An insertion of the fibularis longus is the

medial cuneiform

It lies on the inner side of the foot. It lies in the front of navicular bone and behind the metatarsal.

The medial cuneiform is present under the foot and is considered as an insertion or distal attachment of the fibularis longus.  

Further explanation

Two muscles are grouped together in the leg portion to form peroneal or fibular muscles. These muscles lie in the fibular compartment, starting from the fibula and extending to the metatarsal bones. The motion of the ankle joint and the foot is achieved by the metatarsal bones.

The fibularis longus is also called peroneus longusand is the muscle of the leg found in the lateral compartment. This muscle is linked to the head of the fibula present proximally. It extends down the lateral malleolus of the ankle and finally inserts into the first metatarsal and the medial cuneiform of the foot. The Superficial peroneal nerves innervate the peroneus muscles.  

The cuneiform bones are three in numbers namely the medial or first cuneiform, the intermediate or middle cuneiform, and the lateral cuneiform. They are found between the different metatarsal bones and the navicular bone. The largest cuneiform bone is the medial cuneiform and is located at the foot's medial side, frontwards to the navicular bone and backward of the first metatarsal. The second cuneiform is wedge-shaped with a thin pointed end at the base and is present in the middle of the first and third cuneiform. The lateral cuneiform also resembles a wedge and is present inbetween the tarsal bones.  

The fibularis longus functions to help in the bending of the ankle. It also helps in the stabilization of the portion of the leg present above the foot as it works together with the peroneal retinaculum tendons.

Learn more:

Answer details:

Grade: Higher secondary

Subject: Biology

Chapter: Muscular System

Keywords:

Fibularis longus, peroneus longus, medial cuneiform, intermediate cuneiform, lateral cuneiform, metatarsal bones, fibula, ankle, foot, ankle joint, navicular bone, tarsal bone, tendons, peroneal retinaculum.  

it is called the mitotic spindle