Popliteal fossa for Mmed and Medical students

**popliteal fossa** is a diamond-shaped area located at the back of the knee. It is a shallow depression that serves as an important anatomical region through which various nerves, blood vessels, and muscles pass. The boundaries and contents of the popliteal fossa are as follows:

### Boundaries:
- **Superolateral**: Biceps femoris muscle.
- **Superomedial**: Semimembranosus and semitendinosus muscles.
- **Inferolateral**: Lateral head of the gastrocnemius muscle.
- **Inferomedial**: Medial head of the gastrocnemius muscle.

### Contents:
- **Popliteal artery**: Continuation of the femoral artery.
- **Popliteal vein**: Travels alongside the artery and becomes the femoral vein.
- **Tibial nerve**: A branch of the sciatic nerve that innervates the posterior leg.
- **Common fibular (peroneal) nerve**: Another branch of the sciatic nerve that wraps around the fibula to innervate the lateral and anterior leg.
- **Lymph nodes**: Popliteal lymph nodes.

This region is clinically important, as it can be involved in conditions such as **popliteal aneurysms** or **Baker's cysts**. It is also a common area for palpation to assess pulses or check for swelling.
The **popliteal fossa** is a key area for understanding both anatomical structures and clinical significance, especially due to its complex network of vessels, nerves, and lymphatics.

### Clinical Anatomy of the Popliteal Fossa:

1. **Vascular Importance**:
- **Popliteal artery**: This is a continuation of the femoral artery and is a critical blood supply to the lower leg. The artery lies deep within the fossa and is vulnerable to trauma or vascular diseases. A **popliteal artery aneurysm** can occur here, which may cause compression of surrounding structures, leading to pain or distal ischemia (reduced blood flow).
- **Popliteal pulse**: The popliteal pulse is felt deep within the fossa and is more difficult to palpate compared to other pulses. It can indicate the status of blood flow to the lower limb and is commonly assessed in patients with peripheral vascular disease.

2. **Nerve Structures**:
- **Tibial nerve**: This is the larger branch of the sciatic nerve, which continues down the posterior leg and innervates most of the muscles in the posterior compartment of the leg and foot. Damage to this nerve can result in weakness of plantar flexion (pointing the toes) and inversion of the foot.
- **Common fibular (peroneal) nerve**: This branch runs along the lateral aspect of the knee and around the fibula. It is more superficial and prone to injury, which can result in **foot drop**—an inability to dorsiflex the foot, leading to a steppage gait.

3. **Common Clinical Conditions**:
- **Baker’s Cyst**: Also known as a popliteal cyst, it is a fluid-filled sac that forms when joint fluid bulges out from the knee joint capsule into the fossa. It can cause pain and swelling and may be mistaken for other masses.
- **Popliteal artery entrapment syndrome**: This can be considered and taken

1. 1
popliteal Fossa
SUPERVISOR DR K.E.OBETEN
Kesheni Lemi MMED SURGERY

2. 2
Learning outcome
•At the end of this lecture you should be able to:
oDescribe the popliteal fossa interms of;
–Boundaries ,
–Contents,
–Applied anatomy/Clinical relevance.

3. BOUNDARIES
•Diamond-shaped intermuscular space situated
on posterior aspect of the knee,
•Boundaries;
–Superolateral - biceps femoris
–Superomedial - semimembranosus &
semitendinosus
–Inferolateral - lateral head of gastrocnemius
–Inferomedial - medial head of gastrocnemius
–Posteriorly (roof) - skin and fascia
–Anteriorly (floor) - popliteal surface of
femur, posterior ligaments of the knee
(popliteal ligaments, fibrous capsule) and
popliteus muscle

4. Diagram
4

5. Contents
i. Popliteal artery and its branches
ii. Popliteal vein and its tributaries
iii. Terminal branches of the sciatic
nerve (tibial and common peroneal nerves)
•iv. Posterior cutaneous nerve of thig
•v. Descending genicular branch of the
posterior division of the obturator nerve
5

6. CONTENTS
•vi. Popliteal lymph nodes All the above
mentioned contents are packed in
popliteal fat
6

7. CONTENTS

8. 8

9. Popliteal Fossa - Fascia
•Superficial
–Contains:
•Fat
•Small saphenous vein
•Cutaneous nerves (posterior femoral, medial
and lateral sural)
•Deep
–Forms protective covering for:
•Popliteal artery/vein
•Tibial and common fibular nerves

10. BLOOD SUPPLY
•Popliteal artery
–Continuation of femoral artery after it has
passed through adductor hiatus
–Deepest structure in the popliteal fossa
–Ends at inferior border of popliteus muscle
by dividing into anterior and posterior tibial
arteries
– The popliteal artery is used for measuring
blood pressure in lower limb

11. DIAGRAM
11

12. POPLITEAL VEIN
.The popliteal vein continues as the femoral
vein at the adductor opening.
.The popliteal vein is located superficial
(posterior) to the popliteal artery
Tributaries i. Small saphenous vein ii.
Veins accompanying the branches of the
popliteal artery.
12

13. INNERVATION
•Tibial nerve
–Larger terminal branch of sciatic nerve
–Gives medial sural cutaneous n. and muscular
branch
•Common fibular nerve
–Smaller terminal branch of sciatic nerve
–Winds around the fibular neck, where it is
susceptible to injury

14. diagram
14

15. APPLIED ANATOMY
1.Popliteal /Baker’s cyst
•A cystic swelling in
popliteal fossa is usually
due to inflammation of the
bursae around the knee
joint or due to protrusion
of the synovial membrane
through the fibrous
capsule of knee joint.
15

16. Applied anatomy
•2.Popliteal abscess is
a painful swelling
that presents as a
red swelling in the
popliteal fossa. It
usually arises from
the inflammation of
popliteal lymph
nodes.
16

17. Popliteal aneurysm
The popliteal aneurysm due to dilatation of
popliteal artery presents as a pulsatile midline
swelling in the popliteal fossa. This may cause
edema of leg due to compression of popliteal vein.
The stasis of blood in the aneurysm may favor
formation of thrombosis and emboli, which may
enter the distal arteries causing pain and
ulceration and gangrene in the toes. The operative
treatment of popliteal aneurysm consists of
exposing and clamping the popliteal artery.
17

18. Foot drop
•Injury to common peroneal nerve leads
to paralysis of dorsiflexors of the
ankle joint and evertors of foot
supplied through its deep peroneal and
superficial peroneal branches
respectively. The paralysis of the above
muscles results in foot drop deformity
(inverted and plantarflexed foot). The
patient walks on the toes
18

19. Foot drop
19

20. References
Koshi, Rachel., (2017). Cunningham’s Manual of
Practical Anatomy, Upper and Lower
Limbs, Vo1 (16th ed.). Oxford, Oxford
University Press.
Netter, Frank H., (2011). Atlas of Human
Anatomy (5th ed.). Philadelphia,: Saounders
Elsevier.
Snell, Richard S., (2012). Clinical Anatomy by
Regions ( 9th Ed.). Philadelphia: Lippincott
Williams and Wilkins
20