Anatomy Of The Peroneus Longus Muscle - Everything You Need To Know - Dr. Nabil Ebraheim

Video Description

Dr. Ebraheim’s educational animated video describes the anatomy of Peroneus Longus muscle.

The peroneus longus muscle passes down the outside of the lower leg and on top of the peroneus brevis. The peroneus longus is a longer muscle and has larger muscle belly compared to the peroneus brevis.
Peroneus longus muscle is located within the lateral compartment of the lower leg. The lateral compartment of the lower leg contains both the peroneus longus and the peroneus brevis muscles. The lateral compartment also contains the superficial peroneal nerve. Both muscles of the lateral compartment are innervated by the superficial peroneal nerve.
The origin of the peroneus longus muscle comes from the head of the fibula and the upper 2/3 of the lateral aspect of the fibular shaft. It also originated form the anterior and posterior intermuscular septa of the leg. The peroneus longus tendon is inserted into the plantar posterolateral; aspect of the medial cuneiform and lateral side of 1st metatarsal base. The peroneus brevis tendon runs distally and inserts into the 5th metatarsal base. The peroneus longus tendon is inserted into the plantar posterolateral aspect of the medial cuneiform and lateral side of the 1st metatarsal base.
The superior peroneal retinacula is more important than the inferior retinaculum. The superior retinaculum is located in the distal 3 cm of the fibula. The superior retinaculum originates form the posterolateral ridge of the fibula and inserts into the lateral calcaneous .
Behind the fibula, the tendons run in a sulcus called the peroneal groove which is found on the fibula posteriorly. The tendons are stabilized by the superior peroneal retnaculum and the cartilaginous rim. Within the groove, the peroneus brevis tendon is anterior and medial to the peroneus longus. Both tendons curve anteriorly around the tip of the fibula. The peroneal tendons are contained in a common synovial sheath. Both tendons curve around the tip of the fibula anteriorly with the peroneal tubercle separating the tendons at the level of the calcaneus. At the level of the tubercle, the peroneus brevis is dorsal and the peroneus longus is plantar. next the peroneus longus tendon curves sharply, making a 90 degree turn medially and passing in a groove beneath the cuboid where it crosses to the plantar aspect of the foot before inserting medially into the base of the 1st metatarsal and the medial cunifrom.
The superficial peroneal nerve supplies the peroneal muscles (L5,S1,S2).
The peroneus longus muscle everts the hindfoot, flexes the ankle. The peroneus longus also plantar flexes the first ray (very important function).
Spome conditions that affect the peroneus longus muscle:
1-peroneus longus tendonitis (inflammation)
2-peroneus longus tendon rupture or tear: tears of the peroneus longus tendon are not common and usually occur at the peroneal tubercle.
3-Os Peroneum: there is an interesting observation involving rupture of the peroneus longus tendon that needs to be explained. The Os Peroneum is a sesomoid bone that is present within the peroneus longus tendon in about 20% of people’s feet and it is normally located less than 1 cm proximal or distal to the calcaneocuboid joint. The Os Peroneum moves with normal and abnormal tendon motion. This ossicle is located within the peroneus longus and should not be confused with the Os Vesalianum Pedis accessory bone or an apophysis of the fifth metatarsal. The oblique course of the peroneus longus tendon within the cuboid groove and the presence of the Os Peroneum along with sudden movement such as inversion and supination of the foot may cause rupture of the tendon at the site of the ossicle. If the Os Peroneum has proximal migration more than 1 cm from the calcaneocuboid joint, rupture of the peroneus longus tendon is likely. MRI can confirm the diagnosis. Os Peroneum is bilateral in about 60% of the patients and the ossicle is bipartite in 30% of the patients. Fractures of the Os Peroneum are rare. Fragment separation of 6 mm or more is associated with rupture of the peroneus longus tendon. Fragment separation of 2 mm or less is not important.
4-Peroneal tendon subluxation or dislocation: another condition that may occur involving the peroneus longus tendon is subluxation or dislocation of the tendon. The patient may feel a POP or SNAP sensation as the peroneal tendons move over the lateral malleolus due to rupture of the superior peroneal retinaculum.

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Background music provided as a free download from YouTube Audio Library.
Song Title: Every Step