The Mighty Interossei

By request of one of our readers (Thank you Richard S), we were asked to “dig up” some information about the interossei. After scouring the literature, we turned up an interesting paper, talking about their anatomy. 

Of interesting note, the paper found extensive connections of the musculature with the surrounding fascia (talk about myofascial meridians!) as well as a fairly consistent slip of the peroneus longus which contributes to the 1st dorsal interossei. This is important considering the peroneus fires from midstance on, as do the interossei (and other foot intrinsics). Perhaps (since as the fore foot is extending in late midstance and pre swing) it assists in descending the head of the 1st metatarsal and resisting extension (contracting eccentrically) of the metatarsal phalangeal joints, helping to maintain stability of the fore foot for push off. 

“The extensive connections among the interossei indicate that they could be important stabilisers of the foot during those times when rigidity is required. The pull of the interossei is transformed across the tarsometatarsal joints by means of their attachment to the ligamentous meshwork. Thus they will act upon the tarsometatarsal joints. Crossing those joints on their plantar aspect, the interossei are well placed to assist in resisting extension. Even though their close attachment proximal to the joints creates a short lever arm and therefore relative inefficiency as flexors when weight is borne on the ball of the foot (MacConaill, 1949), the large mass of the combined interossei probably indicates that they do have a significant role in resisting extension at these joints. Also, the shapes of the tarsometatarsal joint surfaces restrict angular motion.”

Definitely a good read and available FREE full text online here

PAUL J. KALINt AND BRUCE ELLIOT HIRSCH: The origins and function of the interosseous muscles of the foot  J. Anat. (1987), 152, pp. 83-91