Lumbrical Muscles of the Hand

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
Lumbricals (hand)

Origin

• 1-2nd Lumbrical: FDP Tendons (radial sides)¹
• 3-4th Lumbrical: FDP tendons (bipennate from medial and lateral sides)^{gilroyAtlasAnatomy202?}

Insertion

• 1st: 2nd digit (DDE)^{gilroyAtlasAnatomy202?}
• 2nd: 3rd digit (DDE)^{gilroyAtlasAnatomy202?}
• 3rd: 4th digit (DDE)^{gilroyAtlasAnatomy202?}
• 4th: 5th digit (DDE)^{gilroyAtlasAnatomy202?}

Innervation

• 1-2nd Lumbrical: Median N.^1,2
• 3-4th Lumbrical: Deep Br. of Ulnar N.^1,2
• (C8, T1)¹

Action

• 2-5 MCP: Flexion¹
• 2-5 PIP, DIP: Extension¹

Notes

Examination

• Bunnell-Littler Test
• Claw hand

References

1.

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

2.

Yang T, Rui YJ. Innervation of the lumbrical and interosseous muscles in hand: Analysis of distribution of nerve fascicles and quantification of their surface projections. Journal of Plastic Surgery and Hand Surgery. 2022;56(5):310-317. doi:10.1080/2000656X.2021.1981348