Posterior Thigh & Popliteal Fossa Flashcards
What are the 3.5 muscles of the posterior thigh?
Hamstrings
- Semitendinosus
- Semimembranosus
- Biceps Femoris: long head and short head
- 5: Adductor Magnus, hamstring portion
What structure can you identify for the anterior tibia?
Tibial tuberosity (location of pes anserinus)
What is the common proximal origin of the posterior thigh muscles?
Ischial tuberosity
-Except short head biceps femoris “odd ball”: lateral sipracondylar line and line aspera
Common innervation of posterior thigh ms?
Tibial division of sciatic n
-Except short head biceps femoris “odd ball”: common fibular division of sciatic n
Common functions of posterior thigh ms?
- Leg flexion @ knee
- Thigh extension @ hip (EXCEPT short head BF m)
- Slightly medially rotate flexed leg
What is the distinguishing part of the semitendinosus muscle?
long cord like tendon that starts 2/3 way down thigh and inserts on Pes anserinus
What is the Pes Anserinus and what muscles contribute?
- 3 fingered conjoining tendon
1. Sartorius (anterior, femoral n.)
2. Gracilis (medial, obturator n.)
3. Semitendinosus (tibial division of sciatic n)
-superficial to MCL
Pes Anserine Bursitis
- Inflammation of Anserine bursa between Pes anserinus and MCL (overuse or trauma)
- Result in consistent, aching pain aggravated by activity (specifically flexion and internal rotation of knee)
What 2 parts does the distal semimembranosus m tendon divide into?
- Medial tibial condyle (muscle attachment)
2. Oblique popliteal l
Oblique popliteal l
- Tendon of semimembranosus m
- Reinforces intercondylar portion of knee joint capsule
- Forms part of popliteal fossa floor
Generally what is a hamstring injury?
- Muscle strain or tear, but also hamstring tendinopathy
- Can involve avulsion fractures from ischial tuberosity
What is a grade 1 - mild hamstring injury?
- Small disruption in structural integrity
- minor swelling and pain
- no or minimal loss of strength
What is a grade 2 - moderate hamstring injury?
- partial tear with some intact muscle fibers
- pain present
- definite loss of strength
What is a grade 3 - severe hamstring injury?
- complete tear
- swelling, severe pain and typically accompanied by hematoma
- complete loss of motor function
When does the external iliac a change to the femoral a?
After it goes under the inguinal l.
When does the femoral a change to the popliteal a?
once it goes through the adductor hiatus
What muscle does the perforating branches of the deep femoral a go through?
adductor Magnus
Which nerves and nerve roots innervate the Biceps Femoris m?
Short head “odd”: common fibular division of sciatic n.
Long head: tibial division of sciatic n
Both L5-S2
What is the nerve root for the fibular division of sciatic n?
L4-S3
What is the nerve root for the Tibial division of sciatic n?
L4-S2
What is the superomedial boundary of the popliteal fossa?
semimebranosus and semitendinosus
What is the superolateral boundary of the popliteal fossa?
biceps femoris
What is the inferolateral boundary of the popliteal fossa?
lateral head of gastrocnemius
What is the inferomedial boundary of the popliteal fossa?
medial head of gastrocnemius
What makes up the floor of the popliteal fossa?
- oblique surface of femur
- oblique popliteal l.
- posterior surface of proximal tibia
How are arteries, veins, lymph nodes, and nerves organized in the popliteal fossa?
Superficial: Nerves
Intermediate: popliteal vein, branches, and lymph nodes
Deep: popliteal artery and branches
What are the nerves found in the popliteal fossa?
common fibular n and tibial n.
What veins are found in the popliteal fossa?
- small saphenous v.
- popliteal v. (union of anterior and posterior tibial v. near inferior border)
- superficial and same fibrous sheath as popliteal a.
What lymph nodes are found in the popliteal fossa?
review this
What arteries are found in the popliteal fossa?
popliteal a. with all branches (deepest structure in popliteal fossa)
What structure differentiates the superior and inferior genicular arteries?
medial and lateral heads of the gastrocnemius
What artery runs closely to distal femur that makes it an extra concern regarding injury?
popliteal a
Metaphyseal fracture of the femur
- transverse fracture across shaft
- most common distal femur fracture
Physeal fracture of the femur
- Commonly described as “Salter-Harris” Classification (1-5 types)
- Transverse fracture involving epiphyseal plate: layers involved range between (growth plate, metaphysic, epiphysis) or crush injury of growth plate
What would be the presentation indicating vascular injury from a distal femoral fracture?
- swelling of popliteal space
- absent/diminished dorsals pedis or posterior tibial pulses
- slow, distal cap refill
- Cole, pale feet
What would be the presentation indicating nerve injury from a distal femoral fracture?
- motor injury w/ foot drop
- sensory deficits to dorsal or plantar foot
What would be a serious complication to distal femur fractures?
acute compartment syndrome
What are the cause and presentation of acute compartment syndrome from a femur fracture?
- increased pressure within closed fascial compartment
- most commonly from hemorrhage and/or edema
- Symptoms: persistent deep ache/burning pain, paresthesia, pain with passive stretch, muscle weakness
Popliteal (Baker’s) cyst
- swelling in popliteal fossa due to enlargement of gastrocnemius-semimebranosus bursa
- associated with degenerative and inflammatory joint disease/injury
- mostly asymptomatic
What is the presentation of a popliteal baker’s cyst enlargement?
- Simulates DVT
- erythema
- edema due to vein compression
- ischemia due to arterial compression
- nerve entrapment
- positive Homan’s sign
What is the presentation of a popliteal baker’s cyst rupture?
- simulates thrombosis or muscle rupture
- warmth, tenderness, erythema
- ecchymoses
- compartment syndrome
- may cause little to no pain and just edema
What is a peripheral aneurysm?
- localized arterial enlargement due to weakened arterial wall
- popliteal are most common
Why are popliteal arteries the most common true peripheral arteries?
they involve all 3 layers of vessel wall
What are symptoms of a peripheral aneurysm?
- claudication or ischemic pain at rest
- sensory/motor deficit
- severe pain behind knee
What is peripheral artery disease?
Atherosclerosis (cholesterol build-up) leading to peripheral artery occlusion
-leads to lack of blood flow and pain to affected muscles
What is the clinical presentation of peripheral artery disease?
- Claudication (pain)
- ischemic pain at rest
- severe diffuse pain
- nonhealing ulcer
- gangrene
What are the consequences of injury to sciatic n?
…
What arteries are involved in the genicular anastomosis?
- Lateral femoral circumflex a, descending branch
- Descending genicular a.: including saphenous and articular branches
- Superior and inferior lateral genicular as
- Superior and inferior medial genicular as
- Middle genicular a
