Dynamic 22 Mhz ultrasound evaluation (HR-US) of the finger: a detailed didactic approach.

Transcription

1 Dynamic 22 Mhz ultrasound evaluation (HR-US) of the finger: a detailed didactic approach. Poster No.: C-2228 Congress: ECR 2014 Type: Educational Exhibit Authors: A. Muda, D. Orlandi, V. Prono, S. Migone, M. Pascale, S Montechiarello, E. Silvestri ; Genova/IT, Genoa/IT, Caserta/IT, 4 Roma/IT Keywords: Musculoskeletal system, Ultrasound, Education, Motility DOI: /ecr2014/C-2228 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 26

2 Learning objectives The purpose of our educational exhibit is to: 1. illustrate the normal anatomy and normal HR-US appearance of finger compartments; 2. describe a systematic technique for HR-US evaluation of such structures; 3. produce anatomical schemes with didactic purpose and show correlations with sonographic imaging. Page 2 of 26

3 Background The complex finger anatomy includes joints and ligament complexes, flexor and extensor tendons, intrinsic hand muscles and neurovascular structures. Currently, HRUS represents the first level imaging in the finger evaluation. For each of the following structures we will provide a dedicated HR-US image compared with a detailed anatomic scheme, and a practical guide on "how we do" a HR-US scan: Palmar side - Palmar aponeurosis; - Flexor digitorum profundus tendon - Flexor digitorum superficialis tendon - Flexor pulleys - Common digital neuro-vascular bundle - Lumbrical and interosseus muscles - Inter-phalangeal joint - Ulnar collateral ligament of the thumb Dorsal side - Extensor digitorum communis tendon - Extensor digitorum superficialis tendon - Extensor digitorum profundus tendon Page 3 of 26

4 Findings and procedure details The standard US protocol can be commenced either from the dorsal or the palmar side of the hand. PALMAR SIDE Check-list. 1.Palmar aponeurosis; 2.Flexor digitorum profundus tendon 3.Flexor digitorum superficialis tendon 4.Flexor pulleys 5.Common digital neuro-vascular bundle 6.Lumbrical and interosseus muscles 7.Inter-phalangeal joint 8.Ulnar collateral ligament of the thumb The hand lies on the table with the ventral side facing up. Palmar aponeurosis. Page 4 of 26

5 Fig. 1: Anatomical scheme of palmar aponeurosis. Page 5 of 26

6 Fig. 2: Axial scan of the palmar aponeurosis. PA: palmar aponeurosis; FT: Flexor tendon. Page 6 of 26

7 Fig. 3: Longitudinal scan of the palmar aponeurosis. PA: Palmar aponeurosis. The palmar aponeurosis covers muscles and tendons of the palm and consists of central, lateral and medial bundles. The base of central bundle divides into four slips, one for each finger, with expansion for proximal phalanx bones, flexor tendon sheaths, and skin. The lateral and medial bundles cover the tumb and little finger muscles, on the radial and the ulnar side, respectively. Flexor digitorum profundus and superficialis tendon Evaluation of the flexor tendons should be commenced at the carpal tunnel level. The changing relationship between superfricial and deep flexor tendons can be appreciated moving the probe distally with axial scans. Page 7 of 26

8 Fig. 4: Axial scan of the flexor digitorum tendon Page 8 of 26

9 Fig. 5: Longitudinal scan of the flexor digitorum tendon Page 9 of 26

10 Fig. 6: Axial scan of the flexor digitorum tendon Page 10 of 26

11 Fig. 7: Longitudinal scan of the flexor digitorum tendon Page 11 of 26

12 Fig. 8: Axial scan of the flexor digitorum tendon Page 12 of 26

13 Fig. 9: Axial scan of the flexor digitorum tendon The flexor digitorum profundus tendon originates from the anterior and medial aspects of the ulna. The flexor digitorum superficialis has two heads, the humero-ulnar and the radial. Both muscles originate from long tendons that enter the carpal tunnel and then insert on the fingers. Flexor pulleys Reflection pulleys can be seen on both axial and longitudinal scans. Page 13 of 26

14 Fig. 10: Anatomical scheme of pulleys Fig. 11: A1 pulley Page 14 of 26

15 Fig. 12: A2 pulley Fig. 13: A3 pulley Page 15 of 26

16 Fig. 14: A4 pulley Fig. 15: A5 pulley Pulleys are the annular part of the fibrous sheathes of the finger. They form a fibroosseous tunnel through which passes the deep and superficial flexor tendons. Common digital neuro-vascular bundle Page 16 of 26

17 Fig. 16: Anatomical scheme of the common digital neuro-vascular bundle Fig. 17: Axial scans of the common digital neuro-vascular bundle Lumbrical and interosseus muscles Page 17 of 26

18 Fig. 18: Longitudinal view of the lumbrical muscles The intrinsic muscles comprise the lumbrical and interosseous groups. There are four lumbrical muscles, which originate in the deep flexor muscles of the fingers, at the level of the middle palmar region of the hand. Page 18 of 26

19 Lumbrical muscles reach the MCP joint at its radial aspect and run palmar to the deep transverse metacarpal ligament and to the transverse axis of the joint, thus acting as flexors for the MCP joint. There are seven interosseus muscles: three palmarand four dorsal. The three palmar muscles have their origins at the second,fourth, and fifth metacarpals. The four dorsal interosseous muscles originate at the adjacent metacarpals. At the MCP joints, the interosseous muscles are located dorsal to the deep transverse metacarpal ligament. Inter-phalangeal join The inter-phalangeal joint must be assessed using longitudinal scans. Fig. 19: Anatomical position of the Inter-phalangeal joint (B and C) and Carpometacarpal joint (A) Page 19 of 26

20 Fig. 20: Longitudinal views of joints Ulnar collateral ligament of the thumb Ulnar collateral ligament can be seen by placing the probe on a longitudinal plane on the ulnar side of the joint. Page 20 of 26

21 Fig. 21: Longitudinal view of the ulnar collateral ligament of the thumb DORSAL SIDE: Check-list: 1. Extensor digitorum communis tendon 2. Extensor digitorum superficialis tendon 3. Extensor digitorum profundus tendon The hand lies on the table with the palm facing down. Extensor digitorum tendons can be assessed using axial scans, moving the probe from the carpus distally to the fingertips. Fig. 22: Anatomical scheme of the extensor tendons Page 21 of 26

22 Fig. 23: Axial view: T: extensor tendon; MC: metacarpal; * sagittal band Page 22 of 26

23 Fig. 24: Longitudinal view Page 23 of 26

24 Fig. 25: Longitudinal view. Page 24 of 26

25 Conclusion HR-US performed with a very high frequency probe allows a detailed, real-time evaluation of finger structures. In addition, dynamic evaluation adds several important information about biomechanics of such superficial structures. Knowledge of the normal anatomy and imaging appearance of these structures is essential for the depiction of their injuries. Page 25 of 26

26 References 1. Clavero J,Golano P, Farin O, Alomar X, Monill J, Esplugas M. Extensor Mechanism of the Fingers: MR Imaging-Anatomic Correlation RadioGraphics 2003;23: Silvestri E., Muda A., Sconfienza L.M. Normal Ultrasound Anatomy of the Musculoskeletal System, Allison SJ., Musculoskeletal ultrasound: evaluation of the finger, AJR Am J Roentgenol, 2011, Page 26 of 26