Fibularis longus
Encyclopedia
In human anatomy, the peroneus longus (also known as fibularis longus) is a superficial muscle
in the lateral compartment of the leg
, and acts to evert
and plantar flex
the ankle
.
It is situated at the upper part of the lateral side of the leg, and is the most superficial of the three peroneus muscles.
It is innervated by the superficial fibular nerve
(superficial peroneal nerve).
Blood is supplied by branches of the anterior tibial and peroneal arteries.
and its 'belly' runs down most of this bone. It becomes a tendon that goes posteriorly around the lateral malleolus
of the ankle
, then continues under the foot to attach to the medial cuneiform and first metatarsal
.
It arises from the head and upper two-thirds of the lateral surface of the body of the fibula, from the deep surface of the fascia, and from the intermuscular septa between it and the muscles on the front and back of the leg; occasionally also by a few fibers from the lateral condyle
of the tibia
. Between its attachments to the head and to the body of the fibula there is a gap through which the common peroneal nerve passes to the front of the leg.
It ends in a long tendon, which runs behind the lateral malleolus
, in a groove common to it and the tendon of the peroneus brevis; the groove is converted into a canal by the superior peroneal retinaculum, and the tendons in it are contained in a common mucous sheath.
The tendon then extends obliquely forward across the lateral side of the calcaneus, below the trochlear process
, and the tendon of the peroneus brevis, and under cover of the inferior peroneal retinaculum
.
It crosses the lateral side of the cuboid, and then runs on the under surface of that bone in a groove which is converted into a canal by the long plantar ligament
; the tendon then crosses the sole of the foot obliquely, and is inserted into the lateral side of the base of the first metatarsal bone
and the lateral side of the medial cuneiform
.
Occasionally it sends a slip to the base of the second metatarsal
bone.
The tendon changes its direction at two points: first, behind the lateral malleolus; secondly, on the cuboid bone; in both of these situations the tendon is thickened, and, in the latter, a sesamoid fibrocartilage (sometimes a bone), is usually developed in its substance.
The Peronæus longus also everts the sole of the foot, and from the oblique direction of the tendon across the sole of the foot is an important agent in the maintenance of the transverse arch.
Taking their fixed points below, the Peronæi serve to steady the leg upon the foot.
This is especially the case in standing upon one leg, when the tendency of the superincumbent weight is to throw the leg medialward; the Peronæus longus overcomes this tendency by drawing on the lateral side of the leg.
Muscle
Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...
in the lateral compartment of the leg
Lateral compartment of leg
The lateral compartment of the leg is supplied by the superficial fibular nerve.Its proximal and distal arterial supply consists of perforating branches of the anterior tibial artery and fibular artery....
, and acts to evert
Eversion (kinesiology)
Eversion is the movement of the sole of the foot away from the median plane. It occurs at the subtalar joint.Peroneus longus and peroneus brevis evert. Both muscles are innervated by the superficial fibular nerve....
and plantar flex
Plantarflexion
Plantarflexion is the movement which increases the approximate 90 degree angle between the front part of the foot and the shin, as when depressing an automobile pedal...
the ankle
Ankle
The ankle joint is formed where the foot and the leg meet. The ankle, or talocrural joint, is a synovial hinge joint that connects the distal ends of the tibia and fibula in the lower limb with the proximal end of the talus bone in the foot...
.
It is situated at the upper part of the lateral side of the leg, and is the most superficial of the three peroneus muscles.
It is innervated by the superficial fibular nerve
Superficial fibular nerve
The superficial fibular nerve innervates the fibularis longus and fibularis brevis muscles and the skin over the greater part of the dorsum of the foot .It passes forward between the fibularis muscles and the extensor digitorum longus, pierces the deep...
(superficial peroneal nerve).
Blood is supplied by branches of the anterior tibial and peroneal arteries.
Etymology
The terms Peroneus (i.e., Longus and Brevis) and Peroneal (i.e., Artery, Retinaculum) are derived from the Greek word Perone meaning pin of a brooch or a buckle. In medical terminology, both terms refer to being of or relating to the fibula or to the outer portion of the leg.Origin and insertion
It is attached proximally to the head of the fibulaHead of fibula
The upper extremity or head of the fibula is of an irregular quadrate form, presenting above a flattened articular surface, directed upward, forward, and medialward, for articulation with a corresponding surface on the lateral condyle of the tibia....
and its 'belly' runs down most of this bone. It becomes a tendon that goes posteriorly around the lateral malleolus
Malleolus
Each leg is supported by two bones, the tibia on the inner side of the leg and the fibula on the outer side of the leg.The medial malleolus is the prominence on the inner side of the ankle, formed by the lower end of the tibia....
of the ankle
Ankle
The ankle joint is formed where the foot and the leg meet. The ankle, or talocrural joint, is a synovial hinge joint that connects the distal ends of the tibia and fibula in the lower limb with the proximal end of the talus bone in the foot...
, then continues under the foot to attach to the medial cuneiform and first metatarsal
Metatarsus
The metatarsus or metatarsal bones are a group of five long bones in the foot located between the tarsal bones of the hind- and mid-foot and the phalanges of the toes. Lacking individual names, the metatarsal bones are numbered from the medial side : the first, second, third, fourth, and fifth...
.
It arises from the head and upper two-thirds of the lateral surface of the body of the fibula, from the deep surface of the fascia, and from the intermuscular septa between it and the muscles on the front and back of the leg; occasionally also by a few fibers from the lateral condyle
Lateral condyle
Lateral condyle can refer to:* Lateral condyle of tibia* Lateral condyle of femur* Lateral condyle on metatarsal...
of the tibia
Tibia
The tibia , shinbone, or shankbone is the larger and stronger of the two bones in the leg below the knee in vertebrates , and connects the knee with the ankle bones....
. Between its attachments to the head and to the body of the fibula there is a gap through which the common peroneal nerve passes to the front of the leg.
It ends in a long tendon, which runs behind the lateral malleolus
Malleolus
Each leg is supported by two bones, the tibia on the inner side of the leg and the fibula on the outer side of the leg.The medial malleolus is the prominence on the inner side of the ankle, formed by the lower end of the tibia....
, in a groove common to it and the tendon of the peroneus brevis; the groove is converted into a canal by the superior peroneal retinaculum, and the tendons in it are contained in a common mucous sheath.
The tendon then extends obliquely forward across the lateral side of the calcaneus, below the trochlear process
Trochlear process
The two oblique grooves of the lateral surface of the calcaneus are separated by an elevated ridge, or tubercle, the trochlear process , which varies much in size in different bones.Its chief anatomical significance is as a point of divergence of the previously common pathway shared by the...
, and the tendon of the peroneus brevis, and under cover of the inferior peroneal retinaculum
Peroneal retinacula
The peroneal retinacula are fibrous bands which bind down the tendons of the Peronæi longus and brevis as they run across the lateral side of the ankle....
.
It crosses the lateral side of the cuboid, and then runs on the under surface of that bone in a groove which is converted into a canal by the long plantar ligament
Long plantar ligament
The long plantar ligament is a long ligament on the underside of the foot that connects the calcaneus with the cuboid bone.-Structure:...
; the tendon then crosses the sole of the foot obliquely, and is inserted into the lateral side of the base of the first metatarsal bone
Metatarsus
The metatarsus or metatarsal bones are a group of five long bones in the foot located between the tarsal bones of the hind- and mid-foot and the phalanges of the toes. Lacking individual names, the metatarsal bones are numbered from the medial side : the first, second, third, fourth, and fifth...
and the lateral side of the medial cuneiform
Cuneiform script
Cuneiform script )) is one of the earliest known forms of written expression. Emerging in Sumer around the 30th century BC, with predecessors reaching into the late 4th millennium , cuneiform writing began as a system of pictographs...
.
Occasionally it sends a slip to the base of the second metatarsal
Metatarsus
The metatarsus or metatarsal bones are a group of five long bones in the foot located between the tarsal bones of the hind- and mid-foot and the phalanges of the toes. Lacking individual names, the metatarsal bones are numbered from the medial side : the first, second, third, fourth, and fifth...
bone.
The tendon changes its direction at two points: first, behind the lateral malleolus; secondly, on the cuboid bone; in both of these situations the tendon is thickened, and, in the latter, a sesamoid fibrocartilage (sometimes a bone), is usually developed in its substance.
Actions
The Peronæi longus and brevis plantar-flex the ankle, in conjunction with the Tibialis posterior, antagonizing the Tibialis anterior and Peronæus tertius, which are dorsi-flexors of the foot.The Peronæus longus also everts the sole of the foot, and from the oblique direction of the tendon across the sole of the foot is an important agent in the maintenance of the transverse arch.
Taking their fixed points below, the Peronæi serve to steady the leg upon the foot.
This is especially the case in standing upon one leg, when the tendency of the superincumbent weight is to throw the leg medialward; the Peronæus longus overcomes this tendency by drawing on the lateral side of the leg.