Flexor digitorum superficialis (''flexor digitorum sublimis'') or flexor digitorum communis sublimis is an extrinsic flexor

muscle Muscle is a soft tissue, one of the four basic types of animal tissue. There are three types of muscle tissue in vertebrates: skeletal muscle, cardiac muscle, and smooth muscle. Muscle tissue gives skeletal muscles the ability to muscle contra ...

of the

finger A finger is a prominent digit (anatomy), digit on the forelimbs of most tetrapod vertebrate animals, especially those with prehensile extremities (i.e. hands) such as humans and other primates. Most tetrapods have five digits (dactyly, pentadact ...

s at the proximal interphalangeal joints. It is in the anterior compartment of the forearm. It is sometimes considered to be the deepest part of the superficial layer of this compartment, and sometimes considered to be a distinct, "intermediate layer" of this compartment. It is relatively common for the Flexor digitorum superficialis to be missing from the little finger, bilaterally and unilaterally, which can cause problems when diagnosing a little finger injury.

Structure

The muscle has two classically described heads – the humeroulnar and radial – and it is between these heads that the

median nerve The median nerve is a nerve in humans and other animals in the upper limb. It is one of the five main nerves originating from the brachial plexus. The median nerve originates from the lateral and medial cords of the brachial plexus, and has cont ...

and ulnar artery pass. The ulnar collateral ligament of elbow joint gives its origin to part of this muscle. Four long

tendon A tendon or sinew is a tough band of fibrous connective tissue, dense fibrous connective tissue that connects skeletal muscle, muscle to bone. It sends the mechanical forces of muscle contraction to the skeletal system, while withstanding tensi ...

s come off this muscle near the wrist and travel through the carpal tunnel formed by the flexor retinaculum. These tendons, along with those of flexor digitorum profundus, are enclosed by a common flexor sheath. The tendons attach to the anterior margins on the bases of the

intermediate phalanges The phalanges (: phalanx ) are digital bones in the hands and feet of most vertebrates. In primates, the thumbs and big toes have two phalanges while the other digits have three phalanges. The phalanges are classed as long bones. Struct ...

of the four fingers. These tendons have a split (Camper's Chiasm) at the end of them through which the tendons of flexor digitorum profundus pass.

Innervation

The Flexor digitorium superficialis muscle is innervated by the

(C7, C8, T1).

Function

The primary function of flexor digitorum superficialis is flexion of the middle phalanges of the four fingers (excluding the thumb) at the proximal interphalangeal joints, however under continued action it also flexes the metacarpophalangeal joints and wrist joint. To test flexor digitorum superficialis, one finger is flexed at the proximal interphalangeal joint against resistance, while the remaining three fingers are held fully extended (to inactivate flexor digitorum profundus).

Additional images

File:Gray416.png, Tendons of forefinger and vincula tendina. File:Gray417_color.PNG, Cross-section through the middle of the forearm. File:Carpal-Tunnel.svg, Transverse section across the wrist and digits. File:Gray423.png, The mucous sheaths of the tendons on the front of the wrist and digits. File:Gray427.png, The muscles of the left hand. Palmar surface. File:Gray527.png, The radial and ulnar arteries. File:Musculusflexordigitorumsuperficialis.png File:Muscles of forearm.jpg, Flexor digitorum superficialis muscle File:Slide9r.JPG, Flexor digitorum superficialis muscle File:Slide5q.JPG, Flexor digitorum superficialis muscle File:Slide3GGG.JPG, Flexor digitorum superficialis muscle File:Slide7RRR.JPG, Flexor digitorum superficialis muscle File:Muscles of upper limb.(cross section - human cadaver).jpg, Muscles of upper limb. Cross section.

References

External links