Vascular dominance in the forearm

The dominance of the radial or ulnar artery at the forearm level and their contributions to the circulation of the hand remain a matter of contention. Therefore, the authors proposed to investigate the predominance of one of these arteries first by anatomic studies on 40 fresh cadaver upper extremities, and then by dynamic studies. The dynamic studies included color Doppler sonography in 22 individuals (44 hands) and five-channel plethysmography in 40 individuals (40 right hands). It was found that the ulnar artery is dominant at the elbow, but after originating its collateral branches, the radial artery becomes the dominant artery in the distal forearm and, consequently, constitutes the major source of vascularization to the hand. The ulnar artery is rarely dominant at the forearm level and is physiologically less important. Therefore, there is no hemodynamic reason to prefer the radial artery to the ulnar artery for any invasive maneuvers.     

Reversed forearm island flap supplied by the septocutaneous perforator of the radial artery: anatomical basis and clinical applications

The cutaneous perforators of the radial artery adjacent to the superficial branch of the radial nerve and the lateral antebrachial cutaneous nerve were investigated, and the vascular anatomical features of the reversed forearm island flap supplied by those accompanying perforators were documented. Ten fresh cadavers were systemically injected with lead oxide, gelatin, and water. Twenty forearms were then dissected, and an overall map of the cutaneous vasculature and source vessels was constructed. The accompanying arteries were observed to lie along the lateral antebrachial cutaneous nerve and the superficial branch of the radial nerve and to nourish the skin through cutaneous branches. Vascular communication among these cutaneous vessels was evaluated, to determine the cutaneous vascular territory of the radial forearm flap. This anatomical information facilitates flap design in the forearm region. Clinical experience regarding the usefulness of the reversed forearm island flap for hand reconstruction for a series of five patients is presented.     

Vascular anatomy of the forearm muscles: a study of 50 dissections

This anatomic study is based on 50 adult cadaver upper extremities. The general disposition of the forearm arteries and muscles and the main anatomic variations encountered are specified. Constant existence of an "anterior oblique artery" satellite of the pronator teres was established. The median nerve artery was principally dedicated to the flexor digitorum superficialis and participated appreciably in the constitution of palmar arches in only one case. A supernumerary intermedial radial muscle was found only in two cases. The abductor pollicis longus and extensor pollicis brevis appeared as a single muscular and vascular unit in 84 percent of cases. All the arteries destined for muscles were reckoned whatever their caliber might be. Despite its limitations, this study confirms the very great number of the forearm muscular pedicles. Each forearm contained an average of 264 muscular vascular pedicles. The systematization of the origins and destinations of the 13,158 muscular pedicles is described in a numbered manner for each of the 20 normal forearm muscles and for each of the 12 studied arterial segments. The pronator teres was likely to be supplied by all the anterior arteries of the upper limb. The flexor carpi radialis had one or two dominant pedicles originated from the recurrens ulnaris anterior, recurrens ulnaris, or ulnaris-interossea communis arteries, and many transversal branches originated from the radial artery. The flexor carpi ulnaris was supplied in its proximal third by the recurrens ulnaris posterior artery and in its distal two-thirds by many branches of ulnar artery.(ABSTRACT TRUNCATED AT 250 WORDS)     

Hypertrophy of radial and ulnar arteries following denervation of the chicken wing

Summary Denervation of radial and ulnar arteries in the growing and adult domestic fowl was achieved by unilateral sectioning of the brachial plexus. Eight weeks later the denervated arteries and those of the contralateral wing were examined with light- and electron microscopy to determine the effect of denervation on arterial structure.In growing fowls, the area of the media in radial and ulnar arteries was increased by 29% and 25%, respectively, after denervation. The number of smooth muscle layers was also significantly increased by 16% (radial) and 14% (ulnar), but no significant variation was seen in the wall/lumen ratio of either growing artery. In adult fowls, the area of the media was increased by 93% (radial) and 32% (ulnar) following denervation and the number of smooth muscle cell layers increased by 39% (radial) and 11% (ulnar). There was also an increased wall/lumen ratio of 64% (radial) and 92% (ulnar).These results indicate that hyperplasia of smooth muscle has occurred in response to denervation. Flow-cytometric DNA analysis of growing arteries also indicates that the increase in muscle-cell volume is a result of cell division (not polyploidy) since no significant differences were found between the control and denervated arteries in any stages of the cell cycle.     

The arteria radialis superficialis. An unusual variation of the arteria radialis of man and its phylogenetic significance

During the clinical investigation of 570 soldiers of the German army, we were not able to feel the pulse in 5 cases at the typical place of the radial pulse in the distal part of the forearm. In these 5 cases we were able to find a subcutaneous artery which coursed superficial to the anatomical snuffbox and crossed superficial to the tendon of the extensor pollicis longus muscle. This superficial radial artery enters the deep aspect of the palm between the first and the second metacarpale bones. In three cases we found a bilateral occurrence of this artery, the other variations were observed unilaterally, two on the right side and one on the left side of the forearm. In the family of two patients other members were found who had the same variation of the radial artery. In one of the cases an arteriography of the vessels was made to find the exact anatomical course of the observed variation. We compared our results with the literature on this variation of the radial artery and found agreement on the following course for this vessel. The radial artery divides in the distal fourth of the forearm (5-7 cm proximal to the wrist joint) into two branches. The dorsal branch courses subcutaneously over the tendon of the brachioradialis muscle and runs over the tendon of the extensor pollicis longus muscle to enter the deep aspect of the palm in the first metacarpal space. This dorsal branch courses parallel to the superficial branch of the radial nerve. The palmar branch can be regarded as the 'normal' radial artery, which continues along the medial border of the brachioradialis muscle and courses deep under the tendons of the dorsal muscles of the thumb. The rare appearance (frequency approximately 1%) of a superficial radial artery in man has probably some phylogenetic importance. This is proven by studies on the comparative anatomy of mammals. This variation of the radial artery seems to be homologous to the superficial radial artery which is described in many lower mammals. In human embryos a superficial radial artery is found as well which courses parallel to the superficial branch of the radial nerve and ends on the dorsal side of the hand. Taking all the anatomical and embryological facts into consideration we propose to name this variation of the radial artery the 'arteria radialis superficialis'.     

Anomalous pattern of median artery in the forearm of Indians

Various anomalous relations between the brachial plexus or its branches and arteries are reported. The present study was conducted on 134 limbs to note the origin and course of the median artery and its relation to the median nerve. In 2 limbs (1.5%), the median artery split the median nerve into two roots in the forearm and the artery passed through the nerve. In both of these limbs (1.5%), the median artery arose from the ulnar artery. The median artery in these 2 limbs (1.5%) was considerably large and supplied the hand. Both the origin of the median artery from the ulnar artery and the splitting of the median nerve by the median artery are rare anomalies which have not been reported in the available literature.     

Reducing morbidity in the radial forearm flap donor site

The radial forearm flap, although widely used, has been criticized for the poor quality of its donor site. To investigate the causes of morbidity, 100 radial artery free-flap donor sites have been reviewed. Sixty-seven patients required skin grafting (group 1), and the remaining 33 patients were closed directly (group 2). Seventeen patients in the series had compound osteocutaneous flaps (group 3). Wound healing proved to be a significant problem in groups 1 and 3, and fracture of the radius occurred in 4 of the 17 patients in group 3 and was the most significant cause of morbidity. The radial artery was reconstructed in 12 patients, but only 6 of the arteries (50 percent) were patent at the time of review. Subjective assessment on a scale of 0 to 10 demonstrated a relatively pain-free donor site with low pain scores (2.5 of 10). The cosmetic result was acceptable in men (1.5 of 10) but was less so in women (4 of 10). Angulated fracture of the radius produced an unacceptable cosmetic result (7 of 10). In light of this experience, we no longer reconstruct the radial artery as a matter of routine. The donor defect is closed directly wherever possible using an ulnar artery-based transposition flap when required. A "boat shaped" osteotomy is used in preference to right-angled bone cuts when harvesting a segment of radius to avoid the complications and sequelae of fracture. These changes in surgical technique have improved the acceptability and minimized the problems associated with this donor site.     

Development of the vasculature of the pectoral fin in the Australian lungfish, Neoceratodus forsteri

The development of the vasculature of the pectoral fin in the Australian lungfish, Neoceratodus forsteri, was studied by the dye-injection method. Only a single primitive subclavian artery appears from the dorsal aorta for the fin anlage, and it passes laterally through the postaxial region of the structure. The venous channel draining into the posterior cardinal vein is located in the preaxial region medially. As development proceeds, the arteriovenous arrangement in the pectoral fin anlage changes as follows: 1) one artery and one venous plexus, 2) two arteries and one vein, 3) three arteries and one vein, 4) four arteries and one vein, 5) three arteries and two veins, and 6) two arteries (radial and ulnar) and three veins (radial, ulnar, and ulnar marginal). The fin anlage through embryonic first rotation has gradually changed its postaxial margin to face dorsally and its preaxial margin to face ventrally. The second rotation causes the original preaxial margin to become dorsal and the original postaxial margin to become ventral. As a result, the radial and ulnar arteries are observed in the dorsal and ventral regions, respectively, in the medial side of the fin instead of in the lateral side as seen in the previous stage.     

Primary closure of radial forearm flap donor defects with a bilobed flap based on the fasciocutaneous perforator of the ulnar artery

To primarily repair a series of radial forearm flap donor defects, a total of 10 bilobed flaps based on the fasciocutaneous perforator of the ulnar artery were designed at the Chang Gung Memorial Hospital in Kaohsiung in the period from January of 2002 to January of 2003. All patients were male, with ages ranging from 36 to 67 years. The forearm donor defects ranged in size from 5 x 6 cm to 8 x 8 cm, with the average defect being 47 cm. One to three sizable perforators from the ulnar artery were consistently observed in the distal forearm and were most frequently located 8 cm proximal to the pisiform, which could be used as a pivot point for the bilobed flap. The bilobed flap consisted of two lobes, one large lobe and one small lobe. With elevation and rotation of the bilobed flap, the large lobe of the flap was used to repair the radial forearm donor defect and the small lobe was used to close the resultant defect from the large lobe. All bilobed flaps survived completely, without major complications, and no skin grafting was necessary. Compared with conventional methods for reconstruction of radial forearm donor defects, such as split-thickness skin grafting, the major advantage of this technique is its ability to reconstruct the donor defect with adjacent tissue in a one-stage operation. Forearm donor-site morbidity can be minimized with earlier hand motion, and better cosmetic results can be obtained. Furthermore, because a skin graft is not used, no additional donor area is necessary. However, this flap is suitable for closure of only small or medium-size donor defects. A lengthy postoperative scar is its major disadvantage.     

Forearm compartment syndrome: anatomical analysis of surgical approaches to the deep space

Forearm compartment syndrome is a surgical emergency that usually requires release of the superficial muscle compartments. In some clinical situations it is imperative to also explore the deep muscle compartments. There are no anatomical guides for surgical exploration of the deep compartments that would minimize collateral damage to surrounding vessels, nerves, and muscles. Surgical injury in the setting of ischemia, especially vascular injury, compounds the tissue damage that has already occurred. The authors evaluated four surgical approaches (three volar and one dorsal) to the deep forearm by performing detailed anatomical dissections on 10 embalmed and plastinated cadavers. They used a scoring system to rate the approaches for their ability to visualize the deep space without causing iatrogenic injury to superficial muscles, arteries, and nerves. In the volar forearm, an ulnar approach to the deep space is simple, causes the least iatrogenic surgical injury, and provides access to the deep volar forearm structures. The plane of dissection is between the flexor carpi ulnaris and the flexor digitorum superficialis. Dividing one or two distal segmental branches of the ulnar artery to the distal flexor digitorum superficialis exposes the pronator quadratus. Lifting the ulnar neurovascular bundle with the flexor digitorum superficialis in the middle third of the forearm exposes the flexor digitorum profundus and the flexor pollicis longus. This approach to the deep space requires no sharp dissection. In the dorsal forearm, a midline approach between the extensor digitorum communis and the extensor carpi radialis brevis is simple and safe.     

Prelaminated free flap reconstruction of complex central facial defects

This article is a review of five patients who underwent reconstruction of nasal and paranasal facial defects with prelaminated forearm free flaps. The defects resulted from thermal injury, gunshot wound, excision of tumor, and arteriovenous malformation (n = 2). The forearm flaps were based on the radial artery (n = 4) and ulnar artery (n = 1) and were prelaminated with grafts of skin and cartilage. All flaps were successfully transferred to the face, but revisions were needed to separate the subunits and improve appearance. A prelaminated free flap should be considered for a patient requiring reconstruction of a complex central facial defect.     

The dorsal arterial network of the wrist with reference to the blood supply of the carpal bones.

The gross examination of 50 minium injected specimens showed us the various patterns of the posterior arterial network of the wrist. This is chiefly provided by the radial artery which gives off a constant dorsal carpal branch over the posterior aspect of the trapezium. This vessel crosses the carpus transversely to the inner border of the hand and is joined in half of the cases by the interosseous artery; contribution of the posterior carpal branch of the ulnar artery was more rarely found than usually described (25%). From the arch thus formed are given off short branches which run upwards along the intercarpal joints and enter the posterior aspects of the proximal carpal bones whose lower halves seem to be the most favorably supplied. On the contrary, the distal carpal bones receive several short twigs which penetrate their posterior surfaces. Although the arrangement of the pedicles may undergo many a variation, attention must be drawn to the fact that the dorsal arteries are smaller but denser than the volar, except for the hamate. Therefore 2 different patterns of arterial supply can be described at the carpus: the blood supply of the outer and axial bones--scaphoid, trapezium, lunate, capitate--derives from the radial and the interosseous arteries and is probably shared equally by volar and dorsal branches; the inner bones--triquetrum, hamate--are primarily supplied by volar or medial branches coming almost exclusively from the ulnar artery.     

Ultrasound studies in varicocele

Renal function, the anatomic and functional status of the vena cava inferior, renal arteries and veins, and spermatic veins were evaluated in healthy individuals and patients with varicocele before and 12 months after laparoscopic ligation of the left spermatic vein. The renal vessels were assessed by color Doppler ultrasonography and renal function was examined by complex radionuclide study with 99mTc-pentatech. There were no significant changes in the diameter of renal arteries and vena cava inferior and the right arterial blood flow velocities in healthy individuals and patients. No difference were found in the diameter of renal veins and in the blood flow velocity in renal arteries and veins. The enlarged renal veins and decreased mean blood flow velocity in the left renal vein in healthy persons and patients with varicocele and lower blood flow in the left renal artery than in the right one indicate left-sided renal hypertension that is attributable to left renal vein overload due to a great variety of collaterals and to compression at the site of "a forcepts". At the same time 12-month postoperative ultrasonic, Doppler and complex radionuclide studies revealed no significant changes in the diameter and blood flow velocity in the left renal vein.     

The forearm flap

We present our experimental and clinical experiences with the free neurovascular forearm flap. The flap is based on the radial artery, one of the great veins of the forearm (cephalic, basilic, or interconnecting vein), and one or two cutaneous forearm nerves (ulnar, median, or lateral). Because of the standard anatomy, the large caliber of blood vessels, the good sensory supply, the quality and quantity of the forearm skin, and the thin layer of subcutaneous fat, the free forearm flap is a technically easy and safe flap for reconstruction of soft-tissue defects, especially those in the head and neck and those areas of the extremities where sensitive skin is desired.     

A musculoskeletal model to estimate the relative changes in wrist strength due to interacting wrist and forearm postures

Wrist rotations about one wrist axis (e.g. flexion/extension) can affect the strength about another wrist axis (e.g. radial/ulnar deviation). This study used a musculoskeletal model of the distal upper extremity, and an optimization approach, to quantify the interaction effects of wrist flexion/extension (FE), radial/ulnar deviation (RUD) and forearm pronation/supination (PS) on wrist strength. Regression equations were developed to predict the relative changes in strength from the neutral posture, so that the changes in strength, due to complex and interacting wrist and forearm rotation postures, can be incorporated within future ergonomics assessments of wrist strength.     

Selective accumulations of aluminum in five human arteries

The aim of the present study was to determine variability of aluminum (Al) accumulation in human arteries and to observe the relationship between Al and five other elements (Ca, Fe, Mg, P, and Si) in the arteries. The Al contents in the thoracic aorta, basilar, coronary, femoral, and radial arteries of 26 human subjects were estimated by an inductively coupled plasma-atomic emission spectrometer and compared quantitatively to five elements. Al was detected in 88% of the cases in both the femoral and radial arteries, 73% in the coronary artery, 58% in the aorta, and 31% in the basilar artery. The average Al content was highest in the femoral artery (48.3 ± 15.0 μg/g dry weight) and lowest in the basilar artery (8.1 ± 3.6 μg/g). The Al had positive correlations with P, Ca, or Mg in both the aorta and femoral artery, and with Ca or P in the basilar artery. In the coronary artery, a correlation was found between Al and Si. No relationships were found between Al and each of the five elements in the radial artery. From these results, Al varied widely among the five arteries and accumulated more in the femoral and radial arteries but less in the basilar artery. These accumulations of Al were positively correlated with Ca or P in several arteries, but not sufficiently to explain the accumulation of Al. Further investigations are required to understand the mechanism of the variability of Al accumulation in the arteries.     

Doppler ultrasonographic assessment of maternal and fetal blood flow in abnormal canine pregnancy

The aim of this study was to describe the changes of uterine artery, umbilical artery and fetal abdominal aorta, renal and internal carotid arteries blood flow in abnormal canine pregnancy. Twenty-two, Brucella-negative pregnant bitches were retrospectively classified into abnormal (which had either interrupted their pregnancy between days 52 and 60 or had perinatal death >60% of the litter; n=11) and normal (which had delivered healthy puppies at term; n=11). In all the animals, color and pulsed-wave Doppler examinations of uterine artery were conducted every 10 days from Day 20 to 50 from estimated luteinizing hormone peak. Doppler ultrasonography was also conducted in the fetuses to assess umbilical artery, abdominal aorta, renal and internal carotid arteries from Day 40 to 60 of gestation. Throughout the study, resistance index (RI) of uterine, umbilical and fetal renal arteries decreased up to -15% compared to -36% (P<0.01), -11% compared to -23% (P<0.05) and 2% compared to -13% (P<0.05), respectively in the abnormal and normal bitches. Fetal abdominal aorta and internal carotid did not differ between groups (P>0.05). It is concluded that in dogs, uterine artery, umbilical artery and fetal renal artery RI differ between normal and abnormal gestation being useful for the prediction of adverse obstetric outcome.     

Embolization of the hepatic artery in cases of atypical anatomical structural variants in patients with malignant liver tumors

Therapeutic embolization of the hepatic artery was performed in 60 patients with nonresectable malignant liver tumors. Atypical topographical anatomical variants of the arterial system of the liver were revealed in 10 of them (16.7%). In 8 patients two hepatic vessels, one coming out of the celiac artery, the other--out of the upper mesenterial or left gastric artery supplied a tumor with blood. In three of them one vessel was embolized, in five patients both arteries were embolized. The blocking of the entire blood flow of a tumor brought about a positive clinical effect in all the patients. Embolization of one blood-supplying artery alone led to no improvement. A conclusion was made of a necessity to achieve arterial devascularization of the entire tumor tissue area during intravascular therapy.     

Comparison of the radial forearm flap and the thinned anterolateral thigh cutaneous flap for reconstruction of tongue defects: an evaluation of donor-site morbidity

The radial forearm flap is commonly used for reconstruction of tongue defects following tumor extirpation. This flap is easy to harvest and offers thin tissue with large-caliber vessels. However, its use leaves behind a conspicuous aesthetic deformity in the forearm and requires the sacrifice of a major artery of that limb, the radial artery. The anterolateral thigh cutaneous flap has found clinical applications in the reconstruction of soft-tissue defects requiring thin tissue. More recently, in a thinned form, the anterolateral thigh flap has been used for reconstructing defects of the tongue with functional results equivalent to that of the radial forearm flap. For the reconstruction of tongue defects, these two flaps could provide similar soft-tissue coverage, but they seem to result in different donor-site appearances. The donor site is closed primarily, leaving only a linear scar that is inconspicuous with normal clothing, and no functional deficit is left behind in the thigh. Thus, for the supply of flaps for tongue defects, a comparison between the radial forearm flap and the anterolateral thigh flap donor sites is provided in this study. Between December of 2000 and August of 2002, 41 patients who underwent reconstruction of defects of the tongue using either a radial forearm flap or an anterolateral thigh flap were evaluated. The focus was on the evaluation of the functional and aesthetic outcome of the donor site after harvesting these flaps for the purpose of reconstructing either total or partial tongue defects. Finally, a comparison was performed between the donor sites of the two flaps. The disadvantages of the radial forearm flap include the conspicuous unattractive scar in the forearm region, pain, numbness, and the sacrifice of a major artery of the limb. In some patients, the donor-site scar of the forearm acted as a social stigma, preventing these patients from leading a normal life. In contrast, the anterolateral thigh cutaneous flap, after thinning, achieved the same results in reconstructing defects of the tongue without the associated donor-site morbidity. Most importantly, the donor site in the thigh could be closed primarily in almost all patients without any functional deficit. The thinned anterolateral thigh cutaneous flap is a viable substitute for the radial forearm flap when reconstructing defects of the tongue. The results achieved are similar to those of the radial forearm flap, and the donor-site morbidity is significantly decreased.     

The radial forearm flap for reconstruction of the upper extremity

The radial forearm flap, owing to its good-caliber arteries of long length and equally well distributed venous system, has proved very reliable. It has not only earned its place and recognition in reconstructive hand surgery, but also has emerged as a workhorse for the microvascular surgeon. We have used 14 radial forearm flaps for upper extremity reconstruction, and we present herein our experience. The technique of extracorporeal tissue transfer, which has been published elsewhere, was used in two patients and is detailed. Four representative patients are presented.