Finger abduction as a novel function of the extensor digitorum brevis manus muscle

AbstractA 25-year-old female presented with a chronic scapho-lunate ligament injury with development of carpal instability requiring reconstruction. During a standard dorsal longitudinal mid-line approach to the carpus, an extensor digitorum brevis manus (EDBM) muscle was found taking its origin from the dorsal wrist capsule overlying the lunate with innervation from the posterior interosseous nerve (PIN). Electrical stimulation of the muscle belly demonstrated abduction of the middle finger. The EDBM is a rare anatomical variant of the extensor compartment of the wrist and may be encountered during surgical approaches. Where possible these variant muscles should be carefully dissected off underlying structures, preserved and repaired at the conclusion of a procedure to ensure no perceived functional deficit to the patient. We present a case of a previously undescribed EDBM muscle function of pure finger abduction with no extension and a surgical technique of preserving its origin. We propose that the middle finger variant of the EDBM should be re-named the extensor digitorum brevis medius to reflect our findings.

Download Full-text

Extensor digitorum brevis manus - its incidence and clinical insight

National Journal of Clinical Anatomy ◽

10.1055/s-0040-1701719 ◽

2018 ◽

Vol 07 (01) ◽

pp. 032-035

Author(s):

Rajeev R Desai ◽

Ashwini R Desai ◽

Manoj P Ambali

Keyword(s):

Tendon Transfer ◽

Middle Finger ◽

Synovial Cyst ◽

Extensor Digitorum ◽

Skin Flaps ◽

Transverse Incision ◽

Extensor Compartment ◽

Finger Skin ◽

Age And Sex ◽

Extensor Digitorum Brevis

Abstract Background and aims: Extensor digitorwn brevis manus is an accessory muscle on the dorsum of the hand. It lies in the fourth extensor compartment of the wrist. Its occurrence is relatively rare. Incidence of this muscle is 4% in the general population. Presence of this muscle is usually asymptomatic but rarely it may produce painful swelling which can be misdiagnosed as lipoma or ganglion or synovial cyst. Aim of the present study was to find out the incidence of extensor digitorwn brevis manus muscle in Indian cadavers. Material and Methods : Study was conducted on 64 human hands of adult Indian cadavers of unknown age and sex in the department of anatomy. A longitudinal incision was placed on the dorsum of hand along the axis of middle finger, skin flaps were raised both on radial and ulnar side. A transverse incision was taken at metacarpo-phalangeal joints from second to fifth fingers. Dorsum of each hand was dissected carefully to see the presence of extensor digitorwn brevis manus. Results: We found extensor digitorum brevis manus muscle in 3 hands [rt.-1; It. - 2] out of 64, i.e. 4.68%. Conclusion: Anatomical knowledge of this muscle present in the extensor compartment may be helpful in planning tendon transfer or graft surgeries Therefore, the knowledge of these variant muscles may be important.

Download Full-text

Variant Superficial Branch of Radial Artery along with Supplementary Tendons on the Dorsum of the Hand and Their Surgical Implications

Case Reports in Surgery ◽

10.1155/2016/9581759 ◽

2016 ◽

Vol 2016 ◽

pp. 1-3

Author(s):

Satheesha B. Nayak ◽

Naveen Kumar ◽

Ashwini Aithal Padur ◽

Surekha D. Shetty

Keyword(s):

Radial Artery ◽

Index Finger ◽

Middle Finger ◽

Extensor Digitorum ◽

Surgical Approaches ◽

Branching Pattern ◽

First Dorsal Interosseous ◽

Superficial Branch ◽

Web Space ◽

Clinically Significant

Variations of radial artery, in both its course and branching pattern in the anatomical snuffbox, are clinically significant for the plastic surgeons, cardiologists, and radiologists. Reports on its abnormal high origin and subsequent superficial course have been well documented. Herein, we report an unusual superficial branch of the radial artery given off before its entry into the palm by passing between the two heads of first dorsal interosseous. It eventually divided into princeps pollicis and radialis indicis arteries at the first web space of palm as a unique vascular variation. Apart from this, in the present case, the tendon of extensor digiti minimi and of extensor indicis divided into two parts. The split tendons of extensor digiti minimi were inserted to the dorsal digital expansion of the digitus minimus. However, lateral tendon of split extensor indicis was inserted along with the tendon of extensor digitorum to the index finger and the medial one was inserted along with the tendon of extensor digitorum to the middle finger. Unusual superficial branch of radial artery on the dorsum of the hand is vulnerable for an iatrogenic injury during surgical approaches in the region. Supplementary extensor tendons on the hand are one of the potential causes for the tenosynovitis.

Download Full-text

Extensor Digitorum Brevis Manus: A Case of Fourth-Compartment Syndrome

Canadian Journal of Plastic Surgery ◽

10.1177/229255030301100306 ◽

2003 ◽

Vol 11 (3) ◽

pp. 149-152

Author(s):

Rc Mahabir ◽

Js Williamson ◽

Dg Williamson ◽

El Raber

Keyword(s):

Diagnostic Imaging ◽

Compartment Syndrome ◽

Extensor Digitorum ◽

Extensor Retinaculum ◽

Normal Anatomy ◽

Imaging Studies ◽

Characteristic Appearance ◽

Extensor Compartment ◽

Extensor Digitorum Brevis

The presence of an extensor digitorum brevis manus represents a variation of the normal anatomy of the fourth extensor compartment of the wrist. It usually presents as a swelling on the dorsum of the wrist and is often inaccurately diagnosed. An awareness of its existence and of its characteristic appearance on diagnostic imaging studies is the basis for diagnosis. Symptomatic cases require division of the extensor retinaculum or excision of the muscle, depending on subtype, while asymptomatic cases require no intervention.

Download Full-text

Pseudohypertrophy of the Extensor Digitorum Brevis in diabetic polyneuropathy

Muscle & Nerve ◽

10.1002/mus.27377 ◽

2021 ◽

Author(s):

Pierre R. Bourque ◽

Kawan S. Rakhra ◽

Jocelyn Zwicker ◽

Catherine E. Pringle ◽

Jodi Warman‐Chardon

Keyword(s):

Diabetic Polyneuropathy ◽

Extensor Digitorum ◽

Extensor Digitorum Brevis

Download Full-text

Painful extensor digitorum brevis manus muscle

The Journal Of Hand Surgery ◽

10.1016/0363-5023(89)90190-1 ◽

1989 ◽

Vol 14 (4) ◽

pp. 674-678 ◽

Cited By ~ 10

Author(s):

Mukund R. Patel ◽

Shekhar S. Desai ◽

Lynn Bassini-Lipson ◽

Tatsuji Namba ◽

J. Sahoo

Keyword(s):

Extensor Digitorum ◽

Extensor Digitorum Brevis

Download Full-text

Isolated flexor muscles of the little toe in the feet of an individual with atrophied or lacking 4th head of the M. extensor digitorum brevis and lacking the 4th tendon of the M. extensor digitorum longus

Annals of Anatomy - Anatomischer Anzeiger ◽

10.1016/s0940-9602(03)80017-1 ◽

2003 ◽

Vol 185 (1) ◽

pp. 81-84 ◽

Cited By ~ 6

Author(s):

Horst Claassen ◽

Andreas Wree

Keyword(s):

Extensor Digitorum Longus ◽

Extensor Digitorum ◽

Flexor Muscles ◽

Extensor Digitorum Brevis

Download Full-text

20 The Extensor Digitorum Brevis Manus Muscle

Clinical Orthopaedics and Related Research ◽

10.1097/00003086-196300280-00021 ◽

1963 ◽

Vol &NA; (28) ◽

pp. 210???212 ◽

Cited By ~ 1

Author(s):

CAPTAIN ADOLPHUS W. DUNN ◽

LIEUTENANT CHARLES M. EVARTS

Keyword(s):

Extensor Digitorum ◽

Extensor Digitorum Brevis

Download Full-text

Normalization in human somatosensory cortex

Journal of Neurophysiology ◽

10.1152/jn.00939.2014 ◽

2015 ◽

Vol 114 (5) ◽

pp. 2588-2599 ◽

Cited By ~ 13

Author(s):

Gijs Joost Brouwer ◽

Vanessa Arnedo ◽

Shani Offen ◽

David J. Heeger ◽

Arthur C. Grant

Keyword(s):

Somatosensory Cortex ◽

Middle Finger ◽

Functional Magnetic Resonance ◽

Stimulus Amplitude ◽

Target Digit ◽

Divisive Normalization ◽

Postcentral Gyrus ◽

Baseline Response ◽

The Right ◽

Stimulation Of

Functional magnetic resonance imaging (fMRI) was used to measure activity in human somatosensory cortex and to test for cross-digit suppression. Subjects received stimulation (vibration of varying amplitudes) to the right thumb (target) with or without concurrent stimulation of the right middle finger (mask). Subjects were less sensitive to target stimulation (psychophysical detection thresholds were higher) when target and mask digits were stimulated concurrently compared with when the target was stimulated in isolation. fMRI voxels in a region of the left postcentral gyrus each responded when either digit was stimulated. A regression model (called a forward model) was used to separate the fMRI measurements from these voxels into two hypothetical channels, each of which responded selectively to only one of the two digits. For the channel tuned to the target digit, responses in the left postcentral gyrus increased with target stimulus amplitude but were suppressed by concurrent stimulation to the mask digit, evident as a shift in the gain of the response functions. For the channel tuned to the mask digit, a constant baseline response was evoked for all target amplitudes when the mask was absent and responses decreased with increasing target amplitude when the mask was concurrently presented. A computational model based on divisive normalization provided a good fit to the measurements for both mask-absent and target + mask stimulation. We conclude that the normalization model can explain cross-digit suppression in human somatosensory cortex, supporting the hypothesis that normalization is a canonical neural computation.

Download Full-text