Arteries + Veins + nerves of LL (pathways+imp. locations)

Question 1

Branches of the lumbosacral plexus

Answer 1

Lumbar plexus:
- formed by the anterior rami of L1-L3 and part of L4
- located within the psoas major musc.

Lumbosacral Trunk:
- Formed by the remainder of the anterior rami of the L4 + anterior rami of L5

Sacral Plexus:
- The lumbosacral trunk enters the pelvis to join the anterior rami of S1-3 and part of S4 to form the sacral pexus
- Located on the posterolateral aspect of the wall of the pelvis

Question 2

Branches of the Lumbar plexus in the LL

Answer 2

–Femoral nerve
– Obturator nerve
– Illoinguinal nerve
– Genitofemoral nerve
– Lateral cutaneous nerve of thigh
– Motor branches (to illiopsoas)

Question 3

Femoral nerve - pathway + branches + innervation

L2-L4

Answer 3

• Originates from L2-L4 of lumbar plexus
• Emerges from lateral part of psoas major
• Passes behind the inguinal ligament in the groove between psoas major and illiacus
• Enters the fem triangle

—-» Here it is split into its posterior and anterior divisions by the lateral circumflex femoral artery - give rise to sensory and motor branches of the fem n.

Motor branches supply:
- All anterior compartment muscles except for illiopsoas musc.
- Pectineus in the medial compartment

Sensory branches:
- Medial fem cutaneous n. (anteromedial aspect of thigh)
- Intermediate fem. cutaneous n. (anteromedial aspect of thigh)
- Saphenous nerve (anteromedial aspect of leg)
sensory innervation to:
- the knee and hip joints
- skin on the anteromedial aspect of the LL to the medial aspect of the foot

The SAPHENOUS N. :
- main sensory branch of the fem. n.
- Enters the add. canal but doesnt leave thru the add. hiatus in the posterior thigh instead travels MEDIALLY
- Instead emerges btwn SARTORIUS and GRACILIS
- To run SUPERFICIALLY down the medial aspect of the leg
- Here it accompanies the GREAT SAPH. V.
- Also gives off infrapatellar and medial crural cutaneous branches

INNERVATION: anterior and medial aspect of the leg and medial side of the foot

Question 4

Saphenous nerve pathway + innervation + Damage to it?

Answer 4

PATHWAY:
- Largest sensory branch of Fem n.
- Fem. n. gives off this branch in the add. canal - runs with fem vessels (V. + A.)
- Doesnt leave thru add hiatus
- Instead pierces sartorius and gracilis to run superficially and down the medial side of the leg.
- Here it accompanies the GREAT SAPH. V.
- Gives off infrapatellar and medial crural branches in the medial leg

INNERVATION:
- Skin on anterior and medial leg
- Skin on medial side of foot

DAMAGE:
when varicose veins are stripped

Question 5

What accompanies the Great saph Vein?

Answer 5

The saphenous nerve

Question 6

Obturator Nerve - Pathway+innervation+associated injuries/diseases/pain

L2-L4

Answer 6

PATHWAY:
– Originates from L2-L4 of lumbar plexus
- Emerges from MEDIAL border of psoas major
- Travels thru obturator canal in upper part of the obturator foramen
- Pierces the obturator externus muscle
- After this it splits into its posterior and anterior branches
—> Anterior branch - anterior to ADDUCTOR BREVIS
—-> Posterior branch - post. to add. brevis

INNERVATION:
—-> Motor:
- All medial compartemnt musc. of thigh except pectineus (fem n.) and hamstring part of add. magnus (sciatic n.)
- Obturator externus (small musc. of hip but also included in medial compartment of thigh)

—–> Sensory:
- Hip and knee joints (*referred pain)
- Innervates the skin on upper part of the medial thigh (** referred pain)

REFERRED PAIN:
* Since obt. n. innervates hip and knee joints
– pain from hip disease can be felt as knee pain - patient presents with knee pain symptoms

** Obt. n. innervates medial part of upper thigh
– Pain from PELVIC INFLAMMATION felt here

Question 7

Which muscle are the anterior and posterior branches of the obturator n. ant. and post. in relation to?

Answer 7

Adductor brevis muscle

Question 8

Ilioinguinal nerve - L1

Answer 8

• Pierces the transverse abdominis
• SUPPLIES:
  – penis + scrotum
  – medial side of upper thigh
  – strip of skin above inguinal ligament

Question 9

Genitofemoral nerve - L1 + L2

Answer 9

• descends on anterior psoas major
  SUPPLIES:
  – Its femoral branch supplies skin on anterior central part of thigh

Question 10

Lateral cutaneous nerve of thigh/Lateral fem. cutaneous nerve – Pathway+innervation+injuries

L2-L3

Answer 10

PATHWAY:
- originates from L2-L3
- Travels superior to and laterally on iliacus muscle
- Passes under lateral part of inguinal ligament
- Travels down lateral side of the thigh

SUPPLIES:
- Skin on lateral aspect of the thigh

INJURY:
Meralgia Paresthetica:
– Tingling, numbness and burning pain on outer thigh
– Due to compression of nerve
– tight clothing, pregnancy, obesity –> common causes

Question 11

Motor branches of lumbar plexus

Answer 11

Supply iliacus and psoas major

Question 12

Two main arteries supplying anterior and medial thigh?

Answer 12

Obturator Artery - branch of internal iliac A.
Femoral artery - Branch of external iliac A.

Question 13

Largest branch of the femoral artery?

Answer 13

Profunda femoris (Deep branch of fem A.)

Question 14

Branches of the profunda femoris? which ones and where they anastomose?

Answer 14

branches:
- Lateral circumflex femoral - supplies head and neck of femur, anterior part of gluteal region + femur +knee jt.
- Medial circumflex femoral - Head and neck of femur
- Perforating branches - Perforate add. magnus and supply posterior compartment of thigh

ANASTOMOSIS:
- medial and lateral circ. fem. A. anastomose encircle the uppermost part of the shaft of the femur and anastomose

Question 15

Main blood supply to hip joint by?

Answer 15

Branches of profunda fem:
- Lateral circumflex femoral
- Medial circumflex femoral

Acetabular branch of obturator A.

Question 16

Anastomosis arnd hip joint - which arteries are involved?

Answer 16

• Inferior gluteal artery
• Medial and lat circum. fem. arteries
• 1st perforating branch of profunda fem.

Question 17

How is the Fem A. clinically important?

Answer 17

• Pressure over the Fem. A can be applied to control heammorhage from the LL
• Radiologists use catheterisation of Fem A to gain access to arterial circulation
• Cardiologists also use catheterisation of the Fem. A. to reach the coronary arteries to perform coronary angiography
• One of the most common site for peripheral arterial disease – artery narrowed resulting in decreased blood supply to the LL.

Question 18

Obturator Artery - Pathway, branches, supply

Answer 18

• Branch of internal iliac A.
• Exits pelvis and enters medial compartment of the thigh through the obturator canal in the upper part of the obturator foramen
• Accompanies the obturator nerve
• As it passes thru obturator canal it gives off branches

BRANCHES:
- Posterior and anterior branches – encircle the obturator membrane margin

• Acetabular branch – enters hip joint by passing thru the acetabular notch and the ligament of the head of the femur to supply the head of the femur

Question 19

Venous drainage of LL - write a note on it

Answer 19

Has superficial, deep and perforating veins similar to in the UL

Superficial veins:

• The lateral part of the dorsal venous arch in the foot drains into the small saphenous vein and the medial part of the arch drains into the great saphenous vein.
• Great Saph V. –>
  > Medial part of dorsal venous arch drains into great saph.
  > Travels anterior to medial malleolus and travels up the medial side of the LL
  > Drains into the Fem. V. (deep vein) after passing thru the saphenous opening
  » Saphenous opening lies inferior to the medial end of the inguinal ligament
• Small Saph. V. –>
  > Travels up the posterior side of the leg
  > Drains into the popliteal Vein behind the knee

Deep veins:
- Accompany the arteries of the LL

Perforating Veins:
- Communicating veins between the deep and superficial veins
- Valves in these veins only allow flow from superficial to deep veins

Question 20

Where does the saphenous opening lie?

Answer 20

Inferior to the medial end of the inguinal ligament

Question 21

What issue/disease may be associated with the deep veins of the LL

Answer 21

Deep Vein thrombosis – blood clot formed in calf veins for example may travel up the Fem V. and eventually enter the Pulm. Artery and block circulation
** increased chance of occurring after surgery

Question 22

Which vein in the LL is frequently used for venous access

Answer 22

Fem. Vein in the fem triangle - easy access
Used in shocked patients w/ v low pressures

Question 23

What makes the Sacral plexus in the lower limb?

Answer 23

Lumbosacral trunk ( part of anterior rami of L4 and whole L5) joined with S1 - S3 and a little of S4 forms the sacral plexus

Question 24

Branches of sacral plexus in LL?

Answer 24

• Sciatic nerve
• Gluteal nerves (inferior+superior)
• Motor branches
• Posterior cutaneous nerve of thigh
• Pudendal nerve

Question 25

Sciatic nerve

Answer 25

• Enters gluteal region inferior to piriformis thru the sciatic foramen
• Travels downwards on posterior surface of the short muscles of the hip
• Enters posterior compartment of thigh and lies deep to hamstrings
• At the superior border of Pop. Fossa it divides into the common fibular/peroneal nerve and the tibial nerve

SUPPLIES:
- All posterior thigh muscles
- Hamstring part of adductor magnus (rest supplied by fem n.)
- branches of it supply all muscles in leg and foot (tibial + common peroneal)

Question 26

Gluteal nerves

Answer 26

Inferior and superior
- Supply Glut max, min and medius as well as tensor fascia latae

Question 27

Which is the only nerve to enter the gluteal region superior to piriformis?

Answer 27

superior gluteal nerve

Question 28

Motor branches of sacral plexus

Answer 28

Supply all small muscles of hip in gluteal region (not obturator externus)

Question 29

Posterior cutaneous nerve of thigh

Answer 29

Enters post. thigh thru greater sciatic foramen
Inferior to piriformis
Accompanies the sciatic nerve
- Innervates skin over posterior aspect of the thigh, the pop. fossa and upper part of the back of the leg