The flexor digitorum brevis 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 unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

aponeurosis An aponeurosis (; plural: ''aponeuroses'') is a type or a variant of the deep fascia, in the form of a sheet of pearly-white fibrous tissue that attaches sheet-like muscles needing a wide area of attachment. Their primary function is to join musc ...

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

vessels and nerves by a thin layer of fascia.

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) or heel bone is a bone of the tarsus of the foot which constitutes the heel. In some other animals, it is the point of the hock. S ...

, 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, high-tensile-strength band of dense fibrous connective tissue that connects muscle to bone. It is able to transmit the mechanical forces of muscle contraction to the skeletal system without sacrificing its ability ...

, one for each of the four lesser toes. Opposite the bases of the first phalanges, each tendon divides into two slips, to allow of the passage of the corresponding tendon of the

flexor digitorum longus The flexor digitorum longus muscle is situated on the tibial side of the leg. At its origin it is thin and pointed, but it gradually increases in size as it descends. It serves to flex the second, third, fourth, and fifth toes. Structure The fl ...

; 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 Flexor digitorum superficialis (''flexor digitorum sublimis'') is an extrinsic flexor muscle of the fingers at the proximal interphalangeal joints. It is in the anterior compartment of the forearm. It is sometimes considered to be the deepest pa ...

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 p ...

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 The quadratus plantae (flexor accessorius) is separated from the muscles of the first layer by the lateral plantar vessels and nerve. It acts to aid in flexing the 2nd to 5th toes (offsetting the oblique pull of the flexor digitorum longus) and is ...

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

* - "The Foot: Muscles"
PTCentral
{{DEFAULTSORT:Flexor Digitorum Brevis Muscle Foot muscles Muscles of the lower limb