Second Plantar Interosseous Muscle

Origin

The second plantar interosseous muscle originates from the medial aspects of the base and body of the fourth metatarsal bone.

Insertion

The fibers of the second plantar interosseous muscle travel anteriorly to the fourth toe and insert, via a short tendon, onto the:

- medial aspect of the base of the proximal phalanx of fourth toe;

- extensor expansion of fourth toe.

Key Features & Anatomical Relations

The second plantar interosseous muscle is located in the fourth layer of muscles that are found in the plantar part of the foot. It is a short, unipennate skeletal muscle.

It is located:

- superior to the adductor hallucis muscle and the third lumbrical muscle of foot;

- inferior to the third dorsal interosseous muscle of foot;

- medial to the fourth metatarsal bone;

- lateral to the third metatarsal bone.

Actions

The second plantar interosseous muscle is involved in multiple actions:

- adducts the proximal phalanx of fourth toe (i.e., draws it towards the longitudinal axial line of the second toe) at the fourth metatarsophalangeal joint;

- simultaneously flexes the fourth metatarsophalangeal joint and extends the interphalangeal joints of the fourth toe (Standring, 2016).

List of Clinical Correlates

- Clawing of the toes

- Charcot-Marie-Tooth disease

References

Standring, S. (2016) Gray's Anatomy: The Anatomical Basis of Clinical Practice. Gray's Anatomy Series 41st edn.: Elsevier Limited.

Actions

The second plantar interosseous muscle is involved in multiple actions:

- adducts the proximal phalanx of fourth toe (i.e., draws it towards the longitudinal axial line of the second toe) at the fourth metatarsophalangeal joint;

- simultaneously flexes the fourth metatarsophalangeal joint and extends the interphalangeal joints of the fourth toe (Standring, 2016).