Lower Extremities

Question 1

Origin
Pecten pubis and pectineal surface of the pubis
Insertion
Pectineal line of femur
Action
Adducts the thigh and flexes the hip joint
Innervation
Femoral nerve usually, although it may sometimes receive additional innervation from the obturator nerve as well (L2, L3, L4)

Answer 1

Pectineus

Question 2

Origin
Anterior surface of inferior pubic ramus, inferior to origin of adductor longus
Insertion
Pectineal line and superior part of medial lip of linea aspera
Action
Adducts and flexes the thigh, and helps to laterally rotate the thigh
Innervation
Anterior or posterior division of obturator nerve (L2, L3, L4)

Answer 2

Adductor Brevis

Question 3

Origin
Anterior surface of body of pubis, just lateral to pubic symphysis
Insertion
Middle third of linea aspera, between the more medial adductor magnus and brevis insertions and the more lateral origin of the vastus medialis
Action
Adducts and flexes the thigh, and helps to laterally rotate the hip joint
Innervation
Anterior division of obturator nerve (L2, L3, L4

Answer 3

Adductor Longus

Question 4

Origin
Inferior pubic ramus, ischial ramus, and inferolateral area of ischial tuberosity
Insertion
Gluteal tuberosity of femur, medial lip of linea aspera, medial supracondylar ridge, and adductor tubercle
Action
Powerful thigh adductor; superior horizontal fibers also help flex the thigh, while vertical fibers help extend the thigh
Innervation
Posterior division of obturator nerve innervates most of the adductor magnus; vertical or hamstring portion innervated by tibial nerve (L2, L3, L4

Answer 4

Adductor Magnus

Question 5

Origin
Inferior margin of pubic symphysis, inferior ramus of pubis, and adjacent ramus of ischium
Insertion
Medial surface of tibial shaft, just posterior to sartorius
Action
Flexes the knee, adducts the thigh, and helps to medially rotate the tibia on the femur
Innervation
Anterior division of obturator nerve (L2, L3

Answer 5

Gracilis

Question 6

Origin
Anterior superior iliac spine
Insertion
Superior aspect of the medial surface of the tibial shaft near the tibial tuberosity
Action
Flexes and laterally rotates the hip joint and flexes the knee
Innervation
Femoral nerve (L2, L3, L4)

Answer 6

Sartorius

Question 7

Origin
Anterior superior iliac spine, outer lip of anterior iliac crest and fascia lata
Insertion
Iliotibial band
Action
Helps stabilize and steady the hip and knee joints by putting tension on the iliotibial band of fascia
Innervation
Superior gluteal nerve (L4, L5, S1)

Answer 7

Tensor Fascia Lata

Question 8

Origin
Straight head from anterior inferior iliac spine; reflected head from groove just above acetabulum
Insertion
Base of patella to form the more central portion of the quadriceps femoris tendon
Action
Extends the knee
Innervation
Muscular branches of femoral nerve (L2, L3, L4)

Answer 8

Rectus Femoris

Question 9

Origin
Superior 2/3 of anterior and lateral surfaces of femur; also from lateral intermuscular septum of thigh
Insertion
Lateral border of patella; also forms the deep portion of the quadriceps tendon
Action
Extends the knee
Innervation
Muscular branches of femoral nerve (L2, L3, L4

Answer 9

Vastus Intermedius

Question 10

Origin
Inferior portion of intertrochanteric line, spiral line, medial lip of linea aspera, superior part of medial supracondylar ridge of femur, and medial intermuscular septum
Insertion
Medial base and border of patella; also forms the medial patellar retinaculum and medial side of quadriceps femoris tendon
Action
Extends the knee
Innervation
Muscular branches of femoral nerve (L2, L3, L4)

Answer 10

Vastus Medialis

Question 11

Origin
Superior portion of intertrochanteric line, anterior and inferior borders of greater trochanter, superior portion of lateral lip of linea aspera, and lateral portion of gluteal tuberosity of femur
Insertion
Lateral base and border of patella; also forms the lateral patellar retinaculum and lateral side of quadriceps femoris tendon
Action
Extends the knee
Innervation
Muscular branches of femoral nerve (L2, L3, L4)

Answer 11

Vastus Lateralis

Question 12

Origin
Common tendon with semitendinosus from superior medial quadrant of the posterior portion of the ischial tuberosity
Insertion
Primarily on fibular head; also on lateral collateral ligament and lateral tibial condyle
Action
Flexes the knee, and also rotates the tibia laterally; long head also extends the hip joint
Innervation
Tibial nerve (L5, S1, S2)

Answer 12

Bicep Femoris (long head)

Question 13

Origin
Lateral lip of linea aspera, lateral supracondylar ridge of femur, and lateral intermuscular septum of thigh
Insertion
Primarily on fibular head; also on lateral collateral ligament and lateral tibial condyle
Action
Flexes the knee, and also rotates the tibia laterally; long head also extends the hip joint
Innervation
Common peroneal nerve (L5, S1, S2

Answer 13

Bicep Femoris (short head)

Question 14

Origin
Superior lateral quadrant of the ischial tuberosity
Insertion
Posterior surface of the medial tibial condyle
Action
Extends the thigh, flexes the knee, and also rotates the tibia medially, especially when the knee is flexed
Innervation
Tibial nerve (L5, S1, S2

Answer 14

Semimembranosus

Question 15

Origin
From common tendon with long head of biceps femoris from superior medial quadrant of the posterior portion of the ischial tuberosity
Insertion
Superior aspect of medial portion of tibial shaft
Action
Extends the thigh and flexes the knee, and also rotates the tibia medially, especially when the knee is flexed
Innervation
Tibial nerve (L5, S1, S2

Answer 15

Semitendious

Question 16

Origin
Lateral condyle of tibia, proximal 1/2 - 2/3 or lateral surface of tibial shaft, interosseous membrane, and the deep surface of the fascia cruris
Insertion
Medial and plantar surfaces of 1st cuneiform and on base of first metatarsal
Action
Dorsiflexor of ankle and invertor of foot
Innervation
Deep peroneal nerve (L4, L5, S1)
Arterial Supply
Anterior tibial artery

Answer 16

Tibialis Anterior

Question 17

Origin
Lateral condyle of fibula, upper 2/3 - 3/4 of medial fibular shaft surface, upper part of interosseous membrane, fascia cruris, and anterior intermuscular septum
Insertion
Splits into 4 tendon slips after inferior extensor retinaculum, each of which insert on dorsum of middle and distal phalanges as part of extensor expansion complex
Action
Extend toes 2 - 5 and dorsiflexes ankle
Innervation
Deep peroneal nerve (L4, L5, S1)

Answer 17

Extensor Digitorum Longus

Question 18

Origin
Anterior surface of the fibula and the adjacent interosseous membrane
Insertion
Base and dorsal center of distal phalanx of great toe
Action
Extends great toe and dorsiflexes ankle
Innervation
Deep peroneal nerve (L4, L5, S1)

Answer 18

Extensor Hallucis Longus

Question 19

Origin
Medial head from posterior nonarticular surface of medial femoral condyle; Lateral head from lateral surface of femoral lateral condyle
Insertion
The two heads unite into a broad aponeurosis which eventually unites with the deep tendon of the soleus to form the Achilles tendon, inserting on the middle 1/3 of the posterior calcaneal surface
Action
Powerful plantar flexor of ankle
Innervation
Tibial nerve (S1, S2)

Answer 19

Gastrocineus

Question 20

Origin
Posterior aspect of fibular head, upper 1/4 - 1/3 of posterior surface of fibula, middle 1/3 of medial border of tibial shaft, and from posterior surface of a tendinous arch spanning the two sites of bone origin
Insertion
Eventually unites with the gastrocnemius aponeurosis to form the Achilles tendon, inserting on the middle 1/3 of the posterior calcaneal surface
Action
Powerful plantar flexor of ankle
Innervation
Tibial nerve (S1, S2)

Answer 20

Soleus

Question 21

Origin
Inferior aspect of lateral supracondylar line of distal femur
Insertion
Middle 1/3 of the posterior calcaneal surface, just medial to Achilles tendon
Action
Plantar flexor of ankle; also flexes knee
Innervation
Tibial nerve (L5, S1, S2)

Answer 21

Plantaris

Question 22

Origin
Posterior aspect of interosseous membrane, superior 2/3 of medial posterior surface of fibula, superior aspect of posterior surface of tibia, and from intermuscular septum between muscles of posterior compartment and deep transverse septum
Insertion
Splits into two slips after passing inferior to plantar calcaneonavicular ligament; superficial slip inserts on the tuberosity of the navicular bone and sometimes medial cuneiform; deeper slip divides again into slips inserting on plantar surfaces of metatarsals 2 - 4 and second cuneiform
Action
Principal invertor of foot; also adducts foot, plantar flexes ankle, and helps to supinate the foot
Innervation
Tibial nerve (L4, L5)

Answer 22

Tibialis Posterior

Question 23

Origin
Posterior surface of tibia distal to popliteal line
Insertion
Splits into four slips after passing through medial intermuscular septum of plantar surface of foot; these slips then insert on plantar surface of bases of 2nd - 5th distal phalanges
Action
Flexes toes 2 - 5; also helps in plantar flexion of ankle
Innervation
Tibial nerve (S2, S3)

Answer 23

Flexor Digitorum Longus

Question 24

Origin
Inferior 2/3 of posterior surface of fibula, lower part of interosseous membrane
Insertion
Plantar surface of base of distal phalanx of great toe
Action
Flexes great toe, helps to supinate ankle, and is a very weak plantar flexor of ankle
Innervation
Tibial nerve (S2, S3)

Answer 24

Flexor Hallucis Longus

Question 25

Origin Anterior part of the popliteal groove on lateral surface of lateral femoral condyle Insertion Posterior surface of tibia in a fan-like fashion, just superior to the popliteal line Action Rotates knee medially and flexes the leg on the thigh Innervation Tibial nerve (L4, L5, S1)

Answer 25

Popliteus

Question 26

Origin Arises with the extensor digitorum longus from the medial fibular shaft surface and the anterior intermuscular septum (between the extensor digitorum longus and the tibialis anterior) Insertion Dorsal surface of the base of the fifth metatarsal Action Works with the extensor digitorum longus to dorsiflex, evert and abduct the foot Innervation Deep peroneal nerve (L5, S1)

Answer 26

Peroneus Tertius

Question 27

``` Origin Inferior 2/3 of lateral fibular surface; also anterior and posterior intermuscular septa of leg Insertion Lateral surface of styloid process of 5th metatarsal base Action Everts foot and plantar flexes ankle Innervation Superficial peroneal nerve (L5, S1, S2) ```

Answer 27

Peroneus Brevis

Question 28

Origin Head of fibula, upper 1/2 - 2/3 of lateral fibular shaft surface; also anterior and posterior intermuscular septa of leg Insertion Plantar posterolateral aspect of medial cuneiform and lateral side of 1st metatarsal base Action Everts foot and plantar flexes ankle; also helps to support the transverse arch of the foot Innervation Superficial peroneal nerve (L5, S1, S2); may also receive additional innervation from common or deep peroneal nerves (L5, S1, S2)

Answer 28

Peroneus Longus

Question 29

``` Proximal Attachment Calcaneus Distal Attachment Extensor tendons of digits 2-4 Innervation Deep fibular nerve (L5, S1) Action Extends digits 2-4 ```

Answer 29

Extensor Digitorum Brevis

Question 30

``` Proximal Attachment Calcaneus Distal Attachment Dorsal aspect of base of digit 1 Innervation Deep fibular nerve (L5, S1) Action Extends digit 1 ```

Answer 30

Extensor Hallucis Brevis

Question 31

``` Proximal Attachment Medial tubercle of tuberosity of calcaneus Distal Attachment Medial side of base of proximal phalanx of digit 1 Innervation Medial plantar nerve (S2, S3) Action Abducts and flexes digit 1 ```

Answer 31

Abductor Hallucis

Question 32

``` Proximal Attachment Medial tubercle of tuberosity of calcaneus Distal Attachment Both sides of middle phalanges of digits 2-5 Innervation Medial plantar nerve (S2, S3) Action Flexes digits 2-5 ```

Answer 32

Flexor Digitorum Brevis

Question 33

``` Proximal Attachment Medial and lateral tubercles of tuberosity of calcaneus Distal Attachment Lateral side of base of proximal phalanx of 5th digit Innervation Lateral plantar nerve (S2, S3) Action Abducts and flexes digit 5 ```

Answer 33

Abductor Digiti Minimi

Question 34

Proximal Attachment Medial surface and lateral margin of plantar surface of calcaneous Distal Attachment Posterolateral margin of tendon of flexor digitorum longus Innervation Lateral plantar nerve (S2, S3) Action Assists flexor digitorum longus in flexing digits 2-5

Answer 34

Quadratus Plantae

Question 35

Proximal Attachment Tendons of flexor digitorum longus Distal Attachment Medial aspect of expansion of digits 2-5 Innervation Medial one: medial plantar nerve (S2, S3) Lateral three: lateral plantar nerve (S2, S3) Action Flex proximal phalanges, extend middle and distal phalanges of digits 2-5

Answer 35

Lumbricals

Question 36

``` Proximal Attachment Plantar surfaces of cuboid and lateral cuneiforms Distal Attachment Both sides of base of proximal phalanx of digit 1 Innervation Medial plantar nerve (S2, S3) Action Flexes proximal phalanx of digit 1 ```

Answer 36

Flexor Hallucis Brevis

Question 37

Proximal Attachment Oblique Head- bases of metatarsals 2-4 Transverse Head- plantar ligaments of MP joints Distal Attachment Lateral side of base of proximal phalanx of digit 1 Innervation Deep branch of lateral plantar nerve (S2, S3) Action Adduct digit 1, assists in transverse arch of foot

Answer 37

Adductor Hallucis

Question 38

``` Proximal Attachment Base of 5th metatarsal Distal Attachment Base of proximal phalanx of 5th digit Innervation Superficial branch of lateral plantar nerve (S2, S3) Action Flexes proximal phalanx of 5th digit ```

Answer 38

Flexor Digiti Minimi Brevis

Question 39

``` Proximal Attachment Bases and medial sides of metatarsals 3-5 Distal Attachment Medial sides of bases of phalanges 3-5 Innervation lateral plantar nerve (S2, S3) Action Adducts digits 2-4 ```

Answer 39

Plantar Interossei

Question 40

``` Proximal Attachment Adjacent sides of metatarsals 1-5 Distal Attachment 1st- medial side of proximal phalanx of digit 2 2nd-4th- lateral sides of digits 2-4 Innervation lateral plantar nerve (S2, S3) Action Abducts digits 2-4 ```

Answer 40

Dorsal Interossei