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 The ulnar artery is the main blood vessel, with oxygenated blood, of the Human Anatomical Terms#Anatomical directions, medial aspects of the forearm. It arises from the brachial artery and terminates in the superficial palmar arch, which joins ...

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 In the human body, the carpal tunnel or carpal canal is a flattened body cavity on the flexor ( palmar/volar) side of the wrist, bounded by the carpal bones and flexor retinaculum. It forms the passageway that transmits the median nerve and the ...

formed by the flexor retinaculum. These tendons, along with those of

flexor digitorum profundus The flexor digitorum profundus or flexor digitorum communis profundus is a muscle in the forearm of humans that flexes the fingers (also known as digits). It is considered an Muscles of the hand#Extrinsic, extrinsic hand muscle because it acts on ...

, 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 The metacarpophalangeal joints (MCP) are situated between the metacarpal bones and the proximal phalanges of the fingers. These joints are of the condyloid kind, formed by the reception of the rounded heads of the metacarpal bones into shallow ...

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