Lecture 47 - Foot Flashcards
Bones of the foot:
A. Tarsals (7) [proximal row=hindfoot=calcaneus and talus; midfoot=cuboid, navicular, medial cuniform, intermed cuniform, medial cuniform)
-distal row=cuboid, medial-lateral-intermediate cuniform
B. Metatarsals (5)
C. Phalanges (14) (1st toe has only 2 - proximal and distal only)
D. Sesamoid bones (Medial and Lateral in the tendons of flexor hallucis brevis muscle)
E. Hind foot (calcaneus and talus)
F. Mid foot (cuboid, navicular, cuneiforms)
G. Fore foot (phalanges and metatarsals
H. Ball of foot (sesamoid of 1st met. and head of 2nd met)
deep fascia of the dorsal surface of the foot:
- Continues with the crural fascia and the fascia of the plantar surface of foot
- Thickening of fascia forms the inferior extensor retinaculum
- Consists of three parts: Stem (Frondiform ligament); Superomedial limb – attaches at the anterior surface of medial malleolus; Inferomedial limb – attaches by blending with the plantar fascia
Cutaneous nerves of the dorsal surface of the foot
- Saphenous nerve: Medial side of foot as far as the 1st metatarsal
- Lateral dorsal cutaneous nerve: Continuation of the sural nerve into the foot
- Superficial peroneal nerve: Medial and intermediate dorsal cutaneous nerves; Supply middle part of the dorsum of the foot
- Deep peroneal nerve: Supplies the skin between 1st and 2nd toes
Tendons and muscles (muscles of the leg and foot)
- Extensor digitorum longus: One tendon for each of the lateral four toes; Dorsal expansions over the toes
- Extensor hallucis longus: To the 1st toe
- Extensor digitorum brevis: Only intrinsic muscle of dorsum of foot; Extends toes 2-4
- Extensor hallucis brevis: Goes to the 1st toe -Part of extensor digitorum brevis
arteries of the dorsal surface of the foot:
-Dorsalis pedis
a. Lateral and medial tarsal
b. Arcuate a- Branches:
• Three dorsal metatarsal arteries. Each dorsal metatarsal gives rise to two dorsal digital arteries;
-The first dorsal digital is a branch of the 1st dorsal metatarsal and the 10th dorsal digital is a branch of the 4th dorsal metatarsal
• Perforating arteries connect the dorsal metatarsal arteries with the deep plantar arch
c. Deep plantar artery: One of the two terminal branches of the dorsalis pedis; Goes to plantar side and joins with the deep plantar arch of the lateral plantar artery
d. First dorsal metatarsal artery: The second terminal branch of dorsalis pedis; Gives rise to three dorsal digital arteries
Veins of the dorsal surface of foot:
- Dorsal venous arch
a. dorsal metatarsal veins (4)
b. dorsal digital veins - Medial dorsal digital vein of the 1st toe and the lateral dorsal digital vein of the 5th toe
- Medial and lateral marginal veins
- Great saphenous vein
- Small saphenous vein
Cutaneous innervation of plantar foot surface:
- Saphenous nerve
- Lateral dorsal cutaneous nerve (Continuation of the sural nerve)
- Calcaneal branches of tibial nerve (Supply the heel area)
- Medial plantar nerve ( similar to median nerve) -Supplies medial 3 ½ digits
- Lateral plantar nerve -Supplies lateral 1 ½ digits (similar to ulnar nerve of upper limb)
Deep fascia of plantar surface:
• Thicker than on the dorsal surface
• Flexor retinaculum: thickening of the plantar fascia
• Plantar aponeurosis:
-Central part of the plantar fascia
-Very thick and strong
-Longitudinally arranged fibers
-Helps to support longitudinal arches of foot
-Prevent foot injury
-Extends from calcaneus to the toes
-Divides into five digital slips: one for each toe that attaches to the fibrous digital sheaths(keeps toes together when stepping- keeps from hurting your toes)
-Vertical septa from the plantar aponeurosis divide the foot into three compartments:
1. Medial compartment
2. Lateral compartment
3. Central compartment
Muscle layers - how many and do what?
- Four layers of intrinsic muscles
- Help to maintain balance and support the arches of the foot
First muscle layer:
a. Abductor hallucis: tuberosity of calcaneous – base of 1st proximal phalanx
b. Flexor digitorum brevis: Tuberosity of calcaneous – middle phalanx of lateral 4 toes
c. abductor digiti minimi (quinti) -Tuberosity of calcaneous – base of 5th proximal phalanx
Second muscle layer
a. Flexor digitorum longus -tendon
b. Flexor hallucis longus - tendon
c. Quadratus plantae: calcaneus – tendon of flexor digitorum longus - no slack
d. Lumbrical muscles (4): tendon of flexor digitorum longus - Flexor sheath of lateral 4 toes
third muscle layer:
a. Flexor digiti minimi brevis -Base of 5th metatarsal. – 5th proximal phalanx
b. Adductor hallucis:
- Oblique head Base of met. 2-4 – base 1st proximal phalanx
- Transverse head: MP joint ligaments – base 1st proximal phalanx
c. Flexor hallucis brevis cuboid – base 1st proximal phalanx (push off in walking)
fourth muscle layer:
a. Peroneus longus tendon
b. Tibialis posterior tendon
c. Plantar interossei muscles (3): Base metatarsals 3-5 – base proximal phalanx of toes 3-5 –> ADDuct the toes
d. Dorsal interossei muscles (4): Adjacent sides 1-5 metatarsals – proximal phalanx of 2-4 toes –> ABDuct the toes
Nerves - tibial branches of foot:
• Medial calcaneal: Supplies sensory innervation to the heel
• Medial plantar nerve
-Larger than the lateral plantar nerve
-Between 1st and 2nd layer
-Passes deep to the abductor hallucis brevis
-Divides into three common plantar digital nerve
-Each common plantar digital gives rise to two proper plantar digital nerves
-Supply cutaneous branch to 3 ½ digits
-Medial plantar nerve also supplies motor branches to: Abductor hallucis; Flexor digitorum brevis; Flexor hallucis brevis; 1st lumbrical
• Lateral plantar nerve (smaller)
-passes deep to the abductor hallucis
-Provides cutaneous branches to lateral 1 ½ digits
-Provides one common plantar digital nerve
-Provides motor branches to the rest of the intrinsic muscles
sural nerve of foot
Sensory to the lateral margin of the foot and the lateral side of 5th toe
