Michael L. Pretterklieber

First Tarsometatarsal Joint: Anatomical Biomechanical Study:

We studied the function of the first tarsometatarsal joint in 100 specimens of 53 cadavers. The study showed that an adduction and abduction movement described earlier was present only in approximately 10% of the specimens. Moreover, eversion of an average of 6.2° often only occurs as a result of dorsal displacement of the joint surfaces of the first metatarsal in relation to the first cuneiform by an average of 2.6 mm. All other movements in the frontal, horizontal, and sagittal plane can be disregarded or are the result of this movement. New conclusions may be drawn from these results, especially with regard to subcapital osteotomies of the first metatarsal and the adductor transfer according to McBride in metatarsus primus varus. These findings challenge the value of the McBride transfer.

The human maxillary artery reinvestigated: I. Topographical relations in the infratemporal fossa.

The topographical relations of the human maxillary artery (IM) in the infratemporal fossa were studied in 102 individuals of both sexes. In the majority of the cases (55.4%), the artery was found in a lateral position to the lower head of the lateral pterygoid muscle (LPTER). In most of these specimens, the IM ran also lateral to the inferior alveolar, lingual and buccal nerves (type LA, 37.2%), whereas in 16.1% only the buccal nerve crossed the IM laterally (type LB). In 4.6%, the artery occupied a medial position to the LPTER. With respect to the branches of the mandibular nerve, an IM, passing deep to the LPTER, was lying either lateral to its main sensory branches (type MA, 1.9%) or coursing lateral to the inferior alveolar and lingual nerves, but medial to the buccal nerve (type MB, 23.8%). In 4.9%, the artery, running medial to the LPTER and the buccal nerve, was found to pierce the inferior alveolar nerve (type MC). In 7.4%, the IM was running medial to both the inferior alveolar and buccal nerves, but lateral to the lingual nerve (type MD), and in 3.9% the IM passed deep to all the branches of the mandibular nerve (type ME). Besides those common anatomical patterns, seven specimens showed different variations of the mandibular nerve. In about one third of the individuals, an asymmetric position of the IM to the LPTER (LM or ML) was present. None of the four cephalometric parameters and the two cephalic indices recorded in 55 individuals showed a significant correlation to the actual position of the IM (lateral or medial).

The Arterial Supply of the Sesamoid Bones of the Hallux: The Course and Source of the Nutrient Arteries as an Anatomical Basis for Surgical Approaches to the Great Toe

The arterial supply of the hallux sesamoids was studied in 29 human feet by anatomical dissection. Eight of them underwent radiographic analysis prior to dissection. The sesamoid arteries branch off from the digital plantar arteries of the hallux, which, in turn, are derived from the medial plantar artery and the plantar arch (type A), the plantar arch (type B), or the medial plantar artery (type C). The respective frequencies of types A, B, and C were 52%, 24%, and 24%. The number of sesamoid arteries varied from one (55%) to three (10%) and the number increased with the size of the sesamoid bones. Anatomical knowledge of the course and distribution of these vessels may be of great help to the orthopedist in the understanding of the pathogenesis of avascular necrosis and may provide insight into several technical aspects regarding surgery of the hallux.

Unilateral persistence of the dorsal ophthalmic artery in man.

The left ophthalmic artery (OA) of a Caucasian male originated from the transverse portion of the cavernous part of the internal carotid artery (ICA), indicating the persistence of a dorsal OA. It entered the orbit through the most medial part of the superior orbital fissure, close to the medial aspect of the ophthalmic nerve. In the orbital cavity, the OA crossed above the optic nerve to reach the medial wall of the orbit. At the medial end of the upper eyelid it anastomosed with the angular artery and thereafter divided into the dorsal nasal and supratrochlear arteries. Whereas the right OA did not present any irregularities, some additional anatomical variations, above all a bilateral pterygospinosus muscle, were found in this individual. Since except the existence neither the course and branching pattern of a persistent dorsal OA nor its occurrence together with other varieties have been previously reported in man, phylogenetic and ontogenetic aspects of this aberrant vessel are discussed.

Dimensions and arterial vascular supply of the sesamoid bones of the human hallux.

The arterial supply of the ossa sesamoidea hallucis was studied in 13 subjects of both sexes by gross anatomical dissection. The majority of the ossa sesamoidea, i.e. 63% of the medial and 58% of the lateral sesamoid bones (SB), were supplied by a single artery. 26% of the medial and 32% of the lateral SB received 2 sesamoid arteries. In left feet only, 3 sesamoid arteries were found to supply 11% of the medial and 10% of the lateral SB. The actual number of sesamoid arteries proved to correspond to the dimensions and compactness (robusticity) of the ossa sesamoidea hallucis as well as to several other parameters, such as anthropometric dimensions, sex and footedness of the individuals.

Fast flair imaging of the brain using the fast spin-echo and gradient spin-echo technique

The purpose of this study was to compare the gradient spin-echo (GRASE) to the fast spin-echo (FSE) implementation of fast fluid-attenuated inversion recovery (FLAIR) sequences for brain imaging. Thirty patients with high signal intensity lesions on T2-weighted images were examined on a 1.5 T MR system. Scan time-minimized thin-section FLAIR-FSE and FLAIR-GRASE sequences were obtained and compared side by side. Image assessment criteria were lesion conspicuity, contrast between different types of normal tissue, image quality, and artifacts. In addition, contrast ratios and contrast-to-noise ratios were determined. Compared to FSF, the GRASE technique allowed a 17% reduction in scan time but conspicuity of small lesions in particular was significantly lower on FLAIR-GRASE images because of higher image noise and increased artifacts. Gray-white differentiation was slightly worse on FLAIR-GRASE. Physiological ferritin deposition appeared slightly darker on FLAIR-GRASE images and susceptibility artifacts were stronger. Fatty tissue was less bright with FLAIR-GRASE. With current standard hardware equipment, the GRASE technique is not an adequate alternative to FSE for the implementation of fast FLAIR sequences in routine clinical MR brain imaging.

A Bilateral Maxillofacial Trunk in Man: An Extraordinary Anomaly of the Carotid System of Arteries

In a Caucasian male, the maxillary artery (M) bilaterally arose with the facial artery anteromedially from the external carotid artery. On the right side, the M entered the infratemporal fossa between the neck of the mandible and the medial pterygoid muscle, whereas the left M pierced the medial pterygoid muscle, first being covered by the muscle and the angle of the mandible. On both sides, the M ran deep to the inferior head of the lateral pterygoid muscle and the buccal nerve. The right M lay deep to the inferior alveolar, but superficial to the lingual nerve, whereas the left inferior alveolar and lingual nerves had formed two roots, thus encircling the left M. The ascending palatine artery was replaced on both sides by palatine branches of the ascending pharyngeal artery. Since a bilaterial maxillofacial trunk with topographical relations as described herein has not been previously reported in man, the embryology and comparative anatomy of this variation are discussed.

The Human Anterior Tympanic Artery

The variability of the origin of the anterior tympanic artery was investigated in 104 individuals of both sexes. A surprising laterality was found: thus, while the left anterior tympanic artery originated as a singular vessel from either the maxillary or the superficial temporal artery with almost equal frequencies (44.7 and 45.9%, respectively), the right anterior tympanic artery predominantly branched off from the maxillary artery (77.8% of cases). Besides the origin from either the maxillary artery or the superficial temporal artery, also anterior tympanic arteries branching off from the external carotid artery were found to occur (4% on the left and 1% on the right side). Although in the majority of individuals, a singular anterior tympanic artery occurred within the infratemporal fossa, duplications of the anterior tympanic artery were found to be present: in one case on the right and in 8 cases on their left side. In 1 female individual, a triplet of left anterior tympanic arteries was found to supply the tympanic cavity. Also in these cases, the anterior tympanic artery arose from either the external carotid, the superficial temporal or the maxillary artery. In singular cases, even several other branches of the maxillary artery, viz. the deep auricular, middle, and accessory meningeal, as well as the posterior deep temporal, inferior alveolar and masseteric arteries were found to form common trunks with the anterior tympanic artery.

Sphenoidal artery, ramus orbitalis persistens and pterygospinosus muscle--a unique cooccurrence of first branchial arch anomalies in man.

In a 76-year-old Caucasian male, the right middle meningeal was replaced by a branch of the ipsilateral ophthalmic artery (O), i.e. the sphenoidal artery (S); the right foramen spinosum was found to be absent. In the orbit, the right O bifurcated into a medial (merely orbital) and a lateral division, i.e. a meningolacrimal trunk. From that trunk, the S branched off and entered the middle cranial fossa at the superolateral angle of the superior orbital fissure. In addition, an anastomotic channel was formed by a remnant of the ramus orbitalis, connecting the right infraorbital with the deep orbital artery. The right accessory meningeal (AM) regularly arose from the maxillary artery and entered the cranial cavity through the foramen ovale, separated from the mandibular nerve by a pterygospinosus muscle. This muscle was merely present in the right infratemporal fossa. Interestingly, the left AM originated from the posterior deep temporal artery. No other anatomical variations were found in this individual. Since the coexistence of an S with variations of other structures derived from the first branchial arch has not been previously reported in man, the embryology and comparative anatomy of this irregular vessel are discussed.

Distribution Pattern of the Superior and Inferior Labial Arteries: Impact for Safe Upper and Lower Lip Augmentation Procedures

Background: Understanding the precise position and course of the superior and inferior labial arteries within the upper lip and the lower lip is crucial for safe and complication-free applications of volumizing materials. Methods: One hundred ninety-three anatomical head specimens (56.5 percent female cadavers) of Caucasian ethnicity were investigated in this large multicenter anatomical study. In total, six 3-cm-long vertical incisions were performed on each lip (midline and 1 cm medial to the angles of the mouth) to identify the position of the superior and inferior labial arteries in relation to the orbicularis oris muscle. Results: Three different positions of the superior and inferior labial arteries were identified: submucosal (i.e., between the oral mucosa and the orbicularis oris muscle in 78.1 percent of the cases), intramuscular (i.e., between the superficial and deep layers of the orbicularis oris muscle in 17.5 percent of the cases), and subcutaneous (i.e., between the skin and the orbicularis oris muscle in 2.1 percent of the cases). The variability in changing the respective position along the labial course was 29 percent for the total upper and 32 percent for the total lower lip. The midline location was identified in both the upper and lower lips to be the most variable. Conclusions: Based on the results of this investigation, a safer location for the application of volumizing material is the subcutaneous plane in the paramedian location of both the upper lip and the lower lip. Care has to be taken when aiming to inject in the midline, as the artery can be identified more frequently in superficial positions.