The anatomy of the ligaments of the wrist and distal radioulnar joints

The ligaments of the wrist are responsible for guiding and constraining the complex motion of the carpal bones relative to the forearm bones, the metacarpals, and contiguous carpal bones. The majority of wrist ligaments are found within the joint capsule as organized thickenings composed of parallel collagen fascicles, small caliber nerves and blood vessels, and lined on their deep surfaces by synoviocytes. The palmar radiocarpal ligament complex is composed of the radioscaphocapitate, long radiolunate, radioscapholunate and short radiolunate ligaments. The ulnocarpal ligaments include the ulnolunate, ulnotriquetral and ulnocapitate ligaments. Dorsally, the radiocarpal joint is spanned by the dorsal radiocarpal ligament. Palmar ligaments connecting the proximal and distal carpal rows include the scaphotrapeziotrapezoid, scaphocapitate, triquetrocapitate and triquetrohamate ligaments. Within each row are interosseous ligaments connecting adjacent carpal bones, each divisible into dorsal and palmar components. There are unique regions within some of the ligaments, such as a zone of fibrocartilage in the proximal regions of the scapholunate and lunotriquetral interosseous ligaments, and strong deep regions connecting the trapezoid, capitate, and hamate. The distal radioulnar joint is connected by the triangular fibrocartilage complex, composed of a fibrocartilaginous disc and the palmar and dorsal radioulnar ligaments. The ulnocarpal ligaments attach to the palmar radioulnar ligament rather than directly to the ulna, allowing increased independence between wrist and forearm motion.     

Differences in the presence of mechanoreceptors and nerve structures between wrist ligaments may imply differential roles in wrist stabilization.

The purpose of this study was to analyze human wrist ligaments with regard to presence of general innervation and mechanoreceptors. The ligaments studied were: dorsal radiocarpal (DRC), dorsal intercarpal (DIC), long radiolunate (LRL), radioscaphocapitate (RSC), ulnocarpal (UC), scapholunate interosseous (SLI) and lunotriquetral interosseous (LTI) ligaments. Specific immunohistochemical markers were used to target neural/perineurial structures. Both Ruffini and Pacini-like mechanoreceptors (sensory corpuscles) as well as nerve fascicles/free nerve fibers were identified. Ruffini corpuscles were primarily identified via their dendritic intracapsular nerve endings, whereas the Pacini-like corpuscles were identified through their thick perineurial capsules with marked p75 immunoreaction. The wrist ligaments were found to vary in innervation, the DIC, DRC and SLI being richly innervated, whereas the LRL being almost without innervation. The difference in innervation between the ligaments might reflect differential function. Ligaments without innervation might act as structures of passive restraint, whereas ligaments with rich innervation are proposed to also provide proprioceptive information. Wrist ligament injuries should, therefore, be regarded as a disturbance not only of the intrinsic carpal kinematics, but also of the coordination and proprioception of the entire wrist joint.     

Clinical applications of volar portals in wrist arthroscopy

Volar portals for wrist arthroscopy have certain advantages over the standard dorsal portals for visualizing dorsal capsular structures as well as the palmar aspects of the carpal ligaments. The volar radial portal is relatively easy to use and is an ideal portal for evaluation of the dorsal radiocarpal ligament and the palmar aspect of the scapholunate interosseous ligament. The volar midcarpal portal may be considered as an occasional accessory portal for visualizing the palmar aspects of the capitate and hamate in cases of avascular necrosis or osteochondral fractures. The volar ulnar portal is especially useful for the viewing and debridement of palmar tears of the lunotriquetral ligament.     

Volar portals in wrist arthroscopy

Volar portals for wrist arthroscopy have certain advantages over the standard dorsal portals for visualizing dorsal capsular structures as well as the palmar aspects of the carpal ligaments. The volar radial (VR) portal is relatively easy to use and is an ideal portal for evaluation of the dorsal radiocarpal ligament (DRCL) and the palmar aspect of the scapholunate interosseous ligament. The volar midcarpal portal may be considered as an occasional accessory portal for visualizing the palmar aspects of the capitate and hamate in cases of avascular necrosis or osteochondral fractures. The volar ulnar (VU) portal is especially useful for the viewing and debridement of palmar tears of the lunotriquetral ligament. Copyright © 2002 by the American Society for Surgery of the Hand     

An anatomic guide for arthroscopic visualization of the wrist capsular ligaments

Wrist arthroscopy allows examination of the palmar capsular wrist ligaments without extensive exposure. Arthroscopic examination of the wrist requires an accurate knowledge of the ligamentous anatomy as seen from inside the joint. In this study 13 fresh cadaver wrists were examined from the inside out to provide a visual guide for ligament identification during arthroscopy. The major palmar capsular ligaments seen from the inside of the wrist at the radiocarpal joint include the radioscaphoid, radioscaphocapitate, radiolunate, radioscapholunate, ulnolunate, ulnotriquetral ligaments, and the ulnar capsule. At the midcarpal joint, the scaphocapitate, radioscaphocapitate, triquetrocapitate, and triquetrohamate ligaments are identified palmarly. Dorsally, constant capsular structures at the radiocarpal joint are the radiolunate and radioulnotriquetral ligaments along with a prominent synovial fold.     

Biomechanical evaluation of the ligamentous stabilizers of the scaphoid and lunate: part III

PURPOSE: This study continued our previous investigations of the ligaments stabilizing the scaphoid and lunate in which we examined the scapholunate interosseous ligament, the radioscaphocapitate, and the scaphotrapezial ligament. In this current study, we examined the effects of sectioning the dorsal radiocarpal ligament, dorsal intercarpal ligament, scapholunate interosseous ligament, radioscaphocapitate, and scaphotrapezial ligaments. In the current study, the scapholunate interosseous ligament, radioscaphocapitate, and scaphotrapezial ligaments were sectioned in a different order than performed previously. METHODS: Three sets of 8 cadaver wrists were tested in a wrist joint motion simulator. In each set of wrists, only 3 of the 5 ligaments were cut in specific sequences. Each wrist was moved in continuous cycles of flexion-extension and radial-ulnar deviation. Kinematic data for the scaphoid and lunate were recorded for each wrist in the intact state, after the 3 ligaments were sectioned in various sequences and after the wrist was moved through 1,000 cycles of motion. RESULTS: Dividing the dorsal intercarpal or scaphotrapezial ligaments did not alter the motion of the scaphoid or lunate. Dividing the dorsal radiocarpal ligament alone caused a slight statistical increase in lunate radial deviation. Dividing the scapholunate interosseous ligament after first dividing the dorsal intercarpal, dorsal radiocarpal, or scaphotrapezial ligaments caused large increases in scaphoid flexion and lunate extension. CONCLUSIONS: Based on these findings, we concluded that the scapholunate interosseous ligament is the primary stabilizer and that the other ligaments are secondary stabilizers of the scapholunate articulation. Dividing the dorsal radiocarpal, dorsal intercarpal, or scaphotrapezial ligaments after cutting the scapholunate interosseous ligament produces further changes in scapholunate instability or results in changes in the kinematics for a larger portion of the wrist motion cycle.     

The dorsal ligaments of the wrist: anatomy, mechanical properties, and function.

The purpose of this study was to examine the anatomy and mechanical properties of the dorsal radiocarpal (DRC) and dorsal intercarpal (DIC) ligaments of the wrist and to better understand the functional design of the dorsal ligaments. The DRC ligament was consistently found to originate from the dorsal margin of the distal radius and extended ulnar obliquely and distally. Its radial fibers attached to the lunate and lunotriquetral interosseous ligament. The DRC ligament then inserted onto the dorsal tubercle of the triquetrum. The DIC ligament originated from the triquetrum and extended radially and attached onto the lunate, inserted into the dorsal groove of the scaphoid, and then extended to the trapezium. The DRC and DIC ligaments together, in their lateral V configuration, act effectively as a dorsal radioscaphoid ligament that has the ability to vary its length by changing the angle between the 2 arms of the V. The DRC-DIC ligaments' lateral V configuration allows normal carpal kinematics while maintaining its indirect dorsal stabilizing effect on the scaphoid throughout the range of motion of the wrist.     

Dorsal wrist ligament insertions stabilize the scapholunate interval: cadaver study

This study examined sequential arthroscopic sectioning of volar, interosseous, and dorsal ligaments about the scapholunate complex in cadaver wrists. We attempted to clarify the contributions of the dorsal ligamentous complex to scapholunate instability and carpal collapse. We found that after sequential sectioning of volar ligaments and the scapholunate interosseous ligament, no scapholunate diastasis or excessive scaphoid flexion occurred. After dividing the dorsal intercarpal ligament, scapholunate instability occurred without carpal collapse. With sectioning of the dorsal radiocarpal ligament from the lunate, a dorsal intercalated scapholunate instability deformity ensued. This information may be of value in comprehending the pathogenesis of scapholunate instability and carpal collapse and in devising the rationales for conservative measures and surgical intervention.     

腕舟骨周围韧带解剖学研究

目的观察和研究分布在腕舟骨周围的腕外源性或内源性韧带的结构及特点。方法采用１４侧成人尸体上肢，分离和解剖出舟骨周围的韧带，观察并记录其起止点、行程、长宽度及解剖结构特征。结果在舟骨周围观察到８根韧带，为桡舟头韧带（ＲＳＣ）、桡舟月韧带（ＲＳＬ）、桡月韧带（ＲＬ）、背侧腕间韧带（ＤＩＣ）、桡三角骨韧带（ＲＴ）、和舟月骨间韧带（ＳＬＩＬ）、舟骨大多角和舟骨小多角骨间韧带。ＲＳＣ、ＤＩＣ和ＳＬＩＬ对舟骨的位置、稳定性和运动尤为重要。结论腕舟骨周围存在复杂的韧带结构，其中ＲＳＣ、ＤＩＣ和ＳＬＩＬ对舟骨的稳定，舟骨骨折后畸形的形成、舟骨不稳定的形成起着重要作用。这些韧带的结构或功能在治疗腕不稳定中应予以恢复     

Ulnar-sided perilunate instability: an anatomic and biomechanic study

A staging system for ulnar-sided perilunate instability is presented based on a series of cadaver dissections and load studies. Stage I: partial or complete disruption of the lunotriquetral interosseous ligament, without clinical and/or radiographic evidence of dynamic or static volar intercalated segment instability deformity; stage II: complete disruption of the lunotriquetral interosseous ligament and disruption of the palmar lunotriquetral ligament, with clinical and/or radiographic evidence of dynamic volar intercalated segment instability deformity; and stage III: complete disruption of the lunotriquetral interosseous and the palmar lunotriquetral ligaments, attenuation or disruption of the dorsal radiocarpal ligament, with clinical and/or radiographic evidence of static volar intercalated segment instability deformity.     

腕关节韧带解剖及组织学特性研究

目的了解腕关节韧带解剖及组织学特性。方法成人腕关节标本34侧,其中32侧为福尔马林固定标本,2侧为新鲜标本。解剖并观察腕关节韧带的起止、走行、与关节囊的关系及韧带的比邻;测量其长度,取每条韧带的中段测量其宽度和厚度。8侧福尔马林固定标本,解剖出部分腕关节韧带石蜡包埋、切片、HE染色,光镜观察。结果腕关节韧带掌侧较强韧,同时数量也多。相邻韧带形成多个“V”形结构。桡舟韧带、桡舟头韧带和桡月韧带的组织结构相似,由肌腱样的胶原纤维束组成,胶原纤维束之间有少量的疏松组织,其间有血管分布,胶原纤维束呈小的波浪状。桡舟月韧带主要由疏松结缔组织组成,没有粗大的肌腱样胶原纤维束,胶原纤维束很少,而血管束丰富。舟月骨间韧带和月三角骨间韧带的掌侧、背侧和近侧的3个部分不同,特别是近侧部与掌侧、背侧部分。背侧部分主要由粗大成束的横行胶原纤维束组成;掌侧部分也由胶原纤维束组成,其排列方向是斜行,在桡舟月韧带与舟月骨间韧带结合处,可见桡舟月韧带的血管束进入舟月骨间韧带掌侧部分;近侧部分主要由纤维软骨成份构成,其间无血管神经分布。结论大部分腕关节韧带由密集粗大的胶原纤维束为主构成。而桡舟月韧带,则主要由疏松结缔组织组成,其间血管丰富,其功能主要是供血。舟月骨间韧带和月三角骨间韧带的近侧部分,主要由纤维软骨成份组成,其间没有血管。     

腕尺桡偏运动时腕韧带长度变化的活体研究

目的 研究腕关节在尺桡偏运动过程中,腕关节韧带长度的变化.方法 对6名志愿者腕关节进行CT扫描,获得腕关节在桡偏20°至尺偏40°内每隔20°的运动范围内各腕骨及尺桡骨远段三维重建图像.男3名,女3名,仅研究单侧右侧腕关节.年龄20～32岁,平均24岁.在腕关节尺桡偏运动过程中,在重建各腕骨及尺桡骨结构图像上以软件测量掌、背侧腕韧带的长度.结果 腕关节尺偏时桡舟头韧带、长桡月韧带、背侧腕间韧带止于舟骨、大多角骨和小多角骨部分的长度较中立位显著伸长,分别伸长(2.4±0.3)mm、(2.3±0.8)mm、(1.2±0.6)mm、(1.2±1.2)mm与(2.6±1.0)mm,差异均有统计学意义(P＜0.05);腕关节桡偏时尺头韧带与背侧桡腕韧带长度显著伸长(P＜0.05),分别为(0.8±0.6)mm和(1.0±0.5)mm.结论 在腕关节尺桡偏运动时,桡舟头韧带、长桡月韧带、背侧腕间韧带于桡偏位缩短,尺头韧带、背侧桡腕韧带长度于尺偏位缩短.这些位置可能使不同腕韧带张力降低,有利于损伤韧带的修复.     

Experimental carpal displacement induced by ligamental lesions]

Ligamentous lesions were created experimentally in 40 fresh cadaver wrists. The precise localization of traumatic rupture of the ligaments and the subsequent carpal imbalance were defined by the comparison between the experimental results and the clinical displacements. The displacements may be permanent, sequential or induced by external forces. Lesions of capsular ligaments cause the displacement. There are 3 functional units; the distal scaphoid complex; the palmar ligaments which form a "belt", consisting of the lateral external ligament, the radiocarpal ligaments an the radiate ligament; the medial ligaments, which also form a "belt" consisting of the palmar triquetral ligaments on each side of the triquetrum. The sprains are caused by a lesion of a functional unit. The lateral sprain is characterized by a lesion of the distal scaphoid complex. The scaphoid moves into a horizontal position, causing a dorsal deviation of the lunate and a scapholunate diastasis. The central sprain is induced by a rupture of the palmar "belt", causing an anteroposterior radiocarpal or mediocarpal drawer movement. The medial sprain is induced by the rupture, of different extents, of the medial ligaments. On examination, there is either a click or a palmar deviation of the lunate, sometimes with a lunotriquetral diastasis. The dislocations of the wrist are caused by lesion of several ligamentous units.     

Palmar-divergent dislocation of the scaphoid and the lunate

We describe a patient with palmar-divergent dislocation of the scaphoid and lunate. After successful closed reduction, the scapholunate and lunotriquetral ligaments were sutured through the dorsal approach, and the anterior capsule was sutured through the palmar approach. The scapholunate and lunotriquetral joints were fixed with Kirschner wires for 7 weeks. At the 1-year follow-up, magnetic resonance imaging showed no evidence of avascular necrosis of the scaphoid or lunate, and radiographs showed no evidence of the dorsal and volar intercalated segment instability patterns associated with carpal instability. However, flexion of the scaphoid and a break in Gilula’s line remained. To our knowledge, this is the first report showing treatment of palmar-divergent dislocation of the scaphoid and lunate by suturing the carpal interosseous ligaments.     

Radiocarpal articular contact characteristics with scaphoid instability

The relative importance of the three major periscaphoid ligament complexes in maintaining the normal radiocarpal articulation was assessed. Pressure-sensitive film recorded the changes in radioscaphoid and radiolunate articular contact that occurred with sequential ligament sectioning in 12 cadaver wrists. Alterations in the radiocarpal articular contact as a result of ligament disruption are evident in the absence of the recognizable static x-ray changes of carpal instability. The scapholunate interosseous ligament is essential in preventing scapholunate diastasis and dorsoradial subluxation of the proximal scaphoid. Rotatory subluxation of the scaphoid occurs when disruption of the scapholunate interosseous ligament is coupled with disruption of either the palmar intracapsular radiocarpal ligaments or the scaphotrapezial ligament complex. These data help explain the development of degenerative arthritis caused by carpal ligamentous instability.     

Radioscapholunate ligament: a gross anatomic and histologic study of fetal and adult wrists

The radioscapholunate ligament was studied using fifty-four dissected adult cadaver wrists. Four of these wrists had arterial perfusions with colored latex and serial sections were made of twenty-one wrists from fetuses ranging in size from 23 to 230 millimeters crown-rump length. The radioscapholunate ligament was consistently identified between the long and short radiolunate ligaments, emerging through the palmar capsule of the radiocarpal joint. It was found to be a neurovascular structure surrounded by synovial tissue with vascular origins from the anterior interosseous and radial arteries and a neural origin from the anterior interosseous nerve. On entering the radiocarpal joint it attaches proximally to the interfacet prominence on the articular surface of the radius and distally to form the proximal membrane of the scapholunate interosseous ligament system. We found no anatomic evidence that this structure should be considered a ligament in a traditional mechanical sense. However, this structure may be clinically important as the vascular supply of the scapholunate interosseous ligament, as well as a sensory pathway from the scapholunate articulation.     

Radiographic analysis of selective ligament sectioning at the carpal scaphoid: a cadaver study

Although scapholunate diastasis with rotatory subluxation of the scaphoid (stage I perilunar instability determined by Mayfield's classification) has been studied by several investigators, the exact contribution of the supporting ligaments is still being defined. We designed and executed an experimental study using six fresh-frozen cadaver specimens to demonstrate the radiographic changes seen on standard and stress wrist radiographs that correlate with the sequential sectioning of the scapholunate stabilizing ligaments. The radioscapho-lunate ligament, the palmar scapholunate interosseous ligament, the dorsal scapholunate interosseous ligament, and the radiocapitate ligament were sectioned sequentially to simulate a progressive wrist injury caused by an extension, intercarpal supination and ulnar deviation force. The results showed significant ligamentous injury must occur before commonly used radiographic limits are exceeded. The lateral scapholunate angle most closely reflected the progressive nature of this injury.     

The anatomy and vascularity of the lunate: considerations applied to Kienböck's disease

PurposeThe purpose of this study was to assess the anatomy and vascularity of the lunate. The genesis of lunatomalacia requires some combination of vascular risk and mechanical predisposition. The findings will be correlated with the major existing theories of the cause of Kienböck's disease.MethodsWe studied 27 cadaver upper limbs using latex injection and the Spalteholz technique. We investigated the blood supply to the lunate. In 24 wrists we evaluated the incidence and distribution of anatomic features, arthrosis, and soft tissue lesions. We correlated the lunate morphology and ligaments disruptions with the arthritic changes.ResultsThe lunate morphology results as classified by Antuña-Zapico were five type I (20.8%), 18 type II (75%) and one type III (4.2%). The lunate was found to have a separate facet for the hamate in 11 cases (45.8%). The most common size of the facet was found to be 3 mm (range, 3–6 mm). Arthrosis was identified with most frequency in the radius (88.2%) and lunate (94.1%). The triangular fibrocartilage complex was found torn in 58.3%, the lunotriquetral interosseous ligament was torn in 20.8% and the scapholunate interosseous ligament (SLIL) was torn in 54.2% of the wrists. There was a correlation between the presence of arthrosis at the hamate and the presence of a lunate facet (P = 0.027) and a correlation between the presence of a tear in the SLIL and arthrosis in the scaphoid (P = 0.002). The nutrient vessels entered the lunate through the dorsal and volar poles in all the specimens. The dorsal intercarpal and radiocarpal arches supply blood to the lunate from a plexus of vessels located directly over the lunate's dorsal pole. Vessels entered the dorsal aspect of the lunate through one to three foramina. One to five nutrient vessels were observed entering the volar pole through various ligament insertions, including the ligament of Testut-Kuentz (radio-scapho-lunate (RSL) ligament) and the radiolunate triquetrum ligament (or dorsoradial carpal ligament) and ulnar lunate triquetral ligament.ConclusionsThe lunate had consistent dorsal and palmar arteries entering the bone in all the specimens. The blood supply and foramina number is greater in the volar pole of the lunate than the dorsal pole. The lunate blood supply comes from different ligaments. In the etiopathogeny of Kienböck's disease it is possible that an acute or chronic, traumatic or non-traumatic injury of the vessel bearing ligaments, particularly because of their structure and the location of the RSL ligament, may have an important role in the appearance of lunate necrosis.     

The role of the dorsal intercarpal ligament in dynamic and static scapholunate instability

PURPOSE: Scapholunate instability (SLI) is the most common carpal instability. Recent studies have suggested that the dorsal intercarpal (DIC) and the dorsal radiocarpal ligaments play an important role in stabilization of the scaphoid and lunate. Differences between dynamic SLI and static SLI with a dorsal intercalated segment instability (DISI) are clearly described in the clinical literature; however, there has never been a clear explanation of the anatomic differences. This study describes the role of the DIC in the development of dynamic and static SLI with DISI in a cadaver model. METHODS: Five fresh cadavers were studied radiographically and by 3-dimensional digitization. Six increasing stages of instability were developed by sectioning progressively the following structures: the dorsal capsule, the palmar and proximal (membranous) portion of the scapholunate interosseous ligament, the DIC from its insertion on the scaphoid and trapezium, the dorsal scapholunate interosseous ligament from the scaphoid, the DIC ligament from its attachment on the lunate, and the lunotriquetral interosseous ligament. RESULTS: The scaphoid position and the scapholunate gap changed significantly after sectioning the entire scapholunate interosseous ligament and DIC from the scaphoid when a 5-kg load was applied. The lunate position was unchanged in both the loaded and the unloaded conditions. After detaching the DIC from the lunate, both the scaphoid and lunate moved and the scapholunate gap increased significantly in both loaded and unloaded conditions and showed a DISI deformity. CONCLUSIONS: This study describes an anatomic difference between dynamic and static scapholunate instability. Complete disruption of the scapholunate ligament did not result in the development of a static collapse of the lunate. The DIC had an important role in stabilizing the scaphoid and lunate and preventing DISI deformity. This study suggests that in the clinical setting the DIC ligament should be assessed intraoperatively and consideration should be given to repair and/or reconstruction of the DIC ligament attachments to both the scaphoid and the lunate.     

A method of defining palpable landmarks for the ligament-splitting dorsal wrist capsulotomy

PURPOSE: The concept of a ligament-splitting dorsal capsulotomy of the wrist has been defined and has been shown to have practical applications. Due to the abundance of peritendinous tissue, however, the ligaments are often difficult to visualize. This article presents a method of defining incision capsular lines based on reliably palpable landmarks. METHODS: The palpable landmarks include the sulcus between the scaphoid and trapezoid, the dorsal tubercle of the triquetrum, and the midpoint between Lister's tubercle and the dorsal rim of the sigmoid notch. These points identify the bisection lines of the dorsal intercarpal and dorsal radiocarpal ligaments. A radial-based capsulotomy can be easily elevated by incising the dorsal wrist joint capsule using these landmarks and then extending the incision along the dorsal rim of the distal radius to the radial styloid process. RESULTS: This method of defining capsular incision lines based on palpable landmarks was used on 253 consecutive dorsal wrist arthrotomies with excellent exposure, accurate splitting of the dorsal radiocarpal and intercarpal ligaments, and no complications. CONCLUSIONS: Using specific, palpable landmarks on the dorsal wrist, an accurate estimation of the locations and courses of the dorsal radiocarpal and intercarpal ligaments can be reliably made. Even when poorly visualized, these ligaments can be split longitudinally in a reliable fashion to create a standard, ligament-sparing dorsal capsulotomy.