Flexor Pollicis Brevis (FPB)

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

Muscle	Origin	Insertion	Innervation	Action
Flexor pollicis brevis

Origin

• Superficial head: Flexor retinaculum¹
• Deep head: Capitate, Trapezium¹

Insertion

Lateral side of base of 1st proximal phalan (via the radial sesamoid)¹

Innervation

• Superficial head: Recurrent Br. of Median N.¹
• Deep head: Deep Br. of Ulnar N.¹
• (C8, T1)¹

Action

1st CMC: Flexion¹

Notes

1.

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