Ulnar styloid triquetral impaction.

BACKGROUND: Ulnar styloid triquetral impaction (USTI), one of many causes of ulnar sided wrist pain, is a pathological entity with clear clinical and radiographic features, distinct and different from the impaction of the ulnar head against the lunate or ulno-carpal impaction (UCI). Pain is ulnar and point-tenderness is present precisely over the ulnar styloid as opposed to the proximal lunate in UCI. The provocative maneouvre of dorsiflexion in pronation followed by supination is markedly different from the ulnar deviation grind test maneouvres used to diagnose UCI. Multiple anatomical and pathological features interplay to produce a situation in which the distance between the tip of the ulnar styloid and the triquetrum is reduced resulting in USTI. The concept of ulnar styloid variance is introduced and anatomical variations of ulnar styloid length are demonstrated. METHODS: The clinical and radiographic features of 56 patients diagnosed with USTI were analysed. One thousand standardised film-file wrist radiographs were measured to determine the average length of the ulnar styloid in the population as well as the average projection of the styloid above the radius (ulnar styloid variance). RESULTS: An aetiological classification system for USTI was developed based on the clinical and radiographic features of the aforementioned patients and radiographs. CONCLUSIONS: The causes of this syndrome are often complex and classification of the aetiological features is clinically useful. It is important for physicians and surgeons to recognise the clinical and radiographic features of this syndrome in order to properly manage the symptoms and prevent an iatrogenic production of USTI.     

Carpal impaction with the ulnar styloid process: treatment with partial styloid resection

Carpal impaction with the ulnar styloid process (stylocarpal impaction) occurs less frequently than with the ulnar head (ulnocarpal impaction), and more commonly develops in wrists with negative ulnar variance. Physical examination, radiographic evaluation, and wrist arthroscopy are all helpful in excluding alternative causes of ulnar wrist pain. When an ulnocarpal stress test elicits pain, and radiographs suggest that this is due to carpal impaction with the ulnar styloid, partial resection of the styloid process provides successful treatment, so long as the insertion of the triangular fibrocartilage at the base of the styloid is not disrupted.     

Changes in ulnar variance in relation to forearm rotation and grip

We studied radiographs of the wrists of 120 healthy volunteers in order to determine the normal range of ulnar variance. They had been taken in various positions under both unloaded (static) and loaded (dynamic) conditions. Pronation posteroanterior, supination anteroposterior and neutral posteroanterior views were taken of each wrist before and during a maximum grip under identical conditions. The mean normal ulnar variance in neutral rotation was +0.74+/-1.46 mm, a value which was significantly lower in males than in females. We found negative variance in 26% of cases. We measured maximum ulnar variance (UVmax +1.52+/-1.56 mm) when gripping in pronation and minimum ulnar variance (UVmin +0.19+/-1.43 mm) when relaxed in supination. We subtracted UVmin from UVmax to calculate a mean maximum dynamic change in ulnar variance of 1.34+/-0.53 mm. We consider this database of normal values to be useful for both the diagnosis and treatment of conditions related to discrepancy in radio-ulnar length and for clinical research.     

Posteroanterior wrist radiography: importance of arm positioning

Proper interpretation of wrist radiography requires a standardized radiographic technique. We obtained posteroanterior (PA) radiographs of the wrist in nine patients in three different arm positions to study the effect of arm position on ulnar styloid process orientation. An appearance simulating a normal anteroposterior (AP) wrist radiograph was present in six of nine PA radiographs when the arm was positioned next to the trunk, and the elbow was flexed to a 90% angle. The orientation of the ulnar styloid was not helpful in differentiating either pronated from supinated wrist positions or AP from PA projections. We concluded that radiographic screening of the carpus should be performed with standardized wrist positioning and nomenclature as described in modern radiographic technological texts. Supplemental projections should be exposed and interpreted with an understanding of the position of the arm and the direction of the incident radiographic beam at the time of examination.     

Validation of the extensor carpi ulnaris groove as a predictor for the recognition of standard posteroanterior radiographs of the wrist

This study was designed to establish the extensor carpi ulnaris groove (ECUG) as a reliable radiographic criterion for recognition of true neutral posteroanterior (PA) radiographs and to verify precise measurements of ulnar variance in a large cohort of patients. In 197 patients 197 wrists were evaluated with a series of radiographic views obtained during routine wrist arthrography. Posteroanterior views were taken in all patients at 90 degrees, 45 degrees, and 0 degrees arm abduction and in 171 patients at 90 degrees elbow flexion and 90 degrees arm abduction with full elbow extension. The ECUG position was classified according to its profile with the ulnar styloid as excellent, acceptable, or unacceptable. Ulnar variance was measured on all x-ray films. Statistical analysis included interobserver reliability with 100 x-ray films measured by 2 evaluators. The ECUG was excellent or acceptable in 100% of the x-rays on standard PA views (arm abducted 90 degrees ), 87% excellent or acceptable and 13% unacceptable on 45 degrees arm abduction views, and 23% excellent or acceptable and 77% unacceptable on 0 degrees arm abduction (adducted) views (all with the elbow flexed at 90 degrees ). With the arm at 90 degrees abduction and full elbow extension the ECUG was excellent or acceptable in 91% of cases. These results show that the ECUG is a reliable criterion to verify arm position during PA wrist radiography and therefore provides a standard for making treatment decisions. The need for repeat radiographs should be reduced.     

Bicortical K-wires for distal radius fracture fixation: how many?

The aim of this study was to find out whether number and position of K-wires influence the stability of distal radius fractures treated by percutaneous wire fixation. Patients who underwent K-wire fixation for unstable fractures of the distal radius over a period of three years were included in this retrospective study. Radiographs taken immediately after the procedure and radiographs taken after removal of K-wires were analysed to study three radiological parameters: palmar or dorsal tilt, radial inclination and ulnar variance. Loss of these angles was analysed statistically against the number of wires (2 or 3) and position of wires (from radial styloid or a combination of styloid and dorsal wires). Ninety-five fractures were analysed with a mean age of 52.8 years and male to female ratio of 1:2. Average loss of radial inclination was 5.2 degrees, loss of palmar tilt was 8.3 degrees and loss of ulnar variance was 3.4 mm. Using 3 wires or using a dorsal wire in addition to the styloid wires both improved the final radial length by 1.2 mm and 2 mm respectively, but the effects were statistically not significant. We found that the number or position of wires did not influence radiological outcome. Based on our findings we recommend the use of two K-wires: one from the radial styloid and one from the dorsal side for these fractures.     

腕部X线正位片形态学测量及临床应用

目的 分析测量正常腕部X线正位片形态学参数的正常值,为判断病理状态下这些参数的变化提供依据.方法 采用标准X线摄片技术,利用Pacs系统软件测量40侧正常腕部X线正位片的9个影像学参数,其中包括7个新的影像学参数:尺骨茎突长度(ulnar styloid length,USL)、尺骨小头长度(ulnar head length,UHL)、尺骨小头直径(ulnar head diameter,UHD)、桡骨远端最大宽度(maximal distal radius width,MDRW)、桡骨远端近侧宽度(proximal distal radius width,PDRW)、乙状切迹宽度(sigmoid notch width,SNW)、乙状切迹长度(sigmoid notch length,SNL).同时将这些参数与第三掌骨长度的比值定义为相应指数.结果 40侧正常腕部X线正位片的7个新的影像学参数:尺骨茎突长度平均为[(3.01 ±1.65)mm,-x±s,下同],长度指数平均为(0.05±0.03);尺骨小头长度平均为(9.11±1.54)mm,长度指数平均为(0.15±0.02);尺骨小头直径平均为(18.56±1.96)mm,直径指数平均为(0.30±0.03);桡骨远端最大宽度平均为(29.60±2.70)mm,宽度指数平均为(0.48±0.04);桡骨远端近侧宽度平均为(27.60±2.00)mm,宽度指数平均为(0.45±0.03);背侧缘突起型乙状切迹宽度平均为(3.32±1.61)mm,宽度指数平均为(0.05±0.02),长度平均为(10.15±1.61)mm,长度指数平均为(0.16±0.02);掌侧缘突起型乙状切迹宽度平均为(3.53±1.15)mm,宽度指数平均为(0.06±0.02),长度平均为(10.96±2.33)mm,长度指数平均为(0.18± 0.03);掌背侧缘均无突起型宽度平均为(1.55±1.01)mm,宽度指数平均为(0.03±0.02),长度平均为(10.32±1.57)mm,长度指数平均为(0.17±0.02).结论 测量所得X线正位片参数可用于腕部相关疾病严重程度的判断.     

How many clinic visits does it take to treat distal radial fractures?

The purpose of this study was to evaluate the changes in alignment during the course of treatment for extra-articular distal radius fracture and the relationship of initial and intermediate radiographs, with the final radiograph taken at fracture union. A cohort of 96 consecutive patients who were conservatively managed for extra-articular distal radius fracture in an 18-month period was undertaken. The radiographs analysed were taken at prereduction, postreduction, a week later and at fracture union. The radiological parameters analysed were radial tilt, radial length, radial inclination, dorsal comminution and ulnar styloid fracture. There was a significant change in radiographic alignment between initial and immediate postreduction radiographs, and between postreduction 1 week later radiographs (p < 0.05), but the number of patients in the 1 week later and fracture union groups remained similar (p > 0.05). All patients with poor radiological outcome had ulnar styloid fractures. This was also associated with dorsal comminution in 86% of patients. Patients with satisfactory radiological outcome had ulnar styloid fracture and comminution in 34% and 43% of patients respectively. The final radiological outcome was not found to be influenced by initial unsatisfactory alignment of radial tilt, radial length and radial inclination individually or in combination. We suggest that two clinic visits after initial reduction of the fracture should be sufficient to manage such injuries; the first visit 1 week after manipulation to detect unacceptable displacement and if found satisfactory, the last visit at fracture union for final review, advice and referral to physiotherapy.     

Ulnar shortening osteotomy in idiopathic ulnar impaction syndrome

BACKGROUND: Idiopathic ulnar impaction syndrome can be defined as a degenerative condition of the ulnar aspect of the wrist in patients with congenital or dynamic positive ulnar variance without a history of fracture or premature physeal arrest. The purpose of this study was to evaluate the clinical features of idiopathic ulnar impaction syndrome and the outcomes of ulnar shortening osteotomy for this group of patients. METHODS: Thirty-one wrists in twenty-nine patients with idiopathic ulnar impaction syndrome were treated with an ulnar shortening osteotomy. Ulnar variance was measured on an anteroposterior radiograph of the wrist, and radioulnar distance was measured on a lateral radiograph, with the forearm in neutral rotation, to evaluate any displacement of the ulnar head from the distal aspect of the radius. All patients were followed clinically and radiographically for a mean of thirty-two months. RESULTS: An average preoperative ulnar variance of +4.6 mm (range, 2 to 7.5 mm) was reduced to an average of -0.7 mm (range, -4 to +1 mm) postoperatively. Preoperatively, the modified Gartland and Werley score was an average (and standard deviation) of 69.5 +/- 7.6, with twenty-four wrists rated poor and seven rated fair. Postoperatively, the score improved to an average of 92.5 +/- 8.0, with twenty-four wrists rated excellent; five, good; one, fair; and one, poor. Dorsal subluxation of the distal aspect of the ulna was found concomitantly in nine wrists, and it was found to be reduced by the shortening osteotomy. Seven patients had cystic changes in the carpal bones preoperatively, but these were not evident one to two years after the operation. CONCLUSIONS: Ulnar shortening osteotomy improved wrist function in patients with idiopathic ulnar impaction syndrome and reduced the subluxation of the distal radioulnar joint, which is commonly found in these patients. Degenerative cystic changes of the ulnar carpal bones appear to resolve following the shortening osteotomy.     

The sensitivity of carpal bone indices to rotational malpositioning

We investigated the dependence of 20 radiographic carpal measurements (carpal indices) on rotational positioning errors in posteroanterior and lateral radiographs. The measurements were made from "true perspective" digitally reconstructed radiographs created from computed tomography data. Most posteroanterior indices were not affected by rotation. Carpal height, carpal height ratio, revised carpal height ratio, capitate-radius distance, and carpal ulnar translocation were particularly robust. Lateral-view indices involving the scaphoid were the most sensitive to simulated malpositioning: radioscaphoid, scapholunate, and scaphocapitate angles were reduced from 58 degrees, 48 degrees, and 56 degrees at true lateral to 30 degrees, 24 degrees, and 34 degrees, respectively, at 20 degrees external rotation. Observers were unable to estimate the degree of malpositioning accurately in either view. Our results support use of the "scaphopisocapitate" criterion for assessing correct positioning in lateral plain radiographs.     

Radiometric assessment of wrist angle values, linear parameters of the forearm and wrist ratios]

With the device of our own invention suitable for static X-ray examination of the wrist 12 radiographic parameters were evaluated. 100 radiograms regarded normal were analyzed, obtained as a comparative in unilateral wrist trauma patients group. Age of the patients ranged from 18 to 60 years. No comparative studies in regard to sex were performed. Obtained data were statistically analyzed. Subsequent values of the radiometric parameters were obtained: scaphoid-lunate angle (SL) 48.61 degrees, radio-lunate angle (RL): -0.83 degrees, palmar inclination of the distal radius metaphysis (RI): 25.96. The most significant linear parameters measured: ulnar length 0.18 mm, ulnar transposition (UT): 0.339 mm.     

Physeal fractures of the distal radius and ulna: long-term prognosis

OBJECTIVES: The long-term prognosis of injuries to the distal physis of forearm bones, including complications such as radioulnar length discrepancy and styloid nonunion, has not been extensively studied. Reliable radiographic prognostic criteria to predict physeal disturbance at trauma are also lacking. The aim of this study is to investigate both issues. DESIGN: Retrospective study. SETTING: University hospital. PATIENTS/PARTICIPANTS: One hundred sixty-three lesions to the distal physis of the forearm bones in 157 patients were available for a long-term follow-up. Seventy-seven injuries of the distal radial physis were radiographically isolated, 54 were associated with a fracture of the ulnar styloid, and 26 with a fracture of the distal ulnar metaphysis. Of the six injuries of the distal ulnar physis, five were associated with a fracture of the distal radial metaphysis, and one was an isolated injury of the distal ulnar physis. INTERVENTION: Treatment consisted of wrist immobilization in a long-arm plaster cast for 6 weeks. Dorsal or volar displacement was reduced using general anesthesia. MAIN OUTCOME MEASUREMENTS: All patients had both clinical and radiographic evaluation, with an average follow-up of 25.5 years (range 14-46 years). The average age of the patients at injury was 11.6 years (range 5-17 years), whereas their average age at follow-up was 35.5 years (range 22-56 years). Both the Salter and Harris and the Ogden classifications were used to classify physeal injuries. RESULTS: According to Salter and Harris, of the 157 radial lesions, 18 were type 1 and 139 type 2. According to Ogden, 14 were type 1A, 4 type 1C, 84 type 2A, 13 type 2B, 17 type 2C, and 25 type 2D. Of the 6 ulnar lesions, 2 were Salter and Harris type 1 (Ogden type 1A), 3 type 2 (Ogden type 2A), and 1 type 4 (Ogden type 4A). Fifty-four radiographically evident fractures of the ulnar styloid associated with injuries of the distal radial physis were classified as Ogden type 7A. At follow-up, all of our patients were fully asymptomatic, except for those who had forearm bone growth failure of more than 1 cm. Shortening of the previously injured forearm bones ranging from 1 to 6.5 cm was observed in 2 open and subsequently infected lesions as well as in 5 uncomplicated lesions of the 157 distal radial physeal injuries (4.4%), and in 3 of the 6 distal ulnar physeal injuries (50%). Shortening of 1 cm or more was observed in the uncomplicated lesions of radial physeal injury with Ogden type 1C, 2B, and 2D lesions, and in ulnar physeal injuries Ogden type 1A, 2A, and 4A. Thirty-eight additional patients had radioulnar length discrepancy that ranged from 2 to 9 mm, and 53 patients had styloid nonunion, but all of them were asymptomatic. CONCLUSIONS: None of the patients reviewed at follow-up, including those with radioulnar length discrepancy of less than 1 cm and those with styloid nonunion, complained of any symptom related to their previous injury, not even those engaged in heavy manual labor. Of the 10 patients with either radial or ulnar shortening of more than 1 cm, only 2 with radial growth arrest and marked radioulnar length discrepancy had severe functional problems. Growth disturbances of more than 1 cm following distal radial physeal injury occurred only in Ogden type 1C, 2B, and 2D lesions, whereas in distal ulnar physeal injuries, growth disturbances occurred regardless of the Ogden classification type.     

Long-term Outcomes of Ulnar Shortening Osteotomy for Idiopathic Ulnar Impaction Syndrome: At Least 5-Years Follow-up

Background

There have been few outcomes studies with follow-up after performing ulnar shortening osteotomy for ulnar impaction syndrome. We investigated the long-term clinical and radiological outcomes of ulnar shortening osteotomy for the treatment of idiopathic ulnar impaction syndrome.

Methods

We retrospectively reviewed 36 patients who had undergone ulnar shortening osteotomy for idiopathic ulnar impaction syndrome for a mean follow-up of 79.1 months (range, 62 to 132 months). The modified Gartland and Werley scores were measured pre- and postoperatively. The radiographic parameters for the assessment of the distal radioulnar joint (DRUJ) as well as the relationship between these radiographic parameters and the clinical and radiological outcomes were determined.

Results

The average modified Gartland and Werley wrist score improved from 65.5 ± 8.1 preoperatively to 93.4 ± 5.8 at the last follow-up visit. The average preoperative ulnar variance of 4.7 ± 2.0 mm was reduced to an average of -0.6 ± 1.4 mm postoperatively. Osteoarthritic changes of the DRUJ were first seen at 34.8 ± 11.1 months follow-up in 6 of 36 wrists (16.7%). Those who had osteoarthritic changes in the DRUJ had significantly wider preoperative ulnar variance, a longer distal radioulnar distance and a greater length of ulnar shortening, but the wrist scores of the patients who had osteoarthritic changes in the DRUJ were comparable to those who did not have osteoarthritic changes in the DRUJ.

Conclusions

The clinical outcomes are satisfactory for even more than 5 years after ulnar shortening osteotomy for treating idiopathic ulnar impaction syndrome despite the osteoarthritic changes of the DRUJ. The patients who need a larger degree of ulnar shortening may develop DRUJ arthritis.     

Non-union of the ulnar styloid process in children is common but long-term morbidity is rare: a population-based study with mean 11 years (9–15) follow-up

Background and purpose — Fracture of the ulnar styloid process (USP) is common in children in connection with distal radius fracture. The long-term morbidity of USP non-union following a childhood distal radius fracture is unclear. We evaluated long-term clinical and radiographic findings of USP non-union.

Patients and methods — All 208 children (< 16 years) who had suffered from distal radius fracture with or without a diagnosed concomitant ulnar fracture during 1992–1999 in the study institution were invited to follow-up at mean of 11 years (9–15) after the injury. Radiographs of both wrists of all 139 participants (67%) were taken; 22 patients showed USP non-union and they made up the study population. Distal radioulnar joint (DRUJ) instability, decreased range of motion (ROM), and weakened grip strength as compared with the uninjured side were the main functional outcomes. Elements of the “Disability of Arm, Shoulder and Hand” questionnaire were used for subjective symptoms.

Results — The rate of USP non-union following childhood distal forearm fracture was 16% (22/139) and only 9 of the ulnar styloid fractures were visible in the radiographs primarily. At follow-up wrist flexion–extension ROM and ulnar and radial deviation ranges did not differ between the injured and uninjured sides. Grip strengths were similar. 6 patients reported pain during exercise. 7 had ulna minus (mean 2.3?mm) but none showed degenerative radiographic findings.

Interpretation — The long-term clinical results of USP non-union following a childhood wrist fracture were good. However, one-third of the patients with USP non-union had ulnar shortening, which may predispose them to degenerative processes later in life.     

The "wafer" procedure. Partial distal ulnar resection.

A technique of partial resection of the distal ulna ("wafer" procedure) for the treatment of patients with symptomatic tears of the triangular fibrocartilage complex or mild ulnar impaction syndrome or both is described. The distal 2-4 mm of the distal ulna is resected while preserving the distal radioulnar joint and the styloid process of the ulna and the ligaments attached to it. The triangular fibrocartilage can be debrided, repaired, or partially excised. The wafer procedure has several advantages and avoids some of the potential complications of other treatment methods.     

Distal radius fractures: a comparison of tension band wiring versus ulnar outrigger external fixation for the management of distal radioulnar instability

PURPOSE: To retrospectively compare the results of immobilization of the forearm in supination with the results of tension band fixation of the ulnar styloid in 35 patients with distal radius fractures, fracture of the base of the ulnar styloid, and distal radioulnar joint instability treated with external fixation. METHODS: Thirty-five patients with fractures of the distal radius, fracture of the base of the ulnar styloid, and unstable distal radioulnar joint had external fixation with adjunctive percutaneous pins and allograft bone to reduce and stabilize the distal radius fracture anatomically. Only those patients with an associated ulnar styloid base fracture displaced over 2 mm with gross distal radioulnar joint instability relative to the contralateral wrist were included in this study. Group 1 consisted of patients in whom the ulnar styloid base fracture was treated with conventional tension band wiring techniques. Group 2 patients were treated with a supplemental outrigger from the external fixator to the ulna and locked in 60 degrees of forearm supination. Groups 1 and 2 had an average follow-up period of 40 and 36 months, respectively. RESULTS: Group 2 had significantly better supination than group 1. In terms of functional outcome it was found that there was no significant difference for the Disabilities of the Arm, Shoulder, and Hand and the Gartland and Werley scores between the 2 treatment groups. There was a lower rate of complications and fewer secondary procedures were required in group 2. The incidence of distal ulna resection was 4 of the 35 patients (2 patients in each group). CONCLUSIONS: Our results indicate that patients in whom the ulnar styloid can be reduced and maintained in supination can be treated effectively with fixed supination outrigger external fixation. This method resulted in a statistically significant improvement in supination and a lower rate of distal radioulnar joint complications, and it required fewer secondary procedures.     

Symptoms and radiographic findings in the proximal and distal ulnar stumps after the Sauvé-Kapandji procedure for treatment of chronic derangement of the distal radioulnar joint

PURPOSE: We analyzed correlations between symptoms and radiographic findings with respect to the proximal and distal ulnar stumps after the Sauvé-Kapandji procedure for treating chronic derangement of the distal radioulnar joint. METHODS: A total of 26 patients were studied (13 men, 13 women) with a mean age of 46 years at examination. Clinical assessment included elicitation of postoperative symptoms related to the proximal and distal ulnar stumps. In the radiographic study the radioulnar distance in the neutral wrist position and the presence or absence of scalloping at the radius were determined from posteroanterior (PA) views. The total mobility distance of the proximal ulnar stump was measured on the PA and lateral views while the wrist moved from radial to ulnar deviation or from extension to flexion. RESULTS: Eleven patients complained of tenderness over the distal ulnar stump and 5 patients felt discomfort around the proximal ulnar stump during forearm rotation. The postoperative radioulnar distance in patients with tenderness was significantly smaller than in the group without tenderness. Scalloping at the radius was shown in 9 patients but it was not related to the radioulnar distance. The total mobility distance of the proximal ulnar stump on the PA view was significantly greater in patients with tenderness than in those without, and it also was significantly greater in patients with scalloping than in those without. The total mobility distance on the lateral view was significantly greater in the group with discomfort than in the group without discomfort. CONCLUSIONS: The radioulnar distance was related to tenderness over the distal ulnar stump but not to the scalloping. Tenderness and scalloping each were related to radioulnar instability of the proximal ulnar stump. Discomfort around the proximal ulnar stump was related to dorsovolar instability of the stump. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic, Level IV.     

Radiographic measurement of internal organs in Spix's macaws (Cyanopsitta spixii)

Radiology is an important diagnostic instrument in avian medicine, but standard measurement ranges for the objective evaluation of radiographs of birds are rare. To establish radiographic reference ranges for the critically endangered Spix's macaw (Cyanopsitta spixii), we measured radiographic silhouettes of the heart, liver, kidneys, spleen, proventriculus, and keel of the sternum on 29 radiographs taken under standardized conditions in adult and juvenile, clinically healthy birds. Ratios were determined for the proventricular diameter-to-keel height, the width of the heart to the width of the thorax, and for the "hourglass shape" (ratio of the width of the heart to the width of the liver). No significant differences were found between the sexes among the adult birds. Compared with adult birds, juvenile females had a significantly larger heart width (19.8 +/- 1.4 mm versus 21.2 +/- 0.7 mm), ratio of the heart width to the thorax width (0.86 +/- 0.08 versus 0.94 +/- 0.09), and horizontal width of the spleen (7.7 +/- 0.6 mm versus 8.5 +/- 0.4 mm). Results of radiographic measurements in the Spix's macaws were comparable to those published from other psittacine species. These reference ranges will facilitate a more objective radiographic evaluation of captive Spix's macaws.     

The anatomy of the bicipital tuberosity and distal biceps tendon

The anatomy of the distal biceps tendon and bicipital tuberosity (BT) is important in the pathophysiology of tendon rupture, as well as surgical repair. Understanding the dimensions of the BT and its angular relationship to the radial head and radial styloid will facilitate surgical procedures such as reconstruction of the distal biceps tendon, radial head prosthesis implantation, and reconstruction of proximal radius trauma. We examined 178 dried cadaveric radii, and the following measurements were collected: radial length, length and width of the BT, diameter of the radius just distal to the BT, distance from the radial head to the BT, radial head diameter, width of the radius at the BT, radial neck-shaft angle, and styloid angle. Furthermore, the morphology of the BT ridge was defined as smooth (absent), small, medium, large, or bifid. Of the specimens, 48 were further analyzed with a computed tomography scanner at the level of the BT to determine the distance to traverse both the anterior and posterior cortex and the anterior cortex alone. Eighteen fresh-frozen cadaveric elbows were dissected, and the insertion footprint of the distal biceps tendon was defined. The BT has a mean length of 22 +/- 3 mm and a mean width of 15 +/- 2 mm. The tendon insertion footprint is a ribbon-shaped configuration on the most ulnar aspect of the BT, and it occupies 63% of the length and 13% of the width of the BT. The BT ridge is absent in 6% of specimens and bifid in 6%, and the remaining 88% of specimens have a single ridge that may be classified as small, medium, or large. The mean diameter of the radial head is 22 +/- 3 mm. The mean radial neck-shaft angle is 7 degrees +/- 3 degrees , and the mean BT-radial styloid angle is 123 degrees +/- 10 degrees . None of the measurements correlated with patient age, sex, or race. We concluded that the morphology of the BT ridge is variable. The insertion footprint of the distal biceps tendon is on the ulnar aspect of the BT ridge. The dimensions of the radius and BT are applicable to several surgical procedures about the elbow.