semitendinous, semimebranous, per anserinus, biceps femoris

Question 1

o Biceps femoris

Answer 1

 Origin
 Lateral head: ischial tuberosity, sacrotuberous ligament ( common head with semiTendinosus)
 Short head: lateral lip of linea aspera and lateral supracondylar line in the middle 3rd of femur
 Insertion
 Lateral side of fibular head
 Action
 knee joint: Flexes leg and laterally (externally) rotates it when flexed; extends thigh
hip joint: ( LONG HEAD ONLY) extends hip, stabilizes pelvis in sagittal plane

innervation: - long head is tibial nerve (L5-S2)
short head is common fibular nerve (L5-S2)

Question 2

o Semitendinosus

Answer 2

 Origin
 Ischial tuberosity + sacrotuberous ligament; common tendon with long head of biceps femoris muscle
 Insertion
 Medial to tibial tuberosity, in pes anserinus along with tendons of gracilis and sartorius
 Action
 hip joint: Extends hip and stabilizes pelvis in sagittal plane
knee joint- flexion and internal rotation
 Can extend trunk when thigh is flexed
- innervation tibial nerve (L5-S2)

Question 3

o Semimembranosus

Answer 3

	Origin
	Ischial tuberosity
	Insertion
	Posterior part of medial tibial condyle; forms oblique popliteal ligament and popliteal fascia
	Action
	hip joint: Extends thigh; flexes leg and rotates medially when flexed
 knee joint: flex and internal rotate
	Can extend trunk when thigh flexed

Question 4

o Pes Anserinus- the goose’s foot

Answer 4

 Think SarGenTS”
 S- Sartorius
 G- gracillis
 T- Semitendonosis
 S- Semimembranosus
 Note: Semimembranosus slightly posterior to pes anserine attachment
 Pes anserine bursa attached to it- protects the tendons

Question 5

o Innervation to Posterior Compartment

Answer 5

 Sciatic Nerve
 Tibial division- medially
 Common fibular division- laterally
 In posterior thigh: they get wrapped up in a common tendon sheath
 1 exception
 short head of biceps femoris
 common fibular division
 in lab, can often see this branch common off sciatic nerve laterally
 Semimembranosus and Semitendonosis get innervation by fibular division of sciatic nerve
 Long head of biceps femoris gets innervation by tibial division of sciatic nerve
 Short head of biceps femoris gets innervation by common fibular division of sciatic nerve

Question 6

• Popliteal fossa

Answer 6

o Boundaries
 Superolaterally: Biceps femoris
 Superomedially: Semitendonosis & Semimembranosus
 Inferiorly: medial and lateral heads of gastrocnemius
 Floor: femur, joint capsule & popliteal fascia
o Contents
 Popliteal artery and genicular branches
 Popliteal vein and tributaries
 Termination of small saphenous vein
 Tibial nerve
 Common fibular nerve: lateral
 Posterior femoral cutaneous nerve: may see this
 Lymph nodes

Question 7

• Popliteal artery

Answer 7

o Begins at adductor hiatus
o Ends at inferior border of popliteus
 Anterior tibial artery
 Posterior tibial artery
• Genicular Anastomosis
o Branching off the popliteal artery
o Femoral artery becomes popliteal artery
o Branches off into superior medial and lateral genicular arteries
o Then lateral on branch off into inferior medial and lateral genicular arteries

Question 8

• Nerves

Answer 8

o Tibial and common fibular nerves
o Both give off branches which become the sural nerve
 Connection between tibial and common fibular nerves along the posterior aspect of thigh

Question 9

• • Muscles acting about hip joint

o Muscles attaching to external surface of ilium

Answer 9

abductors

 Gluteal maximus, medius & minimus

Question 10

o Attaching posteriorly on external surface

Answer 10

: extensors

 Gluteal maximus

Question 11

o Attaching on PSIS/ischium

Answer 11

lateral rotation

 Obturator externus, obturator internus, quadriceps femoris

Question 12

o Attaching on anterior portion of ala/ilium

Answer 12

: flexor or adductors

 Iliacus, sartorius

Question 13

Semitendinosus Actions

Answer 13

The semitendinosus flexes and internally rotates the leg at the knee joint, extends the femur at the hip, and stabilizes the pelvis in the sagittal plane at the hip joint.

Question 14

Semitendinosus Attachments

Answer 14

The semitendinosus originates from the ischial tuberosity and the sacrotuberous ligament and inserts medial to the tibial tuberosity in the pes anserinus. Innervation: Tibial nerve (L5 to S2).

Question 15

Semimembranosus Attachments

Answer 15

The semimembranosus originates from the ischial tuberosity and inserts onto the medial tibial condyle, oblique popliteal ligament, and popliteal fascia. Innervation: Tibial nerve (L5 to S2).

Question 16

Semimembranosus Actions

Answer 16

The semimembranosus flexes and internally rotates the leg at the knee joint. At the hip joint, it extends the femur and stabilizes the pelvis in the sagittal plane.

Question 17

pes anserinus

Answer 17

(goose’s foot) of the leg, the common distal attachment to the medial aspect of the proximal tibia of the following muscles:
the gracilis the sartorius the semitendinosus

Question 18

long head of the biceps femoris attaches to

Answer 18

ischial tuberosity

Question 19

short head of the biceps femoris, and confirm that it attaches

Answer 19

linea aspera

Question 20

sciatic nerve. Trace it inferiorly to identify its termination near or in

Answer 20

popliteal fossa as the tibial and the common fibular nerves.

Locate the popliteal artery

Question 21

Biceps Femoris Attachments

Answer 21

The long head of the biceps femoris originates from the ischial tuberosity and the sacrotuberous ligament. The short head of the biceps femoris originates from the lateral lip of the linea aspera in the middle third of the femur. Both heads of the biceps femoris insert onto the head of the fibula. Innervation: Long head, tibial nerve (L5 to S2); short head, common fibular nerve (L5 to S2).

Question 22

Biceps Femoris Actions

Answer 22

Both the long head and short head of the biceps femoris flex and externally rotate the leg at the knee joint.

The long head of the biceps femoris also extends the femur at the hip and stabilizes the pelvis in the sagittal plane

Question 23

Locate the popliteal artery and vein in the popliteal fossa. Trace them superiorly until they disappear through the

Answer 23

the adductor hiatus. You will see them again in the anterior compartment of the thigh, which they leave via this openin

Question 24

Locate the short saphenous vein

Answer 24

as it enters the popliteal fossa to terminate in the popliteal vein.

Question 25

popliteal fossa:

Answer 25

roof, the crural fascia
medial inferior border, the medial head of
gastrocnemius
lateral superior border, the long head of the biceps femoris
medial superior border, the semimembranosus
floor, the popliteus

Question 26

Gastrocnemius Attachments

Answer 26

The gastrocnemius originates from the medial and lateral epicondyles of the femur and inserts onto the calcaneal tuberosity via the Achilles’ tendon. Innervation: Tibial nerve (S1, S2).

Question 27

Gastrocnemius Actions

Answer 27

The gastrocnemius acts to flex the leg at the knee joint and to plantar flex the foot at the talocrural joint
Talocrural joint: plantar flexion
Knee Joint: flexion

Question 28

Identify the sciatic nerve. It terminates by

Answer 28

dividing into the common fibular and tibial nerves near the superior end of the popliteal fossa

Question 29

sural nerve

Answer 29

Trace the common fibular and tibial nerves inferiorly to identify their medial cutaneous branches, which combine to form

Question 30

Identify the popliteal artery

Answer 30

femoral artery after it passes through adductor hiatus becomes popliteal artery

Question 31

Trace the common fibular nerve inferiorly.

Answer 31

It will give off the lateral sural cutaneous nerve before eventually terminating as the deep and superficial fibular nerves. The common fibular nerve is palpable subcutaneously as it wraps around the neck of the fibula

Question 32

popliteal artery which contributes to genicular anastomosis of knee

Answer 32

a medial and lateral superior genicular
artery
a medial and lateral inferior genicular artery

Question 33

Popliteus Attachments

Answer 33

The popliteus originates from the lateral femoral condyle and the posterior horn of the lateral lemniscus and inserts onto the posterior tibial surface. Innervation: Tibial nerve (L4 to S1).

Question 34

Popliteus Actions

Answer 34

popliteus acts to flex and internally rotate the leg at the knee joint.

Question 35

plantaris

Answer 35

O: lateral epicondyle of femur, proximal to lateral head of gastrocnemius
I: calcaneal tuberosity
I: tibial nerve (S1-S2)
A: may prevent compression of posterior leg musculature during knee flexion

Question 36

soleus

Answer 36

O: on fibular head and neck, posterior surface and tibial soleal line, via tendinous arch
I: calcaneal tuberosity via Achilles tendon
I: tibial N: (S1-S2)
A: talocrural joint: plantar flexion

Question 37

triceps surae

Answer 37

gastrocnemius and soleus muscle