Tendinous insertion of semimembranosus muscle into the lateral meniscus

Forty-two cadaver knees were used for morphologic and MRI observations of the tendinous distal expansions of the semimembranosus m. and the posterior capsular structures of the knee. A tendinous branch of the semimembranosus m. inserting into the posterior horn of the lateral meniscus was found in 43.2% of the knees dissected, besides five already known insertional branches; capsular, direct, anterior and inferior, as well as the oblique popliteal ligament. The tendon had three morphologic types; thin, broad and round. All three types moved the lateral meniscus posteriorly when pulled on. Thus, the semimembranosus m. may also have a protective function for the lateral meniscus as well as the already well established function of protecting the medial meniscus in knee flexion. When a semimembranosus tendon attachment to the posterior horn of the lateral meniscus is present, its normal insertion is difficult to differentiate from a lateral meniscus tear in MRI and this may cause misdiagnosis.

Topographical relationship of the facial and vestibulocochlear nerves in the subarachnoid space and internal auditory canal

PURPOSE

Our purpose was to investigate the topographical relationship of the facial and vestibulocochlear nerves from the brain stem through the internal auditory canal.

METHODS

We dissected 15 formalin-fixed cadaveric heads and performed MR examinations in 35 healthy subjects in order to examine the topographical relationship of the facial and vestibulocochlear nerves. The cadaveric dissections and the in vivo MR imaging findings were compared indirectly.

RESULTS

The relationship between the facial and vestibulocochlear nerves showed some variation among individuals and according to the location of the nerves within the cisterns or canal. Near the brain stem, 53% of the vestibulocochlear nerves were partially segmented on MR images. The vestibulocochlear nerve was completely divided into separate nerves only in the most lateral portion of the canal, except in three cadaveric dissections, in which separation of the superior vestibular nerve was seen near the brain stem. The facial and cochlear nerves were of similar size on 36% of the MR images. The superior vestibular nerve was larger than the inferior vestibular nerve on 81% of the MR images.

CONCLUSION

The appearance of the facial and vestibulocochlear nerves was variable but followed certain consistent patterns.

Anatomy and magnetic resonance imaging of the posterolateral structures of the knee

The purpose of the present study was to provide detailed information of the morphological and radiological characteristics of the posterolateral structures of the knee. Muscles and ligaments of the posterolateral part of the knee were studied by dissections of 50 adult cadaver knees and by Magnetic Resonance Imaging (MRI) before and after dissections for comparisons. Diverse morphological characteristics of the arcuate ligament were found. The fabellofibular ligament was present in 42.1% of the knees dissected, whereas the popliteofibular ligament was found in 37.5%. A ligamentous structure, which could be called the posterior tibial ligament, was found in 31.6% of the cases that originated from the lateral part of the capsule proximally and inserted distally on the mid portion of the proximal tibia. By comparing the cross sections and the dissections of the cadaver knees, the popliteus muscle, the arcuate ligament, the fibular collateral ligament, the popliteofibular ligament, and the fabellofibular ligament could be identified in MRI. Comprehensive understanding of the posterolateral anatomy of the knee and improved identification of the structures in MRI will help clinicians to make a more accurate and noninvasive diagnosis of posterolateral instability.

Right superior bronchial artery arising from the right subclavian artery and accompanying nerve branches: an autopsy case

In one out of 8 examined cadavers a solid, right superior bronchial artery was found to arise from the subclavian artery with its origin at the same level as those of the right vertebral and internal thoracic arteries. This bronchial artery was 1.5 mm in caliber and closely associated with the right sinal nerve arising from the vagus nerve and with the right stellate cardiopulmonary nerves arising from the right stellate ganglion. Such a close association was also observed between other sympathetic cardiac nerves and bronchial arteries and an extracoronary artery. On the basis of these observations it was deduced that the general course of the bronchial arteries serves to pave the way for the extension of the sympathetic cardiac nerves to the heart.

Anterior clinoid process and optic strut in Koreans

The anterior clinoid process and the optic strut are often removed during operation on the anterior part of the cavernous sinus. Therefore it is important for neurosurgeons to verify their dimensions and variations. The purpose of this study was to investigate the dimension and the variation of the anterior clinoid process and to describe the locational variation of the optic strut. Seventy-three skulls of Korean adults were used. The average length, basal width and thickness of the anterior clinoid process were 9.18 +/- 1.55, 9.63 +/- 1.49 and 5.32 +/- 1.07 mm, respectively. The average thickness of the optic strut was 2.9 +/- 1.15 mm and it was commonly attached to anterior two-fifths of the anterior clinoid process. The complete caroticoclinoid canal was observed in 4.1%, however it was incomplete in 11.6%. The incidence of a caroticoclinoid canal in Koreans was relatively low compared with other races.

A variant branch of the internal laryngeal nerve supplying filaments to the cricothyroid muscle: an autopsy case

We report a variant branch of the internal laryngeal nerve found in a Japanese male body. This branch, arising in the piriform fossa from the inferior portion of the loose network formed by the intercommunicating subbranches of the internal laryngeal nerve, descended in the interval between the thyroid and arytenoid cartilages accompanied by a branch of the superior laryngeal artery as far downward as the lowest portion of the thyroid cartilage. Here it crossed lateral to the inferior laryngeal nerve to which it gave off a communicating branch and reached the deep surface of the cricothyroid muscle. In this muscle it split into several divisions, each of which issued filaments to this muscle. The terminal branch of this variant branch ended in the fascia covering the cricothyroid muscle and the cricoid cartilage.

Correlation between the postmortem stature and the dried limb-bone lengths of Korean adult males

The postmortem stature was measured in 57 Korean adult males (age range: 20-86 years old, mean: 52.3 years old) in supine position. After dissection of the corpses, we measured the maximum length of the remaining limb-bones (humerus, radius, ulna, femur, tibia and fibula). The correlation coefficients between the stature and each limb-bone length were calculated. Simple regression equations for estimating stature from each limb-bone length and multiple regression equations from the combination of limb-bone lengths were also obtained.

Mandibular anatomy related to sagittal split ramus osteotomy in Koreans

Sagittal split ramus osteotomy (SSRO) is one of the surgical techniques used to correct mandibular deformities. In order to prevent many surgical anatomical problems, we observed the anatomical structures related to SSRO. In dry mandibles of Koreans, lingular tips were located somewhat posteriorly and superiorly on the mandibular ramus. On the coronal sections of mandible, the mean cortical width of facial cortex was increased toward the ramus region while the lingual cortex was thinnest in the ramus region. On the same sections, all the fusion points of the buccal and lingual cortical plate were located above the mandibular lingula and beneath the mandibular notch. So, performing the SSRO on Koreans, medial horizontal osteotomy should be done through the superior aspect of the mandibular lingula. The cut line is extended 5-8 mm posterior to the mandibular lingula to preserve sufficient cortical width to strengthen the involved osseous segments and reduce possible surgical complications.

High-resolution CT of the pterygopalatine fossa and its communications

The pterygopalatine fossa is an important space because it communicates with the middle cranial fossa, orbit, nasal cavity, oral cavity, pharynx, foramen lacerum, and the infratemporal fossa via eight foramina and canals. We studied the pterygopalatine fossa, foramen rotundum, inferior orbital fissure, sphenopalatine foramen, pterygoid canal, greater and lesser palatine foramen, palatinovaginal canal, and the pterygomaxillary fissure with high-resolution CT to characterise the anatomy and variants of these structures. These structures were evaluated using axial and coronal planes. In the morphometric study, the distance between the foramina rotunda did not show statistically significant differences between the anterior and posterior segments. The pterygoid canal was slightly narrower in the anterior segment (23.9 mm) than in the posterior segment (25.2 mm). The pterygoid canal narrowed in the anterior (1.8 mm) to posterior (1.2 mm) direction (P < 0.01). The distance between the pterygoid canal and the lower wall of the sphenoid sinus was 2.2 mm anteriorly and 2.8 mm posteriorly (P < 0.01). The pterygoid canal showed various relationships with the sphenoid and ethmoid sinuses. In addition, a previously unreported situation, where the foramen rotundum was surrounded by the spheroid sinus, was observed.

Morphometric study of the lumbar spinal canal in the Korean population

STUDY DESIGN

The anatomic dimensions of the vertebral body and spinal canal of the lumbar spine were analyzed in Koreans.

OBJECTIVES

To determine the normal dimension of the lumbar spinal canal in Koreans, to determine whether there are any racial differences in the morphometry of the lumbar spinal canal, and to provide criteria for diagnosing spinal stenosis in the Far Eastern Asian.

SUMMARY OF BACKGROUND DATA

Some radiologic and anatomic studies have been conducted regarding the size of the lumbar spinal canal of whites and blacks in western and African countries.

METHODS

One-thousand-eight-hundred measurements were performed on the transverse and sagittal diameters of vertebral bodies and spinal canals using complete sets of 90 lumbar vertebrae.

RESULTS

The mean mid-sagittal diameter of the lumbar spinal canal in the Korean population was less than that measured in white and African populations, but there was no significant differences between the Korean, white, and African populations regarding the transverse diameter of the lumbar spinal canal.

CONCLUSION

The mid-sagittal diameter of the lumbar spinal canal is narrowest in the Far Eastern Asian population; the radiologic criteria of spinal stenosis should be reconsidered for these people.

Locational relationship of the supraorbital notch or foramen and infraorbital and mental foramina in Koreans

The morphology and locational relationship of the supraorbital notch/foramen, infraorbital foramen, and mental foramen were studied from photographs of 124 Korean skulls (male 35, female 18, unknown sex 71). The infraorbital foramen was on the sagittal plane passing through the supraorbital notch/foramen (36.4%), or lateral to the plane (63.6%). The mental foramen was either on the plane (69.3%), lateral to the plane (21.8%), or medial to the plane (9.0%). The supraorbital notch/foramen, infraorbital foramen, and mental foramen were on the same sagittal plane in 38.1% of the cases. The supraorbital notch (69.9%) was found more frequently than the supraorbital foramen (28.9%). The average distance from the median plane to the center of the supraorbital notch/foramen, infraorbital foramen, and mental foramen was 22.7, 27.2 and 24.4 mm, respectively. The average length of the line from the center of the supraorbital notch/foramen to the center of the infraorbital foramen was 45.6 mm, and the angle of this line to the sagittal plane was 5.8 degrees. The average distance from the infraorbital margin to the center of the infraorbital foramen was 8.6 mm, and that from the inferior margin of mandible to the center of the mental foramen was 15.5 mm in males and 14.0 mm in females. The average horizontal width of the supraorbital notch/foramen, infraorbital foramen, and mental foramen was 4.7, 4.8 and 2.4 mm, respectively. Most commonly, the infraorbital foramen was lateral to the sagittal plane of the supraorbital notch/foramen, and the mental foramen was on that plane. This locational relationship would be helpful clinically to determine the location of the infraorbital and mental foramina, by palpation of the supraorbital notch.

Mid-sagittal canal diameter and vertebral body/canal ratio of the cervical spine in Koreans

In order to ascertain the normal values of the mid-sagittal canal diameter and the canal/body ratio of the cervical spine in Korean adults, ninety sets of cervical vertebral columns were examined. The average mid-sagittal canal diameters from C3 through C7 in the normal Korean are 13.2 +/- 1.3 millimeters in male and 13.1 +/- 2.6 millimeters in female. The normal average canal/body ratio of the cervical spine is 0.93 +/- 0.10 in male and 1.02 +/- 0.09 in female. The mid-sagittal canal diameter is largest in the White population and smallest in Asian, but there is no racial differences in the canal/body ratio, and the lower limit of normal canal/body ratio is 0.8 in Korean. The authors conclude that measurement of the canal/body ratio is more reliable than direct measuring of the mid-sagittal diameter of the cervical spinal canal in the diagnosis of cervical spinal stenosis or predicting the prognosis of cervical spinal cord injury.

Morphometric study of the pedicles of thoracic and lumbar vertebrae in Koreans

STUDY DESIGN

The shape and size of the pedicles of the human spine differs within different races. The authors studied the diameters and angles of the spine pedicle from the T1 to L5 levels in Koreans. The following measurements were made 1) transverse diameter, 2) superoinferior diameter, 3) anteroposterior pedicle angle, 4) horizontal pedicle angle, and 5) pedicle axis angle.

OBJECTIVES

This study obtained indices of pedicle morphology in Koreans to use in transpedicular screw fixation and to explain the difference between other races and Koreans.

SUMMARY OF BACKGROUND DATA

Internal fixators for vertebrae fixation have been developed. Knowledge of pedicle morphology is essential for pedicle screw use. The use of pedicle screws in Asians is questionable. Few reports exist regarding pedicle morphology, and in those few reports, the pedicle isthmus diameter, pedicle angles, and the depth to the anterior cortex are emphasized.

METHODS

The following measurements of the diameter and length of the human cadaver pedicle were done with vernier and dial calipers: 1) transverse diameter of pedicles, 2) superoinferior diameter of pedicles, 3) anteroposterior pedicle angle, and 4) horizontal pedicle and pedicle axis angles.

RESULTS

The widest transverse diameter of the pedicle was seen at the L5 level and the narrowest was at the T4 level. The widest superoinferior diameter of the pedicle was seen at the T12 level, the narrowest was at the T1 level. In the transverse plane, the angles of the pedicles of T11 and T12 were faced laterally. The anteroposterior angle increased rapidly at the T4 level, with the T1 level having the greatest. In the sagittal plane, the horizontal angle of the lumbar vertebra was almost parallel to the horizontal plane. The pedicle axis was longest at the L3 level and shortest at the T1 level. In all areas, the transverse diameter of the pedicle in males was wider than the that in the female.

CONCLUSIONS

The results suggest that using 6-mm screws can violate the cortex of the pedicles in a significant number of levels of the upper lumbar spine. Using a screw longer than 40 mm is dangerous in the lower thoracic spine of a Korean. A statistical difference exists between the transverse diameter of the pedicles of Westerners and Koreans.

Anatomical observation on draining patterns of saphenous tributaries in Korean adults

This study was done to identify the normal and variants of saphenous tributaries in Korean adults. The pattern of confluence of saphenous tributaries, medial accessory saphenous, lateral accessory saphenous, superficial epigastric, superficial circumflex iliac and superficial external pudendal veins, was carefully examined in 249 lower limbs (right, 129; left, 120) of embalmed Korean cadavers (73 males & 56 females). The medial accessory saphenous vein drained into the great saphenous vein directly (in 82.3%) or by a common trunk (in 17.7%) with the superficial epigastric or superficial external pudendal vein. The lateral accessory saphenous vein entered the great saphenous (in 67.1%) or the femoral vein (in 32.9%) directly or, forming a common trunk with other saphenous tributaries. The superficial epigastric vein joined the great saphenous (in 77.1%) or the femoral vein (in 22.9%) directly or, by a common trunk with other saphenous tributaries. The superficial circumflex iliac vein reached the great saphenous (in 83.1%) or the femoral vein (in 16.9%) directly or, by a common trunk with other saphenous tributaries. The superficial external pudendal vein opened into the great saphenous (in 95.2%) or the femoral vein (in 4.8%) directly or by a common trunk with other saphenous tributaries. In Koreans, the incidence of the normal pattern of saphenous tributaries was 23.7% and in 76.3% any one of variant saphenous tributaries entered the femoral or the great saphenous vein by a common trunk with other saphenous tributaries.

Variations of the ventral rami of the brachial plexus

We studied the variations in the ventral rami of 152 brachial plexuses in 77 Korean adults. Brachial plexus were composed mostly of the fifth, sixth, seventh and eighth cervical nerves and the first thoracic nerve (77.0%). In 21.7% of the cases examined, the fourth, fifth, sixth, seventh and eighth cervical and the first thoracic nerves contributed to the plexus. A plexus composed of the fourth, fifth, sixth, seventh and eighth cervical and the first and second thoracic nerves, and a plexus composed of the fifth, sixth, seventh eighth cervical nerves were also observed. The plexuses were classified into three groups according to cephalic limitation, and the plexus of group 2 in which the whole fifth cervical nerve enters the plexus, were observed the most frequent. The average diameter of the sixth and the seventh cervical ventral rami of the plexus was greatest and that of the fifth cervical was smallest. The largest nerve entering the plexus was the sixth or the seventh cervical nerve in about 79% of cases. The dorsal scapular nerve originated from the fifth cervical ventral ramus in 110 cases (75.8%). The long thoracic nerve was formed by joining of roots from the fifth, sixth, and seventh cervical nerves in 76.0% of cases. Also, a branch to the phrenic nerve, the suprascapular nerve, a nerve to the pectoralis major muscle and a nerve to the subscapular muscle arising from the ventral rami of the plexus were observed.

Variability of the surgical anatomy of the neurovascular complex of the cerebellopontine angle

The variability of the anatomic relationship of the anterior inferior cerebellar artery (AICA) to the facial (seventh) and vestibulocochlear (eighth) nerves was studied in 52 cerebellopontine angles (CPAs) from 26 adult cadavers. The AICA originated from the basilar artery (98.1%) or from the vertebral artery (1.9%) as a single (92.3% of CPAs) or duplicate (7.7%) artery. Each of the 52 CPAs had one or more arterial trunks that coursed in close proximity to the seventh and eighth cranial nerves and thus were said to be nerve-related. The nerve-related arterial trunks were divided into three segments based on their relationship to the nerves and meatus: the premeatal, meatal, and postmeatal segments. The nerve-related branches of the AICA gave rise to the internal auditory artery in 92.3% of the CPAs, the recurrent perforating artery in 78.8%, and the subarcuate artery in 30.8%. The importance of understanding the surgical anatomy of the neurovascular complex of the CPA when performing a vestibular neurectomy is reviewed.

Comparison between electrophysiologic and morphologic changes in lead induced peripheral neuropathy in rats

Compound nerve action potential (CNAP) of the mixed peripheral nerve is composed of A alpha beta, A delta, and C potentials. All components of CNAPs in the sciatic nerve were recorded by stimulating the tibial nerve of both control and lead-poisoned rats. Marked decrease of nerve conduction velocity and prolonged duration were found in A alpha beta and A delta fibers especially in large myelinated A alpha beta fibers. The amplitude decreased in A alpha beta potential, but the area did not change. In C potential produced by activation of unmyelinated fibers, nerve conduction velocity slightly decreased, but the amplitude and area did not significantly change. Pathologic correlates revealed prominent segmental demyelination with significant decrease of large myelinated fiber densities. Minimal axonal degeneration of unmyelinated fibers was present. We can conclude that electrophysiologic changes in the lead-poisoned rats correlate with pathologic changes in them.