9/13 Posterior thigh and popliteal fossa

Question 1

posterior thigh muscles

Answer 1

Posterior Thigh Muscles

Hamstrings: – Tendons posterior to knee are used to hang hams of pigs – “Hamstringing” enemy & their horse during ancient times

Common proximal attachment: – Ischial tuberosity, except short head of biceps femoris

Common innervation: – Tibial division of sciatic nerve, except short head of biceps femoris (common fibular portion)

Functions: – Thigh extension, except short head of biceps femoris – Leg flexion (all four)

Question 2

posterior thigh muscles

Question 3

Semitendinosus

• Long, cordlike tendon that begins ~2/3 of the way down thigh
• Function: Extend thigh; flex leg (med. rotate)
• Innervation: tibial division of sciatic nerve

Answer 3

Semitendinosus Attachments

• Ischial tuberosity
• Medial surface of superior aspect of tibia

Question 4

Pes Anserinus

Question 5

Semimembranosus

• Function: Extend thigh; flex leg
• Innervation: tibial division of sciatic nerve

Answer 5

• Ischial tuberosity: – Flattened membranous proximal attachment
• Posterior part of medial condyle of tibia

Question 6

Semimembranosus Attachments

Distal tendon divides into 2 parts:

which are?

Answer 6

– Medial tibial condyle

– Part blends with popliteal fascia and becomes oblique popliteal ligament (reinforces the intercondylar part of joint capsule of knee)

Question 7

Biceps Femoris

what are the two parts?

what is the innovation?

Answer 7

Long head: Flex leg; extend thigh, tibial division of sciatic nerve

Short head: Only flexed leg, common fibular branch of the sciatic

Question 8

biceps femoris short and long heads

Answer 8

Biceps Femoris Attachments

Two heads:

1. Long head – Ischial tuberosity
2. Short head – Distal lateral lip of linea aspera

Common insertion on the head of the fibula

Question 9

Adductor Magnus: “Hamstring” Portion

• Attaches proximally at ischial tuberosity and distally to the adductor tubercle on the medial epicondyle of femur
• Function: Extend thigh
• Innervation: Tibial division of sciatic nerve

Answer 9

Question 10

Posterior Thigh Muscle Schematic

Question 11

popliteal fossa

• Boundaries:

1. Superomedially (semitendinosus & semimembranosus)
2. Superolaterally (biceps femoris)
3. Inferolaterally (lateral head gastrocnemius)
4. Inferomedially (medial head gastrocnemius)

Popliteal fossa contents (superficial to deep):

– Nerves

– Popliteal vein, lymph nodes and branches

– Popliteal artery and branches

Answer 11

Question 12

what is the deepest structure in the popliteal region?

from which artery? and gives rise to which artery?

Answer 12

Popliteal Artery

• Continuation of femoral artery:

– Becomes popliteal artery after passing through adductor hiatus

• Runs close to knee joint capsule:

– Gives rise to genicular branches…

Question 13

Popliteal Artery: Genicular Branches

• Participate in formation of genicular anastomosis: – Important collateral circulation bypassing popliteal artery:
• Knee fully flexed too long
• Narrowed or occluded popliteal vessels
• Supplies articular capsule and ligaments of knee joint

Answer 13

genicular anastomosis

Question 14

Femoral Artery Branches

“Put My Leg Down Please”

Profundus femoris (deep femoral artery)

Medial circumflex femoral artery

Lateral circumflex femoral artery

Descending genicular artery

Perforating Artery

Question 15

Popliteal Artery: Termination Ends by dividing into:

1. ______
2. ______

Answer 15

Anterior tibial artery

Posterior tibial artery

Question 16

Popliteal artery to termination

Question 17

Popliteal Vein

Formed by union of anterior & posterior tibial veins, usually near inferior border of popliteus muscle.

Answer 17

Small saphenous vein terminates into the popliteal vein

• Lies superficial to and in same fibrous sheath as popliteal artery
• Becomes femoral vein after traversing adductor hiatus

Question 18

Nerves in the Popliteal Fossa

Sciatic nerve usually ends at superior angle of popliteal fossa where it divides into the…

_____ and the _____ (peroneal) Nerve

Answer 18

Tibial Nerve and Common fibular

Question 19

Tibial Nerve

• Most superficial (relative to popliteal artery and vein)
• Distribution:

– Superficial and deep posterior leg muscles

– Knee joint

Answer 19

Question 20

Common Fibular (Peroneal) Nerve

• Leaves popliteal fossa by passing superficial to lateral head of gastrocnemius
• Winds around head and neck of fibula (susceptible to injury)
• Deep to fibularis longus it terminates into:

1. Deep fibular nerve
2. Superficial fibular nerve

Question 21

what is the cutaneous nerve in the lower thigh region?

Answer 21

sural nerve

• Composed of…

– medial sural cutaneous nerve from the tibial nerve

– sural (or fibular) communicating branch from the common fibular nerve or the lateral sural cutaneous nerve

• Runs inferiorly with small saphenous vein
• Supplies distal posterior aspect of leg and lateral aspect of ankle & foot

Question 22

sural nerve

Answer 22

Question 23

sural nerve