The knee, leg, ankle and foot part 2

Question 1

Summarise the muscular anatomy of the region

Answer 1

Anterior compartment of the leg
Lateral compartment of the leg
Posterior compartment of the leg

Intrinsic muscles of the foot
Sole – 4 layers
Dorsum – 2 muscles

Question 2

Which muscles of the anterior compartment of the thigh do not cross the knee joint

Answer 2

Pectineus

Ilio-psoas

Question 3

Which muscles of the anterior compartment of the thigh cross the knee joint and which knee movement do they cause

Answer 3

Knee extension

Tensor fasciae latae
Sartorius
Quadriceps femoris
Rectus femoris
Vastus medialis
Vastus intermedius
Vastus lateralis

Question 4

Which muscle from the medial compartment of the thigh acts across the knee joint

Answer 4

Gracilis

Question 5

Which muscles from the posterior compartment of the thigh act across the knee joint and what movement do they cause

Answer 5

Knee flexion

Semimembranosus
Semitendinosus
Biceps femoris

Question 6

Summarise the anterior compartment of the leg

Answer 6

Ankle Dorsiflexors (extensors)
Deep Peroneal Nerve
Anterior Tibial Artery

Tibialis Anterior
Extensor Digitorum Longus
Extensor hallucis Longus

Question 7

Describe the arrangement of the three hamstrings

Answer 7

Biceps femoris lies more laterally (its short head comes from the lateral lip of the linea aspera) and inserts into fibula
Semitendinosus and semimembranosus are more medial and insert into the tibia

Question 8

Describe the attachments of the tibialis anterior and its function

Answer 8

Proximal: Lateral surface of tibia and adjacent interosseous membrane
Distal: Medial and inferior surfaces of medial cuneiform and adjacent surfaces on base of metatarsal I

Function: Dorsiflexion of foot at ankle joint; inversion of foot; dynamic support of medial arch of foot (I,e during walking)

Question 9

Describe the attachments of the extensor hallucis longus and its function

Answer 9

Proximal: Middle one-half of medial surface of fibula and adjacent surface of interosseous membrane

Distal: Dorsal surface of base of distal phalanx of great toe

Function: Extension of great toe and dorsiflexion of foot

Question 10

Describe the attachments and function of the extensor digitorum longus

Answer 10

Proximal: Proximal one-half of medial surface of fibula and related surface of lateral tibial condyle

Distal: Via dorsal digital expansions into bases of distal and middle phalanges of lateral four toes

Function: Extension of lateral four toes and dorsiflexion of foot

Question 11

Describe the attachments and function of the fibularis tertius

Answer 11

Proximal: Distal part of medial surface of fibula
Distal: Dorsomedial surface of base of metatarsal V
Function: Dorsiflexion and eversion of foot.

Question 12

Describe the innervation of the anterior compartment of the leg

Answer 12

All innervated by the deep peroneal nerve (L5-S1)

Except tibialis anterior - deep peroneal nerve (L4,5)

Question 13

Summarise the lateral compartment of the leg

Answer 13

Superficial Peroneal Nerve (L5-S2)
Peroneal Artery

Peroneus Longus
Peroneus brevis

Question 14

Describe the attachments of the fibularis longus muscle and its function

Answer 14

Proximal: Upper lateral surface of fibula, head of fibula, and occasionally the lateral tibial condyle
Distal: Undersurface of lateral sides of distal end of medial cuneiform and base of metatarsal I

Function: Eversion and plantarflexion of foot; supports arches of foot

Question 15

Describe the attachments and function of the fibularis brevis

Answer 15

Proximal: Lower two-thirds of lateral surface of shaft of fibula
Distal: Lateral tubercle at base of metatarsal V
Function: Eversion of foot

Question 16

Describe the passage of the fibularis longus tendon

Answer 16

Distally, the fibularis longus descends in the leg to form a tendon, which, in order:
▪
passes posterior to the lateral malleolus in a shallow bony groove,
▪
swings forward to enter the lateral side of the foot,
▪
descends obliquely down the lateral side of the foot where it curves forward under a bony tubercle (fibular trochlea) of the calcaneus,
▪
enters a deep groove on the inferior surface of one of the other tarsal bones (the cuboid), and
▪
swings under the foot to cross the sole and attach to the inferior surfaces of bones on the medial side of the foot (lateral sides of the base of metatarsal I and the distal end of the medial cuneiform).

passes posterior to fibularis brevis tendon behind lateral malleolus

Question 17

Describe the passage of the fibularis brevis tendon

Answer 17

The tendon of the fibularis brevis passes behind the lateral malleolus with the tendon of the fibularis longus muscle and then curves forward across the lateral surface of the calcaneus to attach to a tubercle on the lateral surface of the base of metatarsal V (the metatarsal associated with the little toe).

Question 18

Where does the tendon of the extensor hallucis longus appear

Answer 18

The tendon of the extensor hallucis longus appears between the tendons of the tibialis anterior and extensor digitorum longus in the lower one-half of the leg and descends into the foot.

Question 19

Which structure does the tibialis anterior go in front of

Answer 19

The medial malleolus

Extensor digitorium longus and fibularis tertius go over lateral malleolus

Question 20

Summarise the anterior and lateral compartments of the leg

Answer 20

Anterior compartment muscles extend (dorsiflex) the foot at the ankle joint and extend the digits. Supplied by the deep branch of the peroneal nerve.

Lateral compartment muscles evert the foot and can contribute to dorsiflexion.

Question 21

Summarise the posterior compartment of the leg

Answer 21

Ankle Plantarflexors and flexion of the digits
Tibial nerve
Posterior Tibial Artery

Superficial
Gastrocnemius
Soleus
Plantaris

Deep
Popliteus
Flexor Digitorum Longus
Flexor Hallucis Longus
Tibialis Posterior 

Superficial and deep compartments separated by a layer of deep fascia

Question 22

What is important to remember about the superficial group of muscles

Answer 22

As a unit, these muscles are large and powerful because they propel the body forward off the planted foot during walking and can elevate the body upward onto the toes when standing. Two of the muscles (gastrocnemius and plantaris) originate on the distal end of the femur and can also flex the knee.

Question 23

Describe the attachments and function of the gastrocnemius

Answer 23

Proximal: Medial head—posterior surface of distal femur just superior to medial condyle (just behind adductor tubercle); lateral head—upper posterolateral surface of lateral femoral condyle

Distal: Via calcaneal tendon to posterior surface of calcaneus

Function: Plantarflexes foot and flexes knee

Question 24

Describe the attachments and function of the plantaris

Answer 24

Proximal: Inferior part of lateral supracondylar line of femur and oblique popliteal ligament of knee

Distal: Via calcaneal tendon to posterior surface of calcaneus

Function: Plantarflexes foot and flexes the knee

Question 25

Describe the attachments and function of the soleus

Answer 25

Proximal: Soleal line and medial border of tibia; posterior aspect of fibular head and adjacent surfaces of neck and proximal shaft; tendinous arch between tibial and fibular attachments Distal: Via calcaneal tendon to posterior surface of calcaneus Function: Plantarflexes the foot

Question 26

Describe the passage of the plantaris tendon

Answer 26

The short spindle-shaped muscle body of the plantaris descends medially, deep to the lateral head of the gastrocnemius, and forms a thin tendon, which passes between the gastrocnemius and soleus muscles and eventually fuses with the medial side of the calcaneal tendon near its attachment to the calcaneus.

Question 27

Describe the soleus ligament (or tendon)

Answer 27

The ligament, which spans the distance between the attachments to the tibia and fibula, arches over the popliteal vessels and tibial nerve as they pass from the popliteal fossa into the deep region of the posterior compartment of the leg.

Question 28

What is the collective term given to the gastrocnemius and soleus

Answer 28

Gastrocnemius (2 heads) and Soleus (1 head) together form Triceps Surae whose distal tendon is tendocalcaneus (Achilles tendon).

Question 29

Describe the attachments and function of the popliteus muscle

Answer 29

proximal: Lateral femoral condyle Distal: Posterior surface of proximal tibia Function: Stabilizes knee joint (resists lateral rotation of tibia on femur) Unlocks knee joint (laterally rotates femur on fixed tibia) Knee twists slightly upon locking (popliteus untwists it)

Question 30

Describe the attachments and function of the flexor hallucis longus

Answer 30

Proximal: Posterior surface of fibula and adjacent interosseous membrane Distal: Plantar surface of distal phalanx of great toe Function: Flexes great toe

Question 31

Describe the attachment and functions of the flexor digitorium longus

Answer 31

proximal: Medial side of posterior surface of the tibia Distal: Plantar surfaces of bases of distal phalanges of the lateral four toes Function: Flexes lateral four toes

Question 32

Describe the attachments and function of the tibialis posterior

Answer 32

Proximal: Posterior surfaces of interosseous membrane and adjacent regions of tibia and fibula Distal: Tuberosity of navicular and adjacent region of medial cuneiform Function: Inversion and plantarflexion of foot; support of medial arch of foot during walking

Question 33

Explain the importance of the popliteus

Answer 33

It unlocks the extended knee at the initiation of flexion and stabilizes the knee by resisting lateral (external) rotation of the tibia on the femur. When initiating gait from a standing position, contraction of the popliteus laterally rotates the femur on the fixed tibia, unlocking the knee joint.

Question 34

Describe the course of the flexor hallucis longus tendon

Answer 34

The muscle fibers of the flexor hallucis longus converge inferiorly to form a large cord-like tendon, which passes behind the distal head of the tibia and then slips into a distinct groove on the posterior surface of the adjacent tarsal bone (talus) of the foot. The tendon curves anteriorly first under the talus and then under a shelf of bone (the sustentaculum tali), which projects medially from the calcaneus, and then continues anteriorly through the sole of the foot to insert on the inferior surface of the base of the distal phalanx of the great toe.

Question 35

Describe the course of the flexor digitorium longus tendon

Answer 35

The flexor digitorum longus descends in the leg and forms a tendon, which crosses posterior to the tendon of the tibialis posterior muscle near the ankle joint. The tendon continues inferiorly in a shallow groove behind the medial malleolus and then swings forward to enter the sole of the foot. It crosses inferior to the tendon of the flexor hallucis longus muscle to reach the medial side of the foot and then divides into four tendons, which insert on the plantar surfaces of the bases of the distal phalanges of digits II to V.

Question 36

Describe the roles of the flexor digitiorium and hallucis longus tendons in gait

Answer 36

The flexor hallucis longus flexes the great toe. It is particularly active during the toe-off phase of walking when the body is propelled forward off the stance leg and the great toe is the last part of the foot to leave the ground. It can also contribute to plantarflexion of the foot at the ankle joint The flexor digitorum longus flexes the lateral four toes. It is involved with gripping the ground during walking and propelling the body forward off the toes at the end of the stance phase of gait.

Question 37

Describe the passage of the tibialis posterior

Answer 37

Near the ankle, the tendon of the tibialis posterior is crossed superficially by the tendon of the flexor digitorum longus muscle and lies medial to this tendon in the groove on the posterior surface of the medial malleolus. The tendon curves forward under the medial malleolus and enters the medial side of the foot. It wraps around the medial margin of the foot to attach to the plantar surfaces of the medial tarsal bones, mainly to the tuberosity of the navicular and to the adjacent region of the medial cuneiform.

Question 38

Describe the position of the long flexor tendons relative to the malleolus

Answer 38

They pass behind the medial malleolus

Question 39

What is the main function of the intrinsic muscles of the foot

Answer 39

Intrinsic muscles mainly modify the actions of the long tendons and generate fine movements of the toes (extensor digitorium longus passes obliques- don't want oblique dorsiflexion). All intrinsic muscles of the foot are innervated by the medial and lateral plantar branches of the tibial nerve except for the extensor digitorum brevis, which is innervated by the deep fibular nerve. The first two dorsal interossei also may receive part of their innervation from the deep fibular nerve.

Question 40

Summarise the intrinsic muscles of the foot

Answer 40

The Sole 4 layers Intrinsic Muscles Tibial nerve Dorsum of the Foot EDB, EHB EDB by Common peroneal nerve

Question 41

Describe the general functions of the intrinsic muscles of the foot

Answer 41

For most people, the intrinsic muscles of the foot function generally act as shock absorbers, adjusting the foot to uneven surfaces. Feet can be “trained” for carrying out fine movements, such as writing and drawing. Individuals lacking upper limbs are able to use their feet to carry out a variety of fine activities.

Question 42

Describe the attachments of the extensor digitorium brevis and its function

Answer 42

Proximal: Superolateral surface of the calcaneus Distal: Lateral sides of the tendons of extensor digitorum longus of toes II to IV Function: Extension of toes 2-4

Question 43

Describe the attachments and function of the extensor hallucis brevis and its function

Answer 43

Proximal: Superolateral surface of the calcaneus Distal: Base of proximal phalanx of great toe Function: Extension of metatarsophalangeal joint of great toe

Question 44

Where is the extensor digitiroium brevisin relation to its longus

Answer 44

The flat muscle belly passes anteromedially over the foot, deep to the tendons of the extensor digitorum longus, and forms three tendons, which enter digits II, III, and IV.

Question 45

Describe the innervation of the EDB and EHB

Answer 45

Deep fibular nerve (S1, S2)

Question 46

Which muscles are found in layer 1 of the sole and describe their innervation

Answer 46

Abductor hallucis Abductor digiti minimi Flexor digitorum brevis All innervated by the Medial plantar nerve from the tibial nerve (S1-3) Except for the abductor digiti minimi which is innervated by the Lateral plantar nerve from the tibial nerve (S1-3)

Question 47

Describe the attachments and function of the abductor hallucis

Answer 47

Proximal: Calcaneal tuberosity Distal: Medial side of base of proximal phalanx of great toe Function: Abducts and flexes great toe at metatarsophalangeal joint

Question 48

Describe the attachments and function of the abductor digiti minimi

Answer 48

Proximal: Lateral and medial processes of calcaneal tuberosity, and band of connective tissue connecting calcaneus with base of metatarsal V Distal: Lateral side of base of proximal phalanx of little toe Function: Abducts little toe at the metatarsophalangeal joint

Question 49

Describe the attachments and function of the flexor digitorium brevis

Answer 49

Proximal: Medial process of calcaneal tuberosity and plantar aponeurosis Distal: Sides of plantar surface of middle phalanges of lateral four toes Function: Flexes lateral four toes at proximal interphalangeal joint Near the base of the proximal phalanx of the toe, each tendon splits to pass dorsally around each side of the tendon of the flexor digitorum longus and attach to the margins of the middle phalanx.

Question 50

Which muscles are found in layer 2 of the sole, describe their innervation and name the tendon that they are attached to

Answer 50

Lumbricals Quadratus plantae Quadratus plantae- Lateral plantar nerve from tibial nerve (S1-3) Lumbricals- 1st lumbrical: medial plantar nerve from the tibial nerve; 2nd-4th: lateral plantar nerve from the tibial nerve (S2-3) Attach the the flexor digitorium longus tendons

Question 51

Describe the attachments of the quadratus plantae and its function

Answer 51

Proximal; Medial surface of calcaneus and lateral process of calcaneal tuberosity Distal: Lateral side of tendon of flexor digitorum longus in proximal sole of the foot Function: Assists flexor digitorum longus tendon in flexing toes II to V

Question 52

Describe the attachments and function of the lumbricals

Answer 52

Proximal: 1st lumbrical: medial side of tendon of flexor digitorum longus associated with toe II; 2nd-4th: adjacent tendons of flexor digitorum longus Distal: Medial free margins of extensor hoods of toes II to V Function: Flexion of metatarsophalangeal joint and extension of interphalangeal joints

Question 53

Describe the two proximal heads of the quadratus plantae

Answer 53

One of the heads originates from the medial surface of the calcaneus inferior to the sustentaculum tali. ▪ The other head originates from the inferior surface of the calcaneus anterior to the lateral process of the calcaneal tuberosity and the attachment of the long plantar ligament.

Question 54

Describe the key features of the lumbricals

Answer 54

The first lumbrical originates from the medial side of the tendon of the flexor digitorum longus that is associated with the second toe. The remaining three muscles are bipennate and originate from the sides of adjacent tendons. The lumbrical muscles act through the extensor hoods to resist excessive extension of the metatarsophalangeal joints and flexion of the interphalangeal joints when the heel leaves the ground during walking.

Question 55

Which muscles are found in layer 3 of the sole; describe their innervation

Answer 55

Flexor hallucis brevis Flexor digiti minimi brevis Adductor hallucis All innervated by the Lateral plantar nerve from tibial nerve (S2-3) EXCEPT for the flexor hallucis brevis which is innervated by the Medial plantar nerve from tibial nerve (S1-2)

Question 56

Describe the attachments of the flexor hallucis brevis and its function

Answer 56

Proximal: Plantar surface of cuboid and lateral cuneiform; tendon of tibialis posterior Distal: Lateral and medial sides of base of proximal phalanx of the great toe Function: Flexes metatarsophalangeal joint of the great toe

Question 57

Describe the attachments and function of the flexor digit minimi brevis

Answer 57

Proximal: Base of metatarsal V and related sheath of fibularis longus tendon Distal; Lateral side of base of proximal phalanx of little toe Function; Flexes little toe at metatarsophalangeal joint

Question 58

Describe the attachments and function of the adductor hallucis

Answer 58

Proximal: Transverse head: ligaments associated with metatarsophalangeal joints of lateral three toes; Oblique head: bases of metatarsals II to IV and from sheath covering fibularis longus Distal: Lateral side of base of proximal phalanx of great toe Function: Adducts great toe at metatarsophalangeal joint

Question 59

Describe the two heads of the flexor hallucis brevis

Answer 59

▪ The lateral head originates from the plantar surfaces of the cuboid, behind the groove for the fibularis longus, and adjacent surface of the lateral cuneiform. ▪ The medial head originates from the tendon of the tibialis posterior muscle as it passes into the sole of the foot. The medial and lateral heads unite and give rise to a muscle belly, which itself is separated into medial and lateral parts adjacent to the plantar surface of metatarsal I. Each part of the muscle gives rise to a tendon that inserts on either the lateral or medial side of the base of the proximal phalanx of the great toe.

Question 60

What structure occurs in each tendon of the flexor hallucis brevis

Answer 60

A sesamoid bone occurs in each tendon of the flexor hallucis brevis as it crosses the plantar surface of the head of metatarsal I. The tendon of the flexor hallucis longus passes between the sesamoid bones.

Question 61

Which muscles are found in layer 4 of the sole and describe their innervation

Answer 61

Palmar interossei Dorsal interossei Dorsal- Lateral plantar nerve from tibial nerve; first and second dorsal interossei also innervated by deep fibular nerve (S2, S3) Palmar- Lateral plantar nerve from tibial nerve (S2, S3)

Question 62

Describe the attachments of the dorsal interossei and their function

Answer 62

Proximal: Sides of adjacent metatarsals Distal: Extensor hoods and bases of proximal phalanges of toes II to IV Function: Abduction of toes II to IV at metatarsophalangeal joints; resist extension of metatarsophalangeal joints and flexion of interphalangeal joints

Question 63

Describe the attachments of the palmar interossei and their function

Answer 63

Proximal: Medial sides of metatarsals of toes III to V Distal: Extensor hoods and bases of proximal phalanges of toes III to V Function: Adduction of toes III to V at metatarsophalangeal joints; resist extension of the metatarsophalangeal joints and flexion of the interphalangeal joints

Question 64

What is important to remember about the dorsal interossei

Answer 64

All four muscles are bipennate and originate from the sides of adjacent metatarsals. The second toe can be abducted to either side of its long axis, so it has two dorsal interossei associated with it, one on each side. The third and fourth toes have a dorsal interosseous muscle on their lateral sides only. The great and little toes have their own abductors (the abductor hallucis and abductor digiti minimi) in the first layer of muscles in the sole of the foot.

Question 65

What is important to remember about the palmar interossei

Answer 65

The great toe has its own adductor (the adductor hallucis) in the third layer of muscles in the sole of the foot and the second toe is adducted back to its longitudinal axis by using one of its dorsal interossei.