Clinical diagnosis
Case 234
【Progress】
Both patients underwent conservative treatment; Case 1 he received to be fixed in place with a splint and bandaged: Case 2 he received a small orthopedic cast.
【Discussion】
In wrist joint, there are three bone prominence on its dorsal side: styloid process of radius, styloid process of ulna and Lister tubercle. Lister tubercle becomes more prominent at extension position of wrist.
Before Lister tubercle description, anatomical refresh of thumb (1st finger) is necessary. There are four kinds of joint in finger: distal interphalangeal (DIP) joint, proximal interphalangeal (PIP) joint, metacarpal pharyngeal (MP or MCP) joint and carpal metacarpal (CM) joint. Of these, a thumb rather than other 4 fingers has three joints of CM, MP and IP (interphalangeal). Three extensor muscles on thumb exist for extension of three joints. In short, extensor pollicis longus (EPL) tendon extends IP joint, extensor pollicis brevis (EPB) tendon extends MP joint and abductor pollicis longus (APL) extends and abducts CM joint. EPB and APL run parallel together while EPL runs alone.
Lister tubercle is on the way of EPL. It plays a role of a pulley of EPL turning 45°angle from straight direction of ulna osseous ligament at origin to oblique direction toward 1st distal phalange at halt (1-3). In case of over extension of wrist, Lister tubercle is susceptible to be injured. In our cases, they injured Lister tubercle in over extension of traffic accident or rolling down in playing a skate-board.
Extensor carpi radialis longus (ECRL) and extensor carpi radialis brevis (ECRB) originate from the distal end of humerus and halt to the proximal end of 2nd metacarpal and the proximal end of 3rd metacarpal, respectively. Meanwhile, EPL, EPB and APL run obliquely. Then, ECRL and ECRB result in cross EPL, EPB and APL. The first or proximal intersection indicate between ECRL & ECRB, and EPB & EPL. Under extensor retinaculum, ECRL & ECRB run straight from the origin to the halt and form the second compartment together. EPB & EPL form the first compartment under retinaculum. Then, the first intersection occurs immediately before entering extensor retinaculum.
Meanwhile, the second or distal intersection occurs under extensor retinaculum between EPL and ECRL & ECRB. EPL forms the third compartment under extensor retinaculum. Then, the second compartment including ECRL and ECRB cross the third compartment including EPL after extensor retinaculum. Lister tubercle is around 3mm in height and around 13mm in length (4-6). It situates under extensor retinaculum. Then, intersection syndrome occurs in the area as the center of Lister tubercle.
De Quervain syndrome is tenosynovitis of the EPB and APL, inducing the pain of the lateral side of thumb. Intersection syndrome and de Quervain syndrome are found in repetitive extension and flexion of wrist such as sports of ski, rolling, table tennis, tennis and typing (4-7).
【Summary】
We presented two cases with Lister tubercle fracture; The first case got injury during skate board riding and the second case did it in the traffic accident. It is borne in mind that Lister tubercle is bony prominence (3mm in height, 13mm in length) at the distal radius, and susceptible to be injured in over extension of wrist. Lister tubercle functions as a pulley of extensor pollicis longus (EPL) and covered with extensor retinaculum. Under extensor retinaculum, the first compartment includes extensor pollicis brevis (EPB) and abductor pollicis longus (APL), the second compartment, Extensor carpi radialis longus (ECRL) and extensor carpi radialis brevis (ECRB) and the third compartment includes EPL, indicating the proximal intersection occurs immediately before extensor retinaculum. The distal intersection between EPL and ECRL & ECRB occurs immediately after extensor retinaculum. Intersection syndrome occurs in the area as the center of Lister tubercle. De Quervain syndrome is tenosynovitis of the EPB and APL. Extensor pollicis longus (EPL) tendon extends IP joint, extensor pollicis brevis (EPB) tendon extends MP joint and abductor pollicis longus (APL) extends and abducts CM joint. EPB and APL run parallel together while EPL runs alone.
【References】
1.Grundberg AB, et al. Pathologic anatomy of the forearm: intersection syndrome. J Hand Surg Am. 1985;10:299-302.
2.Rumball JS, et al. Rowing injuries. Sports Med. 2005;35:537–555.
3.Chan WY,et al. Anatomical Variants of Lister's Tubercle: A New Morphological Classification Based on Magnetic Resonance Imaging. Korean Journal of Radiology. 2017;18: 957–963
4.Fulcher SM, et al. Upper-extremity tendinitis and overuse syndromes in the athlete. Clin Sports Med. 1998;17:433–448.
5.Grundberg AB, Reagan DS. Pathologic anatomy of the forearm: intersection syndrome. J Hand Surg [Am]. 1985;10:299–230
6.Hanlon DP, et al. Intersection syndrome: a case report and review of the literature. J Emerg Med. 1999;17:969-971.
7.Costa CR, et al. MRI features of intersection syndrome of the forearm. AJR Am J Roentgenol. 2003;181:1245-1249.
2021.6.9