Flexor Digitorum Brevis (FDB)

Authors

Affiliations

Nathaniel Yomogida, B.S., SPT

Doctor of Physical Therapy

B.S. in Kinesiology

Chloë Kerstein, B.S., SPT

Doctor of Physical Therapy

B.A. in Neuroscience

Schematic of 1st layer of Plantar Intrinsic Foot Muscles¹
1: Abductor hallucis
2: Flexor digitorum brevis
Abductor digiti minimi

1st Layer Intrinsic Plantar Foot Muscles¹

Overview

Muscle	Origin	Insertion	Innervation	Action
Flexor digitorum brevis	Medial tubercle of calcaneal tuberosity Plantar aponeurosis	Sides of middle phalanx 2-5	Medial Plantar n. S1 - S2	2nd-5th Toe: MTP Flexion, PIP Flexion Arch support: Longitudinal arch support

Origin

• Medial tubercle of calcaneal tuberosity¹
• Plantar aponeurosis¹

Insertion

Sides of middle phalanges #2-5¹

Innervation

Medial Plantar N. (S1, S2)¹

Action

• MTP and PIP 2-5: Flexion¹
• Longitudinal Arch: Support¹

MMT

“The FDL and brevis muscles produce IP joint flexion. The motion is tested with the foot in the anatomic position. If the gastrocnemius muscle is shortened, preventing the ankle from assuming the anatomic position, the knee is flexed. The toes may be tested simultaneously. The foot is held in the midposition, and the metatarsals are stabilized. Resistance is applied beneath the distal and proximal phalanges”²

References

1.

Gilroy AM, MacPherson BR, Wikenheiser JC, Voll MM, Wesker K, Schünke M, eds. Atlas of Anatomy. 4th ed. Thieme; 2020.

2.

Dutton M. Dutton’s Orthopaedic Examination, Evaluation, and Intervention. 5th ed. McGraw Hill Education; 2020.