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Biomedical subjects

H M Schmidt

Publications and source records attributed to H M Schmidt.

At least 19 recordsLinked to original sources
PubMed2006

[Distal clavicle edema].

PURPOSE: Distal clavicle marrow edema: frequency, MRI in the early stage and macroscopic correlation to the bone marrow distribution and to evaluate frequency and diagnostic criteria of a posttraumatic clavicula disorder with an edema pattern on MRI. An additional macroscopic study of the clavicle should elucidate anatomic peculiarities which could explain the reaction of the distal clavicle. MATERIAL AND METHODS: 285 MRI of traumatized patients were analyzed for edema pattern of the distal clavicle. Pattern A edema within the clavicle and the acromion was distinguished from pattern B edema within the clavicle only. Dissection in 20 cadavers should reveal vascular peculiarities and the bone marrow distribution within clavicle and acromion or vascular peculiarities. RESULTS: In 38 patients (13,3%) we found edema within the distal clavicle. Pattern A was found in 28 (9,8%) and pattern B in 10 patients (3,5%). Pattern A was usually associated with swelling of the AC joint (27 out of 28). Other injuries were not evident. 18 cadavers showed hematopoietic marrow within the distal clavicle and fatty marrow within the acromion. CONCLUSION: The distal clavicle can frequently react with edema pattern after trauma without evidence for another injury. Distinguish in cases with and cases without synovitis of the AC joint could have impact on therapy. A peculiar vascular supply of the distal clavicle could not be found.

Adolescent↗
PubMed2004

[Humeroradial plica: frequency and visualization on MRI].

PURPOSE: To determine frequency and size of a humeroradial plica and correlate it with degenerative changes, and to determine frequency of the visualization of a synovial fold on MR-Images (T1-weighted spin-echo and STIR sequences) and correlate it with degenerative changes. MATERIALS AND METHODS: Forty-two elbow specimens were dissected and studied for humeroradial synovial folds (small, medium, large) and degenerative changes (absent, medium, strong), and 88 elbow MR-images were analyzed for a synovial fold (not visible, small, large) and degenerative changes (absent, medium, strong). Comparison was performed using the chi (2) test. RESULTS: Dissections revealed a synovial fold in all cases. The sizes were small in n = 13 (31 %), medium in n = 24 (57 %), and large in n = 5 (12 %). Degenerative changes were absent in n = 9 (21.4 %), medium in n = 29 (69 %), and strong in n = 4 (9.6 %). On MRI the synovial fold was not visible in n = 67 (76 %), small in n = 12 (14 %), and large in n = 9 (10 %). Degenerative changes on MRI were absent in n = 65 (74 %), medium in n = 15 (17 %), and strong in n = 8 (9 %). The size of the fold correlated positively with degenerative changes in the specimen but not with degenerative changes on MRI. The T1-SE sequence was superior to the STIR sequence in revealing the synovial fold. DISCUSSION: A humeroradial plica is a regular finding, but visualized by MRI in only approximately 20 %, probably due to its variable size. Its visualization succeeds best with T1-spin-echo sequences.

Elbow Joint↗
PubMed2001

[Magnetic resonance imaging (MRI) of the bursa around the knee joint].

INTRODUCTION: Since fluid filled bursae lead to visible structures on MR images it is important to establish criteria to recognize them and to differentiate them from tumorous fluid-like structures. With this study the bursae around the knee joint were analyzed for potential differential diagnostic criteria such as localisation, size and shape. MATERIAL AND METHODS: In a retrospective study of 133 MR exams the frequency, localization and morphology were registered. The frequency of occurrence was correlated with the frequency of an effusion by means of the chi 2 test. RESULTS: The most frequently recognized bursae were bursa subtendinea musculi gastrocnemii medialis (54.9%), bursa musculi semimembranosi (21%), and bursa infrapatellaris profunda (18.8%). 8 different bursae were identified in complete. Size roanged from 2 to 18 mm. The shape was round and ovoid. The bursa subtendinea musculi gastrocnemii medialis and bursa musculi semimembranosi correlated with the occureance of an effusion. CONCLUSION: Bursae around the knee are frequently visualized as asymptomatic fluid like structures. Knowledge of the typical localization, size and contour is important for identification and differentiation diagnosis against ganglia, cysts or joint recesses.

Adolescent↗
PubMed2001

[The Architecture of the Fibrous Complex between the Palmar Aponeurosis and the Flexor Retinaculum].

Summary. During cadaver dissections of 34 adult human hands (fixed in formaldehyd solution), we examined a fibrous complex at the distal end of the flexor retinaculum. This fibrous complex was first mentioned by Legueu and Juvara (1892). It is located always ulno-dorsally to the attachment of the palmaris longus tendon into the palmar aponeurosis. Measurements of this special connective tissue show a mean length of 18.6 mm, a mean height of 4.3 mm and a mean width of 3.1 mm.Also, we looked for the fibrous complex in six adult plastinated transverse sections and in 12 fetal hands where it occurred in a constant way. We also found a very close topographic relationship between these oblique criss-crossed fibers and the palmar cutaneous branch of the median nerve. This nerve regularly gives some ulnar branches to the fibrous complex. The clinical relevance of the fibrous complex is discussed in relationship to a carpal tunnel syndrome. The described transverse fibers of the connective tissue complex are in danger as well as the ulnar branches of the palmar cutaneous nerve when releasing the flexor retinaculum during operation.

Adult↗
PubMed2001

[Functional anatomy and biomechanics of the wrist joint].

The osteoligamentous guidance of the carpal bones is similar to a ring under tension. Axial load of the wrist passes through the radiocarpal compartment of the proximal carpal joint on to the forearm. Hand motions in the carpal region produce variable changes of bone position. From that many deformities in cases of carpal instabilities could be explained.

Biomechanical Phenomena↗
PubMed2000

[The nutritive vascular canals. The magnetic resonance differential diagnosis of carpal cystic lesions?].

PURPOSE: To find and describe potential MRI criteria of nutrient vessel canals of carpal bones. METHODS AND MATERIAL: 16 wrists of 13 patients with pain and radiographic depiction of cystic changes within the lunate were examined. The MRI protocol included coronal and sagittal T1- and T2-weighted SE sequences (4 mm slices, 120 FOV, 256 x 256 matrix) as well as coronal STIR images. Final diagnosis was confirmed by surgery (n = 5) and follow up. 10 cadaveric ossa lunata were studied to describe size, number, location and shape of nutrient vessel canals. RESULTS: Ganglion cysts (n = 6) showed characteristic signs. In ulnar impaction syndrome (n = 1) small cystic lesions in the lunate were surrounded by a sclerotic rim and located near the proximal ulnar surface. In Kienböck's disease (n = 3) cystic components were irregular and surrounded by bone marrow edema. Nutrient vessel canals (n = 7) imaged as 1 to 3 small cystic lesions within the palmar or dorsal subchondral region. CONCLUSION: MRI can aid in differential diagnosis of cystic carpal lesions. Nutrient vessel canals may not be mistaken for pathologic cystic lesions. Carpal ganglion cysts show distinct diagnostic pattern.

Adolescent↗
PubMed2000

[The normal bone marrow and its variations in MRT].

Physiology and age-dependent changes of human bone marrow are described. The resulting normal distribution patterns of active and inactive bone marrow including the various contrasts on different MR sequences are discussed.

Aging↗
PubMed2000

[The metacarpal ligament of the thumb. Topography and functional significance of a heretofore unknown fiber tract of the thumb and its anatomic relationship to the internal interosseus muscle].

During cadaver dissections of the thenar muscles of 81 human hands, we found a distinct ligament at the palmar side of the first metacarpal in 58% ([symbol: see text] 47 hands). This not previously described ligament crosses the princeps pollicis artery regularly. The ligament arises from the base of the first metacarpal bone in 83%. Sometimes (in 15%) it arises from the trapezium or from the middle portion of the first metacarpal bone in one case. The primary insertion of this ligament is the ulnar sesamoid. We have named these fibres "metacarpal ligament of the thumb". It could be classified into five different types. We think that this ligament is helpful in the stabilisation of the ulnar sesamoid. Besides it fixes the princeps pollicis artery to the metacarpal bone and therefore it is possible that it could compress the artery. Maybe the "metacarpal ligament of the thumb" is a rudiment of the interosseous muscles of the thumb or of the deep head of the flexor pollicis brevis muscle or of the oblique head of the adductor pollicis muscle. There is a very close topographic relationship between this ligament and the "internal interosseous muscle" of the thumb which was described by Schmidt and Lanz (1992) and which was mentioned by Henle (1858), who named it "M. interosseus volaris primus" for the first time. We could isolate this muscle in 69%.

Aged↗
PubMed1999

[Pulleys of the tendon sheath of the flexor pollicis longus muscle].

The fibrous wall of the flexor tendon sheath of the thumb is reinforced by pulleys similar to those in the fingers. As cited in the literature, there are two annular pulleys A 1 and A 2 and one oblique pulley. On the basis of our investigations, this distribution was found only in 10%. In 90%, the proximal (A 1) and the distal pulley (A 2) can be seen. However, between these two annular pulleys a Y-shaped fiber complex can be dissected at the level of the base and the shaft of the proximal phalanx. This complex can be further divided into an annular part (proximal) and an oblique part (distal). The annular part is associated with the tendon insertion of the adductor pollicis muscle. The oblique part arises distal from the annular part from the ulnar side of the tendon sheath, running to the radial side of the proximal phalanx interwoven with the interphalangeal joint capsule and the palmar plate. Some fiber strands continually pass into the cutaneous ligaments of Cleland. Thin accessory pulley fibers were found between the annular pulley A 1 and the annular part of the Y-shaped fiber complex in 9.5% and in 20.6% between the oblique part and the annular pulley A 2.

Adult↗
PubMed1998

[Surgical anatomy of the distal radio-ulnar joint and the ulno-carpal joint compartment].

Variations in length ratios of both radius and ulna directly influence the profiles of the distal radioulnar joint. During pronation and supination, joint surface incongruity of the two forearm bones permits rotational and translational movements. The ulnocarpal discuss is the central part of the ulnocarpal complex. Together with radioulnar and ulnocarpal ligaments, the ulnocarpal meniscus, the tendon sheath of the extensor carpi ulnaris muscle, the ulnar collateral ligament, and accessory fiber strands the complex guides movements such as pronation and supination and stabilizes the proximal and distal carpal joint.

Carpal Bones↗
PubMed1997

Competitive binding of viral E2 protein and mammalian core-binding factor to transcriptional control sequences of human papillomavirus type 8 and bovine papillomavirus type 1.

The promoter P7535 of human papillomavirus type 8 and the promoter P7185 of bovine papillomavirus type 1 are negatively regulated by viral E2 proteins via the promoter proximal binding sites P2 and BS1, respectively. Mutations of these E2 binding sites can reduce basal promoter activity. This suggests binding of a transcription-stimulating factor and may indicate that repression by E2 is due to competitive binding of viral and cellular proteins. A computer search revealed putative binding sites for core-binding factor (CBF; also referred to as PEA2, PEBP2, or AML), overlapping with P2 and BS1. Binding of recombinant CBF proteins to these sites was confirmed by band shift analysis. Competition of CBF and E2 protein for DNA binding was shown for both human papillomavirus type 8 and bovine papillomavirus type 1. The importance of CBF-E2 competition in E2-mediated repression could be demonstrated by comparing the E2 effect on P7185 activity in two cell lines containing different amounts of endogenous CBF. In cells with large amounts of CBF, E2 repressed P7185 wild-type constructs to the basal promoter activity of a mutant (50%) that could not bind this protein any more. In contrast, in a cell line containing small amounts of CBF, the promoter activities of constructs with wild-type and mutated CBF binding sites hardly differed and specific repression by E2 was not detectable.

Animals↗
PubMed1996

Subacromial fat pad.

The subacromial fat was studied using cadaver dissections and Magnetic Resonance Imaging (MRI). We found that the subacromial fat is not loose connective tissue, but a fat pad surrounded by a fascia. The measurements of this fat pad are presented and the clinical relevance for orthopedics and radiology particularly for the impingement syndrome of the shoulder is discussed.

Acromion↗
PubMed1996

[Clinicoradiologic anatomy of the shoulder region].

Besides the skeletal elements, i.e., the clavicle, scapula and humerus, several muscles and soft tissues also participate in the construction of the human shoulder. These elements from and surround the shoulder girdle joints, which are the acromioclavicular and glenohumeral joint. Towards the trunk a connection is achieved by the sternoclavicular joint. Ossification of the clavicle, scapula and humerus begins within the 5th to 7th embryonic week. Around the age of 20 years ossification is completed. Parallel to this development and during adulthood, age-dependent changes take place in the composition and mixture of the bone marrow from red to yellow marrow. The shoulder girdle joints are constructed to permit a wide range of motion of the arm against the trunk. At the glenohumeral joint the spherical humeral head glides within the concave groove of the glenoid cavity. Stability is attained by the fibrocartilaginous glenoid labrum, which enlarges the articulating areas and the joint capsule with its strengthening ligaments. Variation of the joint capsule insertion, the glenoid labrum or the bony surfaces may predispose to luxation. Additional support to prevent luxation is obtained by the glenohumeral ligaments and the long biceps tendon. Active movement is provided by the superficial muscles and the rotator cuff muscles. Several bursae support free movement and decrease friction of the musculotendineous systems near the joint. Despite this complex construction several degenerative diseases can impair free movement of the human shoulder.

Acromioclavicular Joint↗
PubMed1995

Anatomical aspects of postintubational subglottic stenosis.

The subglottic regions of 54 human adult male and female larynges were studied with regard to anatomical aspects of postintubational stenosis. Fourteen specimens were impregnated with curable polymers and cut into 600-800 microns sections along different planes. Forty formalin-fixed hemilarynges were dissected. Measurements of the upper cricoid lamina and the thickness of the endocricoid soft tissues were taken for statistical analysis. Immediately beneath the glottis, the upper part of the cricoid lamina consists of two lateral plates with an average angle of 110 degrees. Distally, the cricoid adopts a more and more rounded lumen. At the level of the cricothyroid joint, the definite airway lumen is always laterally narrowed by a prominent thickening of the endocricoid soft tissue. Large amounts of loose connective tissue facilitate the development of edema in case of injury in this region. Dorsally, the submucous stratum is smaller and consists mainly of dense connective tissue. The blood vessels are fixed to the cricoid perichondrium by collagenous fibers. Any pressure applied from the airway lumen will force the vessels against the nonresilient cartilage, resulting in occlusion and ischemia. These pathophysiologic mechanisms are important for the development of early laryngeal damage during endotracheal intubation, possibly resulting in posterior stenosis due to scarring later on.

Aged↗
PubMed1995

[Distribution of hematopoietic and fatty bone marrow in the proximal humerus and scapula: magnetic resonance tomography and macroscopic anatomy].

PURPOSE: To establish the distribution pattern of haematopoietic and fatty bone marrow on MRI of the proximal humerus and the scapula in correlation with age, gender and nutritive factors. MATERIAL AND METHODS: 32 shoulder MR examinations (T1-weighted spin-echo and opposed-phase gradient-echo sequences) from 24 patients and 8 volunteers were analysed retrospectively. The amount of haematopoietic bone marrow within the proximal humerus and scapula was classified into four groups and was correlated with age (H-test), gender (chi 2-Test), and thickness of subcutaneous fat (H-test). The marrow distribution within 10 scapulae of cadavers over 60 years of age at death was studied. RESULTS: With increasing age, the amount of haematopoietic bone marrow in the proximal humeral metaphysis tends to decrease from lateral towards medial (H-test, p = 0.3). Diaphysis and epiphysis did not show haematopoietic marrow. The amount of haematopoietic bone marrow within the paraglenoid region of the scapula also revealed a decrease with increasing age (H-test, p = 0.003). Females had higher amounts of haematopoietic marrow than males (chi 2-test, p = 0.03). The thickness of subcutaneous fat was independent of the marrow distribution. CONCLUSION: The amount of haematopoietic bone-marrow of the shoulder girdle decreases with increasing age. The knowledge of marrow distribution patterns based upon these changes is important for shoulder MRI interpretation to prevent confusion with infiltrative disease.

Age Factors↗
PubMed1994

Two portions of the supraspinatus muscle: a new finding about the muscles macroscopy by dissection and magnetic resonance imaging.

Axial MR images of the shoulder joint reveal a central linear band within the supraspinatus muscle void of signal which seems not to represent the only tendon of this muscle. Due to the importance of the supraspinatus muscle for the painful impingement syndrome of the shoulder we studied the fibrous architecture of this muscle comparing 30 MR images and 49 cadaver dissections. We found the supraspinatus muscle to be composed of two distinct portions. The mean length of the ventral portion is 88 mm and of the dorsal portion 106 mm. The angle of the central tendon which is formed by fibers of both muscle portions relative to the frontal plane is 50 degrees. Both muscle portions probably act differently in moving the arm. This finding seems to be important for the pathophysiology of rotator cuff tears which are mainly located anteriorly within the ventral muscle portion and the eccentric central tendon.

Adult↗
PubMed1994

Topographical anatomy of the posterior elbow region during fetal development.

We studied the topography of the elbow region with special regard to the ulnar nerve during fetal life. Plastinated 600 microns thick sections through the right and left arms of ten fetuses with a crown-rump length (CRL) of 105 to 360 mm and of a newborn infant were investigated. The ulnar groove does not appear on the dorsal side of the medial humeral epicondyle earlier than at a crown-rump length of 130 mm. It provides the entrance into a formerly described fibro-osseous tunnel called the cubital tunnel. Its floor is formed by the posterior bundle of the ulnar collateral ligament, which bulges medially on flexion of the elbow joint. Up to 270 mm CRL it is composed of rather loosely arranged connective tissue fibres. Later on, its fibres are densely packed and show a parallel orientation. The ulnar nerve is pushed medially but remains behind the medial epicondyle. None of the specimens showed displacement to the anterior site of the elbow joint. An aponeurotic arch bridging the humerus and ulna and covering the ulnar nerve medially could not be identified. The findings in the newborn infant did not reveal any significant differences compared to the fetal specimens.

Elbow Joint↗