The flexor digitorum brevis or flexor digitorum communis brevishttps://www.anatomyatlases.org/AnatomicVariants/MuscularSystem/Text/F/14Flexor.shtml is a muscle which lies in the middle of the sole of the foot, immediately above the central part of the

plantar Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provi ...

aponeurosis An aponeurosis (; : aponeuroses) is a flattened tendon by which muscle attaches to bone or fascia. Aponeuroses exhibit an ordered arrangement of collagen fibres, thus attaining high tensile strength in a particular direction while being vulnerable ...

, with which it is firmly united. Its deep surface is separated from the lateral

vessels and nerves by a thin layer of

fascia A fascia (; : fasciae or fascias; adjective fascial; ) is a generic term for macroscopic membranous bodily structures. Fasciae are classified as superficial, visceral or deep, and further designated according to their anatomical location. ...

Structure

It arises by a narrow tendon, from the medial process of the tuberosity of the

calcaneus In humans and many other primates, the calcaneus (; from the Latin ''calcaneus'' or ''calcaneum'', meaning heel; : calcanei or calcanea) or heel bone is a bone of the Tarsus (skeleton), tarsus of the foot which constitutes the heel. In some other ...

, from the central part of the plantar aponeurosis, and from the intermuscular septa between it and the adjacent muscles. It passes forward, and divides into four

tendons A tendon or sinew is a tough band of dense fibrous connective tissue that connects muscle to bone. It sends the mechanical forces of muscle contraction to the skeletal system, while withstanding tension. Tendons, like ligaments, are made of ...

, one for each of the four lesser toes. Opposite the bases of the first

phalanges The phalanges (: phalanx ) are digit (anatomy), digital bones in the hands and foot, feet of most vertebrates. In primates, the Thumb, thumbs and Hallux, big toes have two phalanges while the other Digit (anatomy), digits have three phalanges. ...

, each tendon divides into two slips, to allow of the passage of the corresponding tendon of the flexor digitorum longus; the two portions of the tendon then unite and form a grooved channel for the reception of the accompanying long Flexor tendon. Finally, it divides a second time, and is inserted into the sides of the second phalanx about its middle. The mode of division of the tendons of the flexor digitorum brevis, and of their insertion into the phalanges, is analogous to that of the tendons of the flexor digitorum superficialis in the hand.

Innervation

Innervation is by the

medial plantar nerve The medial plantar nerve (internal plantar nerve) is the larger of the two terminal divisions of the tibial nerve (medial and lateral plantar nerve), which accompanies the medial plantar artery. From its origin under the laciniate ligament it pa ...

Variation

Slip to the little toe may occasionally be absent, where it may be replaced by a small fusiform muscle arising from the long flexor tendon or from the quadratus plantæ.

Additional images

File:Gray269.png, Bones of the right foot. Plantar surface. File:Gray357.png, Coronal section through right talocrural and talocalcaneal joints. File:1124 Intrinsic Muscles of the Foot b.png, The bottom-most or first layer of muscles in the human foot include the flexor digitorum brevis.

References

External links