The microvascular anatomy of the proximal segments (M1 and M2) of the middle cerebral artery (MCA) was studied in 70 unfixed brain hemispheres from 35 cadavers. The arteries were injected with a tinted polyester resin and dissected under magnification by microsurgical techniques. The authors studied the outer diameter (OD), length, site of origin, and pattern of branching of the main trunk, secondary trunks, and the initial insular portion of the cortical branches of the MCA. The degree of mobilization of the arteries lying over the insular cortex was also assessed. The main trunk of the MCA, which had an OD of 3 +/- 0.1 mm bilaterally and a length of 15 +/- 1.1 mm in the right hemisphere and 15.7 +/- 1.3 mm in the left hemisphere, could be divided into four groups: Group I: absence of a main division (that is, a single-trunk type of MCA) (in 6% of cases); Group II: bifurcation (64%); Group III: trifurcation (29%); and Group IV: quadrifurcation (1%). The secondary trunks resulting from the division of the main trunk of the MCA had a mean OD ranging from 1.4 to 2.3 mm and a mean length that varied from 12.1 to 14.9 mm. The mean OD of the cortical branches measured near their origin in the main and secondary trunks indicated that the angular artery was the largest vessel, with a mean OD of 1.5 mm on both sides of the brain. The temporopolar artery was the smallest, with a mean OD of 0.8 mm in the right hemisphere and 0.9 mm in the left hemisphere. The authors also describe the patterns of origin of the cortical vessels from the main trunk (early branches) and from the secondary trunks, as well as their branching pattern at the site of origin (single vessels and common stems). These anatomical data indicate that it is possible to perform microvascular reconstructive procedures, such as anastomosis, grafting, and reimplantation of branches in the insular area. The advantages of using unfixed specimens, intravascular injections, and magnification to reproduce in vivo conditions as closely as possible are also discussed.

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The microvascular anatomy of the main trunk and divisions of the middle cerebral artery was studied in 104 unfixed brain hemispheres injected with polyester resin and dissected under the operating microscope. The following anomalies and variations of the middle cerebral artery were found: fenestration (1 case; 1%), located on the first 4 mm of the main trunk of the middle cerebral artery; duplication (1 case; 1%), with vessels arising from the internal carotid artery; accessory middle cerebral artery (2 cases; 2%), originating on the A1 segment of the anterior cerebral artery; single-trunk type of middle cerebral artery (4 cases; 4%), with no division of its main trunk; quadrifurcation (4 cases; 4%), in which the main trunk of the middle cerebral artery divided into four secondary trunks. The clinical implications of these anatomical findings are discussed, and photographs of representative specimens illustrate the anomalies.

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The recurrent arteries of Heubner were studied in 30 unfixed human brains (60 hemispheres) obtained from routine autopsies of individuals with a mean age of 34 years. The arteries were injected with tinted polyester resin via cannulation of the internal carotid arteries, and dissected under microscopic magnification. The recurrent artery of Heubner was absent in two hemispheres and double in seven hemispheres, either with a separate origin (in two) or from a common stem (in five). The artery of Heubner had a mean outer diameter of 0.8 +/- 0.04 mm (range 0.3 to 1.5 mm) and a mean length of 23.4 +/- 1.1 mm (range 12 to 38 mm). It originated from the A2 segment of the anterior cerebral artery (ACA) in 57% of the specimens, from the junction of the ACA and the anterior communicating artery in 35%, and from the A1 segment of the ACA in 8%. Three types of recurrent courses were observed. In the Type I or superior course, seen in 41 (63%) of the 65 arteries, the artery followed the superior wall of the A1 segment of the ACA. In the Type II or anterior course, the arteries found in 22 (34%) of specimens maintained a rostral position in relation to the A1 segment. In the Type III or posterior course, taken by two (3%) arteries, a posterior course of the vessel in the anterior perforated substance was found. The branching pattern was identified down to a range of 100 to 200 mu, and the average number of branches was 6.5 +/- 0.4 (range 3 to 12). Four groups of branches were observed. The olfactory group was represented in 91% by a single olfactory branch, with a mean outer diameter of 0.3 +/- 0.03 mm. On average, 1.9 +/- 0.27 frontal branches were found with a mean diameter of 0.13 +/- 0.01 mm. The branches penetrating the anterior perforated substance had a larger outer diameter (mean 0.4 +/- 0.03 mm) with an average number of 2.5 +/- 0.2 branches. The Sylvian fissure branches were more numerous (mean 3 +/- 0.3) with a mean outer diameter of 0.4 +/- 0.03 mm. The point of penetration of the main trunk was found to be constant at the level of the lateral perforated substance-medial Sylvian fissure in 85% of the cases. This report emphasizes the advantages of the intravascular casting resin injection technique in unfixed human brains over other conventional methods. It also describes the application of these anatomic data to the surgical strategy for the anterior circle of Willis, including the possible use of the recurrent artery of Heubner for microvascular reconstructive procedures.

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An understanding of the microvascular anatomy of the midbrain and posterior diencephalon is essential in the surgical management of lesions in that region. A description of the arterial pattern of blood supply to these areas is the purpose of this study. Perforating branches originating from the last 5 mm of the basilar artery, from the initial 7 mm of both superior cerebellar arteries (SCA's), and from the initial segment (P1 segment) of the posterior cerebral artery were studied in 56 unfixed human cadaver brain hemispheres. The brains were injected with polyester resin. The perforating branches penetrated through a small space in the upper part of the interpeduncular fossa. The anterior two-thirds of this space was occupied by the posterior perforated substance (PPS), and the posterior one-third was the site of penetration of the branches that supply the inferior mesencephalon. The PPS was divided into anterior and posterior halves. The anterior half was perforated by the paramedian thalamic arteries (diameter 0.57 +/- 0.11 mm) while the superior paramedian mesencephalic arteries (diameter 0.20 +/- 0.06 mm) perforated the posterior half. The perforating arteries originated from a trunk exclusive to the anterior half in 30%, from a trunk supplying both halves in 57%, and from a trunk exclusive to the posterior half in 13% of specimens. There were 26 naturally occurring anastomoses between the perforating branches. The paramedian inferior mesencephalic arteries penetrating the posterior one-third of the upper part of the interpeduncular fossa arose from the P1 segment in 32% of the brains studied, from the proximal 7 mm of the SCA in 45%, and from the last 5 mm of the basilar artery in 23%.

Object In this study, the authors estimate the prevalence of injuries to the soft tissue of the neck, cervical vertebrae, and cervical spinal cord among victims of abusive head trauma to better understand these injuries and their relationship to other pathophysiological findings commonly found in children with fatal abusive head trauma. Methods The population included all homicide victims 2 years of age and younger from the city of Philadelphia, Pennyslvania, who underwent a comprehensive postmortem examination at the Office of the Medical Examiner between 1995 and 2003. A retrospective review of all available postmortem records was performed, and data regarding numerous pathological findings, as well as the patient's clinical history and demographic information, were abstracted. Data were described using means and standard deviations for continuous variables, and frequency and ranges for categorical variables. Chi-square analyses were used to test for the association of neck injuries with different types of brain injury. Results The sample included 52 children, 41 (79%) of whom died of abusive head trauma. Of these, 29 (71%) had primary cervical cord injuries: in 21 there were parenchymal injuries, in 24 meningeal hemorrhages, and in 16, nerve root avulsion/dorsal root ganglion hemorrhage were evident. Six children with abusive head trauma had no evidence of an impact to the head, and all 6 had primary cervical spinal cord injury (SCI). No child had a spinal fracture. Six of 29 children (21%) with primary cervical SCIs had soft-tissue (ligamentous or muscular) injuries to the neck, and 14 (48%) had brainstem injuries. There was a significant association of primary cervical SCI with cerebral edema (p = 0.036) but not with hypoxia-ischemia, infarction, or herniation. Conclusions Cervical SCI is a frequent but not universal finding in young children with fatal abusive head trauma. In the present study, parenchymal and/or root injury usually occurred without evidence of muscular or ligamentous damage, or of bone dislocation or fracture. Moreover, associated brainstem injuries were not always seen. Although there was a significant association of primary cervical cord injury with cerebral edema, there was no direct relationship to brainstem herniation, hypoxia-ischemia, or infarction. This suggests that cervical spinal trauma is only 1 factor in the pathogenesis of these lesions.