|Origin||Humeroulnar head: Medial epicondyle of humerus and coronoid process of ulna|
Radial head: Proximal half of anterior border of radius
|Insertion||Bases of middle phalanges of digits two to five|
|Action||Flexion of fingers at proximal interphalangeal joints and at metacarpophalangeal joints|
Can also provide assistance during flexion of wrist
|Nerve||Median nerve (C7, C8, T1)|
Location & Overview
The flexor digitorum superficialis is a forearm muscle that’s commonly considered a superficial muscle. This flexor digitorum superficialis crosses the elbow joint via the common flexor tendon, with the flexor digitorum profundus passing deep to it. The common flexor tendon is a band of fibrous connective tissue that attaches to the medial epicondyle of the humerus. The muscles that attach to the common flexor tendon include: the pronator teres, flexor carpi radialis, palmaris longus, flexor digitorum superficialis, and the flexor carpi ulnaris. Distally, at the wrist, the flexor digitorum superficialis divides into four tendons. These four tendons travel deep to the flexor retinaculum via the carpal tunnel. The carpal tunnel is a narrow passageway formed by the bones and ligaments of the wrist joint. The flexor retinaculum forms the anterior ‘roof’ of the carpal tunnel. When the flexor digitorum superficialis reaches the distal part of the proximal phalanx of the finger, an opening/split appears in the muscle tendon. This opening allows for the tendon of the flexor digitorum profundus muscle to pass through it  . Images of this are included below.
Origin & Insertion
There are two points of origin for the flexor digitorum superficialis muscle. The first is the humeroulnar head of the muscle, which originates from the medial epicondyle of the humerus and the coronoid process of the ulna. The second is the radial head, originating from the proximal half of the anterior border of the radius. The flexor digitorum superficialis then continues distally, where it crosses the wrist joint and reaches the fingers. It the inserts onto the bases of the middle phalanges of digits two to five  .
The flexor digitorum superficialis flexes the proximal interphalangeal joints and metacarpophalangeal joints of digits 2-5. It is also able to provide assistance during flexion of the wrist. The primary flexors of the wrist are the flexor carpi radialis and the flexor carpi ulnaris. The flexor digitorum superficialis is able to flex each of the fingers it connects to independently  .
The median nerve and ulnar artery pass between the humeroulnar and radial heads of the flexor digitorum superficialis muscle. The flexor digitorum superficialis muscle is innervated by the median nerve (C7, C8, T1)  .
Blood is supplied to the flexor digitorum superficialis muscle primarily from the ulnar artery .
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Flexor Digitorum Superficialis Flashcards
|↑1, ↑3, ↑5, ↑7, ↑9||Okafor L, Varacallo M. Anatomy, Shoulder and Upper Limb, Hand Flexor Digitorum Superficialis Muscle. [Updated 2021 Oct 21]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK539723/|
|↑2, ↑4, ↑6, ↑8||Moore KL, Agur AMR, Dalley AF. Clinically Oriented Anatomy. 8th ed. Philadelphia: Lippincot Williams & Wilkins; 2017|