LEA Plantar Foot Part 2 Flashcards
2nd Layer
- 5 muscles (4 lumbricals, quadratus plantae)
- 2 tendons (FDL and FHL); All muscles attach to FDL
Quadratus plantae (flexor accesorius)
- Deep to FDB,
- 2 heads (origins)
Quadratus plantae (flexor accesorius) origin
Medial head: medial surface of calcaneus
Lateral head: trigonum plantare and inferior calcaneus distal to lateral tubercle
Quadratus plantae 2 heads origins are separated by
long plantar ligament
Quadratus plantae (flexor accesorius) insertion
heads unite to insert onto the FDL tendon
Quadratus plantae (flexor accesorius) blood supply
medial and lateral plantar arteries
Quadratus plantae (flexor accesorius) nerve
lateral plantar nerve
Quadratus plantae (flexor accesorius) function
redirects line of pull of FDL, assist in flexing phalanges
Lumbricals (Lumbricale Muscles)
1 is unipennate; 2,3,4 are bipennate
Lumbricals origin
- 1st lumbrical: medial side of 1st tendon of FDL (tendon going to 2nd digit)
- 2 – 4: adjacent tendons
(e.g. 3rd lumbrical: medial side of 3rd FDL tendon, lateral side of 2nd FDL tendon; 2nd lumbrical medial side of 2 FDL tendon, lateral side of 1 FDL Tendon)
lumbricals Tendons pass distally plantar to the
deep transverse metatarsal ligament
Lumbricals insertion
- medial aspect of extensor wing of the extensor expansion at base of proximal phalanx of digits 2-5
- (1st lumbrical goes to 2nd digit, 2nd lumbrical to 3rd digit)
Lumbricals blood
respective plantar metatarsal arteries
Lumbricals nerve
1st – medial plantar nerve
2-4 – deep branch of lateral plantar nerve
lumbricals function
flex MTP joints, extend PIP and DIP joints
3rd layer
3 muscles (FHB, FDMB, ADD Hallucis)
Flexor hallucis brevis 2 heads
medial and lateral
Flexor hallucis brevis origin
- lateral: plantar surface of cuboid and lateral cuneiform
- medial: tibialis posterior tendon
Flexor hallucis brevis insertion
medial and lateral base of proximal phalanx
Respective heads of FHB invest ___ before phalangeal insertion
respective hallux sesamoid bones
-Medial (tibial) and lateral (fibular)
Sesamoids
- increase the mechanical advantage of the FHB
- Weight-bearing structures and decrease friction
Flexor hallucis brevis blood supply
1st plantar metatarsal artery
Flexor hallucis brevis nerve
medial plantar nerve
Flexor hallucis brevis function
flex (plantarflex) hallux MTP joint
Flexor digiti minimi brevis origin
base of the 5th metatarsal, tendon sheath of fibulas longus
Flexor digiti minimi brevis insertion
plantar/lateral aspect of base of proximal phalanx of 5th toe
Flexor digiti minimi brevis bloody supply
lateral plantar artery
Flexor digiti minimi brevis nerve
superficial branch of lateral plantar nerve
Flexor digiti minimi brevis function
flex (plantarflex) 5th digit at MTP joint
adductor hallucis 2 heads
transverse and oblique
adductor hallucis origin
- transverse head: fibrous capsule, plantar plates of digits 3-5, deep transverse metatarsal ligament
- oblique head: plantar aspect of metatarsal bases 2-4; fibularis longus tendon sheath
adductor hallucis insertion
lateral sesamoid and lateral aspect of proximal phalanx base of 1st digit
adductor hallucis blood supply
plantar metatarsal arteries
adductor hallucis nerve
deep branch of lateral plantar nerve
adductor hallucis function
adducts hallux
opponens digiti minimi origin
base of 5th metatarsal, long plantar ligament, FDMB
opponens digiti minimi insertion
lateral shaft of 5th metatarsal and surrounding fascia
opponens digiti minimi function
abduction and flexion of the 5th toe
4th layer
2 muscle groups (dorsal and plantar interossei)
4th layer is located within the
metatarsal spaces
4th layer muscles are not associated with the
hallux
4th layer muscle tendons pass dorsal to the
deep transverse metatarsal ligament
_ plantar interossei and _ dorsal interossei
3, 4
plantar interossei
adduct digits
dorsal interossei
abduct digits
2 tendons of the 4th layer
tibialis posterior, fibularis longus
Plantar Interossei Muscles
- 3 in number, associated with digits 3,4,5
- Unipennate muscles
Plantar Interossei Muscles origin
base and medial aspect of shafts of metatarsals 3, 4, 5
Plantar Interossei Muscles insertion
medial aspect of base of proximal phalanx and extensor expansion (sling of the extensor expansion) of same digit
Plantar Interossei Muscles blood supply
plantar metatarsal arteries 2-4
Plantar Interossei Muscles nerve
- lateral plantar nerve
- Deep branch innervates 1st and 2nd plantar interossei
- Superficial branch innervates 3rd plantar interossei
Plantar Interossei Muscles function
- adduct digits 3-5 toward foot midline
- Flex (plantarflex) 3-5 MTP joint, extend (dorsiflex) IP joints of digits 3-5
Dorsal Interossei
- 4 in number, associated with digits 2-4
- Digit 2 has 2 dorsal interossei muscles inserting
- Bipennate muscles located within the intermetatarsal space
Dorsal Interossei origin
adjacent metatarsal shafts
1st dorsal interossei originates lateral aspect of 1st metatarsal shaft and medial aspect of 2nd metatarsal shaft)
Dorsal Interossei insertion
1st dorsal interossei: medial aspect of base of proximal phalanx and extensor expansion (sling) of 2nd digit
2nd – 4th dorsal interossei: lateral aspect of base of proximal phalanx and extensor expansion (sling) of corresponding digit
Dorsal Interossei blood supply
corresponding dorsal metatarsal artery
Dorsal Interossei nerve
- lateral plantar nerve
- deep branch of lateral plantar nerve innervates 1st – 3rd
- superficial branch of lateral plantar nerve innervates 4th
- 1st and 2nd also receives innervation from deep fibular nerve
Dorsal Interossei function
- abducts digits 2-4
- Flex (plantarflex) MTP joints; extend (dorsiflex) IP joints
1st Intermetatarsal space
1st dorsal interosseous
2nd Intermetatarsal space
2nd dorsal, 1st plantar
3rd Intermetatarsal space
3rd dorsal, 2nd plantar
4th Intermetatarsal space
4th dorsal, 3rd plantar
___ keeps the tendons anchored to the bone
A fibrous flexor sheath
FHL, FDB and FDL are surrounded by a synovial sheath to
reduce friction
Extensor Expansion
A tendinofibroaponeurotic structure that is involved in the extensor function of the digits
Extensor Expansion formed by
- Extrinsic muscles: EDL and EHL
- Intrinsic muscles: EDB, lumbricals, interossei
- Stabilizing ligaments: sling and wing, triangular lamina
EDB joins the
EDL tendon
can form lateral slip instead of EDL
EDB tendons
EHB attaches to base of
proximal phalanx
Lumbrical tendons pass _ to deep transverse metatarsal ligament
plantar
Lumbrical tendons insert into wing which allows them to
flex the MTP joint and extend IP joints
Lumbrical tendons can form
medial slip
Interosseous tendons pass __ to deep transverse metatarsal ligament
dorsal
Interosseous tendons insert into base of
proximal phalanx at the tubercle
Interosseous tendons insert into extensor apparatus at
the sling
Sling
- Proximally located
- Transversely oriented fibers pass around the
- MTP joint and attach the plantar plate, and deep transverse metatarsal ligament
- Interossei insert into the sling
- Anchors EDL allowing it to extend all of the digit
Wing
- Distal portion of extensor expansion
- Fibers are oriented obliquely (triangular shaped), located at the proximal phalanx
- Lumbricals insert into the medial side of the wing
EDL Tendons forms at ___ of extensor expansion
central axis
FDL tendons stabilized by
the sling at the MTP joint
the EDL tendons divide into 3 slips (trifurcates) at
the MTP joint (some say proximal phalanx)
2 slips of EDL tendon: medial and lateral
Extend over dorsum of middle phalanx
Insert into base of distal phalanx as a terminal tendon
1 middle (central) slip of EDL tendon
Inserts into base of middle phalanx
Triangular Lamina is found
between lateral slips of the EDL
Triangular Lamina function
is unknown but believed to anchor medial and lateral slips (keeps them from sliding plantar ward)