Flexor Digitorum Profundus Muscle Anatomy

Overview
Origin Upper three-fourths of anterior & medial surfaces of ulna
Interosseous membrane
Insertion Palmar surface of distal phalanges of digits 2-5
Action Flexes the metacarpophalangeal and interphalangeal joints of digits 2-5
Weak assistance in wrist flexion
Nerve Lateral part (digits 2-3): Anterior interosseous branch of the median nerve (C8-T1)
Medial part (digits 4-5): Ulnar nerve (C8, T1)
Artery Anterior interosseous artery

Location & Overview

The flexor digitorum profundus is located deep to the flexor digitorum superficialis. The flexor digitorum profundus also passes between a split/gap in the flexor digitorum superficialis’ distal tendon. This split/gap is located just before the proximal interphalangeal joint (The proximal interphalangeal joint is located between the middle and proximal phalanx sections of the finger). The flexor digitorum profundus is the only muscle which can flex the distal interphalangeal joints of the fingers (the distal interphalangeal joints are the joints located at the tips of the fingers). It passes deep to the flexor retinaculum, within the common flexor sheath (i.e it passes through the carpal tunnel) [1]Moore KL, Agur AMR, Dalley AF. Clinically Oriented Anatomy. 8th ed. Philadelphia: Lippincot Williams & Wilkins; 2017 [2]Lung BE, Burns B. Anatomy, Shoulder and Upper Limb, Hand Flexor Digitorum Profundus Muscle. [Updated 2021 Oct 30]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. … Continue reading.

Origin & Insertion

The flexor digitorum profundus originates from the upper three-fourths of the anterior and medial surfaces of the ulna. It also originates at the interosseous membrane and the deep fascia of the forearm. It then continues distally down the forearm, crossing the wrist joint via the carpal tunnel and finally connects to the tips of the fingers (distal phalanges). It inserts onto the bases of the distal phalanges of the 2nd, 3rd, 4th and 5th digits [3]Moore KL, Agur AMR, Dalley AF. Clinically Oriented Anatomy. 8th ed. Philadelphia: Lippincot Williams & Wilkins; 2017 [4]Lung BE, Burns B. Anatomy, Shoulder and Upper Limb, Hand Flexor Digitorum Profundus Muscle. [Updated 2021 Oct 30]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. … Continue reading.

Actions

The flexor digitorum porofundus is able to flex the metacarpophalangeal and distal/proximal interphalangeal joints of the index, middle, ring and little fingers. The flexor digitorum porofundus can also assist in flexing the wrist at the midcarpal joint. The medial part of the muscle flexes the pinky/little and ring fingers (digits 4 & 5) the lateral part of the muscle flexes the index and middle fingers (digits 2 & 3) [5]Moore KL, Agur AMR, Dalley AF. Clinically Oriented Anatomy. 8th ed. Philadelphia: Lippincot Williams & Wilkins; 2017 [6]Lung BE, Burns B. Anatomy, Shoulder and Upper Limb, Hand Flexor Digitorum Profundus Muscle. [Updated 2021 Oct 30]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. … Continue reading.

Innervation

The flexor digitorum profundus’ lateral part is innervated by the anterior interosseous nerve which is a branch of the median nerve. The flexor digitorum profundus’ lateral part is located on the index and middle fingers. The flexor digitorum profundus’ medial part is innervated by the ulnar nerve. The flexor digitorum profundus’ medial part is located on the ring and little finger [7]Moore KL, Agur AMR, Dalley AF. Clinically Oriented Anatomy. 8th ed. Philadelphia: Lippincot Williams & Wilkins; 2017 [8]Lung BE, Burns B. Anatomy, Shoulder and Upper Limb, Hand Flexor Digitorum Profundus Muscle. [Updated 2021 Oct 30]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. … Continue reading.

Blood Supply

Blood is supplied to the flexor digitorum profundus via the anterior interosseous artery. The anterior interosseous artery is a branch of the common interosseous artery [9]Lung BE, Burns B. Anatomy, Shoulder and Upper Limb, Hand Flexor Digitorum Profundus Muscle. [Updated 2021 Oct 30]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. … Continue reading.

Images

Highlighted in green, we can see the flexor digitorum profundus from a superficial view.

flexor digitorum profundus muscle

Here we can see the flexor digitorum profundus muscle by itself.

flexor digitorum superficialis muscle

Here we can see a labelled diagram of the bones and the joints of the phalanges of the hand.

origin point of the flexor digitorum profundus muscle

Here we can see the first origin point of the flexor digitorum profundus muscle highlighted in red. The origin is on the upper three-fourths of the anterior & medial surfaces of the ulna.

origin point of the flexor digitorum profundus on the interosseous membrane

Here we can see the second origin point of the flexor digitorum profundus muscle highlighted in red on the interosseous membrane.

insertion points of the flexor digitorum profundus muscle

Here we can see the insertion points of the flexor digitorum profundus muscle highlighted in blue. The insertions are on the palmar surfaces of the distal phalanges of digits 2-5.

Want some flashcards to help you remember this information? Then click the link below:
Flexor Digitorum Profundus Flashcards

References

References
1, 3, 5, 7 Moore KL, Agur AMR, Dalley AF. Clinically Oriented Anatomy. 8th ed. Philadelphia: Lippincot Williams & Wilkins; 2017
2, 4, 6, 8, 9 Lung BE, Burns B. Anatomy, Shoulder and Upper Limb, Hand Flexor Digitorum Profundus Muscle. [Updated 2021 Oct 30]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK526046/