Anterior Leg, dorsum of foot and lateral compartment

Question 1

what are the 4 muscles of the anterior leg

Answer 1

1. tibialis anterior
2. extensor hallucis longus
3. extensor digitorum longus
4. peroneus tertius

Question 2

tibialis anterior:

origin
insertion
action
function
innervation
pathology

Answer 2

• origin: lateral shaft of tibia, IoM, intermusculare septa
• insertion: under extensor retinaculum to medial cuneiform and base of 1st metatarsal
• action: AJ dorsiflexion, supination (STJ and long axis of MTJ)
• function: decellerates pronation and plantar flexion from HC, toe clearance suring swing phase
• innervation: deep peroneal nerve
• pathology: weak: foot drop, excessive pronation
  contracture: supinated foot

Question 3

extensor hallucis longus
origin
insertion
innervation
action

Answer 3

• origin: middle half of medial surface of fibula, IoM
• insertion: dorsal surface of base of distal phalanx of the hallux
• innervation: deep peroneal nerve
• action: AJ dorsiflexion, extends/stabilises hallux phalanges

Question 4

extensor digitorum longus
origin
insertion
innervation
action

Answer 4

• origin: lateral tibial condyle, uper medial fibula, IoM
• insertion: divides into 4 slips, base of distal phalanx of the lesser 4 toes, and base of intermediate phalanx
  contributes to extensor hood
• innervation: deep peroneal nerve
• action: AJ dorsiflexion, extends lesser toe phalanges

Question 5

where do the long and short flexors/extensors insert

Answer 5

• long: distal phalanx - motion at DIPJ
• short: intermediate phalanx - motion at PIPJ

Question 6

peroneus tertius:
closely related to which tendon
origin
insertion
innervation
action

Answer 6

• closely related to which tendon: EDL
• origin: distal 1/4 of fibula and IoM
• insertion: dorsal surface of base of 5th MT
• innervation: deep peroneal nerve
• action: foot eversion, AJ dorsiflexion, weak foot pronator

Question 7

what is the arterial supply to the anterior leg

Answer 7

• anterior tibial artery
• smaller branches of the popliteal artery
• becomes dorsalis pedis in front of the ankle joint

Question 8

where is the retinacular of the anterior leg

Answer 8

• superior extensor retinaculum:
  anterior border of fibular to anterior border of tibia
  continuous with deep fascia
• inferior extensor retinaculum
  y-shaped band
  calcaneous to tibia and plantar aponeurosis

Question 9

flexor retinacula - lacinate ligament

Answer 9

medial malleolus to medial tuberosity of calcaneous
protects and supports medial tendons, vessesl, nerve

Question 10

peroneal retinacula

Answer 10

• superior peroneal retinaculum
  lateral malleolus to lateral calcaneous
• inferior retinacula
  continuous with inferior extensor retinaculum
  peroneal tubercle to plantar aponeurosis

Question 11

what is the nerve of the anterior leg

Answer 11

deep peroneal

Question 12

what is a dermatome

Answer 12

the area of skin supplied by a single spinal nerve, and therefore a single nerve segment

Question 13

what nerves supply the dorsum of the foot (4)

Answer 13

1. superficial peroneal nerve - divides into
   medial and lateral dorsum
2. deep peroneal nerve
3. saphenous nerve
4. sural nerve

Question 14

where is the dorsal venous arch, where does it drain, and what is its relevance

Answer 14

• lies in the cutaneous tissue over the MT heads
• drains into the great saphenous vein medially and the small saphenous vein laterally
• drains a huge amount of blood from the foot via digital veins and communicating vens from the sole of the foot

Question 15

what is the route of the dorsalis pedis artery

Answer 15

• passes deep into the sole of the foot between the 1st and 2nd MT
• joins the lateral plantar artery (plantar arch)
• superficial
• branches into lateral tarsal artery, arcuate artery, 1st dorsal MT artery

Question 16

extensor digitorum brevis:
origin
insertion
innervation
action

Answer 16

• origin: anterior dorsal calcaneous and inferior extensor retinaculum
• insertion: splits into 4 tendons
• innervation: lateral branch of deep peroneal
• action: ext of hallux MTPJ, extension of 2,3,4 MTPJ and IPJs

Question 17

what are the arteries of the dorsal foot

Answer 17

• anterior tibial artery
  smaller branch of popliteal artery
• dorsalis pedis
• arcuate
• dorsal digital

Question 18

what are the muscles of the lateral leg

Answer 18

peroneus longus and brevis

Question 19

what is the blood supply of the lateral leg

Answer 19

branches of the peroneal artery

Question 20

which nerve innervates the lateral leg

Answer 20

superficial peroneal nerve

Question 21

peroneus longus:
origin
insertion
innervation
action

Answer 21

• origin: upper 2/3rd of lateral fibular and intermuscular septa
• insertion: under cuboid to base of 1st MT and medial cuneiform
• innervation: superficial peroneal nerve
• action: everts the foot, foot flexor, stabilisdes 1st ray and forefoot

Question 22

peroneus brevis:
origin
insertion
innervation
action

Answer 22

• origin: lower 2/3rds of lateral fibular and intermuscular septa
• insertion: base 5th MTJ
• innervation: superficial peroneal nerve
• action: everts foot about STJ and oblique axis of MTJ