structure and function of the foot Flashcards
What is the Hallux and in regards to anatomical aspect how would you describe its position
The Hallux is the big toe and it would be described as being positioned on the medial aspect of the foot as it is toward the mid line of the body/ on the inside of the foot
The Hallux is the only toe which consists of 2 phalanges every other toe has three.
Describe the ankle joint/Talocrural in detail
The TRUE Ankle Joint also known as the Talocrural Joint and is a Synovial Joint located in the lower limb. It is made up of the:
Tibia (MEDIAL/ Load Bearing)
Fibula (Lateral)
Talus (Articulates with Tibia/Fibula to form Hinge Joint)
The Ankle joint is often described as Tenon and Mortise Joint (Tibia, Fibula form a squared of notch shape in which the body of the Talus fits acting as the Tenon.
Describe the movement of the ankle joint
The ankle is a Hinge joint which allows triplanar movement across simultaneous planes of movement (Predominantly in the Sagital Plane Up and Down)
The main movement that occur at the ankle joint are Plantar Flexion and Dorsiflexion although the joint also allows for inversion and eversion.
Plantar Flexion also referred to as extension of the ankle is when the plantar surface of the foot is pushed further away from the shin (POINTING OF THE TOES)
Dorsi Flexion is when the Dorsal (Superior/on top/above/top of) surface of the foot is drawn closer to the shin.
Inversion is when the sole of the foot is tilted inwards toward the midline of the body
Eversion is when the sole of the foot is tilted outwards away from the midline of the body
Name the bones of the foot from a Medial aspect
Fibula (Medial)
Tibia (Lateral)
Talus (articulates with fibula/Tibia)
Navicular (In front of the talus on the medial side)
Cuboid (Next to the Navicular on the lateral side)
Cuneiforms (3 bones in front of the navicular)
Metatarsals (5 bones labelled 1 through to 5 starting with the hallux)
Phalanges (14 bones that make up the toes, Hallux has 2 every other toe has 3 Phalanges)
Calcaneus (Largest bone of the foot situated beneath the Talus/Heel Bone)
Describe the Subtalar Joint in detail
Clue JC SM AND FL
The Subtalar Joint is an articulation between the Talus (Superior sits above) and the Calcaneus (Inferior sits below)
The subtalar joint allows for subtalar inversion and eversion and is enclosed by a joint capsule lined by synovial membrane and strengthened by a fiborous layer.
Detail the ligaments on the Medial aspect which stabilize the subtalar joint
Ligaments on the Medial aspect of the subtalar joint are known as the MCL Ligaments or the Deltoid ligaments (Deltoid because of their triangle shape)
Deltoid ligamnets consist of:
- Posterior Tibiotalar Ligament (The back of the Tibia connecting to the Talas)
- Tibiocalcaneal Ligament (The Tibia connecting to the Calcaneous)
- Tibionavicular Ligament (The Tibia connecting to the Navicular)
- Anterior Tibitalar Ligament ( The front of the Tibia connecting to the Talas)
All these ligaments form a triangle type shape on diagram
These ligaments protect against eversion (movement away from the mid line of the body) and give about a 10% range of motion. They are stronger than the anterior ligaments.
Detail the ligaments on the Lateral aspect which stabilize the Subtalar Joint
Clue they all end in Fibular
Ligaments on the Lateral aspect of the subtalar joint are known as the LCL ligaments
Posterior/Anterior TaloFibular
Calcaneofibular
Lateral Ligaments consist of:
- Posterior Talofibular ligament (The back of the Fibula connecting to the Talas)
- Calcaneofibular Ligament (Fibula connecting to the Calcaneus)
- Anterior Talofibular ligament (Back of the Fibula connecting to the Talas
These ligaments protect against Inversion, movement of the plantar surface toward the mid line of the body. These ligaments give around a 20% range of motion limited by the weaker LCL ligaments.
Describe the various functions of the foot
There are 4
- Supporting body weight
- Providing Balance
- Shock Absorption
- Transferring ground reaction forces
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Describe the Hindfoot
- Most Posterior aspect of the foot (Back part)
- Consists of two of the seven tarsal bones these being the Talus and Calcaneus
- The articulation between the Talus and Calcaneus is referred to as the Subtalar joint
Describe the Mid Foot
Clue Junction mid/hind and what joints it consists of
- The Mid Foot consists of 5 of the 7 Tarsal bones, the Navicular, Cuboid and all 3 Cuneiform’s (Medial, Middle, Lateral)
- The junction between the hind and mid foot is termed the Chopart’s joint, which includes the Talonavicular and Calcaneocuboid joints.
Describe the Forefoot
- Most anterior aspect of the foot (Front of the foot)
- Consists of Metatarsals, Phalanges and Sesamoid bones
- 1 Metatarsal and 3 Phalanges for each toe except the Hallux which only has 2 Phalanges
- The articulation between the Forefoot and the Mid foot is known as the Lisfranc joint
Describe the Miditarsal Joint
Don’t forget to mention the articulations between the bones and how the joint is formed
- It consists of two joints, these being the Talonavicular and the Calcaneocuboid joint
- Talonavicular Joint is formed between the anterior head of the talus and the concavity of the Navicular It share a joint capsule with the two Talocalcaneal articulations
- Calcaneocuboid joint is formed between the anterior facet of the Calcaneous and the posterier of the Cuboid
- Very little movement occurs at this joint
Which bones form part of the Medial Longitudinal arch of the foot
Calcneus
Talus
Navicular
All 3 Cuneiforms
1,2,3 Metatarsals
Describe the arch of the foot
The arches of the foot are formed by the Tarsal and Metatarsal bones.
The Tarsal and Metatarsal bones form two longitudinal arches (Medial + Lateral) as well as a Single Transverse arch
Which bones of the foot form the Lateral Longitudinal Arch
The Lateral Longitudunal arch (much flatter than the medial) is formed by:
Calcaneus
Cuboid
Fourth and Fifth Metatarsals
Describe the charecteristics of a Planus Foot
OP VAL H and VAR F
Planus feet are low arched and associated with over pronation (Flat foot) They tend to have a Valgus Hindfoot (turned away from the midline of the body) and or Varus Forefoot (turned inwards toward midline) and are considered a risk factor in the development of overuse injuries
Low Arch
Over Pronation
Valgus Hindfoot (turned away from midline of the body)
Describe the charecteristics of a Cavus Foot
What does it doe to the forefoot
Cavus feet are high arched and associated with hammer toes and claw toe deformities. The high arch causes more pressure to be put on the forefoot on through the metatarsals
Describe the characteristics of Rectus foot
Rectus feet are considered to well aligned hindfoot and forefoot with a moderate foot arch
What is Pronation
Pronation of the foot refers to weight distribution and what part of the foot your weight is distributed as you walk
Pronation - Weight tends to be on the inside of the foot so the foot rotates outward like eversion
What is Supanation
Supanation regarding the foot referes to weight ditribution and what area of the foot the weight is distibuted through
Supination - Weight tends to be distributed tot he outside of the foot causing the foot to rotate inwards (like inversion)
What is Passive Arch support
Passive arch support refers to the support provided for the foot by way of the ligaments in the foot
What are the main ligaments that support the plantar aspect of the foot
ITC, SPRING = PCN and Deltoid = MCL
- Deep Plantar Calcaneocuboid ligament/SHORT LIGAMENT - Runs from anterior tubercle(boney projection) of the calcaneus to the plantar surface of the cuboid. Supports calcaneocuboid part of miditarsal
- Superficial plantar calcaneocuboid ligament/LONG PLANTAR LIGAMENT - Runs from the plantar surface of the calcanues to the plantar surface of the cuboid anterior to the groove for the tendon of the peroneus longus and to the base of 2nd and 5th metatarsal. Suppurts the calcaneocuboid part of the miditarsal joint and the lateral four tarsometatarasl joints
- Platar Calcaneonavicular ligament /SPRING LIGAMENT - runs from the anterior inferior aspect of the sustentaculum tali (of the calcaneus) to the plantar surface of the navicular. It supports the medial part of the subtalar joint and the talonavicular part of the miditarsal.
- Deltoid Ligament/ MEDIAL COLLATERAL LIGAMENT - Fans out and runs from the melleolus to attach onto the navicular, spring ligament, sutenaculum tali and the talus. It supports the medial aspect of the subtalar joint.
- Interosseous talocalcnean ligament - forms main bond between the Talus and the Calcaneous (Subtalar Joint)
- Plantar Aponeurosis broad fan shaped ligament that spans the whole of the Tarus and Metatarsus from the posterior tubrecles of the calcaneus to the bases of the proximal (first) phalanges. It runs anteriorly to the plantar plates and from there attaching to the phalanx of each individual toe
Define Proximal
Situated nearer to the center of the body or point of attachment
What are the functions of the Plantar Aponeurosis
Maintain something? what does it help maintain There are 5 main functions
- Protecting the deep structures of the foot, such as nerves and vessels
- Maintain the longitudinal arches
- For muscular attachment
- Prevent excessive dorsiflexion
- Distribute plantar pressure during static and dynamic loading
Which is the more prominent arch of the foot
Medial Arch is more prominent
Where is the posterior anchoring/attachment point for the longitudinal Lateral arches of the foot
The longitudinal arches of the foot both medial and lateral attach posteriorly at the calcaneus
Where is the attachment point for the longitudinal arches anteriorly on the medial side
The longitudinal arches on the medial aspect anteriorly attach to the 1st 2nd and 3rd metatarsal heads
Where is the attachment point for the longitudinal arches on the lateral aspect anteriorly
Anteriorly on the lateral side the longitudinal arches attach to the 4th and 5th metatarsal heads
What is the keystone of the longitudinal arch and what is the the keystone of the transverse arch
The keystone of the longitudinal arch is the talus and the keystone of the transverse arch is the medial cunieform bone
What is the Tie on truss mechanism explain how it works
Explain the articulation points of the PA
M T of the calcaneus attatching at PP and Bases of P P
- The tie rod on truss mechanism refers to the foot and its triangle arch like shape.
- This shape is formed by the bones and ligaments of the foot.
- The bones of the foot form two struts (Posterior struts formed by Calcaneus and Talus and Anterior struts formed by the Navicular, cuboid, cuneiform and Metatarsals)
- Planter Fascia/Plantar Aponeurosis forms the Tie rod and articulates with the medial tubrcle of the calcaneus running along the plantar foot attatching to the plantar plates and the bases of the proximal phalanges of each toe.
- Strutts resist the compressive loads put upon them during weight bearing
- Tie Rod (Plantar Aponeurosis) balances the tension force or tensile load
What are the advantages of the tie rod on truss mechanism
- Reduces the bending moment of the bone
- Reduces the Load/tension on the ligaments specifically the Spring Ligament on the Medial side of the arch and the Long and Short Plantar ligament seen on the lateral arch
- Reduces the compression forces on the metatarsal heads through the Plantar plates (Plantar plates are comprised of Fibrocartlige which is especially tough against compressive loads) as well as regulating MTP extension
What is the windlass mechanism
Think of it as drawing the two landmarks closer together, mtp joint and the calcaneus what does this do to the arch
The Windlass mechanism refers to the extension of the MTP joint which winds the plantar aporneurosis around the metatarsal heads which inturn raises the longitudinal arch of the foot.
What is the reverse Windlass mechanism
Reverse windlass is the opposite of the windlass mechanism and refers to Flexion of the MTP joints. As the MTP joint is flexed the plantar aponuerosis unwinds from around the metartarsal heads in turn lowering the longitudinal arch.
What is active arch support
Active arch support refers to the arch supported provided by the muscles of the lower leg and foot
What is adduction
Adduction is the movement of limbs closer to the midline of the body
What is abduction
Abduction refers to the movement of limbs away from the mid line of the body
What are extrinsic muscles of the foot
The extrinsic muscle of the foot are muscles which have their origins in the lower leg and insertions in the foot (i.e. cross the ankle joint)
What are the intrinsic muscles of the foot
The Intrinsic muscles of the foot are muscles which are located entirely within the foot (have the origins and insertions within the foot)
If the muscles of the foot have a tendency to plantar flex the Intertarsal Joints, Tarsometatarsal joints or MTP Joints what will happen to the foot arch
Plantar flexion of any of these joints will tend to raise the arches of the foot and reduce the strain on the plantar ligaments
If the muscles of the foot have a tendency to Dorsi flex the Intertarsal Joints, Tarsometatarsal joints or MTP Joints what will happen to the foot arch
Dorsi flexion of any of these joints will tend to flatten the foot arches and increase the strain on the foot ligaments
Name the muscles of the foot Layer 1
TIP, of the 3 muscles in layer 1 Two of them are called ABDUCTOR
Layer 1:
Abductor Hallucis
Flexor digiturum brevis
Abductor digiti quinti (minimi)
Name the muscles of the foot Layer 2
Tip, layer 2 has two Flexor tendons and the QUADRATUS PLANTAE + LUMBRICALS
Layer 2:
Flexor Digitorum Longus Tendon
Flexor Hallucis Longus Tendon
Quadratus Plantae
Lumbricals (4)
Name the muscles of the foot Layer 3
Tip, layer 3 has two FLEXORS AND TWO ADDUCTORS
Tip, layer 3 has two FLEXORS AND TWO ADDUCTORS
Flexor Hallucis Brevis
Flexor digiti quinti
Adductor Hallucis (Oblique head)
Adductor Hallucis (Transverse head)
Name the muscles of the foot layer 4
Plantar Interossei
Dorsal Interossei
What is the trick to learning the nerves which innervate each plantar muscles
Four muscles are innervated by the Medial plantar nerve all the other muscles of the foot are innervated by the lateral Plantar nerve
Abductor Hallucis
Flexor Digitorum Brevis
Flexor Hallucis Brevis
Medial Lumbrical (other lumbricals innervated by lateral nerve)
TIP: All of these muscles are located closest to the Great toe/ Hallux as are the medial plantar nerves
Which two muscles of the foot are not innervated by branches of the tibial nerve
Extensor Digitorum Brevis
The first 2 dorsal Interossei muscles
These two muscles are innervated by the deep fibular nerve
Name the only dorsal foot muscle
Extensor digitorum brevis
Extends the MTP Joint
It splits into four tendons the first inserting at the base of the proximal phalynx (Hallux) the other 3 tendons insert Laterally on the extensor digitorum Longus muscle
