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
The anterior compartment of the forearm (or flexor compartment) contains the following muscles:
The muscles are largely involved with extension and supination. The superficial muscles have their origin on the common flexor tendon. The ulnar ner ...
. 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 and
ulnar artery
The ulnar artery is the main blood vessel, with oxygenated blood, of the medial aspects of the forearm. It arises from the brachial artery and terminates in the superficial palmar arch, which joins with the superficial branch of the radial ar ...
pass. The
ulnar collateral ligament of elbow joint
The ulnar collateral ligament (UCL) or internal lateral ligament is a thick triangular ligament at the medial aspect of the elbow uniting the distal aspect of the humerus to the proximal aspect of the ulna.
Structure
It consists of two porti ...
gives its origin to part of this muscle.
Four long
tendons 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 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
median nerve (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 cav ...
and
wrist joint
In human anatomy, the wrist is variously defined as (1) the carpus or carpal bones, the complex of eight bones forming the proximal skeletal segment of the hand; "The wrist contains eight bones, roughly aligned in two rows, known as the carpal ...
.
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:Gray422.png, 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
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{{Authority control
Muscles of the upper limb
Forearm