Anatomy 2: Foot Flashcards
First layer of muscles of the foot:
Abductor hallucis: originates medial process of calculus, inserts medial side of proximal phalanx great toe, innervated by medial plantar nerve (from tibial nerve), abducts and flexes great toe at MTP joint.
Flexor digitorum brevis: medial process of calcaneal tuberosity and plantar aponeuroisis, inserts sides of plantar surface of middle phalanges of lateral 4 toes, innervated by medial plantar nerve from tibial nerve, flexes lateral 4 toes at proximal IP joint.
Abductor digiti minimi: lateral and medial processes of calcaneus, lateral side of base of proximal phalanx little toe, lateral plantar nerve from tibial nerve, abducts little toe at the MTP joint.
Second layer of muscles of the foot:
Quadratus plantae: originates medial calcaneus, inserts lateral side of flexor digitorum tendon, innervated by lateral plantar nerve (from tibial), assists flexor digitorum longus in flexing toes 2-5.
Lumbricals: arrise from the tendons of the flexor digitorum longus, attach to the medial sides of the extensor hoods of toes 2-5, innervated by medial and lateral plantar nerves (from tibial), flex the metatarsophalangeal joints and extend IP joints.
Third layer of muscles of the foot:
Flexor hallucis brevis: arises from cuboid and lateral cuneiform as well as tendon of tibialis posterior, inserts on lateral and medial of proximal phalanx of great toe, medial plantar nerve innervation, flexes MTP joint of great toe.
Adductor hallucis: transverse head originates from the transverse ligaments of toes 3-5 while oblique head comes from the bases of metatarsals 2-4, inserts on lateral side of base of proximal phalanx of great toe, innervated by lateral plantar nerve, adducts great toe.
Flexor digiti minimi brevis: originates at base of 5th metatarsal, inserts lateral side at base of proximal phalanx 5th toe, innervated by lateral plantar nerve, flexes little toe at MTP joint.
Fourth layer of muscles of the foot:
Dorsal interossei: originate from sides of adjacent metatarsals, insert on the extensor hoods and bases of proximal phalanges of toes 2-4, innervated by lateral plantar nerve as well as deep fibular nerve (toes 2/3), abduct the toes.
Plantar interossei: medial sides of metatarsals 3-5, attach to extensor hoods and bases of proximal phalanges 3-5, innervated by lateral plantar nerve, adduct the toes 3-5
Identify the bones of the foot, as well as the parts of the foot and describe key details of the talus and calcaneus.
a. Bones: Calcaneus, talus, navicular, cuboid, medial, intermediate, and lateral cuneiform, 5 meta tarsals, 14 phalanges.
b. Talus
- 1.Anteriorly lying head that articulates with navicular
- 2.Neck and body w/ superior trochlear surface, articulating with tib/fib
- 3.Inferior surface w/ 3 sites of articulation with calcaneus
- 4.Posterior process w/ medial and lateral tubercle flanking groove for tendon of flexor hallucis longus.
c. Calcaneus
- i.Forms heal, supports talus
- ii.Calcaneal tendon
- iii.Calcaneal tuberosity lies inferior to this, with medial and lateral processes.
- iv.Sustentaculum tali - medial ride of bone that supports talus and is grooved for flexor hallucis longus
- v.Tarsal sinus = gap between anterior surfaces of calcaneus and talus, filled with interosseous ligament.
d. Parts
- i.Hindfoot = talus calcaneus
- ii.Midfoot = navicular, cuboid, cuneiforms
- iii.Forefoot = metatarsals and phalanages
- iv.Plantar surface = sole
- v.Dorsal = superior
- vi.Heel
- vii.Ball
- viii.Hallux
Identify and describe the location and functions of the arches of the foot, as well as the means used to support these arches.
- a.Longitudinal
- -i.Medial longitudinal - highest and most important. Consists of all proximal foot bones and 3 metatarsals.
- -ii.Lateral - much flatter.
- b.Transverse
- -i.Occurs at junction of midfoot and forefoot
- c.Support of arches
- -i.Shapes of bones helps some
- -ii.Ligaments - most important structure. Spring liagemnt, long plantar and short plantar ligament. Plantar aponeurosis also helps
- -iii.Muscle attachements - particularly tibialis post and ant, fibularis longus form sling under arches.
d. CLINICAL NOTE
- i.Pes planus (flat foot)
- -1.Occurs when medial arch is depressed and forefoot is displaced laterally and everted. Can be flexible or rigid, congenital or acquired. Primary cuplriate is elongated spring (plantar calacneonavicular) ligament.
- ii.Pes cavus (claw foot)
- -1.Occurs when medial arch is more high than it should be. Various etiologies from muscular imbalances, excessively taut ligaments, and bone defects.
Describe the cutaneous and motor innervation to the dorsum of the foot.
i.Motor innervation supplied by deep fibular nerve
ii. Cutaneous
- -a.Superficial fibular - medial dorsal and intermediate dorsal cutaneous branches. Supplies majority of dorsum of foot
- -b.Deep fibular nerve - cutaneous sensation on lateral aspect and first digit, as well as medial aspect of second digit (web between big toe and second)
iii. Sural nerve - lateral margin of foot and lateral side of 5th digit
iv. Saphenous - medial side of foot up to first metatarsal
v. Nailbeds - innervated by dorsal branches from proper plantar digits
vi. Dermatomes -
- -1.5th digit = S1
- -2.Web between 1 and 2 = 2 L5
- -3.Medial aspect of foot = L4
Describe and draw on a diagram the origin, course, and branches of the dorsalis pedis artery.
a.Origin: arises as continuation of anterior tibial artery
b. Branches
- i.Lateral tarsal artery - anastomoses with arcuate artery
- ii.Arcuate artery - gives rise to 3 dorsal metatarsal arteries before anastomosing with lateral tarsal.
- –1.Each dorsal metatarsal gives off perforating branches to sole of foot and divide into 2 dorsal digital arteries
- iii.First dorsal metatarsal artery - arises as termination of dorsalis pedis artery, splitting into dorsal digital arteries
- iv.Deep plantar artery - largest branch of dorsalis pedis.
Describe the subdivisions, locations, attachments, and functions of the deep fascia of the sole, as well as the compartments of the foot with their contents.
i. Deep fascia
- a.Medial plantar fascia - over intrinsic muscles of hallux
- b.Lateral plantar fascia - over heel and 5th toe
- c.Plantar aponeurosis - thick, central, dense fibrous CT.
b. Compartments - divided by intermuscular septa from the plantar aponeurosis
- i.Medial compartment: with abductor hallucis and flexor hallucis brevis, as well as tendon for flexor hallucis longus.
- ii.Lateral compartment - abductor digiti minimi and flexor digiti minimi brevis muscles
- iii.Central compartment: flexor digitorum brevis, quadratus plantae, adductor hallucis, for lumbricals, tendons for flexor digitorum longus.
- iv.Interosseous - contains dorsal and plantar interosseous muscles.
