Foot

toc =**Lecture Notes**=

[|Lecture 1] [|Lecture 2]

=**Objectives**=

__Anterior:__ The anterior tibial a. continues through the anterior of the ankle becoming the dorsal pedal a. following the path of the deep fibular n. Extensor digitorum longus, extensor hallucis and tibialis anterior also cross at the anterior side of the ankle. __Lateral:__ Fubularus longus, and brevis pass inferior to the lateral malleous to enter the foot. __Medial:__ tibialus anterior, flexordigitorus longus, and flexor hallucis longus pass inferior to the medial malleous to enter the foot. Posterior tibial a. enters the foot medially as well to become the medial and lateral plantar a. The posterial tibial nerve also follows this path. __Posterior:__ The calcaneal tendon crosses porteriorly to attach to the calcaneus.
 * 1. Demonstrate the continued course of leg muscles, nerves, and vessels into the foot.**

The Intrinsic foot muscles lie within the foot and act primarily in stabilizing the foot in locomotion. They exist on the dorsum of the foot and in four layers on the plantar foot. Dorsum: Plantar layer 1 (suprificial): Plantar layer 2: Plantar layer 3: Plantar layer 4 (deep):
 * 2. Understand the function of intrinsic foot muscles.**
 * Muscle || Innervation || Origin || Insertion || Action ||
 * Extensor Digitorum Brevis || Deep Fibular n. || Calcalneus || Extensor expansion of toes 2-4 || Extends toes 2-4 ||
 * Extensor Hallucis Brevis || Deep Fibular n. || Calcalneus || Prox. phalanx of great toe || Extends great toe ||
 * Muscle || Innervation || Origin || Insertion || Action ||
 * Flexor Digitorum Brevis || Medial plantar n. || Calcaneus || Lateral 4 toes || Flex toes 2-5 ||
 * Abductor Hallucis || Medial plantar n. || Calcaneus || Great toe || Abduct great toe (Important to weight-bearing) ||
 * Abductor Digiti Minimi || Lateral plantar n. || Calcaneus || Little toe || Abduct little toe (Important to weight-bearing) ||
 * Muscle || Innervation || Origin || Insertion || Action ||
 * Quadratus Plantae || Lateral plantar n. || Calcaneus || Tendon of Flexor Digitorum Longus || Flex toes 2-5 ||
 * Lumbricals (4) || Medial (1st) and Lateral plantar n (2nd-4th) || Tendon of Flexor Digitorum Longus || Dorsum surface of extensor expansion 2-5 || Flex metatarsophalangeal joint Extend PIP and DIP of digits 2-5 ||
 * Muscle || Innervation || Origin || Insertion || Action ||
 * Flexor Hallucis Brevis (2 heads) || Medial plantar n. || (cuboid, lateral cuneiform, medial side of the first metatarsal) || (medial belly: medial side of proximal phalanx of the great toe) lateral belly: lateral side of the proximal phalanx of the great toe) || Flex metatarsophalangeal joint of great toe ||
 * Flexor Digiti Mini Brevis || Lateral plantar n. || (base of 5th metatarsal bone) || (proximal phalanx of 5th digit) || Flex metatarsophalangeal joint of little toe ||
 * Adductor Hallucis (2 heads) || Lateral plantar n.(deep branch) || (oblique head: bases of metatarsals 2-4 transverse head: heads of metatarsals 3-5) || 1st Metatarsal (lateral aspect) || Adduct great toe ||
 * Muscle || Innervation || Origin || Insertion || Action ||
 * Plantar Interossei (3) PAD || Lateral plantar n. (deep branch) || Medial side metatarsal 3-5 || Prox. phalange 3-5 || Adduction ||
 * Dorsal Interossei (4) DAB || Lateral plantar n. (deep branch) || Shafts of adjacent metatarsal bones || Bases of the proximal phalanges for digit 2 (both sides) & digits 3,4 (lateral side) || Abduction ||

__Medial longitudinal arch:__ Formed by interlocking of the talus, calcaneus, navicular, cuneiform bones, and three medial metatarsal bones. Head of Talus acts as keystone and is supported by spring ligament and tendon of flexor hallucis longus.
 * 3. Define the arches of the foot and understand how each is maintained.**

__Lateral longitudinal arch:__ Formed by calcaneus, cupoid bone, and lateral two metatarsal bones. The keystone is the cuboid bone and it is supported by the Fibularis longus tendon and the long+short plantar ligaments. (spring ligament)

__Transverse arch(proximal):__ Formed by navicular bone,the three cuniform bones, cuboid bone, and the base of the five metatarsal bones. Supported by tendon on fibularis longus.

__Transverse arch(distal):__ Formed by the heads of the five metatarsal bones and supported by the transverse head of the adductor hallucis.


 * 4. Define the role of the plantar aponeurosis.**

The plantar aponeurosis are longitudinally arranged bands of dense fibrous connective tissue that supports the longtitudinal arches of the foot, holds the parts of the foot together, and helps protect the plantar surface from injury. The plantar aponerosis arises posteriorly from the calcaneus and divides into five bands that split and enclose the digital tendons that attach to the margins of the fibrous digital sheaths and the sesamoid bones of the big toe.