Foot/Ankle Flashcards
(117 cards)
1
Q
Which 3 articulations are the bones of the leg involved with the foot?
A
- The Superior Tibiofibular Joint
- The Inferior Tibiofibular Joint
- The Talocrural Joint (more commonly known as the ankle joint)
2
Q
How are the shafts of the tibia and fibula connected?
A
The shafts of the tibia and fibular are connected by a tough, fibrous sheet known as the interosseous membrane.
3
Q
Is there any active movement between the tibia and fibula
A
No
4
Q
What type of movement occurs between the tibia and fibula?
A
There is conjunct movement between them which occurs as a result of movement at the ankle joint, and as a result of muscle contractions pulling on the two bones.
5
Q
What type of joint is an ankle joint?
A
True hinge joint
6
Q
Which planes of movement does the ankle joint move in?
A
Medial-lateral
Inversion-eversion
7
Q
What is the official joint name for the ankle joint?
A
Talocrural joint
8
Q
Which ligaments connect the tibia and fibula?
A
The superior and inferior tibiofibular joints
9
Q
How does passive movement occur at the superior and inferior tibiofibular joints?
A
Passive movements occur during movements the talocrural (ankle) joint
10
Q
Classify the Superior tibiofibular joint
A
Synovial plane joint
11
Q
GIve the location of the superior tibiofibular joint
A
Between an oval facet on the head of the fibula and a similar facet on the posterolateral aspect of the under surface of the lateral tibial condyle.
12
Q
Which 2 ligaments support the superior tibiofibular joint?
A
- Anterior Superior Tibiofibular Ligament – short, thick, fibrous bands pass obliquely upwards
and medially between the anterior aspects of the fibular head and the lateral tibial condyle - Posterior Superior Tibiofibular Ligament – single fibrous band passing upwards and medially
between the posterior aspects of the fibular head and the lateral tibial condyle.
13
Q
Classify the inferior tibiofibular joint?
A
Fibrous joint (syndesmosis)
14
Q
Where is the inferior tibiofibular joint located?
A
Between a rough triangular convex surface on the medial aspect of the lower end of the fibula and a corresponding area (fibular notch) on the lateral side of the tibia
15
Q
What are the 4 ligaments of the inferior tibifibular joint and give their attachments?
A
- Interosseous ligament – short, fibrous bands passing inferolaterally unites both bones
- Anterior & posterior tibiofibular ligaments – pass from the borders of the fibular notch to
the anterior and posterior surfaces of the lateral malleolus - Transverse tibiofibular ligament – lies deep to the posterior tibiofibular ligament and attaches to
the length of the posteroinferior tibial surface and the upper part of the malleolar fossa
16
Q
Give the location of the interosseous membrane
A
Runs between the interosseous borders of the tibia and fibula, with fibres passing inferolaterally
from tibia to fibula. It does not reach the superior tibiofibular joint but is continuous with the
interosseous ligament of the inferior tibiofibular joint. Openings superiorly and inferiorly transmit
blood vessels from posterior to anterior.
17
Q
Give the functions of the interousseous membrane
A
Stability – the IOM strongly unites the fibula and tibia, resisting separation. It resists excessive
rotational forces occurring at the fibula and transfers force between the two bones – preventing
peak forces from occurring and potentially causing fracture
Division – The IOM divides the lower leg into anterior and posterior compartments, separating
structures with common functions
Attachment – Due to its tough, fibrous nature the IOM provides a point of attachment for many
muscles of the lower leg. This increases the surface area available for muscle attachment in a
relatively congested anatomical area
18
Q
Give the role of the transverse tibiofibular ligament
A
The transverse tibiofibular ligament is important because it deepens the posterior part of the tibial articular surface and so deepens the socket for the talus, thereby improving joint congruency.
18
Q
Give the role of the transverse tibiofibular ligament
A
The transverse tibiofibular ligament is important because it deepens the posterior part of the tibial articular surface and so deepens the socket for the talus, thereby improving joint congruency and posterior stability.
19
Q
Describe the shape, extent and nature of the articular surfaces of the talocrural joint
A
Trochlear surface of body of the Talus forms the entire distal surface of the Talocrural joint.
Superiorly and medially articulating with the tibia.
Laterally articulating with the fibula
Convex in A-P direction
Slightly concave transversely
Surface is broader anteriorly than posteriorly
Structural: Synovial
Classification: Mortise/hinge joint
Uni-Axial
Compound
Functional: Diarthrosis
Movements: Dorsiflexion and plantar flexion of foot
20
Q
Give the static stabilisers of the talocrural joint
A
Bony configuration forming a ‘mortise’ joint
Fibrous capsule of the joint
Transverse tibiofibular ligament (deepening socket posteriorly)
Anterior & posterior ligaments (intracapsular thickenings)
Lateral Collateral Ligament
Medial Collateral (Deltoid) Ligament
Inferior tibiofibular joint ligaments
Interosseous membrane
21
Q
Describe the lateral collateral ligament
A
Strong ligament comprising of 3 separate bands
Reinforces joint capsule laterally
-Anterior talofibular ligament
-Posterior talofibular ligament
-Calcaneus ligament
22
Q
Describe the medial collateral ligament
A
Medial Collateral/Deltoid Ligament
Very strong
4 bands of fibres
-Tibiocalcneal
-Tibionavicular
-Anterior tibiotalar
-Posterior tibiotalar
23
Q
Give the role of the collateral ligaments?
A
Maintaining stability at the ankle joint
Controlling movements of the ankle joint
24
Explain the mechanism behind dorsiflexion of the ankle joint
During dorsiflexion, the wider part of the trochlear surface of the talus rocks backwards into the narrower posterior part of the tibiofibular mortise. This pushes the tibia and fibula apart, which increases the tension in the interosseous and transverse tibiofibular ligaments. Consequently, the talus is held firmly between the malleoli. During dorsiflexion, there is also a tendency for the fibula to be lifted superiorly. At the same time the fibula undergoes some axial rotation, either medially or laterally. The direction of this rotation depends upon the orientation of the lateral articular surface of the talus and varies between different human beings.
25
Describe the stability of the ankle joint during dorsiflexion
The ankle joint is particularly stable during dorsiflexion because of its bony configuration, strong supporting ligaments and tendons which cross the joint and which are bound down by the ankle retinaculae.
26
Explain the mechanism behind plantarflexion of the ankle joint
During plantarflexion, the reverse movements occur with the two malleoli coming together again due to tension in the anterior, posterior and interosseous tibiofibular ligaments, and the contraction of tibialis posterior draw the two bones together. The fibula moves medially and inferiorly, with some axial rotation (the opposite of that occurring in dorsiflexion for that specific human being). These movements of the fibula at the inferior tibiofibular joint are transmitted to the superior tibiofibular joint, which has plane articular surfaces offering no resistance to the movements.
27
Describe the stability of the ankle joint during platarflexion
The ankle joint is therefore relatively unstable in plantarflexion since the grip of the malleoli on the talus is less strong and some sideways movement of the talus can be observed in full plantarflexion of the ankle. It is therefore more common to observe ankle sprains when the ankle is in plantarflexion (for example, landing following a jump) and also the reason why the ATFL of the lateral ligament is most commonly sprained.
28
List the limiting factors of dorsiflexion of the ankle joint
-Lateral Ligament
-Deltoid Ligament
-Posterior part of capsule
-Extent of articular surfaces
-Tension in opposing muscles:
Posterior crural muscle group
29
List the limiting factors of plantarflexion of the ankle joint
-Lateral ligament
-Deltoid ligament
-Anterior part of capsule
-Tension in opposing
30
Describe the close pack position of the ankle joint
The “Close-Pack” position of the ankle joint is full ROM dorsiflexion. This is due mostly to the wider part of the talus being forced between the malleoli and being gripped tightly by the tension generated in the anterior, posterior and interosseous tibiofibular ligaments.
31
Describe the sit to stand mechanism involving the ankle joint
-Plantar grade (slight dorsiflexion) when sat
-Dorsiflexion when accelerating to stand
-Plantar grade when stood
32
Which bones are located in the hindfoot?
-Calcaneous
-Talus
33
Which bones are located in the midfoot?
-Navicular
-Cuboid
-Cuniforms
34
Which bones are located in the forefoot/
Metatarsals
Phalanges
35
Give functions of the human foot
Support the weight of the body, absorb the forces transmitted to it and provide spring and lift during activity
36
Identify the bony components of the medial longitudinal arches
The medial part of the longitudinal arch originates at the calcaneus, rises to the talus and descends through the navicular, the 3 cuneiforms and the heads of the 3 medial metatarsals. So high that the medial portion of the foot between the ball and the heel doesn’t touch the ground when you walk.
37
Identify the bony components of the lateral longitudinal arhces
The lateral part of the of the longitudinal arch also originates at the calcaneus, rises at the cuboid and descends to the heads of the 2 lateral metatarsals.
38
Identify the bony components of the transverse arch
The transverse arch is found between the medial and lateral aspects of the foot and is formed by the navicular, 3 cuneiforms and the bases of the 5 metatarsals.
39
Give functions of the arches of the foot
* Distribute body weight to the weightbearing areas (heel, heads of 1st and 5th metatarsals)
* Absorbs forces and shock
* Stores force for use in propulsion (windlass effect) during locomotion
* Bone concavity provides safe passage for neurovascular structures (nerves, veins, arteries) throughout the foot
Lateral longitudinal arch is shorter and stiffer as weightbearing occurs more significantly on the lateral aspect of the foot.
40
Give the articulation of the subtalar joint
The articulation between the talus which rests on and articulates with the calcaneus.
41
Describe the capsule of the subtalar joint
* Loose, fibrous capsule attaches to all joint margins
* Anterior part is adjacent to the sinus tarsi and is the thinnest.
* Lined with synovial membrane
* Capsular thickenings occur laterally, medially, and posteriorly:
* Lateral talocalcaneal ligament; Lateral process of talus to lateral calcaneus
* Medial talocalcaneal ligament; Medial tubercule (of the posterior process) of the talus to posterior sustentaculum tali
* Posterior talocalcaneal ligament; Lateral tubercule (of the posterior process) of the talus to upper, posterior calcaneus
42
Classify the subtalar joint
Synovial articulation between the inferior surface of the body of the talus and the superior surface of the calcaneus. Simple, planar, multi-axial
43
Describe the shape, extent and nature of the articulating surfaces
Plane synovial simple multi-axial joint between an oval articular facet on the superior surface on the under surface of the body of the talus. The facet on the calcaneus is a concavo-convex about its long axis, matching the reciprocally shaped facet on the talus.
All surfaces covered in hyaline cartilgae
44
What is the role of the interosseous talocalcanean ligament
Plays an essential role in maintaining the stability of the subtalar joint, both at rest and during activity.
45
Describe the position and fearures of the interosseous talocalcanean ligament
It occupies a central position between the subtalar and talocalcaneonavicular joints, lying directly below the long axis of the leg. It acts as a fulcrum around which movements of the leg and foot occur, it is continually being subjected to twisting and stretching strains.
2 thick bands attaching to the floor of the sinus tarsi: anterior runs obliquely superiorly, anteriorly and medially to the neck of the talus; posterior runs superiorly, posteriorly and laterally to the talus anterior to the joint.
It is very thick and strong stabilising ligament, being at least 2.5 cm. in breadth from side to side, and serves to bind the calcaneus and talus firmly together.
46
Identify the movements which occur at the subtalar joint and their limiting factors
Combined movements at the subtalar and midtarsal joints produce inversion/abduction and eversion/adduction. Because the talus participates in both joints, adduction at the subtalar joint is always accompanied by supination at the midtarsal joint and abduction is always accompined by pronation.
47
What is the role of the interosseous and cervical ligaments
Bind the talus with the calcaneus and limit all extreme motion of the subtalar joint but dominantly the inversion motion.
48
Give the locations and functions of the calcaneofibular ligament and the talocalcaneal ligament
The calcaneofibular ligament laterally and the talocalcaneal ligament medially of the ankle joint act as accessory ligaments for the subtalar joint and provide additional support. Movements of the subtalar joint often occur simultaneously with movements of the talocalcaneonavicular and calcaneocuboid joint (midtarsal joint).
49
Give the position of the Medial Talocalcaneal Ligament
From the medial posterior talar tubercle to the posterior border of the sustentaculum tali.
50
Give the position of the Posterior Talocalcaneal Ligament
From the lateral talar tubercle to the superomedial calcaneal surface.
51
Give the position of the Lateral Talocalcaneal Ligament
From the lateral talar tubercle to the lateral surface of calcaneus parallel and deep to the calcaneofibular ligament.
52
Give the position of the Ligamentum Cervicis
Attaches to the calcaneus and talus. It is lateral to the tarsal sinus and medial to the attachment of extensor digitorum brevis. It is taut in inversion. Strong, cord-like structure. Acts to limit inversion of the hindfoot
53
Describe the articulations of the midtarsal (transverse tarsal) joint
* Talocalcaneonavicular joint; and
* Calcaneocuboid joint.
54
Classify the calcaneocuboid joint
Articulating from the calcaneous to the cuboid.
Synovial, simple, plane, multi-axial
Lateral aspect of the midtarsal joint
Thickened dorsally forming the dorsal calcaneocuboid ligament
55
Classify the talocalcaneonavicular joint
Articulating from the talus to the calcaneus to the navicular
Synovial, compound, ball and socket, multi-axial
Medial aspect of the subtalar joint
56
Give the ligaments of the talocalcaneonavicular joint
Plantar Calcaneonavicular “Spring” Ligament
Bifurcate Ligament
Dorsal Talonavicular Ligament
57
Describe the plantar calcaneonavicular spring ligament
Anterior and medial sustentaculum tali to entire width of inferior navicular and tubercule
Smooth, superior surface contains a fibrocartilaginous plate for articulation with head of talus
Blends with and is supported by the deltoid ligament. It’s a thick wide band of cartilaginous connective tissue that supports the medial longitudinal arch of the foot, failure in the spring ligament leads to flat foot deformity. Resists inferior displacement of the talus
58
Describe the bicurfate ligament
A strong band, attached behind to the deep hollow on the upper surface of the calcaneus and dividing in front in a Y-shaped manner into a calcaneocuboid and a calcaneonavicular part. It is a structure that stabilizes the calcaneocuboid joint. The BL also stabilizes the talocalcaneonavicular and midtarsal joints, and therefore, has been described as the keystone of the transverse tarsal joint. Completes socket laterally. Attaches from upper, anterior calcaneus to adjacent lateral navicular (upper fibres)
59
Briefly describe the Dorsal Talonavicular Ligament
From the talar neck to the dorsal surface of navicular: reinforces joint capsule. Tense in inversion.
60
Give the 5 ligaments of the Calcaneocuboid joint
Long Plantar Ligament
Short Plantar Ligament
Bicurfate Ligament
Dorsal Calcaneocuboid Ligament
Calcaneocuboid Ligament
61
Describe the Long Plantar Ligament
Attached posteriorly between anterior and posterior calcaneal tubercles.
Fibres pass forwards:
* Deep fibres attach to the ridge of the cuboid
* Intermediate fibres attach beyond the groove of the cuboid – form a fibrous arch over peroneus longus
* Superficial fibres attach to the base of the lateral four metatarsals
This ligament converts the groove on the plantar surface of the cuboid into a canal for the tendon of the Peronæus longus.
Superficial to Short Plantar Ligament.
Posteriorly, it attaches between the medial and lateral processes of the calcaneal tuberosity
Supports the lateral, plantar aspect of the foot
62
Describe the Short Plantar Ligament
Cone-shaped, consisting of a deeper and superficial part. It connects the inferior calcaneus to the plantar aspect of the cuboid bone and runs slightly medial and deep to the long plantar ligament. Is a stabiliser of the calcaneocuboid joint, which forms the lateral part of the midtarsal (Chopart) joint. Blends with joint capsule inferiorly. Strong and short. Arises from a rounded eminence on the inferior calcaneus to attach to the inferior cuboid, posterior to the groove for peroneus longus
63
Describe the Bicurfate Ligament
Arises from same origin as calcaneonavicular part (upper, anterior calcaneus)
Attaches to the dorsomedial angle of the cuboid
64
Describe the Dorsal Calcaneocuboid Ligament
Thin yet broad capsular thickening
Passes between dorsal surfaces of calcaneus and cuboid
65
Identify the movements which occur at the Midtarsal Joint
Inversion/adduction/supination
Eversion/abduction/pronation
Complex, combined movements of three joints
Movements of the foot in a modified coronal/frontal plane
(remember, the ankle joint itself is uniaxial and so movement occurs only in a sagittal plane)
Enables:
Maximal foot contact with the floor over uneven surfaces/slopes
Changes of direction, supplementing the uni-axial ankle joint, particularly when moving at speed
66
Is it possible to move the TCNJ without moving the CCJ?
Although this “joint” is composed of two distinct joints they act functionally as one unit. It is not possible to produce movement at the TCNJ without producing movement at the CCJ, and vice versa. We therefore consider them as part of the same overall “joint”, particularly in terms of their movements
67
Describe 'inversion' of the foot
Where the sole of the foot is turned towards the midline – is a combination of adduction of the hindfoot, and supination of the mid/forefoot.
Navicular moves medially (abduction) and superiorly (supination) while the cuboid moves downwards.
Tension in dorsal talonavicular ligament, bicurfate ligament, ligamentum cervics
68
Describe 'eversion' of the foot
Where the sole of the foot is turned away from the midline – is a combination of abduction of the hindfoot, and pronation of the mid/forefoot.
Cuboid moves laterally (adduction) and superiorly (supination) while the navicular moves downwards
69
Where are the tarsometatarsal joints located?
The tarsometatarsal joints are where the midfoot and forefoot meet.
70
Where are the intermetatarsal joints located?
The intermetatarsal joints are interactions between the 5 different metatarsal bones of the foot.
71
Classify and give the role of the tarsometatarsal and intermetatarsal joints
Both synovial/plane joints
Supported by dorsal, plantar and interosseous
ligaments.
These joints are flexible and allow the foot to adapt to uneven surfaces.
72
Where are the Metatarsophalangeal joints located?
Between the metatarsals and phalanges
73
Where are the interphalangeal joints located?
Between the phalanges
74
Classify the Metatarsophalangeal and the interphalangeal joints
Metarsophalangeal are synovial/condyloid joints, Interphalangeal joints are synovial/ hinge joints.
They are both supported by medial & lateral collateral ligaments, and plantar ligaments.
75
Define 'intrinsic muscle'
An intrinsic muscle inserts in a certain anatomical area and originates in the same anatomical area. For example, Flexor Digitorum Brevis originates in the foot, and acts on the toes of the foot, and is therefore classed as an intrinsic muscle.
76
Define 'extrinsic muscle'
An extrinsic muscle inserts in a certain anatomical area, but originates elsewhere. For example, Flexor Digitorum Longus originates in the calf, but acts on the toes of the foot, and is therefore classed as an extrinsic muscle.
77
Give the 2 compartments of fascia
-Deep fascia
-Superficial fascia
78
Describe the 'intermuscular septa'
Elongations of the undersurface of the deep fascia which insert onto the tibia and divide the thigh muscles into 4 fascial sections known as compartments.
79
Give the 4 compartments of the extrinsic muscles of the foot
-Superficial Posterior Compartment
-Deep Posterior Compartment
-Lateral Compartment
-Anterior Compartment
80
Describe and give the muscles of the superficial posterior compartment, including their movement and nerve supply
These muscles are involved in plantarflexion of the ankle joint.
Typically supplied by the Tibial Nerve (S1-2).
* Gastrocnemius
* Soleus
* Plantaris
81
Describe and give the muscles of the deep posterior compartment, including their movement and nerve supply
These muscles are typically extrinsic muscles of the foot producing inversion of the foot, or flexion of the toes.
Typically supplied by the Tibial Nerve (S1-2).
* Popliteus
* Tibialis posterior
* Flexor hallucis longus
* Flexor digitorum longus
82
Describe and give the muscles of the lateral compartment, including their movement and nerve supply
These muscles are typically involved in eversion of the foot.
Typically supplied by the Superficial Peroneal Nerve
* Peroneus longus
* Peroneus brevis
83
Describe and give the muscles of the anterior compartment, including their movement and nerve supply
These muscles are typically involved in dorsiflexion of the ankle, or extension of the toes.
Typically supplied by the Deep Peroneal Nerve.
* Tibialis anterior
* Extensor hallucis longus
* Extensor digitorum longus
* Peroneus tertius
84
Fully classify the Gastrocnemius
* Position/Shape/Special features- Most superficial calf muscle
* Origin- Medial head- medial supracondylar ridge and adductor tubercle of femur; lateral head- outer surface lateral condyle of femur.
* Insertion- Via tendocalcaneus to posterior surface calcaneus
* Nerve supply and root value- Tibial nerve, S1, 2
* Action(s)- Plantarfelxes ankle and flexes knee (via attachment to femur)
* Function(s)- Powerful propelling muscle
85
Fully classify the soleus
* Position/Shape/Special features- Deep to gastrocnemius
* Origin- Soleal line posterior surface of tibia, posterior surface upper third fibula and fibrous arch between
* Insertion- Via tendocalcaneous with gastrocnemius into posterior surface
* Nerve supply and root value- Tibial nerve, S1, 2
* Action(s)- Plantarfelxes ankle
* Function(s)- Postural anti-gravity role, e.g. preventing the body swaying forwards whilst standing.
86
Fully classify the Popliteus
Popliteus:
* Shape/Position/Special Features Deeply posterior to knee joint, Short, triangular muscle. Tendon is intra-capsular but extra-synovial
* Origin Outer surface lateral condyle of femur
* Insertion Posterior surface of tibia above soleal line
* Nerve Supply and Root Value: Tibial nerve (L5)
* Action(s) Medially rotates tibia- inversion of foot, flexion of toes
* Function(s) Role depends on the position of the lower limb. Laterally rotates femur on tibia to unlock knee when foot is fixed, also pulls lateral meniscus backwards to prevent entrapment
87
Fully classify the tibialis posterior
* Position/Shape/Special features- Deepest muscle in the calf
* Origin- Upper part posterior surface of tibia (below soleal line), posterior surface of fibula and adjacent interosseous membrane.
* Insertion- Tubercle of navicular and medial cuneiform with expansions to all tarsal bones except talus.
* Nerve supply and root value- Tibial nerve L4, 5
* Action(s)- Inverts and plantarflexes foot
* Function(s)- Important role in maintaining balance and sustaining the arches of the foot
88
Fully classify the flexor hallucis longus
* Position/Shape/Special features- Strong muscle
* Origin- Unipennate muscle arising lower two-thirds posterior surface of fibular
* Insertion- Plantar surface base of distal phalanx
* Nerve supply and root value- Tibial nerve S1, 2
* Action(s)- Plantarflexes big toe and then ankle
* Function(s)- Produces the final thrust from the foot during the ‘push-off’ phase of walking. Helps to maintain the medial longitudinal arch.
89
Fully classify the Flexor Digitorum Longus
* Position/Shape/Special features- Lies deep to the soleus , pierces and passes through flexor digitorum brevis
* Origin- Medial part posterior surface of the tibia below soleal line
* Insertion- Tendon passes behind the medial malleolus and divides into 4 to insert into plantar surface base distal phalanx of the lateral 4 toes.
* Nerve supply and root value- Tibial nerve L5, S1, 2
* Action(s)- Plantarflexes the distal and proximal interphalangeal joints, metarsophalangeal and ankle joints
* Function(s)- Flexion of digits 2-5 in the foot/curling of toes
90
Fully classify the Tibialis Anterior
* Position/Shape/Special features- Tibialis anterior is a fusiform muscle whose tendon runs below the superior and inferior extensor retinacula, enclosed in its own sheath
* Origin- Upper two-thirds lateral surface of tibia and adjacent interosseous membrane.
* Insertion- Medial side of medial cuneiform and base 1st metatarsal
* Nerve supply and root value- Deep peroneal nerve L4, 5
* Action(s)- Dorsiflexes and inverts the foot
* Function(s)- Acts as a stabiliser, balancing the body and maintaining the medial longitudinal arch of the foot. During the swing phase of gait it acts to prevent the toes catching the ground and on heel strike lowers the foot eccentrically to the floor. If paralysed the characteristic ‘foot drop’ gait results. One of four ‘anterior tibial muscles’ contained in a osseofascial compartment. Swelling or hypotrophy in this limited space through overuse is common cause of ‘compartment syndrome.
91
Fully classify the Extensor Hallucis Longus
* Position/Shape/Special features- Tendon passes under superior and inferior extensor retinacula in own synovial sheath
* Origin- Middle half anterior surface fibula and adjacent interosseous membrane
* Insertion- Base dorsal surface distal phalanx of hallux
* Nerve supply and root value- Deep peroneal nerve L5, S1
* Action(s)- Dorsiflexes joints of hallux and then ankle
* Function(s)- Assists tibialis anterior in holding the foot up during swing phase of gait and lowering it (eccentrically) on heel strike
92
Fully classify the Extensor Digitorum Longus
* Position/Shape/Special features- The single tendon passes below the superior and inferior retinacula in a synovial sheath and divides into 4. Lumbrical muscles join the extensor hood on its medial side.
* Origin- Upper two-thirds anterior surface fibula, interosseous membrane and lateral tibial condyle
* Insertion- Forms extensor hood which attaches to distal and middle phalanx of lateral 4 toes on their dorsal surface- the same arrangement as in the hand
* Nerve supply and root value- Deep peroneal nerve L5, S1
* Action(s)- Dorsiflexes interphalangeal, metatarsophalangeal joints of toes and ankle joints
* Function(s)- Assists tibialis anterior in holding the foot up during swing phase of gait and lowering it (eccentrically) on heel strike
93
Fully classify the Peroneus Longus
* Position/Shape/Special features- Enclosed in synovial sheaths and pass in a groove behind the lateral malleolus with brevis being next to the bone. They’re held in position here by the superior peroneal retinaculum before crossing the calcaneus where it passes below the peroneal tubercle. It then turns medially to cross the foot, grooving the cuboid.
* Origin- Upper two-thirds lateral surface and head of the fibula
* Insertion- Plantar surface medial cuneiform and adjacent base 1st metatarsal
* Nerve supply and root value- Superficial peroneal nerve L5, S1
* Action(s)- Everts and plantarflexes foot
* Function(s)- Maintains balance by preventing sideways sway. Works with tibialis anterior in supporting the medial side of the foot during powerful activities such as running.
94
Fully classify the Peroneus Brevis
Position/Shape/Special features- Enclosed in synovial sheaths and pass in a groove behind the lateral malleolus with brevis being next to the bone. They’re held in position here by the superior peroneal retinaculum before crossing the calcaneus where it passes above the peroneal tubercle.
* Origin- Lower two-thrids lateral surface fibula
* Insertion- Tubercle on lateral base 5th metatarsal
* Nerve supply and root value- Superficial peroneal nerve L5, S1
* Action(s)- Everts and plantarflexes foot
* Function(s)- Maintains balance by preventing sideways sway. Supports the lateral ligament of the ankle, preventing overinversion.
95
What is retinaculae?
Deep fascia is thickened by transversely orientated bands forming retinacula.
96
Give the role of retinaculum of the ankle
These serve to hold the tendons passing across the ankle joint in position and prevent “bowstringing”. In the event of a ruptured or absent retinaculum, muscle contraction transfers to the tendon, which takes the path of least resistance. Due to the nature of the foot being at a right ankle to the rest of the lower leg, muscles are required to “turn a corner” as they move from the leg into the foot. If a muscle contracted without the presence of a retinaculum, all that would happen is the tendon would move away from the bone and no movement would be produced at the distal part. The function of the muscle in producing movement of the skeleton is therefore impaired. This would look like the string of a bow (with the bones representing the wood of the bow).
97
Which retinaculae is most protected?
The most well developed of these retinaculae is the extensor retinaculum.
98
How is the retinaculae protected?
As tendons pass beneath retinaculae they are protected from friction by enclosure in synovial sheaths.
99
Where is retinaculae located in the body/
Retinaculae are typically found in areas of the body where tendons are required to change direction as they produce force (e.g. ankle, wrist, fingers)
100
List the 4 principle retinaculae of the ankle
* Flexor
* Superior Extensor
* Inferior Extensor
* Peroneal
101
Describe the location of the deep fascia of the foot
On the plantar aspect of the foot there is a thickening of the deep fascia called the plantar aponeurosis (better known as the plantar fascia). The deep fascia covering the dorsum of the foot is much less specialized and well developed. It is known as the fascia dorsalis pedis and is a thin layer continuous with the inferior extensor teinaculum above. It covers only one muscular structure – the intrinsic muscle Extensor Digitorum Brevis.
102
Give the role of the deep fascia of the foot
Support the arches of the foot,
Allows for an increased surface area for muscle attachment,
Absorbs load,
Stores energy
Recoils in gait
Provides protection to the structures in the sole of the foot.
103
Describe 'static stability' provided by arches of the foot
Static stability afforded to the arches of the foot occurs through intrinsic factors such as the shape of bones and fibrous structures such as the plantar fascia/spring ligament
104
Describe 'dynamic stability' provided by arches of the foot
Dynamic stability is the other key element of arch integrity – muscle tissue provides contractile support to the bones and soft tissue of the foot
105
Which muscles contribute to dynamic stability in the medial longitudinal arch?
* Flexor Hallucis Longus
* Tibialis Anterior
* Intrinsic foot musculature
* Tibialis Posterior
106
Which muscles contribute to dynamic stability in the lateral longitudinal arch?
* Peroneus Longus
* Flexor Digitorum Longus
* Intrinsic foot musculature
107
Which muscles contribute to dynamic stability in the transverse arch?
* Tibialis Posterior
* Peroneus Longus
Other intrinsic musculature such as Adductor Hallucis have important effects on the forefoot transverse arch
108
Give the intrinsic muscle in the dorsal aspect of the foot
Extensor digitorum brevis
Calcaneus to phalanges
Deep peronal nerve (L5-S1)
109
Give the intrinsic muscles in the 1st layer of the plantar aspect of the foot
-Abductor Hallucis (calcaneus to big toe)
-Flexor digitorium brevis (calcaneus to lat 4 toes)
-Abductor digiti minimi (calcaneus to little toe)
All supplied by the medial plantar nerve (S1-2)
110
Give the intrinsic muscles in the 2nd layer of the plantar aspect of the foot
-Lumbricals (med and lat plantar nerve S1-3)
-Flexor Accessorius (lat plantar nerve (S2-3)
111
Give the role of the Lumbricals
* Lumbricals are situated inferior to the joint axis of the MTPJ but superior to the joint axes of the IPJ
* They therefore act on contraction to flex the MTPJ and extend the IPJ
* They help to correct the tendency of FDL to “claw” the toes through flexion of the IPJ before flexion of the MTPJ
112
Which tendons are located in the 2nd layer of the plantar aspect?
* Flexor Digitorum Longus
* Flexor Hallucis Longus
113
Give the intrinsic muscles in the 3rd layer of the plantar aspect of the foot
-Flexor Hallucis Brevis (med plantar nerve S1-2)
-Flexor Digiti Minimi Brevis (lat plantar nerve S2-3)
-Hallucis Brevis (lat plantar nerve S2-3)
114
Give the intrinsic muscles in the 4th layer of the plantar aspect of the foot
-Dorsal interossei
-Plantar interossei
(lat plantar nerve S2-3)
115
What are the 2 main functions of the foot
* At rest, the foot needs to provide a firm base of support for the weight of the body.
* During activity, the foot needs to provide a lever to propel the body along.
116
Describe the windlass mechanism
One of the methods by which human beings enhance their efficiency during locomotion is by storing and releasing energy gained during the movement process.
The Windlass Mechanism is one such method. During movement of the foot, the head of the 1st metatarsal in particular acts as a pulley, around which the plantar fascia and tendon of Flexor Hallucis Longus are pulled. During the toe-off phase of gait, the great toe is extended at the MTPJ, and the tendon of FHL and plantar fascia are pulled taut. This has the impact of storing energy in these structures, and also increase the height of the longitudinal arches, creating stability within them and bearing load – protecting the structures of the foot (particularly in the medial longitudinal arch). This provides a stable surface for propulsion. At terminal stance phase, this stored energy is released, aiding in propulsion of the foot into swing phase at no extra energy cost to the human being.
