Sm 2 RA week 5 Flashcards
Bones of the foot?
7 tarsal, 5 metatarsal + 14 phalanges
hindfoot = talus + calcaneus (talus rests on sustentalculum tali medially)
midfoot = navicular, cuboid + 3 cuneiforms (medial, intermediate + lateral cuneiforms)
navicular articulates with talus + 3 cuneiforms, cuboid articulates with calcaneus
forefoot = metatarsals + phalanges, see sesamoid bones on ventral surface mt 1st toe
longitudinal + transverse arches on ventral surface of foot
inferior surface of cuboid = groove made by peroneus longus
Soft tissues of foot?
attachments?
Forms?
Deep fascia - thick central portion, weaker medially + laterally
plantar aponeurosis - superficial ligament formed by central portion of deep fascia
proximal attachment to calcaenus → divides into 5 bands distally, continuous with fibrous digital sheaths
Forms vertical intermuscular septae: divides muscles into middle, central and lateral compartments
compartments of foot?
Split by intermuscular septae
plantar and dorsal interossei in between metatarsals
compartments used to describe muscles?
layer 1?
Attachments?
muscles of foot usually described from superficial to deep
Layer 1 →
Abductor hallicus (1)
medial tubercle of calcaneus + flexor retinaculum → medial base of proximal phalanx
Flexor digitorum brevis (2)
medial tubercle of calcaneus → middle phalanges of lateral 4 toes
Abductor digiti minimi (3)
medial + lat. tubercle of calcaneus → lateral base of proximal phalanx
…
foot layer 2?
attachments?
long flexor tendons of the toes - FDL + FHL
Lumbricals
from tendons of FDL → medial side of dorsal tendon expansion
Quadratus plantae
medial + lateral surfaces of calcaneus → lateral side of FDL tendon
lumbricals on medial side of FDL tendons
FDB lie superficial to FDL
FDB will only go to middle phalynx, FDL goes to distal phalynx - so FDB splits into 2 (pic)
foot layer 3?
Attachments?
Flexor hallicus brevis
cuboid + lateral cuneiform → both sides base proximal phalanx of hallux
Adductor hallicus
transverse head: plantar ligament of MTP joints
Oblique head: base metatarsals 2-4
→ lat side base of proximal phalanx of hallux
Flexor digiti minimi brevis (* in pic)
base 5th metatarsal → base proximal phalanx 5th digit
…
foot layer 4?
attachments?
Function?
Note?
Interossei
3 x plantar interossei
bases + medial side of metatarsals 3-5 (unipennate) → medial side of proximal phalanx of 3-5 digits
PAD = plantar adduct
4 x dorsal interossei
adjacent sides of metatarsals 1-5 (bipennate)
→ 1st on medial side of proximal phalanx 2nd digit
→ 2nd-4th on lateral side of proximal phalanx digits 2-4
DAB = dorsal abduct
note - 2nd tie is axial digit of the foot for abduction/adduction - can onlybe abducted (not adducted, but is abducted in both directions)
(dont need on some digits due to adductor/abductor hallicus etc)
tendons?
Tendons
peroneus longus (* in pic)
Tibialis posterior
…
plantar nerves?
Pathway?
Divisions?
terminal branches of tibial nerve deep to flexor retinaculum
enter foot deep to abductor hallicus
medial plantar nerve = between abductor hallicus + FDB
lateral plantar nerve = between layers 1 + 2, deep and superficial branches (deep branch between layers 3+4)
Innervation of muscles of the foot?
roots?
medial plantar nerve
abductor hallucis
flexor digitorum brevis
1st lumbrical
flexor hallucis brevis
Lateral plantar nerve = all other muscles
roots = S2, S3
Calcaneal branches from tibial nerve
arterial supply to sole of foot?
pathway?
branches?
medial and lateral plantar arteries from posterior tibial artery deep to plexor retinaculum
enter foot deep to adbuctor hallicus
medial plantar artery = muscles of hallux + overlying skin (occasionally forms superficial plantar arch)
lateral plantar artery = initially between layers 1+2, deep plantar arch between layers 3+4 (deep plantar arch from dorsalis pedis) → arch gives off plantar metatarsal + digital arteries
yellow arrow = PT artery
bones of the foot organised?
See where?
Function of arches?
bones of the foot organised to produce longitudinal + transverse arches
Inferior view of foot can see transverse arch due to arrangement of cuneiform ones
longitudinal arches best seen on medial and lateral views, note medial arch higher than lat
Functions = distribute weight, act as shock absorbers, act as spring-boards
Transverse arch?
Supported by?
In which areas?
pic
supported by - tendon of tibialis posterior, tendon of peroneus (fibularis) longus, adductor hallucis muscle + deep transverse metatarsal ligament
TP + PL = suport tarsal arch
AH muscle (particularly transverse head) = supports metatarsal arch
deep transverse metatarsal ligament = anterior arch
lateral longitudinal arch of the foot bones?
when standing?
bones of lateral arch = calcaneus, cuboid, metatarsals 4+5
lateral arch rests on ground when standing
medial longitudinal arch of the foot bones?
significance?
bones of medial arch = calcaneus, talus, navicular, 3 cuneiforms, metatarsals 1-3
higher and more important than lateral arch
longitudinal arch support?
Examples
dynamic support from muscles + passive support from ligaments
dynamic support
intrinsic muscles of foot
flexor hallicus longus
flexor digitorum longus
passive support:
plantar calcaneonavicular (spring) ligament - deepest
short plantar ligament (calcaneocuboid)
long plantar ligament
plantar aponeurosis
weight distribution within the foot?
weight distributed almost equally between calcaneus + heads of metatarsals
Joints of the foot?
navicular will articulate with all 3 cuneiform bones
tarsometatarsal joints between medial cuneiform + 1st metatarsal, intermediate cuneiform + 2nd metatarsal, lateral cuneiform + 3rd metatarsal, and finally cuboid will articulate with both the 4th + 5th metatarsal
head of the metatarsal will articulate with proximal phalanx of toe
subtalar joint type?
articular surfaces?
plane synovial
talus = slightly concave posterior calcaneal articular surface
calcaneus = convex posterior articular facet
other articular surfaces that form talocalcaneal part of talocalcaneonavicular joint - not anatomically part of subtalar joint but functionally cant have movement at anatomical subtalar joint without movement here
ligaments of subtalar joint?
strongest?
weak capsule supported by medial, lateral, interosseous + posterior talocalcaneal ligaments
interosseous ligament is particularly strong
transverse (mid)tarsal joint?
talocalcaneonavicular joint
talocalcaneal part = plane synovial
talonavicular part = ball and socket
+ calcaneocuboid joint = plane synovial
can see facet on calcaneus where it will articulate with cuboid
cans see very rounded head of talus + cavity formed on proximal surface of navicular that will act as ball of ball + socket joint
ligaments of midtarsal joint?
2 ligaments on dorsal surface:
bifurcate ligament = calcaneus → navicular + cuboid (most medial)
dorsal calcaneocuboid ligament = calcaneus → cuboid
plantar surface:
Most superficial is long plantar ligament = calcaneus → cuboid + metatarsals (in pic can see diagnonal peroneus longus tendon creating groove on cuboid)
adjacent and deep to long plantar ligament is short plantar ligamant = calcaneus → cuboid
spring ligament = calcaneus (sustentaculum tali) → navicular (therefore span just underneath head of talus + support it)
…
Movements of joints of the foot?
Subtalar + talocalcaneal part of talocalcaneonavicular joints = inversion/eversion
midtarsal joint = augments inversion/eversion
(muscles attach on midfoot/forefoot, start of inversion/eversion → forefoot + midfoot rotate on hindfoot at midtarsal joint)
forefoot, midfoot and calcaneus rotate under talys = subtalar joint
tarsometatarsal joints?
type?
also called?
anterior tarsal bones (cuboid & cuneiforms) + base of metatarsals
plane synovial
called Lisfranc’s joint
…
tarsometatarsal ligaments?
dorsal, plantar + interosseous ligaments bind the bones together
MTP joint type?
Movements?
IP joints?
Photograph A shows the plantar surface still covered in skin. The skin on the plantar surface is thick skin and is usually harder in texture where the foot touches the floor – for example over the heel. Photographs B and C show deeper layers of the foot. As you dissect the foot you will uncover the tendons of extrinsic muscles. These muscles have their muscle bellies outside the foot but their tendons attach to the digits or metatarsal bones. These muscles face a challenge in the foot that their equivalent muscles of the hand do not. Flexor tendons to the digits of the hand can pass straight through the carpal tunnel; tendons to the digits of the foot cannot pass over the calcaneus or they will be crushed during walking. The long flexor tendons to the toes must instead pass around the medial malleolus of the ankle to reach the plantar surface of the foot. As you dissect you will also see intrinsic muscles of the foot that lie completely within the foot and also attach to the digits or metatarsals.
Once the skin of the foot has been removed, the plantar aponeurosis is revealed (photograph A). The aponeurosis will stick to the skin above and the muscles underneath. It is a tough connective tissue layer designed to protect the soft tissues of the foot and hold the skin to the structures underneath to prevent the skin from slipping. It attaches to the calcaneus and passes distally to end near the base of the digits.
Once the aponeurosis is removed, flexor digitorum brevis is revealed (photograph B). It attaches to the calcaneus and the middle phalanx of the lateral 4 digits. It flexes the digits but does not flex the distal interphalangeal joint. Flexor digitorum brevis is innervated by the medial plantar nerve.
The plantar aponeurosis covers the more central parts of the plantar surface of the foot, in the same way as the palmar aponeurosis does in the hand. Either side of the palmar aponeurosis there are the eminences of the palm that contain muscles that abduct and flex the thumb and little finger. A very similar pattern exists in the foot. Photograph A shows the foot with the aponeurosis intact and a muscle passing along the medial side of the foot – abductor hallucis. Photograph B shows that abductor hallucis attaches to the calcaneus and inserts into the base of the first proximal phalanx. It will abduct and flex the 1st digit (the big toe or hallux) and is innervated by the medial plantar nerve. Photograph C shows its counterpart on the lateral side of the foot – abductor digiti minimi. It also attaches to the calcaneus but inserts into the proximal phalanx of the 5th digit (or little toe). It abducts the 5th digit and is innervated by the lateral plantar nerve.
Abductor hallucis, abductor digiti minimi and flexor digitorum brevis form the first muscular layer of the foot. The neurovascular plane of the foot lies between the first and second muscle layers. Photograph A shows the posterior tibial artery passing from behind the medial malleolus to enter the plantar surface of the foot. Here it forms its terminal branches of the medial and lateral plantar arteries. The lateral plantar artery is usually the larger branch and will form most of the plantar arch.
Photograph B shows the tibial nerve passing around the medial malleolus with the posterior tibial artery. It also forms its terminal branches in the plantar surface of the foot – the medial and lateral plantar nerves. Instead of trying to remember all of the innervations to the muscles of the plantar surface (the sole) of the foot, it is easier to simply remember those muscles supplied by the medial plantar nerve – flexor digitorum brevis, abductor hallucis, flexor hallucis brevis and the first lumbrical. All of the other intrinsic muscles of the plantar surface of the foot are supplied by the lateral plantar nerve. The medial and lateral plantar nerves also supply cutaneous innervation to the sole of the foot.
The next muscular layer of the foot contains the tendon of flexor digitorum longus, the lumbrical muscles and quadratus plantae.
Photograph A shows how the tendon of flexor digitorum longus crosses the plantar surface of the foot after passing behind the medial malleolus. Several small muscles attach to this tendon as it passes across the sole of the foot. Photographs A and B show quadratus plantae (flexor accessorius) that attaches to the calcaneus and to the lateral border of the tendon of flexor digitorum longus. Quadratus plantae straightens the pull of the tendon, assisting in flexion of the lateral 4 digits. It is innervated by the lateral plantar nerve.
Photograph C shows the other small muscles that attach to the tendon of flexor digitorum longus – the lumbricals. The lumbricals are numbered 1 to 4 from medial to lateral. They insert into the dorsal digital expansions of digits 2 to 5 (all the toes except the big toe). They flex the metatarsophalangeal joint and extend the proximal interphalangeal joints of these digits (in a similar fashion to the finger movements performed by the lumbricals in the hand). The first lumbrical is innervated by the medial plantar nerve, the rest by the lateral plantar nerve.
The next muscular layer contains flexor hallucis brevis (photograph A), flexor digiti minimi brevis (photograph B) and adductor hallucis (photograph C).
Flexor hallucis brevis attaches to the cuboid bone and forms two parts so that it attaches to both sides of the base of the proximal hallucial (1st) phalanx. It acts to flex the big toe and is innervated by the medial plantar nerve.
Flexor digiti minimi brevis lies on the lateral side of the sole of the foot. It attaches to the base of the 5th metatarsal and inserts into the proximal phalanx of the 5th digit (little toe). It acts to flex the little toe and is innervated by the lateral plantar nerve.
Adductor hallucis forms two heads. The oblique head attaches to the 2nd to 4th metatarsal bases and the transverse head attaches to the metatarsophalangeal ligaments of digits 3 to 5. Both heads insert into the base of the 1st proximal phalanx (there may be a sesamoid bone here also). It acts to adduct the big toe and is innervated by the lateral plantar nerve.
The next layer of the foot contains the plantar arch (photographs A and B), some of the long tendons that pass into the foot (photograph B) and the interossei muscles.
The plantar arch is an extension of the lateral plantar artery that anastomoses with dorsalis pedis. The arch gives off metatarsal arteries that then branch to form digital arteries to supply the toes. Note that the arches shown in photographs A and B are not identical in shape.
Some of the long tendons that pass into the foot help to support the arches of the foot. Photograph B shows the tendon of peroneus longus as it crosses the foot from lateral to medial to insert into the 1st metatarsal and the medial cuneiform bones.
Photograph C shows the deepest muscles of the foot – the interossei. The four dorsal interossei lie between the metatarsal bones and the plantar interossei lie slightly inferior to the metatarsal bones (on the plantar surface). The interossei attach to the dorsal digital expansions of the toes and act to abduct (dorsal) and adduct (plantar) all of the toes except the big toe. They are innervated by the lateral plantar nerve.
Photograph A shows the plantar nerves and vessels as they pass the metatarsal bones. These nerves and vessels then form digital branches that lie either side of the each digit (photograph B). Photograph C shows the tendon of flexor digitorum longus as it passes towards the distal phalanx of the 2nd toe and also shows how the tendon of flexor digitorum brevis splits to insert into the lateral sides of the middle phalanx of the 2nd toe. This same pattern is created by flexor digitorum profundus and flexor digitorum superficialis in the fingers.
This slide helps to show how deep within the plantar surface of the foot the ligaments are. Photograph A shows the skin, photograph B shows the foot partially dissected and photograph C shows a deep dissection of the foot. It is only at this stage that some of the ligaments become visible, many are still covered by the soft tissues of the foot. Although there are many small ligaments between the bones of the foot, only 3 main ligaments will be described here – the long plantar, the short plantar and the plantar calcaneonavicular ligaments.
Photograph A shows the long plantar ligament. It extends from the calcaneus to the cuboid (deep fibres) and the bases of the 2nd to 4th metatarsals (superficial fibres). It helps to support the lateral longitudinal arch of the foot by limiting depression of the arch.
Photograph B shows the long plantar ligament and under it, the short plantar ligament. The short plantar ligament is also called the plantar calcaneocuboid ligament as it attaches to these bones. It also helps to support the lateral side of the longitudinal arch of the foot. Photograph B also shows the plantar calcaneonavicular ligament – this is sometimes called the spring ligament.
Photograph C shows some of the long tendons from the muscles of the leg which are also present deep within the plantar surface and can assist with support of the foot.
The slide shows the ligaments on the lateral side of the ankle joint. The calcaneofibular ligament passes between the calcaneus and the lateral malleolus. This ligament is normally crossed by the tendons of peroneus longus and brevis but they have been reflected here to show the ligament more clearly. The anterior talofibular ligament and posterior talofibular ligament (not shown) pass between the talus and the fibula. All three of these ligaments form the lateral collateral ligaments of the ankle joint.
The slide shows the medial side of the ankle joint. The ligaments collectively form a deltoid shape and so are often called the deltoid ligament – together they are the medial collateral ligaments of the ankle joint. The deltoid ligament is composed of the tibionavicular, tibiocalcaneal, posterior tibiotalar and anterior tibiotalar ligaments. The anterior tibiotalar ligament is not shown here as it forms a deeper part of the deltoid ligament.
It is common to confuse the names of the ligaments on the medial and lateral sides of the ankle joint. Try to remember the name of the bigger bone comes first on the medial side – tibionavicular for example, but comes second on the lateral side – calcaneofibular for example.
