Appendicular Muscles- Lower Extremities Flashcards

1
Q

What is the fascia lata?

A
  • The deep fascia of the thigh
  • Encircles thigh muscles like a supportive stocking and tightly binds them together
  • The fascia lata along with the intermuscular septa partition the thigh muscles into compartments, each with its own blood and nerve supply
  • Most muscles of the thigh attach proximally to the os coxae and distally to the femur
  • They work together to stabilize the highly mobile hip joint and support the body during standing and walking
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2
Q

What do the anterior compartment muscles do? (thigh)

A
  • Either extend the knee or flex the thigh
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3
Q

What do the medial compartment muscles do? (thigh)

A
  • Act as adductors of the thigh
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4
Q

What do the posterior compartment muscles do? (thigh)

A
  • Act as both flexors of the knee and extensors of the thigh

- Some also may abduct the thigh

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5
Q

What are the psoas major and iliacus muscles? (anterior compartment)

A
  • Attach to the anterior femur and flex the thigh at the hip
  • Have different proximal attachments but share the same distal attachment to the lesser trochanter of the femur
  • Together these muscles merge and attach to the femur as the iliopsoas
  • They work synergistically to flex the thigh
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6
Q

What is the sartorius? (anterior compartment)

A
  • A long, thin muscle that crosses over the anterior thigh and helps flex the thigh
  • The rectus femoris also does this
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7
Q

What are the medial compartment muscles?

A
  • Adductor longus, adductor brevis, gracilis and pectineus (primary adductors/ thigh flexors)
  • Adductor magnus extends laterally and rotates the thigh as well as flexing it
  • The obturator externus does not adduct the thigh but laterally rotates it
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8
Q

What is the lateral compartment muscle?

A
  • Single muscle called the tensor fasciae latae
  • Attaches to a lateral thickening of the fascia lata, called the iliotibial tract
  • Abducts and medially rotates the thigh
  • The iliotibial tract extends from the iliac crest to the lateral condyle of the tibia
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9
Q

What are the posterior compartment muscles?

A
  • Includes 3 gluteal muscles and the hamstring muscle group
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10
Q

What is the gluteus maximus?

A
  • The largest of the 3 gluteal muscles and one of the largest muscles in the whole body
  • The chief extensor of the thigh
  • Laterally rotates the thigh
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11
Q

What is the gluteus medius?

A
  • Deep and lateral to the gluteus maximus
  • Powerful abductor of the thigh
  • Also medially rotates the thigh
  • Intramuscular injections are often given in this muscle
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12
Q

What is the gluteus minimus?

A
  • The smallest of the gluteal muscles
  • Lies deep to the gluteus medius
  • Abducts and medially rotates the thigh
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13
Q

What posterior compartment muscles are deep to the gluteal muscles?

A
  • Piriformis, superior gemellus, obturator internus, inferior gemellus and quadratus femoris
  • Organized from superior to inferior within the posterior thigh
  • All laterally rotate the thigh and the hip joint, as when the legs are crossed with one ankle resting on the knee
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14
Q

What are the hamstrings? (posterior compartment)

A
  • Biceps femoris, semimembranosus, and semitendinosus
  • Share a common proximal attachment to the ischial tuberosity of the os coxae and distally attach to the leg
  • These muscles move the thigh and the knee (primary thigh movement is extension)
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15
Q

What is the anterior (extensor) compartment of the thigh?

A
  • Composed of the large quadriceps femoris
  • Agonist of knee extension and the most powerful muscle in the body
  • Has 4 heads: rectus femoris, vastus lateralis, vastus medialis and vastus intermedius which all converge into the single tendon
  • Extends to the patella and then continues inferiorly as the patellar ligament and attaches to the tibial tuberosity
  • Acts with the iliopsoas to flex the hip while the leg is kicking off the ground
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16
Q

What is the rectus femoris? (quadriceps femoris)

A
  • On the anterior surface of the thigh
  • Proximally attaches to the os coxae
  • Also flexes the thigh
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17
Q

What is the vastus lateralis? (quadriceps femoris)

A
  • Forms the anterolateral surface of the thigh
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18
Q

What is the vastus medialis?

A
  • Forms the anteromedial surface of the thigh
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19
Q

What is the vastus intermedius?

A
  • Positioned deep to the rectus femoris and sandwiched between the other 2 vastus muscles
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20
Q

What is the sartorius? (anterior compartment)

A
  • Projects obliquely across the anterior surface of the thigh from the superolateral to the inferomedial side
  • Acts on both the hip and knee joints, flexing and laterally rotating the thigh while flexing the leg
  • Longest muscle in the body (used when crossing our legs)
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21
Q

What is the gracilis? (medial compartment)

A
  • Adducts the thigh

- Also flexes the leg, as it spans the knee joint

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22
Q

What is the biceps femoris? (posterior compartment)

A
  • 2 headed muscle that attaches to the lateral side of the leg
  • Can laterally rotate the leg while it’s being flexed
  • The long head proximally attaches to the ischial tuberosity with the semimembranosus and semitendinosus
  • The short head attaches proximally to the linea aspera of the femur (cannot move the thigh but assists in flexing the leg)
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23
Q

What is the semimembranosus? (posterior compartment)

A
  • Deep to the semitendinosus
  • Extends from the ischial tuberosity to the medial side of the leg
  • Medially rotate the leg while flexed
24
Q

What is the semitendinosus? (posterior compartment)

A
  • Superficial to the semimembranosus
  • Attached to the medial leg
  • Medially rotate the leg while flexed
25
Q

What are the crural muscles?

A
  • Muscles that move the ankle, foot and toes
  • Some of these muscles also help to flex the leg
  • Deep fascia partitions the leg musculature into 3 compartments (anterior, lateral and posterior)
26
Q

What is the extensor digitorum longus? (anterior compartment)

A
  • Sends 4 long tendons to attach to the dorsal surface of toes 2-5
  • Dorsiflexes the foot and extends toes 2-5
27
Q

What is the extensor hallucis longus? (anterior compartment)

A
  • Sends a tendon to the dorsum of the great toe (hallux)

- Dorsiflexes the foot and extends the great toe

28
Q

What is the fibularis tertius? (anterior compartment)

A
  • Extends from the extensor digitorum longus muscle
  • It dorsiflexes and weakly everts the foot
  • The presence of this muscle varies among populations and individuals
29
Q

What is the tibialis anterior? (anterior compartment)

A
  • The primary dorsiflexor of the foot and ankle
  • Attaches to the medial plantar side of the foot
  • Also inverts the foot
30
Q

What is extensor retinaculum? (anterior compartment)

A
  • Holds tendons of the muscles within the anterior compartment tightly against the ankle
  • Are multiple deep fascia thickenings
31
Q

What is the fibularis longus? (lateral compartment)

A
  • Long and flat muscle that is superficial and lateral
  • Covers the fibula
  • Its tendon attaches to the plantar side of the foot on the base of metatarsal I and the medial cuneiform
  • Powerful evertor of the foot and weak plantar flexor
32
Q

What is the fibularis brevis? (lateral compartment)

A
  • Lies deep to the fibularis longus
  • Its tendon attaches to the base of the fifth metatarsal
  • Powerful evertor of the foot and weak plantar flexor that works synergistically with the fibularis longus
33
Q

What is the superficial layer of the posterior compartment?

A
  • Contains 3 muscles: gastrocnemius, soleus and plantaris
34
Q

What is the gastrocnemius? (superficial posterior compartment)

A
  • The most superficial muscle
  • Has 2 thick bellies (lateral and medial heads)
  • Collectively form the prominence of the posterior part of the leg (referred to as the calf)
  • Spans both the knee and ankle joints
  • Flexes the leg and plantar flexes the foot
  • Tendon of the lateral head may have a normal variant sesamoid bone or cartilage called fabella
35
Q

What is the soleus? (superficial posterior compartment)

A
  • Deep to the gastrocnemius
  • Broad and flat muscle that resembles a flat fish
  • Muscle plantar that flexes the foot
36
Q

What is the plantaris? (superficial posterior compartment)

A
  • Small muscle that is absent in some individuals
  • Projects obliquely between the gastrocnemius and soleus muscles
  • Weak leg flexor and plantar flexor of the foot
37
Q

What is the triceps surae? (superficial posterior compartment)

A
  • Gastrocnemius and soleus collectively form this muscle group
  • Most powerful plantar flexors of all the leg muscles
  • Share a common distal tendon called the calcaneal tendon or achilles tendon
38
Q

What is the deep layer of the posterior compartment?

A
  • Contains 4 muscles: flexor digitorum longus, flexor hallucis longus, tibialis posterior and popliteus
39
Q

What is the flexor digitorum longus? (deep posterior compartment)

A
  • Attaches to the distal phalanges of toes 2-5
  • Plantar flexes the foot
  • Flexes the MP, PIP and DIP joints of does 2-5
40
Q

What is the flexor hallucis longus? (deep posterior compartment)

A
  • Proximally attaches to the fibula
  • Tendon travels medially and runs along the plantar side of the foot to attach to the distal phalanx of the great toe
  • Plantar flexes the foot and flexes the great toe
41
Q

What is the tibialis posterior? (deep posterior compartment)

A
  • The deepest posterior compartment muscle

- It plantar flexes and inverts the foot

42
Q

What is the popliteus? (deep posterior compartment)

A
  • Forms the floor of the popliteal fossa and acts to flex the leg
  • Medially rotates the tibia slightly to “unlock” the fully extended knee joint
  • Attaches both proximally and distally in the popliteal region so it only moves the knee and not the foot
43
Q

What do the intrinsic muscles of the foot do?

A
  • Support the arches and move the toes to aid locomotion
  • Most of these muscles are comparable to the intrinsic muscles of the hand (not as precise movements can be made with the foot however)
  • Made up of a dorsal and plantar group of muscles
44
Q

What is the extensor hallucis brevis? (dorsal foot muscle)

A
  • Extends the MP joint of the great toe
45
Q

What is the extensor digitorum brevis? (dorsal foot muscle)

A
  • Deep to the tendons of the extensor digitorum longus

- Extends the MP, PIP and DIP joints of toes 2-4

46
Q

What is the plantar aponeurosis? (plantar foot muscle)

A
  • Supports the plantar surface of the foot
  • Formed from deep fascia of the foot
  • Extends between the phalanges of the toes and the calcaneus
  • Also encloses plantar muscles of the foot
47
Q

What is flexor digitorum brevis? (superficial plantar foot muscle)

A
  • Attaches to the middle phalanges of the toes so it can flex MP and PIP joints (not DIP joints though) of toes 2-5
48
Q

What is the abductor hallucis? (superficial plantar foot muscle)

A
  • Abducts the great toe
49
Q

What is the abductor digiti minimi? (superficial plantar foot muscle)

A
  • Abducts the small toe
50
Q

What is the quadratus plantae? (deep plantar foot muscle)

A
  • Thick, medial muscle that attaches to the tendons of the digitorum longus
  • Pulls the slanted flexor digitorum longus tendons in a posterior fashion so that toes 25 may be flexed properly and not at an angle
51
Q

What are the lumbrical muscles? (deep plantar foot muscle)

A
  • Small muscles that attach to the tendons of the flexor digitorum longus
  • Serve to flex MP joints and extend DIP and PIP joints of toes 2-5
52
Q

What is the adductor hallucis? (deeper plantar foot muscle)

A
  • Adducts the great toe
53
Q

What are the flexor hallucis brevis? (deeper plantar foot muscle)

A
  • Medial muscle that flexes the great toe
54
Q

What is the flexor digiti minimi brevis? (deeper plantar foot muscle)

A
  • Lateral muscle which flexes the small toe
55
Q

What are the dorsal and plantar interossei? (deepest plantar foot muscle)

A
  • Dorsal: abduct the totes

- Plantar: adduct the toes