Fourth Dorsal Interosseous Muscle of Foot
Musculus interosseus dorsalis pedis quartus
Read moreQuick Facts
Origin: Lateral aspect of body of fourth metatarsal bone and medial aspect of body of fourth metatarsal bone.
Insertion: Lateral aspect of base of proximal phalanx of fourth toe and extensor expansion of fourth toe.
Action: Abducts fourth toe at its metatarsophalangeal joint; simultaneously flexes metatarsophalangeal joint and extends interphalangeal joints of fourth toe.
Innervation: Superficial branch of lateral plantar nerve (S2-S3).
Arterial Supply: Arcuate, dorsal and plantar metatarsal, and dorsal digital arteries of foot.
Origin
The fourth dorsal interosseous muscle of foot consists of two heads:
- the medial head, which originates from the lateral aspect of the body of fourth metatarsal bone;
- the lateral head, which originates from the medial aspect of the body of fifth metatarsal bone.
Insertion
The fibers of the fourth dorsal interosseous muscle of foot travel anteriorly to the fourth toe and insert, via a short tendon, onto the:
- lateral aspect of the base of the proximal phalanx of fourth toe;
- extensor expansion of fourth toe.
Key Features & Anatomical Relations
The fourth dorsal interosseous muscle of foot is located in the fourth layer of muscles that are found in the plantar part of the foot. It is a short, bipennate skeletal muscle.
It is located:
- superior to the fourth lumbrical muscle of foot, and the second plantar interosseous muscle of foot;
- medial to the fifth metatarsal bone;
- lateral to the fourth metatarsal bone.
One of the perforating branches of deep plantar arch travels in between the two heads of the fourth dorsal interosseous muscle of foot.
Actions
The fourth dorsal interosseous muscle of foot is involved in multiple actions:
- abducts the proximal phalanx of fourth toe (i.e., draws it away from 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, which occurs when the third lumbrical and second plantar interosseous muscles of foot contract simultaneously with it (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 fourth dorsal interosseous muscle of foot is involved in multiple actions:
- abducts the proximal phalanx of fourth toe (i.e., draws it away from 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, which occurs when the third lumbrical and second plantar interosseous muscles of foot contract simultaneously with it (Standring, 2016).
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Foot Muscle
The extrinsic foot muscles are those whose muscle bellies reside proximal to the foot, but tendons directly insert into the bones and ligaments.
