Rajan. T¹, Manjunath K.Y · 6 Original Article Rajan. T¹, Manjunath K.Y.2 ABSTRACT Introduction: Knowledge of extensor tendons over the dorsum of hand is important for anatomist

6

Original Article

2Rajan. T¹, Manjunath K.Y.

ABSTRACT

Introduction: Knowledge of extensor tendons over the dorsum of hand is important for anatomist

as well as clinicians to carry out surgical repairs of tendons and to treat pathological conditions

associated with tendon.

Aim: To study frequency of occurrence of variations of the Extensor Digitorum Communis tendon

slips on the dorsum of hand in South Indian cadavers.

Materials and Methods: Material for the study consisted of 50 formalin fixed adult cadavers (100

upper limbs) of South Indian origin aged between 30 and 70 years old allotted for undergraduate

dissection in the Department of Anatomy, Aarupadai Veedu Medical College, Pondicherry.

Observations: Out of hundred dorsums of the hand studied, Extensor Digitorum Communis

showed four slips in 95 specimens I.e., one for index finger (EDCI), one for middle finger (EDCL),

one for ring finger (EDCR) and one for little finger (EDCS). Variations were observed in five hands,

four of right side and one of left side. Maximum tendon slips identified of Extensor Digitorum

Communis were 7 in number in one right side hand. In no hand Extensor Digitorum Communis was

found with less than four slips.

Conclusion: Complete knowledge of variations in extensor tendons of the hand is very important

during reconstructive surgeries and other procedures in treating hand injuries. The findings of the

present study may be of use during surgical procedures involving the tendon of Extensor Digitorum

Communis.

Keywords: Extensor Digitorum , Tendinous slip, Dorsum of hand.

INTRODUCTION:

he complexity and intricacy of hand

function are reflected by the anatomy. TExtensor muscles have a relatively

consistent architecture but also have notable 1

anatomic variations of their tendons. A detailed

knowledge of the extensor tendons anatomy is

essential for understanding the consequences of

tendon injury at various levels. This tendon injury

may be either due to external trauma or

spontaneous rupture as in patients with rheumatoid 2

arthritis and distal radioulnar joint osteoarthritis.

The tendons of the Extensor Digitorum Communis

(EDC) are frequently injured in hand trauma.

Dislocation and spontaneous rupture can also occur

during the course of wrist osteoarthritis and

Address for correspondence:

Dr. Rajan T, Professor and HOD, Department of Anatomy, Aarupadai Veedu Medical College, Puducherry - 607402.

Mob : 9787100875 E-mail: [email protected]

Variations of the Extensor Digitorum Communis Tendon of Hand

A Cadaveric Study in South Indians

http://dx.doi.org/10.31975/NJBMS.2018.9101

¹Professor & HOD , Department of Anatomy , Aarupadai Veedu Medical College , Puducherry - 607402.2Former Professor, Department of Anatomy, Annapoorna Medical College, Salem-636308.

National Journal of Basic Medical Sciences | Volume 9 | Issue 1 | 2018

7

OBSERVATIONS:

In present study out of hundred upper limbs, four

slips of Extensor Digitorum Communis were seen

in 95 specimens, i.e., one each for index finger

(EDCI), middle finger (EDCL), ring finger

(EDCR) and little finger (EDCS). Variations were

found in other five hands, four of right side and one

of left side. Two right hands showed five slips, one

each for index finger (EDCI), middle finger

(EDCL), ring finger (EDCR) and two for little

finger (EDCS) (Fig. 1&2). Six slips were found in

one specimen on both sides, one for index finger

(EDCI), two for middle finger (EDCL), two for

ring finger (EDCR) and one for little finger (EDCS)

(Fig. 3). Maximum number of slips, 7 in number

were observed in Extensor Digitorum Communis

of right hand, i.e., one for index finger (EDCI), four

for middle finger (EDCL), two for ring finger

(EDCR) and none for little finger (EDCS)(Fig. 4).

In none of the hands, Extensor Digitorum

Communis was found with less than four slips.

(Table.1)

TABLE -1: NUMBER OF TENDONS OF EDC

OF HAND (N=50 IN EACH SIDE) IN

PRESENT STUDY.

rheumatoid arthritis. The EDC exhibits many

variations including splitting of its individual slips 3

to the medial four fingers or their absence.

Literature on variations in the tendinous slips of

Extensor Digitorum Communis of hand is scarce

especially concerning South Indians. The purpose

of the present study was to investigate the anatomy

of the Extensor Digitorum Communis of hand in

cadavers of local population. The data obtained

from this study might help the clinicians and the

surgeons to arrive at better diagnosis, and during

surgery of hand reconstruction.

MATERIAL AND METHODS :

The present study was carried out in the

Department of Anatomy, Aarupadai Veedu Medical

College, Pondicherry. Fifty formalin fixed adult

cadavers (of both sexes) of South Indian origin

aged between 30 and 70 years allotted for

undergraduate dissection were used for this study.

Extensor compartment of the forearm and the

dorsum of the hands were exposed after the

reflexion of skin and the superficial fascia on the

dorsum of each hand, the muscles of the extensor

compartments were cleaned; the extensor

retinaculum (ER) was defined. The ER was split

vertically to expose the underlying tendons.

Extensor Digitorum Communis were examined to

study the basic arrangement and determine the

presence of variations in the number of these

tendons. Then they were photographed using a

digital camera. The obtained data was then

tabulated and the percentages were calculated.

Rajan.T, et.al : Extensor Digitorum Communis


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Fig-1: Dorsum of the right hand showing

Number of tendons of Extensor Digitorum

Communis. Fig - 1



Communis.

Fig - 1

Fig - 2

Fig - 3

Fig - 4

Fig-3: Dorsum of the left hand showing Number

of tendons of Extensor Digitorum Communis.



Communis.

EDCI: Extensor Digitorum Communis Index; EIP: Extensor Indicis Proprius; EDCL: Extensor Digitorum Communis Longus;

EDCR: Extensor Digitorum Communis Ring; EDCS: Extensor Digitorum Communis small.

DISCUSSION:

4Godwin and Ellis have studied the distribution of extensor tendons on the dorsum of the hand and

observed each of the tendons of extensor digitorum (ED) is usually single, but those of the middle and ring

fingers are occasionally multiple and the ED tendon of the little finger lies close to that of the ring finger,

with which it may be fused, or it may be absent. They suggested that it may be undergoing evolutionary



9

reduction. Their finding was almost similar to

present study except close association of EDCS to

EDCR. In present study it was found close to

extensor digiti minimi tendon in two hands. Von 5

Schroeder and Botte observed double or triple

EDC - long tendon, a single or triple EDC-ring

tendon and a single or double EDC - small tendon in

43 adult hands. Findings in present study were

similar to their study except the percentage was less 6

in our study. El-Badawi et al., have reported that

Extensor digitorum often has multiple tendons for

the middle and ring fingers. Its contribution to the

little finger was found to be usually by a bifurcating

tendon common with that of the ring finger. The

index finger always received a single tendon. Their

result was almost similar to present study. Zilber 7and Oberlin observed the pattern of distribution of

tendons of extensor digitorum communis in 50

hands as follows:

The EDC provided one tendon to the index finger,

one to the middle finger, two to the ring finger, and

none to the little finger. In present study except one

hand EDC provided one or two slips to little finger 8

of almost all hands. Celik et al., dissected fifty-four

adult hands and observed following distribution of

pattern for extensor digitorum (ED): index- single

tendon; middle - single tendon; ring - single tendon;

little finger - absent. Their result was almost similar

to present study except in our study except one hand

remaining all hands received EDCS to little finger. 9Dass et al., studied 98 specimens and observed, in

77% of the specimens the EDC distally had tendons

to the middle three fingers (EDC index, EDC

longus and EDC ring). The EDC tendon for little

finger was present in only 34% of samples. Their

result is almost close to observations of Zilber and 7

Oberlin .

10Abdel-Hamid et al., dissected ninety five upper

limbs of adult cadavers and the variations in the

extensor tendons of the fingers, both proximal and

distal to the extensor retinaculum, and their mode

of insertion were observed and the data obtained

was analyzed. In the majority of specimens,

extensor digitorum had no independent slip to the 7

little finger similar to those by Zilber and Oberlin

(Table 2).

TABLE-2: SHOWS THE RESULTS OF PRESENT

STUDY COMPARED WITH PREVIOUS STUDIES

REGARDING THE NUMBER OF THE SLIPS

( S T R A N D S ) I N E X T E N S O R D I G I TO R U M

COMMUNIS.

CONCLUSION:

From our study we came in to a conclusion that,

extensor digitorum communis of South Indian

cadavers shows no less variability in the

arrangement of tendons when compared to other

studies. Absence of tendon was very rare. EDCI

received single tendon. Single tendon was most

common for EDCL and four tendons were rarely

found. Double tendons were common for EDCR.

Single tendon was most common for EDCR and

double tendons were common but four tendons

were rare.



10

REFERENCES:

1. Von Schroeder HP, Botte MJ. Functional

anatomy of the extensor tendons of the digits.

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2. Casal D, Pais D, Bilhim T, Ribeiro V, Cunha

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Almeida M, Goyri-O'Neill J. A rare variation

of the extensor indicis proprius tendon with

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3. Yammine K. The Prevalence of the Extensor

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4. Godwin Y and Ellis H. Distribution of

extensor tendon on the dorsum of the hand.

Anat Clini. 1992;5:394.

5. Von Schroeder HP, Botte MJ. Anatomy of the

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Received on 12/07/2018 Revised on 30/07/2018 Accepted on 03/08/2018


Documents

Rajan. T¹, Manjunath K.Y · 6 Original Article Rajan. T¹, Manjunath K.Y.2 ABSTRACT Introduction: Knowledge of extensor tendons over the dorsum of hand is important for anatomist