Anatomical review of the lateral collateral ligaments of the ankle: a cadaveric study.

Arrangements of the lateral collateral ligaments of the ankle are complex. Injuries to these ligaments can occur in the inverted planter flexed position of the ankle. Traditionally, the anterior talofibular ligament (ATFL) is the first ligament involved in such ankle injuries. We reviewed the anatomical arrangements of the lateral ankle. Twenty ankles from ten Caucasian cadavers were carefully dissected. Length and width of each ligament were measured in neutral, dorsiflexion and plantar flexion. The angle between the ATFL and other ligaments was also recorded. ATFL was present in 95% of ankles dissected. Five ankles showed two slip configuration of the ATFL. One ATFL was noted as being significantly thicker and another one was significantly narrow. Mean length of the ATFL in neutral was 15.5 mm (range 10-21 mm), which increased in plantar flexion to 18 mm (range 11-25 mm) and decreased slightly in dorsiflexion to 14.5 mm (range 10-19 mm). The calcaneofibular ligament was present in all dissections and had a mean measurement of 18.5 mm in neutral (range 14-23 mm) decreasing to 17 mm in planter flexion and 15.5 mm in dorsiflexion. Treating ligamentous ankle injuries can be very costly, thus creating a large economic burden to both patients and health institutions. Understanding the anatomical characteristics of the lateral collateral ligament complex of the ankle provides the basic foundation for understanding injuries and helps to clinically manage such injuries appropriately.

The meniscofemoral ligaments influence lateral meniscal motion at the human knee joint.

PURPOSE: The purpose of this study was to investigate the effect of the meniscofemoral ligaments on lateral meniscal motion during flexion and extension of the human knee joint. METHODS: A cadaveric biomechanical study was performed. The effect of meniscofemoral ligament tension on the dynamics of the posterior horn of the lateral meniscus was determined by image analysis. RESULTS: We found that the meniscofemoral ligaments functioned in a reciprocal manner, with the anterior meniscofemoral ligament developing tension with flexion and the posterior meniscofemoral ligament tensioning with extension. Analysis of posterior horn motion showed that the meniscofemoral ligaments caused a medial, superior, and anterior displacement of the posterior horn throughout knee motion, thus increasing the congruity of the posterior meniscal arch and the lateral femoral condyle. There was a significant correlation between meniscofemoral ligament tension and displacement of the posterior meniscal horn (r = 0.76, P < .0001). CONCLUSIONS: Where both meniscofemoral ligaments were present, the posterior horn of the lateral meniscus was subject to a displacing force throughout the range of knee motion tested. The degree of displacement correlated with the magnitude of ligament tension, and its direction was anteromedial and superior. CLINICAL RELEVANCE: The findings of this study provide further information on the role of the meniscofemoral ligaments at the human knee joint and may influence decisions regarding the management of ligamentous or lateral meniscal injury.

Relationship between hand-grip isometric strength and isokinetic moment data of the shoulder stabilisers.

The purpose of this study was to examine the relationship between hand-grip (HG) isometric strength and isokinetic moment of the shoulder musculature in 18 healthy male volunteers. HG isometric strength at 0 degrees , 90 degrees and 180 degrees of shoulder flexion and isokinetic peak and average concentric moments of the shoulder rotators and abductors and the elbow flexors at 60 degrees s(-1) were measured on both the dominant and non-dominant sides. Pearson correlation coefficients revealed statistically significant positive relationships between HG isometric strength and isokinetic moments of the shoulder external rotators (r=0.40-0.54), the shoulder abductors (r=0.42-0.71) and the elbow flexors (r=0.45-0.66) regardless of hand dominance. The positive relationships between HG isometric strength and isokinetic strength of the shoulder stabilisers was probably attributed to mechanisms providing stability to the elbow and shoulder joints either by force transmission via myotendinous and myofascial pathways or by "overflow" of muscular activity via neural circuits. The results of the present findings suggested that HG isometric strength can be used to monitor isokinetic strength of certain muscle groups contributing to the stability of the shoulder joint; however, HG strength may account only for approximately 16-50% of the variability in isokinetic strength of these muscle groups.

The anatomy of the Achilles tendon.

The Achilles tendon is the strongest and largest tendon in the body. It is the conjoined tendon of the gastrocnemius and the soleus muscles, and may have a small contribution from the plantaris. The muscles and the Achilles tendon are in the posterior, superficial compartment of the calf. Through the Achilles tendon, they are the main plantar flexors of the ankle. The Achilles tendon is subjected to the highest loads in the body, with tensile loads up to ten times body weight during running, jumping, hopping, and skipping. This article discusses the anatomy of the Achilles tendon.

Relationship of the common peroneal nerve and its branches to the head and neck of the fibula.

The common peroneal nerve (CPN) lies on the neck of the fibula, which forms the floor of the so-called 'fibular tunnel.' The tunnel entrance is a musculo-aponeurotic arch derived from the soleus and peroneus longus muscles and it is here that the CPN is commonly compressed in cases of peroneal nerve palsy. This study aims to define the relationship of the CPN and its branches to the apex of the head of the fibula and to the tunnel, with special regard to possible sites of entrapment. The distances from the apex of the fibula to the opening of the fibular tunnel, the CPN bifurcation, and the exit point of the deep peroneal nerve (DPN) from the tunnel, were measured in 30 legs to ascertain possible sites of entrapment. The angle that the CPN subtended with the long axis of the fibula was measured to gauge the range of positions of the CPN at the neck of the fibula. An unyielding musculo-aponeurotic fibular arch at the entrance to the fibular tunnel was confirmed in all specimens. The DPN exited through a crescentic opening in the anterior intermuscular septum in all cases and no DPN branches were found in the lateral compartment in any specimen. The mean (+/-SD) distance from the apex of the head of the fibula to the opening of the fibular tunnel was 3.2 +/- 1.0 cm, to the CPN bifurcation was 3.8 +/- 0.9 cm, and to the DPN exit point was 7.0 +/- 1.5 cm. The mean angle subtended anteriorly from the long axis of the fibula by the CPN was 18.9 +/- 9.0 degrees. We recommend further study of the mean distances and reference angle in relation to fibular landmarks, for use in possible minimally invasive surgical procedures to decompress the fibular tunnel.

Chronic exertional compartment syndrome: the controversial "fifth" compartment of the leg.

BACKGROUND: The existence of a "fifth" compartment in the leg capable of developing distinct chronic exertional compartment syndrome remains a subject of controversy. HYPOTHESIS: Specific pressure recordings and dissection will confirm or disprove the existence of a fifth compartment. STUDY DESIGN: Empirical anatomic study. METHODS: Radiopaque dye was injected directly into the tibialis posterior muscle of 25 embalmed cadaveric legs while intracompartmental pressure was monitored. Radiographs demonstrated dye distribution, and dissection-documented fascial and epimysial layers. RESULTS: Evidence was found that the fibular origin of the flexor digitorum longus muscle, when present, could create subcompartments within the deep posterior compartment. The nature of this attachment varied from being absent, to small (<8 cm), to extensive (>8 cm). The attachment partially covered the tibialis posterior muscle in the majority of the 14 legs that developed high pressures, and it was limited or absent in the 11 legs that did not. Radiographs demonstrated that the dye was confined to the tibialis posterior muscle in four legs. CONCLUSIONS: No consistent fifth compartment exists in the leg; however, subcompartments within the deep posterior compartment created by the fibular origin of the flexor digitorum longus muscle may develop pressures congruent with chronic exertional compartment syndrome. CLINICAL RELEVANCE: Potential deep posterior subcompartments demand accurate pressure investigation. A modified technique to decompress the entire deep posterior compartment, including the tibialis posterior muscle, is necessary for successful treatment of chronic exertional compartment syndrome.

Suture-endobutton fixation of ankle tibio-fibular diastasis: a cadaver study.

Suture-Endobutton fixation is proposed as a minimally invasive, flexible fixation of ankle tibio-fibular diastasis, which would not require routine removal. This study tested the Suture-Endobutton construct in a cadaver syndesmosis injury model and compared this against A.O. syndesmosis screw fixation. Sixteen embalmed cadaver legs were used. Phase one consisted of placing the leg in a jig, generating an external rotation torque and measuring diastasis with increasing intraosseous membrane division. Phase two then compared the Suture-Endobutton construct vs. single four-cortex 4.5 mm A.O. screw fixation. Diastasis increased significantly with increasing intraosseous membrane division (p<0.001). No significant differences were seen in the mean rate of failure between the Suture-Endobutton and A.O. screw fixation. However, the Suture-Endobutton did give a significantly more consistent performance; the distribution of standard deviations for A.O. screw fixation was 0.64 mm higher than that for the Endobutton (95% C.I. 0.46 to 0.84). These results show that Suture-Endobutton fixation at least equals the performance of screw fixation and encourages clinical trials in ankle injuries with a syndesmosis diastasis.

Successful intraosseous infusion in the critically ill patient does not require a medullary cavity.

OBJECTIVES: To demonstrate that successful intraosseous infusion in critically ill patients does not require bone that contains a medullary cavity. DESIGN: Infusion of methyl green dye via standard intraosseous needles into bones without medullary cavity-in this case calcaneus and radial styloid-in cadaveric specimens. SETTING: University department of anatomy. PARTICIPANTS: Two adult cadaveric specimens. MAIN OUTCOME MEASURES: Observation of methyl green dye in peripheral veins of the limb in which the intraosseous infusion was performed. RESULTS: Methyl green dye was observed in peripheral veins of the chosen limb in five out of eight intraosseous infusions into bones without medullary cavity-calcaneus and radial styloid. CONCLUSIONS: Successful intraosseous infusion does not always require injection into a bone with a medullary cavity. Practitioners attempting intraosseous access on critically ill patients in the emergency department or prehospital setting need not restrict themselves to such bones. Calcaneus and radial styloid are both an acceptable alternative to traditional recommended sites.