Peroneus quartus. A case report

Peroneus quartus: prevalance and clinical importance

INTRODUCTION

The most common variant muscle of the ankle, peroneus quartus muscle, is located in the lateral leg compartment. In literature there is ambiguous nomenclature of this muscle because of its different origin and insertion sides. It is related to many pathologic conditions in the lateral ankle compartment but also it can be used as a tendon graft for reconstructive procedures.

MATERIAL AND METHOD

We dissected 115 cadaver legs and investigated prevalence of peroneus quartus. We also present 2 year result of a patient who had torn superior peroneal retinaculum reconstructed with peroneus quartus tendon.

RESULTS

The peroneus quartus muscle, with a number of different attachments, was present in 5.2 % (6/115) of the legs. It most commonly arose from the peroneus brevis muscle and inserted into the retrotrochlear eminence of the calcaneus. Associated pathologies are longitudinal degeneration and tear in the tendon of peroneus brevis. There is no any association between the prevalence of peroneus quartus and the height of retrotrochlear eminence or presence of peroneal tubercule (p > 0.05). But there is strong relationship between peroneus brevis degeneration and peroneus quartus existence (p: 0.03). We also defined a new type of peroneus quartus with a bifurcated insertion around the peroneus brevis. In literature our case report is unique because we present a patient who has torn superior peroneal retinaculum which is reconstructed with peroneus quartus tendon with 2 year follow up.

CONCLUSION

Peroneus quartus may lead to some pathologic conditions (pain, snapping, tear, synovitis, etc.) in the lateral ankle compartment but it may be used to reconstruct some pathologic conditions. Orthopaedics, anatomists and radiologists should be aware of this accessory tendon structure because of its clinical importance.

Clinical implications of novel variants of the fibularis (peroneus) quartus muscle inserting onto the cuboid bone: peroneocuboideus and peroneocalcaneocuboideus

Two variants of the fibularis (peroneus) quartus muscle were identified and photographed in the legs of a 70-year-old white male cadaver. A rare peroneocuboideus (fibulocuboideus) muscle (as described by Chudzinski) and a novel peroneocalcaneocuboideus (fibulocalcaneocuboideus) muscle was found in the right and left leg, respectively. The latter muscle has not been previously reported and was termed "peroneocalcaneocuboideus" on the basis of its origin and insertions. Also, the distal attachment of both muscles inserted onto the distal lip of the peroneal sulcus of the cuboid bone, which differs from the historical data. The insertion of the peroneocuboideus muscle was previously described as being at the tuberosity of the cuboid bone or, simply, the lateral surface of the cuboid. Therefore, the present case study provides the first gross anatomic photographs of these variant leg muscles along their entire length, identifies a novel fibularis quartus variant, and describes a new insertion site for the peroneocuboideus muscle. Throughout our report, the historical data are reviewed to list the prevalence and describe the clinical implications of the fibularis quartus muscle and its variants. The presence of variant fibularis quartus muscles has been known to cause lateral ankle pain and stenosis, ankle instability, fibular tenosynovitis, subluxation of the fibular (peroneal) tendons, and longitudinal splitting of the fibularis brevis tendon in radiologic and case studies. Therefore, surgeons, radiologists, and clinicians should be aware of these variant muscles when considering various diagnoses, interpreting radiographs, and pursuing surgical intervention to relieve lateral ankle pathologic features.

The peroneal tubercle: description, classification, and relevance to peroneus longus tendon pathology

BACKGROUND

The size and configuration of the peroneal tubercle has been implicated in the pathogenesis of peroneal tendon tears and tenosynovitis. The purpose of this study was to determine the size and prevalence of the peroneal tubercle and devise a classification scheme according to the structure of the tubercle.

METHODS

One hundred and seventeen calcanei were selected from 59 human skeletons in an osteological collection (one calcaneus was missing). Three were excluded because of the poor condition, leaving 114 calcanei. The peroneal tubercle was measured in length, height, and depth and its structure subjectively described as flat, prominent, concave, or tunnel for each specimen when present.

RESULTS

This study revealed a peroneal tubercle prevalence of 90.4% (103) in 114 calcanei. The average length, height, and depth of the tubercle were 13.04 mm (range 3.61 mm to 26.66 mm), 9.44 mm (range 3.67 mm to 23.40 mm), and 3.13 mm (range 1 to 10), respectively. The peroneal tubercle was classified structurally as flat in 44 (42.7%), prominent in 30 (29.1%), concave in 28 (27.2%), and tunnel in one (1.0%).

CONCLUSION

This data may further help to understand the size and assorted configurations of the peroneal tubercle and how they relate to peroneus longus tendon pathology.

Peroneus quartus muscle: a case report and review of the literature

The peroneus quartus is a supernumerary muscle of the lateral compartment of the lower leg. There are several variations of this accessory muscle, and its terminology is very confusing. The peroneus quartus is found with a frequency varying from 10 to 21.7% of observed individuals. It is rarely involved in pathologic processes of the foot and ankle. Only a few reports exist in the literature involving peroneus quartus in a "retromalleolar conflict" (lateral ankle stenosis), sometimes in association with longitudinal attrition and tears of the peroneus brevis. We present a novel case, together with a review of the clinical, anatomic, and radiologic references about this muscle, and we try to make order in classification and terminology of its different forms.

Magnetic resonance imaging of anomalous leg muscles: accessory soleus, peroneus quartus and the flexor digitorum longus accessorius

Since the availability of magnetic resonance imaging (MRI), the suspected diagnosis of an accessory muscle of the lower extremity can now be confirmed without the need for invasive procedures. The accessory soleus, peroneus quartus, and flexor digitorum longus accessorius are anomalous muscles of the lower extremity that can be diagnosed by MRI. These accessory muscles are probably more common than once thought and can now be easily distinguished from other space occupying lesions that can occur around the ankle. MRI of these anomalous muscles enables one to make a definitive diagnosis without a biopsy. In those symptomatic patients, the origins and insertions of these accessory muscles can be accurately evaluated by MRI prior to any anticipated surgical intervention.

Congenital variations of the peroneus quartus muscle: an anatomic study

There has been little research concerning this muscle since the 1920s, when Hecker described this muscle to be present in (13%) of his dissections of cadaver legs. The purpose of our dissections was to establish the incidence of the peroneus quartus muscle, its origins, and insertions. One hundred and twenty-four legs from 65 fresh human cadavers were dissected under loupe magnification. When the peroneus quartus tendon was found, its origin, insertion, and anatomic relationship to the peroneus longus and peroneus brevis were observed. All specimens were sketched and photographed. The peroneus quartus muscle was present in 27 legs (21.7% of specimens). Its origins, insertions, and size varied. In 17 legs (63%) the muscle originated from the muscular portion of the peroneus brevis, and inserted on the peroneal tubercle of the calcaneus. The peroneal tubercle was hypertrophied at the insertion in most cases. The results of this study in general show that there was much higher incidence of the peroneus quartus muscle than Hecker claimed. Its course, origin, and insertion varied. Its tendon can be used for reconstructive procedures about the lateral aspect of the ankle, especially in anterior dislocation of the peroneal tendons and reconstruction of lateral ligaments.