Plantar aponeurosis and internal architecture of the ball of the foot.
On the basis of its internal structure, the ball of the foot can be divided into three transverse areas, each with a different mechanical function: (1) an area proximal to the heads of the metatarsals in which the retinacula cutis are developed into a series of transverse bands, and in which the deep fibres of the plantar aponeurosis form ten sagittal septa connected to the deep transverse metatarsal ligament and through this the proximal phalanges of the toes, (2) an area below the heads of the metatarsals in which vertical fibres from the joint capsules and the sides of the fibrous flexor sheaths form a cushion below each metatarsal head, and in which fat bodies cover the digital nerves and vessels in their passage between the cushions, and (3) a distal area which comprises the interdigital web. The superficial fibres of the plantar aponeurosis are inserted into the skin of this distal area, and deep to them the plantar interdigital ligament forms a series of transverse lamellae connected to the proximal phalanges by a mooring ligament which arches from one fibrous flexor sheath to the next. When the metatarsophalangeal joints are extended, the fibres of the three areas are tensed and the skin is anchored firmly to the skeleton. The direction of the fibres in the distal and proximal area promotes the transfer of forces exerted on the skin during push-off and braking respectively, while the intermediate area is adapted to bear the weight of the body. A concentration of Pacinian corpuscles is found along the digital nerves in the weight-bearing area below the transverse metatarsal ligament. The nerves for the second, and especially for the third, interstice are close to or in contact with the sharp proximal edges of the sagittal septa. (+info)
High-impact exercise and growing bone: relation between high strain rates and enhanced bone formation.
We investigated whether high-impact drop jumps could increase bone formation in the middiaphyseal tarsometatarsus of growing rooster. Roosters were designated as sedentary controls (n = 10) or jumpers (n = 10). Jumpers performed 200 drop jumps per day for 3 wk. The mechanical milieu of the tarsometatarsus was quantified via in vivo strain gauges. Indexes of bone formation and mechanical parameters were determined in each of twelve 30 degrees sectors subdividing the middiaphyseal cortex. Compared with baseline walking, drop jumping produced large peak strain rates (+740%) in the presence of moderately increased peak strain magnitudes (+30%) and unaltered strain distributions. Bone formation rates were significantly increased by jump training at periosteal (+40%) and endocortical surfaces (+370%). Strain rate was significantly correlated with the specific sites of increased formation rates at endocortical but not at periosteal surfaces. Previously, treadmill running did not enhance bone growth in this model. Comparing the mechanical milieus produced by running and drop jumps revealed that jumping significantly elevated only peak strain rates. This further emphasized the sensitivity of immature bone to high strain rates. (+info)
Rheumatoid plantar synovial cysts.
A patient is described with rheumatoid arthritis and a painful synovial cyst, which originated from a metatarsophalangeal joint and presented as a swelling on the plantar surface of the foot. The cyst was successfully excised. (+info)
Metatarsal osteotomy for metatarsalgia.
An oblique osteotomy in the distal half of the metatarsal shaft is described for the treatment of metatarsalgia due to prolapse of one or more of the middle three metatarsal heads. Thirty-eight patients who have had this operation have been followed up for a period of from two to five years. The operation is simple, recovery is rapid and symptoms have been well relieved. (+info)
Case report: recovery of Calliphora vicina first-instar larvae from a human traumatic wound associated with a progressive necrotizing bacterial infection.
Human myiasis caused by Calliphora vicina is rare in Europe. Here we report a case of C. vicina infection occurring in the traumatic leg wound of a healthy 21-year-old man. Firstly, a progressive necrotizing infection developed in the wound despite administration of antibiotics. Aeromonas hydrophila was isolated from the wound samples. Secondly, during debridement, C. vicina first-instar larvae were isolated from the wound. To our knowledge, this is the first European case of C. vicina wound myiasis associated with severe A. hydrophila infection. (+info)
A regulatory cascade involving retinoic acid, Cbfa1, and matrix metalloproteinases is coupled to the development of a process of perichondrial invasion and osteogenic differentiation during bone formation.
Tissue-remodeling processes are largely mediated by members of the matrix metalloproteinase (MMP) family of endopeptidases whose expression is strictly controlled both spatially and temporally. In this article, we have examined the molecular mechanisms that could contribute to modulate the expression of MMPs like collagenase-3 and MT1-MMP during bone formation. We have found that all-trans retinoic acid (RA), which usually downregulates MMPs, strongly induces collagenase-3 expression in cultures of embryonic metatarsal cartilage rudiments and in chondrocytic cells. This effect is dose and time dependent, requires the de novo synthesis of proteins, and is mediated by RAR-RXR heterodimers. Analysis of the signal transduction mechanisms underlying the upregulating effect of RA on collagenase-3 expression demonstrated that this factor acts through a signaling pathway involving p38 mitogen-activated protein kinase. RA treatment of chondrocytic cells also induces the production of MT1-MMP, a membrane-bound metalloproteinase essential for skeletal formation, which participates in a proteolytic cascade with collagenase-3. The production of these MMPs is concomitant with the development of an RA-induced differentiation program characterized by formation of a mineralized bone matrix, downregulation of chondrocyte markers like type II collagen, and upregulation of osteoblastic markers such as osteocalcin. These effects are attenuated in metatarsal rudiments in which RA induces the invasion of perichondrial osteogenic cells from the perichondrium into the cartilage rudiment. RA treatment also resulted in the upregulation of Cbfa1, a transcription factor responsible for collagenase-3 and osteocalcin induction in osteoblastic cells. The dynamics of Cbfa1, MMPs, and osteocalcin expression is consistent with the fact that these genes could be part of a regulatory cascade initiated by RA and leading to the induction of Cbfa1, which in turn would upregulate the expression of some of their target genes like collagenase-3 and osteocalcin. (+info)
The foot in chronic rheumatoid arthritis.
The feet of 200 consecutive admissions with classical or definite rheumatoid arthritis were studied. 104 were found to have pain or deformity. Clinical involvement of the joints was seen more often than radiological joint damage in the ankle, but the reverse was the case in the midtarsal joints. The metatarsophalangeal joints were involved most frequently both clinically and radiologically. Sixty per cent of the patients required modified shoes but only a third of these had received them. The need for more shoes is clear, and although this is a highly selected group of patients they were all under specialist care. The increased expenditure on special footwear would benefit the patient, firstly by improving ambulation, and secondly perhaps by reducing the number of operations necessary. Hallux valgus was very common and occurred with similar frequency to disease in the other metatarsophalangeal joints. Although not exclusive to rheumatoid arthritis, hallux valgus must have been caused for the most part by the rheumatoid arthritis and if so, then it is suggested that the provision of suitable shoes for patients may be less costly than subsequent surgical treatment. (+info)
Polydactyly and brachymetapody in two English families.
Two new pedigrees of polydactyly associated with brachymetapody are discribed. In one the two defects occur in different members of the family, while in the other both occur in the same individuals. Both anomalies appear to be inherited as dominants, the polydactyly showing incomplete manifestation. (+info)