Variations in size and in symmetry of foramina of the human skull

The goal of this report is to define an average size and size range for many of the skull's foramina and to determine in which paired foramina asymmetry is commonly found so that researchers and clinicians examining foramina may have an anatomical reference. The incidence of foraminal variations is also discussed. Information on skull foraminal size and symmetry is increasingly important because of the advancements in radiologic techniques such as magnetic resonance imaging (MRI) and computed tomography (CT). These methods are making difficult diagnoses of pathologic conditions of skull foramina possible. The foramina of 100 randomly selected dry skulls were measured and the symmetry of paired foramina was noted. The average, largest, and smallest sizes for 29 different foramina and the length of one canal are listed. Information regarding the symmetry of 27 paired foramina and the length symmetry of the infraorbital canal was also gathered. Specific data collected for paired foramina include the percent of skulls in which (1) neither foramen of the pair was present, (2) both foramina of a pair were present, (3) both foramina of the pair are present and were both the same size within 0.5 mm, and (4) both foramina of a pair are present but there was greater than 0.5 mm difference in size between them.

A comparison of peripheral nerve repair using an absorbable tubulization device and conventional suture in primates

Median nerve regeneration was studied in 30 adult primates after repair by microsurgical suture or tubulization with a nonwoven, bioabsorbable, polyglycolic acid device. The two methods were compared electrophysiologically and histologically 6 and 12 months after repair. The electrophysiology included recording of electrically evoked compound action potentials and subsequent determination of threshold, conduction velocity, amplitude, and area above the baseline for each component. Measurements were obtained before nerve transection and at the time of biopsy by stimulating both proximal and distal to the transection site. Analysis of all electrophysiological parameters revealed no statistically significant differences (p less than 0.05) between the two repair techniques. Histopathology included examination of cross sections proximal and distal to the repair sites and longitudinal sections through the coaptation site. End organs (Meissner's and Pacinian corpuscles and muscle) were sectioned to determine the degree of reinnervation. No significant differences between the repair techniques were observed by histological analysis of these sections. These evaluations indicated that the tubulization repair technique produced results comparable to that of the suture technique.

The third head of gastrocnemius in CT images

A 17 year old male patient was undergoing a CT scan for pain and swelling of the left knee. The CT images of both legs, taken simultaneously, revealed an asymmetry of the musculature in the popliteal fossa of the right leg. Serial images indicated the presence of a third head joining the medial head of gastrocnemius.

Human persistent left superior vena cava with doubled coronary sinus

A heart with a persistent left superior vena cava was found in a 72 year old man during routine dissection. The right superior vena cava was absent. The right brachiocephalic vein crossed over the aortic arch and its branches to the left side of the heart. This variation reportedly occurs in about 0.16% of humans. The azygos vein was, as a result, also left sided with a hemiazygos vein on the right side. The left superior vena cava drained into a channel contained with the posterior wall of the left atrium of the heart above, and parallel with the coronary sinus. The channel of the left superior vena cava opened into the right atrium above the opening of the coronary sinus. The coronary sinus may have been doubled during embryonic development. The two vessels were joined by a small connecting vessel.

Musculus comitans nervi mediani (M. palmaris profundus)

Palmaris profundus muscles were found in two cadavers during routine dissection of the upper limb. This rare muscle was found in two forms. In the first case, the muscle resembled a diminutive palmaris longus with the belly arising from the common flexor tendon. In the second case however, a reversed muscle with the belly emerging from beneath the transverse carpal ligament and its long thin tendon extended to and inserted in the common flexor tendon. The similarity therefore of these muscles to variable forms of palmaris longus is remarkable but they differed in one very important aspect from palmaris longus. The muscles are of special interest because, in both cases, the muscles were found enclosed in a common fascial sheath with the median nerve. These unusual muscles, in spite of mimicking palmaris longus, may perhaps, be better named "musculus comitans nervi mediani" to denote their very important relationship to the median nerve, that of being the intimate traveling companion of the median nerve through the forearm and into the hand by way of the carpal canal beneath the transverse carpal ligament. In one case, a well developed median artery was also found which also entered the carpal canal along with the median nerve and its muscular companion.

Pituitary metastases: MR findings

Tumors metastatic to the pituitary gland are uncommon, and they are difficult to differentiate radiologically from pituitary adenomas. We retrospectively reviewed the MR examinations and clinical records of nine patients with radiographic and/or clinical evidence of pituitary metastases. The most common clinical symptoms included cranial nerve deficits (67%) and/or pituitary dysfunction (30%). Both occurred acutely and progressed rapidly over 1-4 weeks in all patients. Cranial nerve involvement was predominantly multiple (83%), a reflection of involvement of the adjacent cavernous sinus. In contrast to previous reports indicating a predilection for symptoms related to posterior lobe involvement (71%), our study shows that symptoms related to the anterior lobe are as common as posterior lobe symptoms. Useful MR findings included a relatively small, enhancing pituitary lesion (< or = 1.5 cm in 56%) that was relatively isointense to brain on both T1- and T2-weighted images (78%) and involvement of the hypothalamus/pituitary infundibulum (44%) or cavernous sinus (56%).

Human doubled renal and testicular arteries

Doubled renal and testicular arteries were found in a well-developed 69-year-old caucasian male. The right kidney had two renal arteries, one at its usual midorgan (hilar) position and one inferior polar. One testicular artery arose from the mid-point of the usual renal artery, passed under the renal vein at its junction with the inferior vena cava, and then crossed over the inferior polar renal artery. The second testicular artery arose from the inferior polar renal artery near its origin from the abdominal aorta. The two testicular arteries remained doubled throughout their course and both entered the right testis at separate sites on the organ. The inferior vena cava passed under the inferior polar and over the superior testicular artery and the superior renal artery.

Target pedicle of T-12: radiologic-anatomic correlation

The authors prospectively studied 250 consecutive thoracic and lumbar spinal radiographic examinations and 56 dried skeletons to elucidate the peculiar target appearance in the pedicle of T-12 and occasionally T-11. Target pedicles were seen in 13 of the spines (23%) and in 85 of the 250 radiographic examinations (34%). Similar target pedicles were observed at T-11 in two radiographic examinations and in one spine. Anatomic correlation revealed that the inferior and lateral tubercles contribute to the ring shadow within the pedicle.

Congenital anorectal anomalies: MR imaging

Twenty-one patients with anorectal anomalies were evaluated with magnetic resonance (MR) imaging. In seven preoperative patients, MR imaging demonstrated the level of atresia correctly by showing the rectal pouch and sphincter muscles. The exact location and development of the sphincter muscles were estimated and associated anomalies involving the kidneys and the spine and its contents were evaluated. In 14 postoperative patients, the location of the pulled-through intestine was examined in relation to the sphincter muscles. MR imaging demonstrated operative complications affecting rectal continence--such as a misplaced neorectum, inadvertently pulled-through mesenteric fat, and an implantation mucous retention cyst--and provided objective data for individuals with persistent incontinence after surgery who were under consideration for repeat surgery. The authors recommend MR imaging in all patients being considered for repeat procedures and in any patient without prior surgery who is suspected of having a high anomaly; any degree of sacral agenesis; or spinal, genito-urinary tract, or cloacal anomalies.

The accessory sacroiliac joint: a common anatomic variant

We identified the accessory sacroiliac joint on 13 (13%) of 100 CT scans of the pelvis and in nine (16%) of 56 dried skeletons. The joint is situated between the medial aspect of the posterior superior iliac spine and a rudimentary transverse tuberosity just lateral to the second sacral foramen. Some joints are true diarthrodial joints and are present at birth, but more commonly they are acquired fibrocartilaginous joints that result from the stress of weight-bearing. Our experience suggests that the accessory sacroiliac joint is not rare and that it is visible on CT scans in many patients.

Variations of the median nerve in the carpal canal

Eight hundred twenty-one median nerves were retrospectively and prospectively reviewed for variations during operations to treat carpal tunnel syndrome. Ninety-two cadaver median nerves were also dissected to document the incidence of variations within the carpal canal. The combined incidence of anomalies at operation (Lanz groups 1 to 4) was 9.8% and in the cadaver series 18%. The discrepancy reported by Poisel, 54% in the Lanz group 1 series, versus ours of 1.42% cannot be explained.

Neurogenic muscular atrophy in Behcet's disease

A child is reported with Behcet's disease who presented with skin and joint manifestations, oral ulcers, brainstem syndrome and neurogenic muscular atrophy. The neurogenic muscular atrophy was confirmed by electrophysiologic, histologic and histochemical studies. Electron microscopy of muscle showed a vasculopathy. The possible etiology of the muscle lesions is discussed. The relevant literature on muscle and peripheral nerve involvement in Behcet's disease is reviewed. It is proposed that neuromyopathy be added to the neurological manifestations of Behcet's disease. To our knowledge, this is the first case of neurogenic atrophy reported in Behcet's disease.

Partial (localized) lipodystrophy. Report of a case with muscle and skin abnormalities

The light and electron microscopic myopathologic and dermatopathologic features in one patient with the partial (localized) type of lipodystrophy are described. The myopathologic changes involve both the contractile elements and the intracellular organelles, especially mitochondria that show hyperplasia and structural alterations of cristae. The dermatopathologic changes consist of a reduction in subcutaneous fat, intercellular edema, and the presence of intracytoplasmic lipid droplets. This is the first report in the literature in which the myopathologic features and detailed electron microscopy of skin in this condition are described. The myopathologic features of partial lipodystrophy are compared with those of congenital generalized lipodystrophy. It is proposed that a myopathy may be one of the manifestations of partial lipodystrophy.

Clofibrate-induced myotoxicity in rats. Temporal profile of myopathology

In this report, the temporal sequence of myopathology during a clofibrate-induced muscular syndrome and its recovery in rats is described using histopathologic, histochemical and electron microscopic technics. Two stages of myopathology are described: an early stage characterized by myopathic features, and a later stage characterized by neurogenic features. Although muscle histology returns to normal after 1 week of discontinuing the drug, electron microscopic abnormalities persist through the second week. It is proposed that clofibrate, in addition to its myotoxic effect, may be neurotoxic.

Survey of neuromuscular disorders in Lebanon. I. Profile of the genetically determined muscular dystrophies

The clinical and laboratory profiles of 130 cases of muscular dystrophy in Lebanon collected over 35 years (1947-1982) are presented. Data collection included hospital records; registries in the department of pathology, hospital laboratories, electron microscopy facility and electromyography laboratory; and records from a private hospital neurosurgical unit. The yield from each of these sources is presented. The data was fed into an Apple II computer and analyzed using thirty seven parameters. The results are discussed and compared with three other similar studies from India and America.

Ultrastructural configuration of sarcomeres in passive and contracted frog sartorius muscle

The structural configuration of passive and contracted sarcomeres from frog sartorius muscle was determined for sarcomere lengths between 1.4 and 3.07 microns. Sarcomeres fixed with glutaraldehyde, without detectable contractile activity, were invariably rectangular in shape in longitudinal section regardless of sarcomere length. The structure of sarcomeres excited by osmium tetroxide and contracted depended upon sarcomere length. For lengths greater than 1.6 microns, longitudinally sectioned sarcomeres were convexoconvex (or barrel-shaped). At 1.6 microns, contracted sarcomeres were invariably rectangular in shape. Below 1.6 microns, sarcomeres were compressed and appeared concavoconcave. The results of this study provide models for isovolumetrically contracted sarcomeres which differ significantly from those previously reported.

Postganglionic cholinergic dysautonomia: report of muscle findings in 1 case

Heretofore unreported findings in skeletal muscle in a 4th case of pure postganglionic dysautonomia are described. They consist of variation in fiber size, Z line and myofilamentous disorganization, intracytoplasmic inclusions and honeycomb formations. The most striking alterations, however, was excess lipid accumulation without concomitant mitochondrial alterations. Sural nerve histology and cytology were normal. The mechanism of lipid accumulation in skeletal muscle of patients with dysautonomia remains unexplained.

Thyrotropin secreting pituitary tumours: a cause of hyperthyroidism

Pituitary thyrotropin excess resulting in hyperthyroidism has been previously reported in only 25 patients, of whom 19 had a pituitary tumour. This report describes a patient in whom a thyrotropin-producing pituitary tumour was associated with triiodothyronine thyrotoxicosis. Hypophysectomy was followed by a prompt fall in serum thyrotropin and a return to a euthyroid state.

Tourniquet ischemia: ultrastructural and histochemical observations of ischemic human muscle and of monkey muscle and nerve

Biopsies of muscle from ten patients and of muscle and nerve from three monkeys were obtained during periods of continuous ischemia and studied by light and electron microscopy and by histochemical means. Between the third and fourth hours of ischemia, swelling of the mitochondria was noted in monkey muscle. One week later the appearance was normal. In the monkey nerves degenerated myelin was seen one week later but appeared to be normal at 2 weeks. If after 3 hours the tourniquet was deflated for 30 minutes and then reapplied for 2 additional hours, no changes were found. Succinic dehyrogenase analysis was used to identify swelling of the mitochondria. No mitochondrial changes were seen in human muscle made ischemic by a tourniquet for 2 hours.

A possible role for electron microscopy in detection of carriers of Duchenne type muscular dystrophy

Five carriers of the gene of Duchenne type muscular dystrophy are described. Muscle histology was minimally to moderately abnormal in two and normal in three. Electron microscopy was abnormal in all five and showed massive aggregates of subsarcolemmal mitochondria, paracrystalline mitochondria, Z line streaming, central nuclei, dilated sacs of sarcoplasmic reticulum, focal loss of myofilaments, and lipid lysosome bodies. The electron microscopic literature on the carrier state is reviewed and analysed. The possible role of electron microscopy in detection of carriers is discussed.