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3KELETAL MUSCULAR SYSTEM / LOWER LIMB

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CN: -eel free to use the colors used for the letter labels on piates 65 and 66.

~~ose letters are presented here for Identification, and the muscies they reter *: are not meant to be colored. Also notę that plantar surface attachment sites :< :hcse extrinsic foot muscies have been omitted in the illustration of the turth layer but can be found on the two preceding piates. (1) 8egin with the :crth layer and complete each illustration oetore gomg on to the next.

~ne dorsal intrinslc muscies of the foot (those that ansę and insert .v:hin the dorsum of the foot) are limited to two smali axtensors of the '7-es shown at right. most of the extensor function being derived from r •trmsic extensors.

"oe intrinsic muscies of the plantar region of the foot are shown here - four layers. The plantar mterossei. wedged between the metatarsal :ones, constitute the deepest (4th) layer. They adduct toes 3-5. flex ~e metatarsophalangeai (MP) joints of these toes, and contribute to i -tension of the interphalangeal (IP) joints of these toes through the -ecnanism of the extensor expansion. The dorsal mterosseiabduct 'zes 3-5 and tacilitate the other actions of the plantar interossei

"ne third layer of muscies acts on the great toe (hallux) and 5th digit cigiti minimi). The second layer includes the guadratus plantae,

'sertmg mto the lateral border of the common tendon (H) of flexor c.gitorum longus (FOL). It assists that muscle in flexion of the toes ‘•'.e iumbricals arise from the md:vidual tendons ot FDL and insert into the —sdial aspect of the extenscr expansion (dorsal aspect). They flex the MP joints and extend the IP joints of toes 2-5 via the extensor expansion.

*he superficial (first) layer consists of the aóductors of the ist and 5th aigits and the tlexor digitorum previs. The plantar muscies are covered by "ie thickened deep fascia of the sole. the plantar aponeurosis, extendmg ‘•om calcaneus to the tibrous sheath of the flexor tendons.