The myofascial compartments of the foot: a cadaver study

Lower extremity infections: Essential anatomy and multimodality imaging findings

In modern practice, imaging plays an integral role in the diagnosis, evaluation of extent, and treatment planning for lower extremity infections. This review will illustrate the relevant compartment anatomy of the lower extremities and highlight the role of plain radiographs, CT, US, MRI, and nuclear medicine in the diagnostic workup. The imaging features of cellulitis, abscess and phlegmon, necrotizing soft tissue infection, pyomyositis, infectious tenosynovitis, septic arthritis, and osteomyelitis are reviewed. Differentiating features from noninfectious causes of swelling and edema are discussed.

An anatomical approach to the tarsal tunnel syndrome: what can ankle's medial side anatomy reveal to us?

BACKGROUND

The heel is a complex anatomical region and is very often the source of pain complaints. The medial heel contains a number of structures, capable of compressing the main nerves of the region and knowing its anatomical topography is mandatory. The purpose of this work is to evaluate if tibial nerve (TN) and its main branches relate to the main anatomical landmarks of the ankle's medial side and if so, do they have a regular path after emerging from TN.

METHODS

The distal part of the legs, ankles and feet of 12 Thiel embalmed cadavers were dissected. The pattern of the branches of the TN was registered and the measurements were performed according to the Dellon-McKinnon malleolar-calcaneal line (DML) and the Heimkes Triangle (HT).

RESULTS

The TN divided proximal to DML in 87.5%, on top of the DML in 12,5% and distal in none of the feet. The Baxter's nerve (BN) originated proximally in 50%, on top of the DML in 12,5% and distally in 37.5% of the cases. There was a strong and significant correlation between the length of DML and the distance from the center of the medial malleolus (MM) to the lateral plantar nerve (LPN), medial plantar (MPN) nerve, BN and Medial Calcaneal Nerve (MCN) (ρ: 0.910, 0.866, 0.970 and 0.762 respectively, p <  0.001).

CONCLUSIONS

In our sample the TN divides distal to DML in none of the cases. We also report a strong association between ankle size and the distribution of the MPN, LPN, BN and MCN. We hypothesize that location of these branches on the medial side of the ankle could be more predictable if we take into consideration the distance between the MM and the medial process of the calcaneal tuberosity.

Compartment Syndrome of the Foot

Foot compartment syndrome is an uncommon condition that should be recognized by all orthopedic surgeons. The clinical presentation is often less clear than other limb compartment syndromes and requires high clinical suspicion with a low threshold for direct measurement of compartment pressure. Controversy exists regarding the number of anatomic compartments and the most effective treatment. Both acute surgical intervention and delayed management can result in significant morbidity and long-term sequelae.

Human plantar fascial dimensions and shear wave velocity change in vivo as a function of ankle and metatarsophalangeal joint positions

The plantar fascia (PF), a primary contributor of the foot arch elasticity, may experience slack, taut, and stretched states depending on the ankle and metatarsophalangeal (MTP) joint positions. Since PF has proximodistal site difference in its dimensions and stiffness, the response to applied tension can also be site specific. Furthermore, PF can contribute to supporting the foot arch while being stretched beyond the slack length, but it has never been quantitatively evaluated in vivo. This study investigated the effects of the ankle and MTP joint positions on PF length and localized thickness and shear wave velocity (SWV) at three different sites from its proximal to distal end using magnetic resonance and supersonic shear imaging techniques. During passive ankle dorsiflexion, rise of SWV, an indication of slack length, was observed at the proximal site when the ankle was positioned by 10°-0° ankle plantar flexion with up to 3 mm (+1.5%) increase in PF length. On the other hand, SWV increased at the distal site when MTP joint dorsiflexed 40° with the ankle 30°-20° plantar flexion, and in this position, PF was lengthened up to 4 mm (+2.3%). Beyond the slack length, SWV curvilinearly increased at all measurement sites toward the maximal dorsiflexion angle whereas PF lengthened up to 9 mm (+7.6%) without measurable changes in its thickness. This study provides evidence that the dimensions and SWV of PF change in a site-specific manner depending on the ankle and MTP joint positions, which can diversify foot arch elasticity during human locomotion.NEW & NOTEWORTHY Joint angle dependence and site specificity of the plantar fascial dimensions and SWV were examined by combining sagittal magnetic resonance and supersonic shear imaging techniques. We revealed that the site-specific changes in PF SWV were related to joint angle positions, i.e., PF slackness and elasticity changed in varying combinations of ankle and MTP angle. Our findings suggest that PF can elastically support the foot arch throughout the stance phase of human bipedal locomotion.

Advanced Ankle and Foot Sonoanatomy: Imaging Beyond the Basics

Ankle/foot pain is a common complaint encountered in clinical practice. Currently, due to the complex anatomy, the diagnosis and management of the underlying musculoskeletal disorders are extremely challenging. Nowadays, high-resolution ultrasound has emerged as the first-line tool to evaluate musculoskeletal disorders. There have been several existing protocols describing the fundamental sonoanatomy of ankle/foot joints. However, there are certain anatomic structures (e.g., Lisfranc ligament complex or Baxter nerve) which are also clinically important. As they are rarely elaborated in the available literature, a comprehensive review is necessary. In this regard, the present article aims to brief the regional anatomy, illustrate the scanning techniques, and emphasize the clinical relevance of the ankle/foot region.

Anatomy of foot Compartments: a systematic review

INTRODUCTION

There are discrepancies regarding the anatomy of the foot which complicate standardizing foot compartment treatment. We synthesized the existing evidence regarding the compartmental anatomy of the foot MATERIALS AND METHODS: A systematic review was performed evaluating the anatomy of the foot compartments in non-pathologic specimens. The search strategy was performed in MEDLINE, Scopus, Web of Science, and EMBASE. Three reviewers worked independently and in duplicate to screen all references via a title/abstract and full-text phase. The risk of bias was assessed with the Anatomical Quality Assurance (AQUA) checklist.

RESULTS

Ten studies were included. All were performed in cadavers except one. Half of them evaluated the plantar section of the foot and the other half evaluated the whole foot. Methods employed across studies tended to vary: anatomical dissections, dye infusion, imaging studies, or a combination of these. Five studies directly addressed the anatomic limits of each compartment and eight addressed the anatomical structures inside each of them. There seems to be an agreement regarding the number of compartments in the plantar region (three major compartments divided by the medial and lateral intermuscular septum), nevertheless, disagreements across authors tend to arise when describing its dorsal section. Only two studies were ranked with an overall low risk of bias, agreeing on nine compartments.

CONCLUSION

This review provides the best available anatomical evidence regarding the anatomy of the foot compartments for compartment syndrome management. Future research should focus on settling the discrepancies highlighted to reach a more accurate anatomical description.

Clinical-anatomic mapping of the tarsal tunnel with regard to Baxter's neuropathy in recalcitrant heel pain syndrome: part I

Purpose

Neuropathy of the Baxter nerve (BN) seems to be the first cause of the heel pain syndrome (HPS) of neurological origin.

Methods

41 alcohol–glycerol embalmed feet were dissected. We documented the pattern of the branches of the tibial nerve (TN) and describe all relevant osteofibrous structures. Measurements for the TN branches were related to the Dellon–McKinnon malleolar-calcaneal line also called DM line (DML) for the proximal TT and the Heimkes Triangle for the distal TT. Additionally, we performed an ultrasound-guided injection procedure of the BN and provide an algorithm for clinical usage.

Results

The division of the TN was 16.4 mm proximal to the DML. The BN branches off 20 mm above the DML center or 30 mm distally to it. In most of the cases, the medial calcaneal branch (MCB) originated from the TN proximal to the bifurcation. Possible entrapment spots for the medial and lateral plantar nerve (MPN, LPN), the BN and the MCB are found within a circle of 5 mm radius with a probability of 80%, 83%, and 84%, respectively. In ten out of ten feet, the US-guided injection was precisely allocated around the BN.

Conclusions

Our detailed mapping of the TN branches and their osteofibrous tubes at the TT might be of importance for foot and ankle surgeons during minimally invasive procedures in HPS such as ultrasound-guided ankle and foot decompression surgery (UGAFDS).

A prospective study of surgical outcomes and quality of life in severe foot trauma and associated compartment syndrome after fasciotomy

The purpose of the present prospective study was to analyze the predictors of outcome and review the quality of life of patients who underwent emergency fasciotomy for foot compartment syndrome after blunt trauma. A total of 14 patients were identified and followed for an average of 24 (range 14 to 33) months. The mean interval from initial presentation to decompressive fasciotomy was 5.8 (range 3 to 11) hours. The follow-up data from our patients revealed satisfactory functional and quality of life outcomes, with 11 of 14 (78.6%) able to return to work. Two (14.3%) patients developed claw-toe deformities and 3 (21.4%) patients had sensory deficits directly attributed to compartment syndrome. Finally, 4 (28.6%) patients required modified shoes or shoe inserts for comfortable ambulation. Our findings suggest that earlier fasciotomy results in better quality of life scores, American Orthopaedic Foot and Ankle Society scale scores, and visual analog scale pain scores and a greater likelihood of being able to wear all shoes comfortably, ambulate independently, and return to work. A shorter interval to fasciotomy, younger age, the absence of bony injury, the absence of other concomitant injuries, and a low velocity crush injury all tended to be predictors of good outcomes at the final review.

Foot compartment syndrome: diagnosis and management

Although uncommon, foot compartment syndrome (FCS) is a distinct clinical entity that typically results from high-energy fractures and crush injuries. In the literature, the reported number of anatomic compartments in the foot has ranged from 3 to 10, and the clinical relevance of these compartments has recently been investigated. Diagnosis of FCS can be challenging because the signs and symptoms are less reliable indicators than those of compartment syndrome in other areas of the body. This may lead to a delay in diagnosis. The role of fasciotomy in management of FCS has been debated, but no high-level evidence exists to guide decision making. Nevertheless, emergent fasciotomy is commonly recommended with the goal of preventing chronic pain and deformity. Surgical intervention may also be necessary for the correction of secondary deformity.

Neuroanatomical basis for the tarsal tunnel syndrome

BACKGROUND

The results of surgical treatment for tarsal tunnel syndrome have been suboptimal, especially in the absence of space-occupying lesions. We attribute this to a poor understanding of the detailed anatomy of the `tarsal tunnel' and potential sites of nerve compression.

METHODS

This study involved the dissection of 19 cadaveric feet. All findings and measurements were documented with digital photography and digital calipers.

RESULTS

This study demonstrated three well-defined, tough fascial septae in the sole of the foot. In addition to the flexor retinaculum and the abductor hallucis, two of these septae represented potential sites of compression of the posterior tibial nerve and its branches. The medial plantar nerve may be entrapped under the medial septum. However, in 16 of 19 feet, the medial plantar nerve did not traverse beneath the septum. The lateral plantar nerve traversed beneath the medial septum in all specimens. The nerve to abductor digiti minimi may be trapped under the medial and intermediate septum.

CONCLUSION

We detailed the anatomical relationship of the nerve branches relative to the fibrous septae and found that the medial plantar nerve did not traverse a septae in all specimens.

CLINICAL RELEVANCE

We believe better understanding of the anatomical relationships of the tarsal tunnel and a clear communication system among anatomists, neuroradiologists and foot and ankle surgeons will facilitate accurate preoperative localization of the site of nerve compression possibly leading to better outcomes.

Compartments of the foot: topographic anatomy

Recent publications have renewed the debate regarding the number of foot compartments. There is also no consensus regarding allocation of individual muscles and communication between compartments. The current study examines the anatomic topography of the foot compartments anew using 32 injections of epoxy-resin and subsequent sheet plastination in 12 cadaveric foot specimens. Six compartments were identified: dorsal, medial, lateral, superficial central, deep forefoot, and deep hindfoot compartments. Communication was evident between the deep hindfoot compartment and the superficial central and deep central forefoot compartments. In the hindfoot, the neurovascular bundles were located in separate tissue sheaths between the central hindfoot compartment and the medial compartment. In the forefoot, the medial and lateral bundles entered the deep central forefoot compartment. The deep central hindfoot compartment housed the quadratus plantae muscle, and after calcaneus fracture could develop an isolated compartment syndrome.

Three-dimensional morphology of heel fat pad: an in vivo computed tomography study

Heel fat pad cushioning efficiency is the result of its structure, shape and thickness. However, while a number of studies have investigated heel fat pad (HFP) anatomy, structural behavior and material properties, no previous study has described its three-dimensional morphology in situ. The assessment of the healthy, unloaded, three-dimensional morphology of heel pad may contribute to deepen the understanding of its role and behavior during locomotion. It is the basis for the assessment of possible HFP morphological modifications due to changes in the amount or distribution of the loads normally sustained by the foot. It may also help in guiding the surgical reconstruction of the pad and in improving footwear design, as well as in developing a correct heel pad geometry for finite element models of the foot. Therefore the purpose of this study was to obtain a complete analysis of HFP three-dimensional morphology in situ. The right foot of nine healthy volunteers was scanned with computed tomography. A methodological approach that maximizes reliability and repeatability of the data was developed by building a device to lock the foot in a neutral position with respect to the scan planes during image acquisition. Scan data were used to reconstruct virtual three-dimensional models for both the calcaneus and HFP. A set of virtual coronal and axial sections were extracted from the three-dimensional model of each HFP and processed to extract a set of one- and two-dimensional morphometrical measurements for a detailed description of heel pad morphology. The tissue exhibited a consistent and sophisticated morphology that may reflect the biomechanics of the foot support. HFP was found to be have a crest on its anterior dorsal surface, flanges on the sides and posteriorly, and a thick portion that reached and covered the posterior surface of the calcaneus and the achilles tendon insertion. Its anterior internal portion was thinner and a lump of fat was consistently present in this region. Finally, HFP was found to be thicker in males than in females.

Acute exertional medial compartment syndrome of the foot after playing basketball

Compartment syndrome of the foot is an uncommon event. The most common cause of compartment syndrome of the foot is a crush injury. Exceedingly rare is acute compartment syndrome of the foot occurring in the absence of trauma. We describe the clinical scenario involving a 23-year-old healthy male who developed acute exertional compartment syndrome isolated to the medial compartment of the foot after playing basketball. The patient had no evidence of injury nor trauma, and the diagnosis was made based on physical exam, magnetic resonance imaging (MRI), and compartment pressure measurements. The patient did undergo successful fasciotomy on the day of presentation to the emergency department and has since completely recovered. We found four cases reported in the literature of acute exertional medial compartment syndrome of the foot in the absence of trauma or injury. This is the second case reported after playing basketball, while the others occurred after aerobics, a long distance run, and football. The most recent case was reported by Miozzari et al. [Am J Sports Med. 36(5):983-6, 2008] and involved a marathon runner who developed an isolated medial compartment syndrome of the foot. We would like to increase awareness of this uncommon clinical presentation in the absence of trauma and present the dramatic radiographic findings.

Hallux varus as complication of foot compartment syndrome

Hallux varus can present as a congenital deformity or it can be acquired secondary to trauma, surgery, or neuromuscular disease. In the present report, we describe the presence of hallux varus as a sequela of calcaneal fracture with entrapment of the medial plantar nerve in the calcaneal tunnel and recommend that clinicians be wary of this when they clinically, and radiographically, evaluate patients after calcaneal fracture.

Acute compartment syndrome of the foot following fixation of a pilon variant ankle fracture

Acute traumatic compartment syndrome of the foot is a serious potential complication after fractures, crush injuries, or reperfusion injury after vascular repair. Foot compartment syndrome in association with injuries to the ankle is rare. This article presents a case of acute compartment syndrome of the foot following open reduction and internal fixation of an ankle fracture. A 16-year-old girl presented after sustaining a left ankle injury. Radiographs demonstrated a length-stable posterior and lateral malleolar ankle fracture. Initial treatment consisted of a bulky splint and crutches pending the improvement of her swelling. Over the course of a week, the soft tissue environment of the distal lower extremity improved, and the patient underwent open reduction and internal fixation of both her fibula and distal tibia through 2 approaches. Approximately 2 hours from the completion of surgery, the patient reported worsening pain over the medial aspect of her foot and into her calcaneus. Physical examination of the foot demonstrated a swollen and tense abductor hallicus and heel pad. Posterior tibial and dorsalis pedis pulses were palpable and her sensation was intact throughout her foot. Emergently, fasciotomy of both compartments was performed through a medial incision. Postoperatively, the patient reported immediate pain relief. At 18-month follow-up, she reported no pain and had returned to all of her preinjury athletic activities.

Accuracy of medial foot compartment pressure testing: a comparison of two techniques

BACKGROUND

Foot compartment syndrome is diagnosed with intracompartmental pressure measurements. The purpose of this study was to determine the ability of two techniques to accurately place a needle tip within the medial foot compartment and to compare the proximity of the needle tip to the medial foot compartment neurovascular structures between the two techniques.

MATERIALS AND METHODS

This was a laboratory study using ten unembalmed cadaveric ankle-foot specimens. Two 18-gauge side-ported needles were placed into the medial foot compartments of each cadaveric specimen utilizing two separate techniques (Mollica and Reach techniques). Ultrasound was used to confirm needle tip placement within the medial foot compartment and needle proximity to the neurovascular structures.

RESULTS

Both needle placement techniques accurately placed the needle tip within the medial foot compartment. However, the distance between the needle tip and the neurovascular structures of the medial foot compartment was significantly closer (p = 0.037) using the Mollica technique (mean = 3.9 mm ± 2.2 mm) than the Reach technique (mean = 10.9 mm ± 5.2 mm). Neither needle placement technique perforated the medial foot neurovascular structures.

CONCLUSION

While both medial foot compartment pressure techniques accurately placed the needle tip within the medial foot compartment, the needle tip was significantly further from the medial foot neurovascular structures using the Reach technique than the Mollica technique. The Reach technique involves inserting the needle 6 cm below the distal tip of the medial malleolus, and advancing it 1 cm in a medial to lateral direction.

Compartment syndrome of the lower leg and foot

Compartment syndrome of the lower leg or foot, a severe complication with a low incidence, is mostly caused by high-energy deceleration trauma. The diagnosis is based on clinical examination and intracompartmental pressure measurement. The most sensitive clinical symptom of compartment syndrome is severe pain. Clinical findings must be documented carefully. A fasciotomy should be performed when the difference between compartment pressure and diastolic blood pressure is less than 30 mm Hg or when clinical symptoms are obvious. Once the diagnosis is made, immediate fasciotomy of all compartments is required. Fasciotomy of the lower leg can be performed either by one lateral incision or by medial and lateral incisions. The compartment syndrome of the foot requires thorough examination of all compartments with special focus on the calcaneal compartment. Depending on the injury, clinical examination, and compartment pressure, fasciotomy is recommended via a dorsal and/or medial plantar approach. Surgical management does not eliminate the risk of developing nerve and muscle dysfunction. When left untreated, poor outcomes with contractures, toe deformities, paralysis, and sensory neuropathy can be expected. In severe cases, amputation may be necessary.

LEVEL OF EVIDENCE

Level III. See Guidelines for Authors for a complete description of levels of evidence.

Compartment syndrome and lower-limb fasciotomies in the combat environment

Prophylactic and therapeutic treatment of leg compartment syndrome with decompression by double-incision fasciotomy prevents progression of soft-tissue injury in high-energy trauma. This treatment is the standard of care in civilian trauma and combat settings. More controversial is the use of either single- or dual-incision fasciotomy of the foot for prophylactic treatment of foot compartment syndrome. Fasciotomy must be performed in the face of major trauma to the foot with severe swelling and unremitting pain. The role for prophylactic fasciotomy of the foot is unclear and should be considered on a case by case basis. The surgeon must maintain a high degree of vigilance for the development of compartment syndrome in the combat casualty.

Chronic lumbar paraspinal compartment syndrome: a case report and review of the literature

A 25-year-old male weightlifter felt increasing intractable low back pain during training but denied any acute injury. The physical examination, blood parameters, radiographs and MRI were unremarkable. He had been treated non-operatively by various means, with only temporary relief. The pressures in the lumbar paraspinal compartment were abnormally high and he was treated by surgical decompression. This gave rapid relief, he returned to training, and one year later the pain had not recurred.