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PubMed1984

A contribution to the study of the innervation of the sternocleidomastoid muscle.

Studies on the innervation of the sternocleidomastoid muscle have shown the highly variable arrangement of the nerve fibers originating from the accessory nerve (eleventh cranial pair) and cervical nerves which supply the muscle. The results of 100 dissections described in this study confirmed these variations and led to propose a classification of the innervation of the sternocleidomastoid according to three main types. The classical "anastomotic" type of innervation (also referred to as Maubrac's type of innervation) was the most frequent, although present in only half of all cases. Innervation of the sternocleidomastoids in symmetrical fashion was an exceptional finding. The functional attributes of these anatomical variations are discussed.

Accessory Nerve↗

PubMed1998

Sonographic characteristics of the cavum velum interpositum.

BACKGROUND AND PURPOSE: Differential considerations for pineal region CSF collections include both true cysts and normal cystlike anatomic variations. Our purpose was to determine the sonographic characteristics of pineal region fluid spaces that reflect the presence of a normal persistent cavum velum interpositum (CVI). METHODS: Eighteen neonates and infants who had sonographic findings of "cysts" in the pineal region were examined prospectively with conventional sonography and color Doppler sonography to evaluate the shape of the fluid collection and its anatomic relationship with the color-coded internal cerebral veins. Subsequent MR images were obtained in eight of these infants to determine the exact nature of the cystlike collections. RESULTS: The cystlike spaces in the pineal region were of an inverted helmet shape in 14 subjects and roundish in four. All were situated inferior or slightly anteroinferior to the splenium of the corpus callosum and 2.5 to 4 mm away from the quadrigeminal plate. The internal cerebral veins were either inferior (n = 12) or inferolateral (n = 6) to the cystlike spaces at sonography. Subsequent MR studies confirmed eight of these cystlike spaces to be the posterior portion of the CVI. CONCLUSION: The CVI may appear as a cyst in the pineal region on neonatal sonograms. Usually, it has a characteristic inverted helmet shape and is situated beneath the fornices and above the internal cerebral veins.

Brain Diseases↗

PubMed2006

[The asymptomatic thoracic outlet compression syndrome].

The thoracic outlet compression syndrome has a great number of clinical variations. Arterial and venous perfusion impairment is an associated symptom, nerve irritation can occur with or without vascular problems. The degree of nerve damage ranges from transient irritation to permanent motoric and sensory defects. The lack of space in the supracostoclavicular compartment is the cause for nerve compression. The degree of neural damage depends on the degree and duration of the compression. Anatomic variations between the clavicle and first rib are frequent causes for the TOS: accessory ribs and muscles, and fibrous bands have been described. A preexisting chronic compression may lead to a subclinical TOS, in this case an inadequate trauma of minor degree may be sufficient to manifest a plexus palsy. Intraoperative findings in children with incomplete and complete brachial plexus palsy and the corresponding findings in adults prompted us to present this communication.

Adult↗

PubMed1995

The accuracy of duplex ultrasonography in the planning of skin flaps in the lower extremity.

The septocutaneous perforators represent one of the major sources of the blood supply to the skin of the lower extremity. Despite several well-described anatomic accounts, the location of lower leg septocutaneous perforators, as they originate from each of the three main infrapopliteal vessels in the leg, remains inconsistent as a result of individual anatomic variations. With the aid of duplex ultrasonography (color Doppler imaging), preoperative, mapping and size determination of these perforators can be provided. The skin paddle can then be designed to lie exactly over these perforators, ensuring blood supply to the skin paddle. The location and distribution of medial septocutaneous perforators in the leg, which originate from the posterior tibial artery, were mapped using anatomic dissections (29 lower extremities). These findings were then compared with duplex ultrasonographic data in 9 living volunteers (18 lower extremities). The medial septocutaneous perforators were chosen for this study because they course directly over the posterior tibial artery, making their location difficult to assess with standard Doppler techniques. The hand-held Doppler is incapable of distinguishing flow originating from the perforators versus the posterior tibial artery. No significant difference existed between cadaver and duplex distributions. "Large" perforator vessels (> 1 mm outer diameter) were evenly distributed with a central tendency at 140 to 150 mm from the medial malleolus. The distribution of "small" perforator vessels (< 1 mm outer diameter) was skewed. Fifty percent were found within 80 mm of the medial malleolus and the remainder spread proximally in the leg.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

[Roentgenographical and anatomical study of the midcarpal joint--morphology and degenerative change of ulnar side].

The present investigator has studied the following anatomic variations and degenerative changes of the articular cartilage of the ulnar side of the midcarpal joint: the perforation of the triangular fibrocartilage (TFC), and the ruptures of the scapholunate and lunotriquetral interosseous ligaments (S-L lig., L-T lig.). The materials were 127 wrist joints obtained from 66 cadavers (age 32-95, average age 74) and were studied radiographically and anatomically. Two types of the ulnar side of the midcarpal joint were classified radiographically and anatomically. In the first type, there was no articulation present between the hamate and the lunate in 42.5% of the dissected specimens. In the second type, there was an articulation present between the hamate and the lunate in 57.5% of the dissected specimens. Wrists of the second type correlated significantly with the ulnar shift ratio of lunate on the radiographical measurement (p < 0.01). Significant cartilage erosion and exposed subchondral bone were found at the joints of the second type. There was no correlation between the TFC perforation, the carpal interosseous ligament ruptures and degenerative changes of the articular cartilage of the ulnar side of the midcarpal joint.

Adult↗

PubMed1992

A teaching model to illustrate the variation in size and shape of the maxillary sinus.

A technique to produce teaching models of the maxillary sinus is described. Dental impression material is injected into the maxillary sinus of a cadaver and subsequently dissected out. Using an impression and mould technique in a series of steps, a stone model of the maxillary sinus is produced. The shape, size and configuration of the model can be seen and the dimensions measured. A radiopaque impression material can be used so that the radiographic outline of the maxillary sinus on standard radiographic projections can be shown. Models of both dentate and edentulous patients can be used to show anatomical variation and the relationship to teeth and are useful in teaching both gross and radiographic anatomy. Since 10 out of 11 specimens had 3 walls leading to the apex from a 4-sided base, it would appear that the classical description of a 4-sided pyramidal shape to the maxillary sinus is relatively uncommon.

Humans↗

PubMed2004

[Congenital or acquired disposition of the separate compartment of the extensor pollicis brevis tendon associated with stenosing tendovaginitis (de Quervain's disease)? Macroanatomical and fetal-plastinationhistological studies of the first compartment of the wrist].

Our macroanatomical studies with cadaver specimens and clinical findings in the operative treatment of tendovaginitis stenosans de Quervain confirm the high number of anatomical variations in the first dorsal compartment of the wrist. With the help of thick transparent transversal-sections in one of 14 fetal wrists manufactured by plastination histology we found the first compartment with two tendons of the abductor pollicis longus and dorsal of this compartment a connective tissue formation and a separate compartment for the extensor pollicis brevis tendon, proved as a primary anatomical disposition. Macroscopically the septation is always located distal and dorsal-ulnar to the first compartment and is evidentally more common as an intraoperative than an cadaver dissection finding and probably should be considered as a pathological condition. The secondary formation of an incomplete until complete separate septum may depend on the multiple abductor pollicis longus tendons and on chronical inflammatory reaction of the synovialis of the constricted extensor pollicis brevis tendon.

Female↗

PubMed1996

Surgical results and the related topographic anatomy in paraclinoid internal carotid artery aneurysms.

Paraclinoid internal carotid artery aneurysms arising between the roof of the cavernous sinus and the origin of the posterior communicating artery are of considerable interest with regard to their anatomical variations and technical surgical challenges. Twenty-seven patients with 30 paraclinoid aneurysms were treated surgically through pterional intradural approach. Neck clipping was performed in 22 (73%) of the 30 aneurysms, coating in seven, and trapping in one. The surgical outcome was excellent in 24 patients (24/27, 89%), with two patients showing ipsilateral partial visual field defect (2/27, 7%). There was one death (4%) due to infarction after unintended carotid artery trapping. The characteristic topographic anatomical features which we considered to pose technical difficulties and to be responsible for the complications or failure in neck clipping were aneurysmal dome extending into the anterior clinoid process, atheroma at the neck, multiple paraclinoid aneurysms, ophthalmic artery originating at the neck, and marked supero-medial shift of the C2 segment of the carotid artery. pre-operative depiction of the topographical anatomy around the paraclinoid aneurysm is essential but not always possible on the basis of conventional angiography. Magnetic resonance or three-dimensional computerized tomographic angiography, and their axial source imaging, were useful in delineating the topography with unusual aneurysmal growth, overlap of aneurysm with the parent artery, and uncommon variations of the surrounding structures.

Adult↗

PubMed2006

Counting ribs on CT by assessing costal attachments to the proximal xiphoid: is this method accurate?

OBJECTIVES: To evaluate the usefulness of the method of counting ribs by assessing anatomic variations of the attachments of costal cartilages to the proximal xiphoid. MATERIALS AND METHODS: From January to September 2005, 224 subjects (136 men, 88 women, age 13 to 89 years, mean age 55 years) underwent computed tomography examination of the chest. Axial images of the chest were obtained on a 16-slice multidetector computed tomography. Counting ribs was performed by using the medial clavicle as an anatomic landmark to identify the first costal cartilage. We analyzed variety and incidence of the attachment patterns of costal cartilages to the proximal xiphoid. RESULT: Out of the 224 patients, the last costal attachments to the proximal xiphoid were the sixth costal cartilages bilaterally for 2 (0.9%) subjects, one 6th and one 7th for 4 (1.8%) subjects, bilateral seventh for 191 (85.3%) subjects, one 7th and one 8th for 15 (6.7%) subjects, and bilateral eighth for 12 (5.4%) subjects. CONCLUSIONS: The method of counting ribs from the proximal xiphoid is inaccurate because the sixth, seventh, and eighth costal cartilages may each attach to the proximal xiphoid.

Adolescent↗

PubMed2002

Magnetic resonance angiographic evidence of sex-linked variations in the circle of willis and the occurrence of cerebral aneurysms.

OBJECT: In this study the authors investigated the relationship between variations in the circle of Willis observed on magnetic resonance (MR) angiograms and locations of cerebral aneurysms, and evaluated the risk of aneurysm formation. METHODS: One hundred thirty-one patients with cerebral aneurysms were retrospectively selected from a series of 4518 patients who underwent MR angiography at one neurosurgical institute. Variations in the anatomy of the circle of Willis were simply classified into Type A, in which there was no visualization of a unilateral A1 segment, and Type P, in which there was a fetal type of posterior cerebral artery that was continuously delineated from the internal carotid artery (ICA) through the posterior communicating artery. All other variations in the circle of Willis were defined as Type O (ordinary type of variations). An additional 440 patients who did not harbor cerebral aneurysms were randomly selected for a comparison. Anterior communicating artery aneurysms were significantly related to the Type A anatomy and ICA aneurysms to Type P anatomy. Male patients who did not harbor aneurysms tended to have Type A anatomy, whereas women had a significantly greater incidence of Type P. CONCLUSIONS: This sex-linked difference in anatomical variations may be correlated to the well-known sex-linked difference in aneurysm distribution.

Adult↗

PubMedDate not supplied

A study of the variation of colonic positioning in the pararenal space as shown by computed tomography.

In a review of 1708 consecutive CT examinations of the abdomen the position of the ascending and descending colon in relation to the posterior and lateral edge of the kidney was studied. It was found that part of the colon was positioned posterior or posterolateral to the kidney's edge in percentages that varied between 14.2% and 0.9% in the different sex groups at the levels of upper, mid- and lower poles of the right and left kidney. It is concluded that this anatomical variation should be known if colon perforation is to be avoided during percutaneous nephrostomy or biopsy.

Adult↗

PubMed2005

Computer-assisted surgical navigation in revision endoscopic sinus surgery.

The anatomical variations of surgical landmarks associated with revision endoscopic sinus surgery (ESS) represent a significant challenge even to the most experienced surgeon. Multiple studies have demonstrated higher rates of both minor and major complications associated with revision cases. In the past decade, the availability of multiple computer-assisted surgical navigation systems has resulted in its widespread adoption as a tool in ESS.Computer-aided surgery (CAS) allows for triplanar anatomic localization, which may improve spatial orientation and help avoid trauma to vital structures, namely the orbit and anterior skull base.Theoretically, this would result in a lower rate of complications and a more complete surgical exploration. Future advances in CAS involve real-time computer-assisted surgical navigation using an operating room-based CT, C-arm, or MRI unit.

Endoscopy↗

PubMed2003

Aberrant formation and clinical picture of brachial plexus from the point of view of a neurosurgeon.

UNLABELLED: Variations detected during surgery stimulated us to study the variations of the formation of the brachial plexus. METHODS: We examined 110 brachial plexus in 55 adult cadavers in order to determine the incidence of neural variations. We observed the contribution of the C4 root and possibly Th2 root as well as various anomalies in the origination of each plexiform root and its branches from the spinal cord, and variations of the formation of the neural trunks, fascicles and peripheral branches. We examined their course, anastomosis, thickness and possible absence. We observed the plexiform but not the spinal roots. We saw the pretruncal part of plexus including segment of spinal nerve in the sulcus spinal nerve and anterior branch of the spinal nerve. Motor innervation anomalies in relation to diagnostics are emphasized as well, apart from the anatomic variability. Attention focused on the mechanism and the morphologic reasons for particular types of injuries. RESULTS: The prefixed type was present in 26 cases (47.3%), and was postfixed in one case. We did not observe any anomaly in the formation of the plexus in 9 cases. We observed 143 anomalies in 46 cases (83.6%). There was one anomaly present in 11 cases and in 35 two or more anomalies were noted. The anomalies were present more frequently on the left side--in 60 cases (41.2%) and bilaterally in 48 cases (33.6%). The anomalies were usually anatomic and in the area of the formation of the terminal branches. The least number of anomalies was present in the area of neural roots. CONCLUSION: This study allowed us to find out and describe unusual and previously not described anatomic variations in the formation of neural roots, trunks, fascicles and terminal branches of the brachial plexus. The formation of the axillary nerve as a continuation of the posterior branch of the superior trunk was noted. (Tab. 4, Fig. 8, Ref. 10.).

Brachial Plexus↗

PubMed1990

[Cystic duct anomalies found by ERCP and their clinical implications].

The site of confluence of cystic duct (CD) and common bile duct (CBD) was surveyed by ERCP in 1100 cases. Abnormal confluence was found in 65 (5.9%). There were three types of variations: (1) Low-sited confluence in 54/65 (83%), in which the length of CBD was significantly shorter than that of common hepatic duct (CHD). (2) Very low-sited confluence in 9/65 (13.8%), in which CD joined CBD at the level of CBD sphincter (3) High-sited confluence in 2/65 (3.2%), in which CD joined right hepatic duct or the beginning of CHD. The clinical implications of these anatomical variations are discussed.

Adolescent↗

PubMedDate not supplied

Anatomic dissociation between the intrahepatic bile duct and portal vein: risk factors for left hepatectomy.

The anatomic variations of the intrahepatic portal vein and bile duct were analyzed to evaluate the potential risk of left hepatectomy. A total of 210 cholangiograms and hepatic arterioportograms were performed in which the ramifications of the intrahepatic portal vein and bile duct were investigated. The orientation of the intrahepatic duct and portal vein were classified into five types. In 175 patients (83.33%), the intrahepatic portal vein and bile duct had the same anatomic classification. In 24 patients (11.43%), the right anterior or posterior intrahepatic duct drained into the left hepatic duct at the umbilical portion (type IV); there were only 15 patients (7.14%) whose portal veins fell into this category. All patients with type IV portal veins had type IV hepatic ducts, but there were 9/49 patients (18.36%) whose hepatic duct distribution belonged to type IV but their portal veins belonged to type II (6 cases) or III (3 cases). Without complete knowledge of the intrahepatic portal and biliary anatomy, insufficient portal perfusion and bile duct complications may result from the left hepatectomy operation. Preoperative portal vein evaluation or left portal vein clamping can provide significant information, but there are still 18.36% of patients where type IV biliary ducts were not detected in those with type II and III portal veins. Cholangiography is of paramount importance in these two groups of patients, as it can prevent inadvertent injury to the right intrahepatic ducts, which drain into the left intrahepatic duct. On the other hand, intraoperative ultrasonography is recommended to identify or exclude an aberrant portal vein if type VI biliary anatomy is detected during intraoperative cholangiography.

Bile Ducts, Intrahepatic↗

PubMed1985

Pancreas divisum: congenital anatomic variant or anomaly? Contribution of endoscopic retrograde dorsal pancreatography.

The relationship between pancreas divisum and pancreatic disease has been studied in a series of 304 patients. This congenital anatomic variant, consisting of a separate pancreatic ductal system, was diagnosed by endoscopic pancreatography and dorsal duct opacification was achieved in 97 of these patients. This anatomic variation was observed with the same frequency in cases of pancreatitis (acute and chronic) (6.9%) and in the series of patients investigated by endoscopic pancreatography taken as a whole (5.7%). Moreover, incidences of pancreatic disease in patients with and without pancreas divisum were not statistically different when compared. These results show that pancreas divisum should not be regarded as an etiologic factor in pancreatitis but should be considered as a coincidental anatomic variant encountered in nearly 10% of the population. The results obtained herein do not support the hypothesis that stenosis of the accessory papilla occurs frequently in cases of pancreas divisum. We conclude that no further therapy should be systematically proposed for patients with pancreas divisum and pancreatitis.

Adult↗

PubMed1981

Retrocecal appendicitis.

The clinical presentation of 105 cases of retrocecal appendicitis was reviewed. Thirty-six percent of the patients had the classic appendicitis scenario of periumbilical pain localizing to the right lower quadrant, accompanied by anorexia, nausea and vomiting, and tenderness and guarding in the right lower quadrant. The remaining 64 percent had subtle variations of this presentation. Retrocecal appendicitis did not have a distinctive clinical pattern in our series. Twelve of the 105 retrocecal appendices were also retroperitoneal. The diagnosis was delayed in four patients and two had flank pain. Five of the twelve appendices were either gangrenous or perforated. Although the number of patients is small, we conclude that the traditional type of retrocecal appendicitis can occur in the retroperitoneal subgroup but that his anatomic variation is infrequent. The incidence in our series was 2.5 percent.

Adolescent↗

PubMed1998

Co-existing biliary anomalies and anatomical variants in choledochal cyst.

BACKGROUND: Excision is the treatment of choice for choledochal cyst, and free bile drainage is essential to avoid ascending cholangitis. However, anastomosis between the relatively narrow common hepatic duct and bowel (conventional anastomosis) in case of type IV-A cyst, co-existing biliary anomalies and anatomical variations may cause ascending cholangitis resulting from insufficient biliary decompression. METHODS: One hundred and four patients with choledochal cyst were treated by cyst excision. Conventional anastomosis was performed in 22 patients and hilar anastomosis in 82. RESULTS: An anastomotic stricture developed in nine of the 22 conventional anastomosis cases and all required reoperation. Of the 82 hilar anastomosis cases, only one required reoperation for a primary stricture. Co-existing biliary anomalies and anatomical variants were seen in 26 patients: (1) primary stricture in 18; (2) aberrant posterior duct in two; (3) low confluence of the hepatic ducts in two; (4) aberrant hepatic artery in two; and (5) very small bile duct in two. All 26 patients underwent widening of the ductal lumen (ductoplasty) or additional procedures. CONCLUSION: Complete removal of the extrahepatic bile duct and a wide hilar anastomosis is essential to prevent ascending cholangitis. Ductoplasty or additional procedure can be performed only at the hilum.

Adolescent↗