MSK Session 7 - Foot and Ankle Flashcards
Desctibe the structure of the ankle joint.
- The ankle joint (or talocrural joint) is a synovial joint located in the lower limb.
- It is formed by the bones of the leg and the foot – the tibia, fibula and talus.
- Functionally, it is a hinge type joint, permitting dorsiflexion and plantarflexion of the foot.
Outline the articulating surfaces of the ankle joint.
- The ankle joint is formed by three bones; the tibia and fibula of the leg, and the talus of the foot.
- The tibia and fibula are bound together by strong tibiofibular ligaments, producing a bracket shaped socket, which is covered in hyaline cartilage. This socket is known as a mortise.
- The body of the talus fits snugly into the mortise formed by the bones of the leg. The articulating part of the talus is wedge shaped. It is wider anteriorly, and thinner posteriorly.
Describe the medial ligament of the malleolus.
- There are two sets of ligaments, which originate from each malleolus.
- The medial ligament (or deltoid ligament) is attached to the medial malleolus.
- It consists of four separate ligaments, which fan out from the malleolus, attaching to the talus, calcaneus and navicular bones.
- The primary action of the medial ligament is to resist over-eversion of the foot.
Describe the lateral ligament of the malleolus.
The lateral ligament originates from the lateral malleolus. It resists over-inversion of the foot. It is comprised of three distinct and separate ligaments:
- Anterior talofibular: Spans between the lateral malleolus and lateral aspect of the talus.
- Posterior talofibular: Spans between the lateral malleolus and the posterior aspect of the talus.
- Calcaneofibular: Spans between the lateral malleolus and the calcaneus.
Describe the movements and the muscles involved in the ankle joint.
- The ankle joint is a hinge type joint, with movement only possible in one plane.
- Thus, plantarflexion and dorsiflexion are the only movements that occur at the ankle joint.
- Eversion and inversion are produced at the other joints of the foot, such as the subtalar joint.
I. Plantarflexion – Produced by the muscles in the posterior compartment of the leg; gastrocnemius, soleus, plantaris and posterior tibialis.
II. Dorsiflexion – Produced by the muscles in the anterior compartment of the leg; tibialis anterior, extensor hallucis longus and extensor digitorum longus.
Describe the neurovascular supply of the ankle.
- The arterial supply is derived from the malleolar branches of the anterior tibial, posterior tibial and fibular arteries.
- Innervation is provided by tibial and deep fibular nerves.
What is the subtalar joint?
- The subtalar joint is an articulation between two of the tarsal bones in the foot – the talus and calcaneus.
- The joint is classed structurally as a synovial joint, and functionally as a plane synovial joint.
Describe the articulating surfaces of the subtalar joint.
- The subtalar joint is formed between two of the tarsal bones:
I. Inferior surface of the body of the talus – the posterior talar articular surface.
I. Superior surface of the calcaneus – the posterior calcaneal articular facet.
- As is typical for a synovial joint, these surfaces are covered by articular cartilage.
Outline the stability of the subtalar joint.
- The subtalar joint is enclosed by a joint capsule, which is lined internally by synovial membrane and strengthened externally by a fibrous layer.
- The capsule is also supported by three ligaments:
I. Posterior talocalcaneal ligament
II. Medial talocalcaneal ligament
III. Lateral talocalcaneal ligament
- An additional ligament – the interosseous talocalcaneal ligament – acts to bind the talus and calcaneus together.
- It lies within the sinus tarsi (a small cavity between the talus and calcaneus), and is particularly strong; providing the majority of the ligamentous stability to the joint.
Describe the movements of the ankle joints.
- The subtalar joint is formed on an oblique axis and is therefore the chief site within the foot for generation of eversion and inversion movements.
- This movement is produced by the muscles of the lateral compartment of the leg. and tibialis anterior muscle respectively.
- The nature of the articulating surface means that the subtalar joint has no role in plantar or dorsiflexion of the foot.
Describe the neurovascular supply of the subtalar joint.
- The subtalar joint receives supply from two arteries and two nerves. Arterial supply comes from the posterior tibial and fibular arteries.
- Innervation to the plantar aspect of the joint is supplied by the medial or lateral plantar nerve, whereas the dorsal aspect of the joint is supplied by the deep fibular nerve.
Describe the structure, role and components of the muscles in the anterior compartment of the leg.
- There are four muscles in the anterior compartment of the leg; tibialis anterior, extensor digitorum longus, extensor hallucis longus and fibularis tertius.
- Collectively, they act to dorsiflex and invert the foot at the ankle joint. The extensor digitorum longus and extensor hallucis longus also extend the toes. The muscles in this compartment are innervated by the deep fibular nerve (L4-L5), and blood is supplied via the anterior tibial artery.
Describe the structure, attachments, actions and innervation of the tibialis anterior.
- Structure: The tibialis anterior muscle is located alongside the lateral surface of the tibia. It is the strongest dorsiflexor of the foot.
- To test the power of the tibialis anterior, the patient can be asked to stand on their heels.
- Attachments: Originates from the lateral surface of the tibia, attaches to the medial cuneiform and the base of metatarsal I.
- Actions: Dorsiflexion and inversion of the foot.
- Innervation: Deep fibular nerve.
Outline the structure, attachments, actions and innervation of the extensor digitorum longus.
- Structure: The extensor digitorum longus lies lateral and deep to the tibialis anterior. The tendons of the EDL can be palpated on the dorsal surface of the foot.
- Attachments: Originates from the lateral condyle of the tibia and the medial surface of the fibula. The fibres converge into a tendon, which travels to the dorsal surface of the foot. The tendon splits into four, each inserting onto a toe.
- Actions: Extension of the lateral four toes, and dorsiflexion of the foot.
- Innervation: Deep fibular nerve
Outline the structure, attachments, actions and innervation of the extensor hallucis longus.
- Structure: The extensor hallucis longus is located deep to the EDL and TA.
- Attachments: Originates from the medial surface of the fibular shaft. The tendon crosses anterior to the ankle joint and attaches to the base of the distal phalanx of the great toe.
- Action: Extension of the great toe and dorsiflexion of the foot.
- Innervation: Deep fibular nerve.
Outline the structure, attachments, actions and innervation of the fibularis tertius.
- Structure: The fibularis tertius muscles arises from the most inferior part of the EDL. It is not present in all individuals, and is considered by some texts as a part of the extensor digitorum longus.
- Attachments: Originates with the extensor digitorum longus from the medial surface of the fibula. The tendon descends with the EDL, until they reach the dorsal surface of the foot. The fibularis tertius tendon then diverges and attaches to metatarsal V.
- Actions: Eversion and dorsiflexion of the foot.
- Innervation: Deep fibular nerve.
Describe the structure, function and components of the muscles in the lateral compartment of the leg.
- There are two muscles in the lateral compartment of the leg; the fibularis longus and brevis (also known as peroneal longus and brevis).
- The common function of the muscles is eversion – turning the sole of the foot outwards. They are both innervated by the superficial fibular nerve.
Describe the structure, attachments, actions and innervation of fibularis longus.
- Structure: The fibularis longus is the larger and more superficial muscle within the compartment.
- Attachments
I. The fibularis longus originates from the superior and lateral surface of the fibula and the lateral tibial condyle.
II. The fibres converge into a tendon, which descends into the foot, posterior to the lateral malleolus.
II. The tendon crosses under the foot, and attaches to the bones on the medial side, namely the medial cuneiform and base of metatarsal I.
- Actions: Eversion and plantarflexion of the foot. Also, supports the lateral and transverse arches of the foot.
- Innervation: Superficial fibular (peroneal) nerve, L4-S1
Describe the structure, attachments, actions and innervation of the fibularis brevis.
- Structure: The fibularis brevis muscles is deeper and shorter than the fibularis longus.
- Attachments:
I. Originates from the inferolateral surface of the fibular shaft. The muscle belly forms a tendon, which descen ds with the fibularis longus into the foot.
II. It travels posteriorly to the lateral malleolus, passing over the calcaneus and the cuboidal bones.
III. The tendon then attaches to a tubercle on metatarsal V.
- Actions: Eversion of the foot.
- Innervation: Superficial fibular (peroneal) nerve, L4-S1
Describe the structure, function and components of the muscles in the posterior compartment of the leg.
- The posterior compartment of the leg contains seven muscles, organised into two layers – superficial and deep. The two layers are separated by a band of fascia.
- The posterior leg is the largest of the three compartments. Collectively, the muscles in this area plantarflex and invert the foot. They are innervated by the tibial nerve, a terminal branch of the sciatic nerve.
Outline the structure and function of the superficial muscles of the leg.
- The superficial muscles form the characteristic ‘calf’ shape of the posterior leg. They all insert into the calcaneus of the foot (the heel bone), via the calcaneal tendon. The calcaneal reflex tests spinal roots S1-S2.
- To minimise friction during movement, there are two bursae (fluid filled sacs) associated with the calcaneal tendon:
I. Subcutaneous calcaneal bursa – lies between the skin and the calcaneal tendon.
II. Deep bursa of the calcaneal tendon – lies between the tendon and the calcaneus.
Outline the structure, attachments, actions and innervation of the gastrocnemius muscle.
- Structure: The gastrocnemius is the most superficial of all the muscles in the posterior leg. It has two heads – medial and lateral, which converge to form a single muscle belly.
- Attachments: The lateral head originates from the lateral femoral condyle, and medial from the medial condyle. The fibres converge, and form a single muscle belly. In the lower part of the leg, the muscle belly combines with the soleus to from the calcaneal tendon, with inserts onto the calcaneus (the heel bone).
- Actions: It plantarflexes at the ankle joint, and because it crosses the knee, it is a flexor there.
- Innervation: Tibial nerve.
Outline the structure, attachments, actions and innervation of the plantaris muscle.
- Structure: The plantaris is a small muscle with a long tendon, which can be mistaken for a nerve as it descends down the leg. It is absent in 10% of people.
- Attachments: Originates from the lateral supracondylar line of the femur. The muscle descends medially, condensing into a tendon that runs down the leg, between the gastrocnemius and soleus. The tendon blends with the calcaneal tendon.
- Actions: It plantarflexes at the ankle joint, and because it crosses the knee, it is a flexor there. It is not a vital muscle for these movements.
- Innervation: Tibial nerve.
Outline the structure, attachments, actions and innervation of the soleus muscle.
- Structure:The soleus is located deep to the gastrocnemius. It is large and flat, named soleus due to its resemblance of a sole – a flat fish.
- Attachments: Originates from the soleal line of the tibia and proximal fibular area. The muscle narrows in the lower part of the leg, and joins the calcaneal tendon.
- Actions: Plantarflexes the foot at the ankle joint.
- Innervation: Tibial Nerve.
Describe the deep muscles of posterior compartment of the leg.
- There are four muscles in the deep compartment of the posterior leg.
- One muscle, the popliteus, acts only on the knee joint.
- The remaining three muscles (tibialis posterior, flexor hallucis longus and flexor digitorum longus) act on the ankle and foot.
Outline the structure, attachments, actions and innervation of the popliteus muscle.
- Structure: The popliteus is located superiorly in the leg. It lies behind the knee joint, forming the base of the popliteal fossa. There is a bursa (fluid filled sac) that lies between the popliteal tendon and the posterior surface of the knee joint. It is called the popliteus bursa.
- Attachments: Originates from the posterior surface of the proximal tibia. The fibres pass upwards and laterally, attaching to the lateral condyle of the femur and the lateral meniscus of the knee joint.
- Actions: Laterally rotates the femur on the tibia – ‘unlocking’ the knee joint so that flexion can occur.
- Innervation: Tibial nerve.
Outline the structure, attachments, actions and innervation of tibialis posterior muscle.
- Structure: The tibialis posterior is the deepest out of the four muscles. It lies between the flexor digitorum longus and the flexor hallucis longus.
- Attachments: Originates from the interosseous membrane between the tibia and fibula, and posterior surfaces of the two bones. The tendon enters the foot posterior to the medial malleolus, and attaches to the plantar surfaces of the medial tarsal bones.
- Actions: Inverts and plantarflexes the foot, maintains the medial arch of the foot.
- Innervation: Tibial nerve.
Outline the structure, attachments, actions and innervation of flexor digitorum longus.
- Struscture: the FDL is (surprisingly) a smaller muscle than the flexor hallucis longus. It is located medially in the posterior leg.
- Attachments: Originates from the medial surface of the tibia, attaches to the plantar surfaces of the lateral four digits.
- Actions: Flexes the lateral four toes.
- Innervation: Tibial nerve.
Outline the structure, attachments, actions and innervation of flexor hallucis longus.
- Structure: the flexor hallucis longus muscle is found on the lateral side of leg. This is slightly counter-intuitive, as it is opposite the great toe, which it acts on.
- Attachments: Originates from the posterior surface of the fibula, attaches to the plantar surface of the phalanx of the great toe.
- Actions: Flexes the great toe.
- Innervation: Tibial nerve.
Describe the anatomical course of the common fibular (peroneal) nerve.
- The nerve begins at the apex of the popliteal fossa, where the sciatic nerve bifurcates into the tibial and common fibular nerves.
- The common fibular nerve follows the medial border of the biceps femoris, running in a lateral and inferior direction, over the lateral head of the gastrocnemius. At this point, the nerve gives rise to two cutaneous branches, which contribute to the innervation of the skin of the leg.
- To enter the lateral compartment of the leg, the nerve wraps around the neck of the fibula, passing between the attachments of the fibularis longus muscle. Here, the common fibular nerve terminates by dividing into the superficial fibular and deep fibular nerves.
Outline the sensory functions of the common fibular (peroneal) nerve.
- There are two cutaneous branches that arise directly from the common fibular nerve as it moves over the lateral head of the gastrocnemius.
I. Sural communicating nerve: This nerve combines with a branch of the tibial nerve to form the sural nerve. The sural nerve innervates the skin over the lower posterolateral leg.
II. Lateral sural cutaneous neve: Innervates the skin over the upper lateral leg.
- In addition to these nerves, the terminal branches of the common fibular nerve also have a cutaneous function:
I. Superficial fibular nerve: Innervates the skin of the anterolateral leg, and dorsum of the foot (except the skin between the first and second toes).
II. Deep fibular nerve: Innervates the skin between the first and second toes.
Describe the anatomical course of the deep fibular (peroneal) nerve.
- The deep fibular nerve originates from the sciatic nerve.
- The sciatic nerve bifurcates into the common fibular and the tibial nerves at the apex of the popliteal fossa, at the back of the knee.
- The common fibular nerve wraps around the neck of the fibula, moving anterolaterally, and gives rise to two terminal branches: the superficial and the deep fibular nerves.
- The deep fibular nerve arises in the superolateral aspect of the leg, between the fibularis longus muscle and the neck of the fibula.
- The nerve moves from the lateral compartment to the anterior compartment of the leg. It then follows the course of the anterior tibial artery, in an inferomedial direction.
- Together, the two structures pass between the TA (tibialis anterior) and the EDL (extensor digitorum longus) in the superior portion of the leg, and between the TA (tibialis anterior) and the EHL (extensor hallucis longus) in the inferior leg.
- The deep fibular nerve crosses the ankle joint, passing anterior to the distal tibia, and travels deep to the extensor retinaculum.
- It terminates in the dorsum of the foot, where it divides into:
I. A lateral branch: Supplies motor innervation to some of the intrinsic muscles of the foot,
II. A medial branch: A cutaneous nerve, innervating the skin between the 1st and 2nd toes.
Outline the sensory functions of the deep fibular (peroneal) nerve.
- The deep fibular nerve terminates in the dorsum of the foot as a cutaneous nerve.
- This innervates the webbed spaceof skin between the great toe (hallux) and the second toe.
Outline the motor functions of the deep fibular (peroneal) nerve.
- The deep fibular nerve innervates the muscles in the anterior compartment of the leg, including:
I. Tibialis anterior
II. Extensor hallucis longus
III. Extensor digitorum longus
IV. Fibularis tertius
- These muscles are responsible for dorsiflexion of the foot at the ankle joint. During the gait cycle for walking, dorsiflexion is required:
I. When a person strikes their heel on the floor in the stance phase.
II. During the swing phase.
- The deep fibular nerve also innervates the extensor digitorum brevis and extensor hallucis brevis, which are intrinsic muscles of the foot. These muscles are responsible for extending the toes at the metatarsophalangeal joints and interphalangeal joints.
Briefly, describe the different arches of the foot.
- The foot has three arches: two longitudinal (medial and lateral) arches and one anterior transverse arch. They are formed by the tarsal and metatarsal bones, and supported by ligaments and tendons in the foot.
- Their shape allows them to act in the same way as a spring, bearing the weight of the body and absorbing the shock produced during locomotion. The flexibility conferred to the foot by these arches facilitate functions such as walking and running.
Outline the structure, muscular support, ligamentous support and bony support of the medial arch of the foot.
- The medial arch is the higher of the two longitudinal arches.
- It is formed by the calcaneus, talus, navicular, three cuneiforms and first three metatarsal bones.
- It is supported by:
I. Muscular support: Tibialis anterior and posterior, fibularis longus, flexor digitorum longus, flexor hallucis, and the intrinsic foot muscles
II. Ligamentous support: Plantar ligaments (in particular the long plantar, short plantar and plantar calcaneonavicular ligaments), medial ligament of the ankle joint.
III. Bony support: Shape of the bones of the arch.
IV. Other: Plantar aponeurosis
Outline the structure, muscular support, ligamentous support and bony support of the lateral arch of the foot.
- The lateral arch is the flatter of the two longitudinal arches, and lies on the ground in the standing position.
- It is formed by the calcaneus, cuboid and 4th and 5th metatarsal bones.
- It is supported by:
I. Muscular support: Fibularis longus, flexor digitorum longus, flexor hallucis, and the intrinsic foot muscles.
II. Ligamentous support: Plantar ligaments (in particular the long plantar, short plantar and plantar calcaneonavicular ligaments).
III. Bony support: Shape of the bones of the arch.
IV. Other: Plantar aponeurosis.
Outline what muscles are involved in the heel-strike phase of walking.
- In the heel-strike stage, the foot hits the ground heel first.
- There are three muscles/muscle sets involved, each acting at a different joint:
I. Gluteus maximus – acts on the hip to decelerate the lower limb.
II. Quadriceps femoris – keeps the leg extended at the knee and hip.
III. Anterior compartment of the leg – maintains the ankle dorsiflexion, positioning the heel for the strike.
Outline what muscles are involved in the support stage of walking.
- After the heel strike stage, the leading leg hits the ground, and the muscles work to cope with the force passing through the leg.
- This is known as the support stage:
I. Quadriceps femoris – keeps the leg extended, accepting the weight of the body.
II. Foot inverters and everters – contract in a balanced manner to stabilise the foot.
III. Gluteus minimus, medius and tensor fascia lata – abducts the lower limb. This keeps the pelvis level by counteracting the imbalance created from having most of the body-weight on one leg
Outline what muscles are involved in the toe-off stage of walking.
In the toe-off phase, the foot prepares the leave the ground – heel first, toes last.
I. Hamstring muscles – extends the leg at the hip.
II. Quadriceps femoris – maintains the extended position of the knee.
III. Posterior compartment of the leg – plantarflexes the ankle. The prime movers include gastrocnemius, soleus and tibialis posterior.
Outline what muscles are involved in the leg lift stage of walking.
Once the foot has left the ground, the lower limb is raised in preparation for the swing stage.
I. Iliopsoas and rectus femoris – flexes the lower limb at the hip, driving the knee forwards.
II. Hamstring muscles – flexes the lower limb at the knee joint.
III. Anterior compartment of the leg – dorsiflexes the ankle.
Outline what muscles are involved in the swing stage of walking.
- In the swing phase, the raised leg is propelled forward.
- This is where the forward motion of the walk occurs:
I. Iliopsoas and rectus femoris – keep the hip flexed, resisting gravity as it tries to pull the leg down.
II. Quadriceps femoris – extends the knee, positioning the foot for landing.
III. Anterior compartment of the leg – maintains ankle dorsiflexion so that the heel is in place for landing.
Next, the heel hits the ground, and the whole cycle repeats.
Describe the stages when walking becomes running.
Describe the features of antalgic gait.
- Painful leg
- Short stance phase affected leg
- Lack of body weight unaffected leg
- Uneven
- Walking stick – opposite hand (shift body weight onto stick)
Describe the features of diplegic gait.
- Neuromuscular disorders – cerebral palsy
- Scissoring
- Tight Muscle groups – Psoas / Adductors / HS / Calf
- Ankle plantar flexed
- Forefoot Initial Contact
Describe the features of high steppage gait.
- Foot Drop
I. Sciatica
II. Common Peroneal n. Palsy
III. Neuromuscular disorders
- Toes hanging down
- Excessive hip flexion affected side
- Foot slap
Describe the features of parkinsonian gait.
- Neurological disease – Parkinsons
- Shuffling / Short step
- Forward flexed
- No arm swing
- Festinant
Describe the features of achilles tendonitis and tendon rupture.
- Achilles tendon
I. Largest tendon in the body
II. Vascular “watershed” 6cm from insertion into calcaneum
III. Rupture typically in 30-50 year old “weekend warriors”
IV. Often complain of being “kicked on the back of the heel
- Thompson’s test (Simmond’s)
Describe the Ottawa Rules of when to X ray an ankle fracture.
- Tenderness over the medial malleolus
- Tenderness over the lateral malleolus
- Tenderness over navicular
- Tenderness over base of metatarsal
- Inability to bear weight
Discuss what is meant by stable and unstable ankle fractures.
Describe the features of bunions.
- Hallux (toe) Valgus (deformity)
I. Valgus: deviation of the distal limb away from the midline
II. Varus: deviation of the distal limb towards the midline
- Largely affects middle-aged females
- Presentation
I. Don’t like the look of feet
II. Pain over the bump
III. Difficulty with shoes
Describe the features of the relationship between diabetes mellitus and the foot.
- 15% of diabetics experience foot problems
- 25% of diabetic hospitalisations for the foot
- 50% of major amputations are in diabetics
- 66% probability of contra-lateral amputation within 5 years
- 50-70% mortality within 5 years after major amputation worse than a lot of cancers
- Diabetes causes loss of protective sensation in foot.
- This leads to severe infections (immunocompromised)
- Thorough clean up required (debridement)
Outline the features of charcot arthropathy
- Loss of sensation leads to destruction of joints
- Leads to massive deformity and bone loss
- Pathology is challenging
I. Loss of bone stock
II. Soft bone due to inflammation
III. Lack of pain as a reminder
- Obese
- Cognitive problems: “candy brain”
- Immunocompromised
- Self neglect
Outline the clinical relevance of ankle sprain
Outline the clinical relevance of the ankle ring
Outline the clinical relevance of calcaneal fracture
Outline the clinical relevance of foot drop
How does one locate the common fibular nerve?
Outline the clinical relevance of the rupture of the calcaneal tendon
Outline the clinical relevance of pes planus
Outline the clinical relevance of pes cavus
Outline the clinical relevance of trendelenburg gait
Outline the clinical relevance of a Potts Fracture
