Preliminary observations of muscle fibre cross sectional area of flexor digitorum brevis in cadaver feet with and without claw toes

Abstract

BackgroundIn order to facilitate normal gait, toes require to be in a rectus position during the propulsive phase. This requires a correct balance and sequence of activity of the intrinsic musculature of the feet. Alteration of this balance and sequence may lead to the development of claw toes. Atrophy of the lumbricals occurs in the development of claw toes, but it is not known if changes occur in any other intrinsic muscles, including flexor digitorum brevis. This study set out to investigate whether hypertrophic changes were evident in flexor digitorum brevis in feet with claw toes.MethodsFour cadaver feet were investigated, two with rectus toes and two with claw toes. Flexor digitorum brevis was removed from each, and seven anatomically significant tissue sections from each muscle were routinely processed, cut and stained. One hundred and sixty muscle fibre cross sectional areas were measured from each section.ResultsThe mean age of the donors was 81.5 years, and three of the four were female. Results showed that the cross sectional area of fibres from feet with claw toes was 417 μg2 significantly greater (p < 0.01) than the cross sectional area of fibres from feet with rectus toes, which was 263 μg2.ConclusionsAlthough this study has several limitations, preliminary observations reveal that flexor digitorum brevis muscle fibre cross sectional area is significantly reduced in feet with claw toes. This would indicate a relationship between muscle fibre atrophy of flexor digitorum brevis and clawing of the lesser toes.

Ultrasound evaluation of foot muscles and plantar fascia in pes planus

“…Tibialis anterior contracts in early stance to allow gradual plantarflexion of the foot and to decelerate downward motion of the foot. FHL and FDL further contribute to the maintenance of the MLA [16] but their actions are perhaps more coupled with intrinsic muscle and plantar fascia function than TP and TA, since all these structures insert into the digits [17,18]. However, the relationship between the extrinsic and intrinsic foot structures that share common functions has not been reported in pes planus.…”

Foot posture is associated with morphometry of the peroneus longus muscle, tibialis anterior tendon, and Achilles tendon

“…However, there are no published studies that have explored the association between foot posture and lower limb muscle and tendon morphology. Two studies have investigated differences in flexor digitorum brevis and longus muscle cross‐sectional area comparing individuals with claw and normal toes; however, these studies only investigated a small sample of cadaveric specimens (Semple & Baird, ; Locke et al., ).…”

Relationship between transverse arch height and foot muscles evaluated by ultrasound imaging device

“… ). Further, some studies on cadaver feet showed that the muscular slip for the fifth toe, or for the fifth and fourth toes is much smaller and the tendons are thinner than that for the other toes 18 , 22 , 23 ) . Therefore, the flexor force applied to the PIP joint of the second, third, and fourth toes could be greater, thereby increasing the height of the second, third, and fourth metatarsal heads, respectively; the height of the first and fifth metatarsal heads did not increase.…”

“…FDB is a fusiform muscle originating from the medial calcaneal process and the plantar aponeurosis. At its distal aspect, it is divided into four parts, which gives rise to four tendons that insert into the lateral four toes on the plantar surface of the intermediate phalanx 18 ) . Anatomical muscle CSA and muscle volume are valuable predictors of muscular strength and power output 19 , 20 , 21 ) .…”