Chronic tendon lesions are degenerative conditions and may represent a failure to repair or remodel the extracellular matrix after repeated micro-injury. Since TGF-β is strongly associated with tissue repair, we investigated the expression of TGF-β isoforms (β1, β2 and β3) and their 2 signalling receptors (TGF-βRI and TGF-βRII) in normal and pathological Achilles tendons. In all tissues, all 3 TGF-β isoforms and the 2 receptors were present at sites of blood vessels. Cells in the matrix showed no staining for TGF-β1 or β3, while TGF-β2 was associated with cells throughout the normal cadaver tendon. Tissue from tendons with pathological lesions showed an increase in cell numbers and percentage TGF-β2 expression. TGF-βRII showed a wide distribution in cells throughout the tissue sections. As with TGF-β2, there was an increase in the number of cells expressing TGF-βRII in pathological tissue. TGF-βRI was restricted to blood vessels and was absent from the fibrillar matrix. We conclude that despite the presence and upregulation of TGF-β2, TGF-β signalling is not propagated due to the lack of TGF-βRI. This might explain why chronic tendon lesions fail to resolve and suggests that the addition of exogenous TGF-β will have little effect on chronic tendinopathy.

The uppermost superficial surface layer of articular cartilage, the ‘lamina splendens’ which provides a very low friction lubrication surface in articular joints, was investigated using atomic force microscopy (AFM). Complementary specimens were also observed under SEM at −10 °C without dehydration or sputter ion coating. Fresh adult pig osteochondral specimens were prepared from the patellas of pig knee joints and digested with the enzymes, hyaluronidase, chondroitinase ABC and alkaline protease. Friction coefficients between a pyrex glass plate and the osteochondral specimens digested by enzymes as well as natural (undigested) specimens were measured, using a thrust collar apparatus. Normal saline, hyaluronic acid (HA) and a mixture of albumin, globulin, HA (AGH) were used as lubrication media. The surface irregularities usually observed in SEM studies were not apparent under AFM. The articular cartilage surface was resistant to hyaluronidase and also to chondroitinase ABC, but a fibrous structure was exhibited in alkaline protease enzymes-digested specimens. AFM analysis revealed that the thickness of the uppermost superficial surface layer of articular cartilage was between 800 nm and 2 μm in adult pig articular cartilage. The coefficient of friction (c.f.) was significantly higher in chondroitinase ABC and alkaline protease enzymes digested specimens. Generally, in normal saline lubrication medium, c.f. was higher in comparison to HA and AGH lubrication media. The role of the uppermost, superficial surface layer of articular cartilage in the lubrication mechanism of joints is discussed.

Seven discrete cranial traits usually categorised as hyperostotic characters, the medial palatine canal, hypoglossal canal bridging, precondylar tubercle, condylus tertius, jugular foramen bridging, auditory exostosis, and mylohyoid bridging were investigated in 81 major human population samples from around the world. Significant asymmetric occurrences of the bilateral traits were detected in the medial palatine canal and jugular foramen bridging in several samples. Significant intertrait associations were found between some pairs of the traits, but not consistently across the large geographical samples. The auditory exostosis showed a predominant occurrence in males. With the exception of the auditory exostosis and mylohyoid bridging in a few samples, significant sex differences were slight. The frequency distributions of the traits (except for the auditory exostosis) showed some interregional clinality and intraregional discontinuity, suggesting that genetic drift could have contributed to the observed pattern of variation.

This concludes a series of descriptive statistical reports on discrete cranial traits in 81 human populations from around the world. Four variants classified as vessel and nerve related characters were investigated: patent condylar canal; supraorbital foramen; accessory infraorbital foramen; and accessory mental foramen. A significant asymmetric occurrence without any side preference was detected for the accessory mental foramen. Significant intertrait associations were found between the accessory infraorbital and supraorbital foramina in the panPacific region and Subsaharan African samples. The intertrait associations between the accessory infraorbital foramen and some traits classified as hypostotic were found mainly in the samples from the western part of the Old World, and those as hyperostotic traits in the samples from eastern Asian and the related population samples. With a few exceptions, the occurrence of a patent condylar canal and a supraorbital foramen was predominant in females, but the accessory infraorbital and accessory mental foramina were predominant in males. The frequency distributions of the traits showed interregional clinality and intraregional discontinuity. A temporal trend was found in the Northeast Asian region in the frequencies of the accessory infraorbital and accessory mental foramina. The diversity of modern human discrete cranial traits may at least in part be attributable to differential retention or intensification from an ancestral pattern.

The large literature on the human vomeronasal organ (VNO) offers little consensus as to its persistence in the adult. We have already documented the existence of the VNO from embryonic day 33 through the neonatal stages. This has now been extended to human adults: 27 cadaver nasal septa, aged 2–86 y, were either dissected or decalcified, serially sectioned, stained and examined. The consistent presence of the VNO is reported as a homologue, in the form of a duct-like structure on the nasal septum at all ages. Also reported are size variability, pronounced bilateral asymmetry, a nonchemosensory pseudostratified ciliated epithelium with considerable structural variation and generally without medial–lateral differentiation, nasal septal glands opening into the VNO lumen, a lack of correlation between postnatal age and VNO size, visualisation of the human VNO with certainty by histological means alone, and a minute opening as its only visible surface feature. The human VNO is a discrete structure that should not be confused with the nasopalatine fossa, the septal mucosal pits or VNO openings.

The steroidogenic interrenal cells in the adrenal homologue of the male stickleback (Gasterosteus aculeatus) were studied in relation to the reproductive cycle by means of histological and ultrastructural observations, and using histochemical methods for the localisation of 3β-hydroxysteroid dehydrogenase (3βHSD) and 17β-hydroxysteroid dehydrogenase (17βHSD). To determine the various stages of the reproductive cycle, the testes were also examined by histological and histochemical methods (3βHSD). The results indicate that in this teleost the interrenal cells can undergo a cycle in which phases characterised by different cytological aspects are observed. During this cycle there is a renewal of organelles, in particular mitochondria and SER. Periodic degenerative processes are also found. Organelle cytology showed that the cell cycle has at least 3 different aspects during the year. An analogy with some cytological aspects of the adrenal zonation in mammals is possible. It is postulated that the interrenal gland activity could substitute or supplement androgen production by the testes.

The aim of the present study was to locate the sensory and autonomic ganglia innervating the female genital musculature in pigs. The retrograde neuronal tracers horseradish peroxidase (HRP) or fast blue (FB) were injected into the left retractor clitoridis muscle (RCM), which was treated as a typical model of the genital smooth musculature. Labelled cells were found in ipsilateral dorsal root ganglia Sl–S4, in bilateral sympathetic paravertebral ganglia from L5–L6 or L6–L7 to S3 and in the left and right caudal mesenteric ganglion. In two of the five animals treated, presumably preganglionic parasympathetic cells were labelled in the ipsilateral intermediate grey substance of the segments Sl–S2.

The tilting angle and the shape of the glenoid cavity are considered to relate closely to shoulder stability. They are also important when planning arthroplasty and developing new designs. This study examines the glenoid cavity using 3-dimensional MRI. Forty volunteers (20 men, 20 women; average age 21.4; range 18–35 y) were enrolled in the study. The tilting angles of the glenoid bone were measured in 5 consecutive axial planes perpendicular to the glenoidal long axis. Cross sections were divided into 3 types (concave, flat, convex) according to the shape on each plane.

The average tilting angles for the 5 planes from the bottom to the top were 3.3±4.1, 1.4±3.8, −0.6±1.9, −1.4±3.3, and −6.2±3.3 degrees anteriorly, indicating that the 3-dimensional bony structure of the glenoid was twisted anteriorly to posteriorly. Images on the bottom plane consisted of 82.5% concave type, 15% flat type and 2.5% convex type, while only 3 cases (7.5%) showed concave at the top plane. The shape of the glenoid cavity is thought to be conducive to glenohumeral motion and stability.

The distribution of muscle fibres classified on the basis of their content of different myosin heavy chain (MHC) isoforms was analysed in vastus lateralis muscle biopsies of 15 young men (with an average age of 22 y) by correlating immunohistochemistry with specific anti-MHC monoclonal antibodies, myofibrillar ATPase (mATPase) histochemistry and in situ hybridisation with probes specific for MHC β-slow, MHC-IIA and MHC-IIX. The characterisation of a large number of individual fibres was compared and correlated on a fibre-to-fibre basis. The panel of monoclonal antibodies used in the study allowed classification of human skeletal muscle fibres into 5 categories according to the MHC isoform they express at the protein level, types I, I+IIA, IIA, IIAX and IIX. Hybrid fibres coexpressing two isoforms represented a considerable proportion of the fibre composition (about 14%) and were clearly underestimated by mATPase histochemistry. For a very high percentage of fibres there was a precise correspondence between the MHC protein isoforms and mRNA transcripts. The integrated methods used demonstrate a high degree of precision of the immunohistochemical procedure used for the identification and quantification of human skeletal muscle fibre types. The monoclonal antibody S5-8H2 is particularly useful for identifying hybrid IIAX fibres. This protocol offers new prospects for muscle fibre classification in human experimental studies.

The posterolateral tunnel on the superior surface of the first cervical (atlas) vertebra is of normal occurrence in monkeys and other lower animals, but its presence in the form of a tunnel-like canal, for the passage of the third part of the vertebral artery over the posterior arch of the human atlas vertebra is not reported. The aim of the present study was to detect the presence of such a canal, in addition to other types of ponticuli (little bridges) reported by earlier investigators, in macerated atlas vertebrae and routine cadaveric dissections. The posterolateral tunnel was detected in 1.14%, and the posterior and lateral ponticuli in 6.57 and 2% of vertebrae. Probably the bony roof of the posterolateral tunnel serves the purpose of additional lateral extension for the attachment of the posterior atlanto-occipital membrane in quadrupeds, where the load of the head is supported by the extensor muscles of the neck, ligaments and posterior atlanto-occipital membrane. In man, where the weight of the head is borne by the vertical loading of the superior articular process of the atlas, the roof of the tunnel has disappeared.

The articular processes (AP) of the neural arch have been implicated in weight transmission through the cervical spine. To analyse the mechanism of weight transmission in the AP, we studied the direction of forces within it, in particular, the pattern of trabecular trajectories. Twenty-two AP from C4 vertebrae were studied in anatomical sections, and corresponding photoelastic models from selected sections were constructed and analysed. Anatomical and photoelastic findings show the subarticular spongiosa of the superior articular process (SAP) to be orthogonally arranged with vertical and oblique trabeculae in the direction of compressive forces and additional trabeculae always oriented perpendicular to the former. Vertical and oblique trabeculae are divided into rostral, middle and posterior groups. Rostral and middle trabeculae end in the anterior wall of the SAP and the transitional zone with the pedicle. Posterior trabeculae end in the subarticular spongiosa of the inferior articular process (IAP). The findings relating to trabecular trajectories in the SAP differ from previous descriptions and instead suggest that a part of the weight forces distributed within the AP transmit to the subchondral zone of the IAP. Knowledge of the trajectorial architecture of the AP may contribute to refining finite element analytical models for investigating its weight-bearing function.

The sciatic artery is the major arterial supply to the lower limb bud at an early embryological stage. It primarily originates from the dorsal root of the umbilical artery. After the 22 mm embryological stage, the sciatic artery involutes and the femoral artery system develops as the major inflow source to the lower limb. In the adult, remnants of the sciatic artery persist as the proximal portion of the inferior gluteal artery, the popliteal and peroneal arteries (Williams et al. 1989). It is suggested that either failure in development of the femoral system or failure in regression of the sciatic artery results in persistence of this artery (Arey, 1965). We report a rare example of persistent sciatic artery (PSA) accompanied by arterio-arterial and arteriovenous anastomoses.

A separate supernumerary muscle in the lateral cubital fossa originating from the humerus or brachioradialis and inserting into the radius, pronator teres or supinator muscle has been considered as a variation of the brachioradialis muscle (Dawson, 1822; Meckel, 1823; Lauth, 1830; Halbertsma, 1864; Gruber, 1868b; Testut, 1884; LeDouble, 1897; Spinner & Spinner, 1996). However, a similar description was used to report additional heads of the brachialis or biceps brachii muscles (Gruber, 1848; Wood, 1864, 1868; Macalister, 1864–66, 1966–69, 1875; Gruber, 1868a; Wolff-Heidegger, 1937).

The innervation of these variant muscles would be a good tool to assign each variation to its associated muscle. Consequently, innervation by the radial nerve would indicate that it is a derivative of the humero–radialis group of muscles, while innervation by the musculocutaneous nerve would support it as a derivative of the anterior musculature of the arm (Rolleston, 1887; Lewis, 1989). However, no references to the innervation were found in the available literature.

Therefore this study set out to establish the phylogenetic origin of the brachioradialis accessorius muscle and, with the help of its innervation, to determine its incidence and unreported detailed morphology.

The abdominal surgeon is largely unappreciative of the peritoneal reflections of the ileocaecal region. This is not surprising since the literature on this subject is sparse. The available descriptions in standard texts (Hollinshead, 1971; McMinn, 1994; Williams et al. 1995) outline the appendicular mesentery as developing from the lowest aspect of the ileal mesentery. The inferior ileocaecal recess develops between the mesentery of the appendix and the ileocaecal fold; the superior ileocaecal recess develops between the ileal mesentery and the vascular fold of the caecum. The clinical significance of these recesses is minimal as they neither predispose to entrapment of bowel nor serve as useful landmarks. In this context, the peritoneal flange on the anti-mesenteric aspect of the terminal ileum warrants consideration (Fig. 1). This extension of the ileocaecal fold along a variable distance on the antimesenteric terminal ileum is largely underappreciated as it may hold value as a useful landmark to the abdominal surgeon.

The sternalis muscle (musculus sternalis) is the name usually given to this common anatomical variant, but the terms ‘episternalis’, ‘presternalis’, ‘sternalis brutorum’, ‘rectus thoracis’, ‘rectus sterni’, ‘superficial rectus abdominis’ and ‘japonicus’ have also been used in the literature (for reviews see Le Double, 1879; Calori, 1888; Pichler, 1911; Blees, 1968). According to Turner (1867), Cabrolius was the first, in 1604, to describe sternalis. Nevertheless this muscle is often unknown even in clinical practice (Bailey & Tzarnas, 1999; Vandeweyer, 1999).

Thus far, investigations on the incidence of sternalis have been made both in large populations such as the American (Barlow, 1935) and small populations, for example in Taiwan (Shen et al. 1992; Jeng & Su, 1998). In Europe, all studies on the frequency of this muscle have been made amongst subpopulations in Western (e.g. Cunningham, 1888; Le Double, 1890, 1897) and Northern Europe (Gruber, 1860) although the reported frequencies have been quite different. There is a lack of information about sternalis in Eastern European populations. We therefore present data from a study on the incidence of sternalis muscle in Bulgaria.

Aodán Breathnach, Emeritus Professor of Anatomy at the University of London at St Mary's Hospital Medical School, and Honorary Senior Research Fellow Division of Physiology and Institute of Dermatology, UMDS, St Thomas' Hospital, died in London after a prolonged illness on 17 April 2000, at the age of 77. He had been a member of the Anatomical Society of Great Britain and Ireland since 1949, of the Societas Dermatologica Italica from 1978, of La Société Française de Dermatologie Syphiligraphie since 1979, and of the Society for Investigative Dermatology since 1984. He is survived by his wife Babs, his two sons Stephen and Richard, and their families, to whom our deepest sympathy is extended.