arterialnetwork caudally and medially (medial cubital articularrete); collateral ulnar A.V. building an articular arterialnetwork caudally and laterally (lateral cubital articularrete); recurrent interosseous A.V. contribute to the lateralcubital articular rete; recurrent ulnar A.V.; transversecubital A.V.; and superficial brachial A.V. which con-tinue as superficial antebrachial A.V.

The veins without arterial satellite are the cephalic andthe median cubital Vv.

Fig 8. Elbow joint of a dog—caudal aspect full flexion.

Fig 9. Elbow joint of a dog—cranial aspect.

Fig 10. Radius and ulna in pronation—cranial view.

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Nerves (Figs 1–3)

The nerves around the elbow are the median N., deepand superficial branches of the radial N., and ulnar N.

The Elbow Joint

The elbow joint is a compound joint, consisting of thehumeroradial, humeroulnar, and proximal radioulnarjoints. There is a joint capsule, collateral ligaments, andother ligaments. The joint capsule covers only the cranialaspect of the elbow. The fibrous joint capsule is attachedon humerus proximal to the radial fossa and foramensupratrochleare, and under the head of radius afterblending with the annular ligament. The fibrous jointcapsule ends laterally and medially at the lateral andmedial collateral ligaments, respectively. The collateralligaments attach proximally to the lateral and medial ep-icondyles of humerus, respectively, and are divided dis-

Fig 12. Distal humerus—cranial view.

Fig 11. Radius and ulna in supination—cranial view.

Fig 13. Distal humerus—caudal view.

Fig 14. Distal humerus—distal view.

Fig 15. Capitulum of radius—articular view.

139CONSTANTINESCU AND CONSTANTINESCU

tally into 2 crura. The crura of the lateral collateral lig-ament blend with the annular ligament and often containa sesamoid bone. The cranial crura of both ligamentsattach to the radius, whereas the caudal crura attach tothe ulna. They are considered thickenings of the fibrousjoint capsule. There is no fibrous joint capsule on thecaudal aspect of the elbow in the dog.

Despite the fact that the oblique ligament is not listedin the Nomina Anatomica Veterinaria (NAV),8 it is aconstant structure listed in books and atlases. It attachesproximal to the lateral aspect of the radial fossa and dis-tally on the medial side of the neck of radius. The distalattachment is bifurcated to allow the passage of the ten-dons of biceps brachii and brachialis Mm. An additionalelastic ligament joins the medial border of the olecranon

Fig 16. Proximalulna—cranial view.

Fig 18. Elbow in neutral caudal position.

Fig 17. Elbow in neutral lateral position. Fig 19. Elbow in neutral medial position.

140 CANINE ELBOW ANATOMY

Fig 21. Elbow cranial aspect 15–201 craniolateral–caudomedial

oblique.

Fig 22. Transverse section through a dog elbow—oleranon

level.

Fig 20. Elbow in extreme flexed medial position.

Fig 23. Transverse section through a dog elbow—humeral

epicondyle level.

141CONSTANTINESCU AND CONSTANTINESCU

fossa to the medial aspect of the olecranon, just distal tothe olecranon tuberosity. This is the olecranon ligament.

The proximal radioulnar joint is provided with theannular ligament, which attaches to the lateral and me-dial ends of the radial notch of ulna and is covered by thecollateral ligaments. It blends its fibers with the fibrousjoint capsule. The annular ligament does not attach to theradius, to allow it to rotate during pronation and supi-nation (Figs 6–9).

Figures 10 and 11 show the relationships between theradius and ulna during the maximal pronation and max-imal supination, respectively.

The synovial membrane intimately lines the fibrousjoint capsule, and also the olecranon fossa. During flex-ion and extension, several recesses are formed (Figs 6–9).Cranially, 1 recess lies in the fossa radialis. It delegates 1small recess under the attachments of the biceps brachii

M. (medially) and another small recess under the attach-ments of the extensor carpi radialis and common digitalextensor Mm. Distally, the synovial membrane insinuatesunder the annular ligament. Caudally, 1 recess is found inthe olecranon fossa, which sends a small recess under themedial epicondyle of humerus. The caudal recess iscovered by the olecranon ligament. The recesses commu-nicate with each other.

The elbow joint as a whole is a trochlearthrosis orginglymus (a hinge joint), allowing flexion and extensionof the humerus over the radius and ulna. In dogs, thecircumference of the radius (on the caudal aspect of thehead of radius) is capable of rotating in the radial notchof the ulna during pronation and supination.

The Bones

The distal extremity of the humerus and the proximalextremities of the radius and ulna including the olecranonare illustrated in Figs 12–16.

Figures 17 and 18 show the neutral lateral view, andthe caudal view of the elbow bones, respectively.

The neutral medial aspect is shown in Fig 19, and theextreme flexed medial aspect in Fig 20.

The 15–201 craniolateral–caudomedial oblique aspectis shown in Fig 21.

Fig 24. Transverse section through a dog elbow—proximal

radioulnar level.

Fig 25. Sagittal section through a dog elbow.

Fig 26. Coronal section through distal humerus and proximal

radius and ulna—left thoracic limb in pronation.

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Topography

The topography of the bones, ligaments, muscles, ves-sels, and nerves is shown in 3 cross sections, 1 sagittal and1 coronal section, in conjunction with computed tomog-raphy images. The cross sections are made in a proximo-distal direction, as follows: at the level of the olecranontuberosity (Fig 22), at the level of the lateral and medialepicondyles of humerus (Fig 23), at the proximal radio-ulnar level (Fig 24). The sagittal section is made throughthe humerus, ulna and radius at the level of the medialcoronoid process (Fig 25). The coronal section is made infront of cranial part of the medial coronoid process withthe limb in pronation (Fig 26).

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