Thigh, Leg, Foot

Question 1

Which muscles flex the thigh at the hip?

Answer 1

• strongest = iliopsoas
• sartorius (also abducts and laterally rotates the thigh. It also flexes the leg at the knee)
• rectus femoris (the other vastus quadriceps only extend leg at knee)
• pectineus (also adducts)
  
  • All innervated by femoral nerve

Question 2

quadriceps:

What are the 4 muscles?

Innervation?

Action?

Answer 2

Quads =

• Rectus femoris
• Vastus lateralis
• Vastus intermedius
• Vastus medialis
• All innervated by femoral nerve (L2-L4)
• All cause extension of the leg at the knee
• The rectus femoris also crosses the hip joint and is a flexor of the thigh at the hip

Question 3

anterior thigh - what are the 3 major muscles?

What are they innervated by?

Answer 3

• There are 3 major muscles in the anterior thigh – the pectineus, sartorius and quadriceps femoris
• All innervated by the femoral nerve
  
  • Sartorius muscle = a flexor of the thigh at the hip and a flexor of the leg at the knee. It also causes external rotation of the thigh.
  • Quadriceps muscles = rectus femoris, vastus lateralis, vastus intermedius, and vastus medialis. These muscles cause extension of the leg at the knee; the rectus femoris also crosses the hip joint and is a flexor of the thigh at the hip.
  • Pectineus = a flexor and adductor of the thigh at the hip.

Question 4

rectus femoris

Answer 4

• One of the quadriceps muscles.
• Part of anterior thigh, innervated by femoral nerve (L2-L4)
• In addition to causing extension of leg at the knee, also crosses the hip joint and is a flexor of the thigh at the hip

Question 5

pectineus muscle

Answer 5

• Pectineus is a flexor and adductor of the thigh at the hip.
• Part of the anterior thigh, innervated by posterior fibers of the femoral nerve

Question 6

Dermatome of femoral nerve?

Answer 6

• The dermatome of the femoral nerve = the skin of the anterior to anteromedial thigh.
• As the femoral nerve reaches the inferior aspect of the thigh, it continues as a cutaneous-only nerve, the saphenous nerve, which provides cutaneous innervation to the anteromedial leg.
  
  • (Note the parallelism to the musculocutaneous nerve of the upper limb)

Question 7

Dermatome of obturator nerve?

Answer 7

• A small ovoid area on the inferomedial thigh.

Question 8

medial thigh:

What are the 3 muscles, what do they all do?

Innervation?

Answer 8

• Medial thigh is innervated by obturator nerve
• The medial compartment consists of three adductors:
  
  • adductor brevis
  • adductor longus
  • adductor magnus.
  • These 3 muscles are all adductors of the thigh at the hip.
    
    • The adductor magnus also can extend the thigh at the hip and flex the leg at the knee.
• Medial compartment also includes 2 other adductor muscles innervated by obturator: gracilis and obturator externus

Question 9

adductur magnus

Answer 9

• One of the three muscles of medial thigh
• Innervated by obturator nerve
• In addition to acting as adductor of the thigh at the hip, the adductor magnus also can extend the thigh at the hip and flex the leg at the knee

Question 10

obturator externus

• Compartment?
• Innervation?
• Actions?

Answer 10

• Part of medial thigh, innervated by obturator nerve
• Adductor of thigh at hip, and also…
• Lateral rotator of the thigh at the hip

Question 11

Sciatic nerve:

What is it, where does it split?

Answer 11

• Sciatic nerve = part of lumbosacral plexus (L4-S3)
• Exits just inferior to the piriformis muscle.
• When the sciatic nerve reaches the superior border of the popliteal fossa, it splits into the tibial nerve and common fibular nerve.
  
  • The tibial nerve continues straight down, whereas the common fibular nerve swings laterally to pass over the neck of the fibula.

Question 12

quadriceps vs. hamstrings

Answer 12

• They’re antagonists
• The quadriceps is the group of four muscles at the front of the thigh.
  
  • Innervated by femoral nerve
  • The vastus lateralis, vastus medialis, vastus intermedius, and the rectus femoris
• The hamstrings are three muscles at the back of the thigh.
  
  • All of the true hamstrings (those that cross both the hip and knee joints) are innervated by the tibial nerve, and cause extension of the thigh at the hip and flexion of the leg at the knee. These include the semitendinosus, semimembranosus, and the long head of the biceps femoris. The short head of the biceps femoris (not a true hamstring) is innervated by the common fibular nerve.

Question 13

describe movements at hip joint

Answer 13

Question 14

movements at knee joint

Answer 14

Question 15

movements at ankle joint

Answer 15

Question 16

What causes eversion of the foot?

Answer 16

• The superficial fibular nerve innervates the lateral compartment of the leg, which cause eversion of the foot.
  
  • Eversion = turn sole of foot outwards
• There are two muscles in the lateral compartment of the leg; the fibularis longus and brevis (aka peroneal longus and brevis).

Question 17

Which muscles cause inversion of the foot?

Innervation?

Answer 17

• Anterior compartment of the leg causes dorsiflexion and some inversion of the foot
• 4 muscles in anterior compartment:
  
  • Tibialis anterior
  • Extensor digitorum longus
  • Extensor hallucis longus
  • Fibularis tertius
• Also, the dorsal foot muscles (they’re a continuation)
• Innervated by deep fibular nerve

Question 18

What are the 3 compartments of the thigh?

3 compartments of the leg?

(Muscles in the same compartment tend to share the same innervation and blood supply.)

Answer 18

Thigh:

• Anterior compartment - Femoral nerve
• Medial compartment - Obturator nerve
• Posterior compartment - Tibial nerve
  
  • Except the short head of the biceps, which is innervated by common fibular nerve
  • Blood supply for all = deep femoral artery. Posterior compartment gets the perforating branches.

Leg:

• Anterior compartment - Deep fibular nerve
  
  • ​Anterior tibial artery
• Lateral compartment - Superficial fibular nerve
  
  • ​Fibular artery
• Posterior compartment - Tibial nerve
  
  • ​Posterior tibial artery
• ​(All the blood supply are divisions of the popliteal artery, which is the name for the femoral artery once it passes through adductur hiatus.)

Question 19

extension at knee

Answer 19

• Extension of the leg at the knee is accomplished by the femoral nerve, which innervates the quadriceps muscles.
  
  • Quads = rectus femoris, vastus lateralis, vastus medius, and vastus intermedius
• Antagonist = hamstrings, innervated by tibial nerve

Question 20

flexion at knee

• what are the true hamstrings?

Answer 20

• The hamstring group muscles (semitendinosus, semimembranosus, and biceps femoris) flex the knee and extend the hip
• True hamstrings (everything except short head of biceps femoris) are innervated by tibial nerve
  
  • ​short head = common fibular nerve
• Antagonist = quadriceps, innervated by femoral nerve

Question 21

unlock knee

• muscle?
• innervation?

Answer 21

• Unlocking of the knee is the role of the popliteus muscle
• Innervated by the tibial nerve (posterior compartment of the leg).

Question 22

plantar flexion

Answer 22

• Plantar flexion is accomplished by the tibial nerve, which innervates the posterior compartment of the leg.
  
  • (Responsible for plantarflexion and foot inversion.)
• 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.
  
  • 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

Question 23

Name nerves that contribute to

cutaneous innervation of the leg?

Answer 23

• common fibular nerve
  
  • Includes superficial fibular nerve
  • Gives off lateral sural nerve.
  • (Also includes deep fibular nerve, but that’s just the flip flop.)
• femoral nerve
  
  • Continues into the leg as the saphenous nerve
• superficial fibular nerve
• tibial nerve

Question 24

bones that comprise knee joint

Answer 24

• the knee joint is formed from the two femoral condyles (a lateral and a medial one) sitting atop the tibial plateau.
• Tibia = main weight-bearing bone

Question 25

muscles for flexion and extension at knee

Answer 25

* flexion = **hamstring muscles** of the posterior thigh and the **gastrocnemius** of the posterior leg, * extension = **quadriceps** muscles of the anterior thigh.

Question 26

name ankle joint and two foot joints and the major bones

Answer 26

* The **talocrural joint of the ankle** is a _hinge joint_ that is stabilized by large bony protuberances: the **lateral malleolus** (fibula) and the **medial malleolus** (tibia). * just plantar and dorsal flexion * two _gliding joints_ in the foot: * the **subtalar joint** lies between the talus and the calcaneus. * **two transverse tarsal joints**: the navicular articulates with the talus and the cuboid articulates with the calcaneus. * **Inversion and eversion** occur at the transverse tarsal and subtalar joints.

Question 27

muscles of anterior leg and dorsal foot * innervation, blood supply * actions

Answer 27

* The muscles of the anterior leg are **primarily dorsiflexors, with some inversion ability** as well. * All muscles in this compartment are innervated by the **deep fibular nerve and receive their blood supply from the anterior tibial artery**. * Remember that the superficial and deep fibular nerves split just after the common fibular nerve passes the neck of the fibula; the anterior and posterior tibial arteries split from the popliteal artery near the superior aspect of the interosseus membrane and ride down its respective anterior and posterior surfaces. * **tibialis anterior**, which dorsiflexes and also everts, given its insertion on the medial foot. * **extensor digitorum longus** is analogous to the extensor digitorum of the posterior forearm, and causes extension of the metatarsophalangeal joints (MTP) of digits 2 through 5. * The **extensor hallucis longus** also causes extension at the MTP of the hallux (big toe); it also is a weak inverter of the foot. * The compartment of the dorsal foot should be thought of as an extension of the anterior leg; the two muscles in it (**extensor digitorum brevis and extensor hallucis brevis**) fuse their tendons with the “longus” versions of the same muscles and simply provide assistance to these muscles.

Question 28

muscles of posterior leg * innervation, blood supply * actions

Answer 28

* The posterior leg muscles are **all plantar flexors**. * all share the same innervation and blood supply: the **tibial nerve and the posterior tibial artery** * The **plantaris** is a rather thin muscle that sends a long, narrow tendon down to the calcaneus (the longest tendon in the body); it is actually absent in approximately 10% of the population. * The bulk of the posterior leg compartment consists of the **gastrocnemius** and **soleus** muscles, which merge their tendons to form the **Achilles tendon** that inserts onto the calcaneus. * gastrocnemius also crosses the knee joint, and is a minor flexor of the leg at the knee. * The **popliteus** muscle is a weak flexor of the leg at the knee, but is better known for its role in laterally rotating the femur to unlock the knee. * The **tibialis posterior** causes plantar flexion and also inverts the foot, given its insertion onto the medial foot. * The **flexor digitorum longus** is analogous to the flexor digitorum profundus of the forearm, in that it acts as distally as the DIP joints of the toes. * The **flexor hallucis longus** is analogous to the flexor pollicis longus, and flexes the big toe at the interphalangeal joint.

Question 29

tarsal tunnel * what passes through? * how can you get tarsal tunnel syndrome?

Answer 29

* "Tom Dick and A Very Nervous Harry" * The tarsal tunnel is analogous to the carpal tunnel; its floor is the medial surface of the talus and calcaneus. Its roof is another flexor retinaculum. * Through the tarsal tunnel pass the tendons of three of the muscles of the posterior compartment of the leg: * **Tibialis Posterior, flexor Digitorum longus, posterior tibial Artery and Vein, tibial Nerve, flexor Hallucis longus** * **Tarsal tunnel syndrome**, though less common than carpal tunnel syndrome, can result from **impingement of the tibial nerve in the tarsal tunnel**. * causes shooting pain into the plantar aspect of the foot, and weakness of some of the intrinsic muscles of the foot if severe.

Question 30

where are the main muscles for eversion of the leg?

Answer 30

* lateral leg compartment is the main player for eversion. * The **fibularis longus and brevis are innervated by the superficial fibular nerve** and will both plantar flex and evert. * The small fibularis tertius everts, but dorsiflexes and is innervated by the deep fibular nerve; it functionally bridges between the lateral and anterior leg compartments. * All three muscles are supplied by the **fibular artery**

Question 31

review movements at knee joint * flexion is mostly what nerve? * extension is mostly what nerve?

Answer 31

Question 32

reveiw movements at ankle joint * which nerves for plantar flexion, dorsiflexion, inversion, eversion?

Answer 32

Question 33

which muscle has 3 different functions?

Answer 33

Sartorius * In anterior compartment of the thigh, innervated by Femoral nerve * In addition to typical **flexion at the hip**, also **laterally rotates hip**, and **flexes the knee** * longest muscle!

Question 34

what are the strongest plantar flexors of the foot? innervation?

Answer 34

* strongest plantar flexors of the foot = **gastrocnemius and soleus** * tibial nerve * Standing on the tip-toes is a test for tibial nerve function

Question 35

nerves for inversion of foot eversion of foot

Answer 35

* inversion: tibial nerve, deep fibular nerve * eversion: superficial fibular nerve

Question 36

Answer 36

Semitendinosus, Semimembranosus, Biceps femoris long head (all these true hamstrings extend thigh at hip and flex leg at knee) * the recuts femoris flexes thigh at the hip, and extends the leg at the knee (vastus medius, lateralis, intermedius help with that extension)

Question 37

* muscles for plantar flexion / eversion, innervation? * muscles for dorsiflexion / inversion, innervation?

Answer 37

Any muscle in posterior leg versus anterior leg. * **gastrocnemius/ soleus** (tibial nerve, plantar flexion) vs. **tibialis anterior/ extensor hallucis longus/ extensor digitorum longus** (deep fibular nerve, dorsiflexion) * **Tibialis anterior and posterior** (ankle dorsiflexion, foot inversion -- deep fibular) vs. **Fibularis longus and brevis** (plantar flexion, eversion - superficial fibular)

Question 38

* innervation of posterior leg muscles? * distinguish tibialis posterior from tibialis anterior?

Answer 38

* all posterior leg muscles are innervated by **tibial nerve** * **both tibialis posterior and anterior invert the foot** * however: * **tibialis posterior is innervated by tibial nerve, also plantar flexes** * **tibialis anterior is innervated by the deep fibular nerve, also dorsiflexes** Tibial nerve review: Deep * Popliteus – Laterally rotates the femur on the tibia to unlock the knee. * Flexor Hallucis Longus – Flexes the big toe and plantar flexes the ankle. * Flexor digitorum Longus – Flexes the other digits and plantar flexes the ankle. * Tibialis Posterior – Inverts the foot and plantar flexes the ankle. Superficial * Plantaris – Plantar flexes the ankle. * Soleus – Plantar flexes the ankle. * Gastrocnemius – Plantar flexes the ankle and flexes the knee.

Question 39

most common cause of ankle sprain? #1 most commonly injured ligament? where is the pain? #2, #3 most injured ligaments

Answer 39

* usually caused by **inversion** of foot * #1 injury = AFTL - **anterior talofibluar ligament** * **​**#2 injury = CFL - calcaneofibular ligament * #3 injuy = PTFL - posterior talofibular ligament * (strained in order of anterior to posterior) * pain at lateral ankle, anterior to the malleolus (not on the bone)

Question 40

iliotibial band friction syndrome

Answer 40

* overuse injury common to runners * localization of pain to the lateral femoral condyle of knee * **because hip abductors (including TFL) have weakened** --\> so there's a hip drop (Trendlenburg gait) that puts extra **stress on the IT band** (continuation of TFL) --\> IT band crosses over lateral femoral condyle