Dorsal Interossei of the Foot
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Description[edit | edit source]
The dorsal interossei muscles are a group of four bicephalic muscles that fill the space between the metatarsal bones of the foot. Their function lies in spreading the toes apart and in flexing the metatarsophalangeal joints of the second to fifth toe.
Origin[edit | edit source]
The interossei dorsales pedis originate on the base of the metatarsal bones I-V[1]. With two heads each, they emenate from the two adjacent bone sides facing each other and integrate into one insertion. Parts of of the Mm. interossei dorsales pedis originate from the Lig. plantare longum which is situated on the bottom side of the foot.
They are part of the deep central forefoot compartment[2], also described as the forth layer [3].
Insertion[edit | edit source]
The M.interosseus dorsalis I inserts on the medial side of the base of the second toe's phalanx proximalis[1].
The Mm. interossei dorsales II-IV insert on the lateral side of the base of phalanges proximales II-IV[1].
Nerve[edit | edit source]
Nervus plantaris lateralis, S2-S3; (Nervus tibialis) [1]
Function[edit | edit source]
- Flexion of the metatarso-phalangeal joints (MTPJ) II-IV, medial adduction of the second toe and lateral adduction of the third and fourth toe[1]
- Extension of the proximal phalangeal joints II-IV[1]
Synergists[edit | edit source]
MTPJ II-IV[4]:
- Flexion: M. flexor digitorum longus, M. flexor digitorum brevis, Mm. interossei plantares 1-2 (III-IV), Mm. lumbricales pedis 1-3 (II-IV)
Antagonists[edit | edit source]
MTPJ II-IV[4]: - Flexion: M. extensor digitorum longus, M. extensor digitorum brevis - Abduction: Mm. interossei plantares 1-2 (III-IV)
Clinical relevance[edit | edit source]
The M. interosseus dorsalis pedis IV is an easily accessible muscle and is likely to be used for routine electromyographic diagnosis of neurological diseases: "Abnormal [spontaneous activity] in [fourth dorsal interosseus pedis] correlates well with the overall neurologic condition, and it may be a useful muscle to include in routine electrodiagnostic evaluation."[5]
Assessment[edit | edit source]
An Oxford scale muscle strength assessment can be done as follows for the scales of 0/1 and 2/3. Since the interossei dorsales pedis can rarely be activated willingly, the resitance tests are usually avoided. - 0/1: supine position, knee is in supported flexion. Therapist holds the foot in neutral position and instructs the patient to "spread your toes". - 2/3: supine position, knee is in supported flexion. Therapist holds the foot in neutral position, watching for small movements of the toes and instructs the patient to "try to spread your toes".
Treatment[edit | edit source]
Trigger points:[edit | edit source]
Trigger points of the interossei dorsales pedis can be located when palpating the muscle belly inbetween the dorsal metatarsi on the instep. Typical patterns are pain on the base of the toes, in some cases expanding all the way to the tip of the toes, or pain on the instep extending to the anterior of the ankle and lower leg.
Strechting[edit | edit source]
Stretching the Mm. interossei dorsalis pedis (MIDP): --> remember: main function is flextion and abduction in the MTPJ - MIDP I: pulling the second toe into extentsion and lateral abduction - MIDP II: pulling the second toe into extentsion and medial abduction - MIDP III: pulling the third toe into extension and medial abduction - MIDP IV: pulling the fourth toe into extension and medial abduction
Muscle control & strengthening[edit | edit source]
Since the interossei dorsales pedis can rarely be willingly controlled and many patients have weak foot muscles in general, the first step is to establish a feeling of muscle activation. This can be approached by toe-spreading exercises, perhaps with pre-positioning of the toes by the therapist and the command to "keep the toes in this position". Further, the patient can be instructed to strengthen the interossei dorsales pedis by spreading the toes without assistance. In general, foot muscle strengthening exercises can be used to train the whole musclature, e.g. walking in sand, picking up tissues with the toes or holding sticks or pencils between toes.
Resources[edit | edit source]
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Putz, R., & der Anatomie, P. R. S. A. (2004). des Menschen. Limitierte Jubiläumsausgabe: der komplette Atlas in einem Band. 21. Aufl.
- ↑ Faymonville, C., Andermahr, J., Seidel, U., Müller, L. P., Skouras, E., Eysel, P., & Stein, G. (2012). Compartments of the foot: topographic anatomy. Surgical and radiologic anatomy, 34(10), 929-933.
- ↑ Teach Me Anatomy Series (2020). Muscles of the foot. Internet document: https://teachmeanatomy.info/lower-limb/muscles/foot/ [last accessed: 22.09.2020]
- ↑ 4.0 4.1 Valerius, K. P., Frank, A., Kolster, B. C., Hamilton, C., Alejandre Lafont, E., & Kreutzer, R. (2002). Das Muskelbuch. Anatomie Untersuchung Bewegung, 6.
- ↑ Siddiqi, Z. A., Nasir, A., & Ahmed, S. N. (2007). The fourth dorsal interosseus pedis muscle: a useful muscle in routine electromyography. Journal of Clinical Neurophysiology, 24(6), 444-449.
