This document provides information about the anatomy of the femoral triangle region. It describes the boundaries and contents of the femoral triangle, including the femoral nerve, artery, and vein. It also discusses the lymphatic drainage of the lower limb, specifically mentioning the superficial and deep inguinal lymph nodes. Additionally, it summarizes the course of the great saphenous vein and its tributaries as well as varicose veins and perforating veins.

1. Dr. Akram Jaffar
Dr.AkramJaffar
The Femoral TriangleThe Femoral Triangle
Akram Jaffar, Ph.D.

2. Dr. Akram Jaffar
Dr.AkramJaffar
References and suggested reading
• Moore KL & Dalley AF (2006): Clinically oriented anatomy. 5th
ed. Lippincott Williams
& Wilkins. Baltimore
• Snell RS (2006): Clinical anatomy by systems. Lippincott Williams & Wilkins.
Baltimore

3. Dr. Akram Jaffar
Dr.AkramJaffar
Objectives
After completion of this session, it is expected that the students will be able to
•Musculoskeletal Anatomy: Describe the deep fascia of the thigh: iliac fascia, inguinal ligament & lacunar ligament,
fascia lata & iliotibial tract, cribriform fascia, obturator membrane, compartments (anterior, posterior, medial) and the
intermuscular septa (lateral & medial); List the muscles of the femoral triangle: psoas major, iliacus, sartorius,
pectineus, adductor longus
•Neurovascular Anatomy: Describe: the course and branches of the femoral artery, the course and branches of the
profunda femoris artery: medial and lateral circumflex arteries and the perforating arteries, the course and branches
femoral nerve, the course and tributaries of the: great saphenous vein, femoral vein; the origin of the femoral nerve
from the lumbar plexus; the cutaneous innervation of the thigh
•Regional Anatomy: Describe: the borders and contents of the femoral triangle:
•Surface Anatomy: Define: the femoral triangle, saphenous opening; Locate: pubic tubercle, the iliac spines and crest,
the ischial tuberosity, the greater trochanter of the femur, the adductor tubercle, femoral condyles and epicondyles;
Delineate: the course of the femoral artery, nerve and vein in the femoral triangle, the great saphenous vein;
Demonstrate: the inguinal ligament, the iliotibial tract, femoral pulse
•Clinical Anatomy: Explain the clinical significance of: the midpoint of the inguinal ligament: palpation, compression
and cannulation of the femoral artery. the femoral canal; Femoral hernia: More common in females, Liable to
strangulate and difficult to reduce, Does not become of very big size; Cannulation of the femoral vein to reach the right
side of the heart; Cannulation of the femoral artery coronary angiography; Formation of varicose veins; The use of
great saphenous vein in grafting to bypass obstruction in blood vessels; Deep venous thrombosis and mechanism of
venous return to the heart.
•Indicate: Effects and diagnosis of femoral artery: Sudden occlusion, Gradual occlusion; Arterial anastomosis in
femoral artery occlusion; The site of femoral artery and vein puncture; The method, consequences and indications for
femoral nerve block; The differential diagnosis of a femoral triangle lump; The site, mechanism and effects of fractured
shaft of femur; Dermatomes of the thigh and overlap in sensory innervation; The area affected in meralgia
parasthetica; Saphenous nerve injury in venous cut down in front of the medial malleolus; The importance of the pubic
tubercle in differentiating femoral from inguinal hernia.
•Radiological Anatomy: Identify: the antero-posterior and lateral views of the proximal femur; the greater trochanter,
lesser trochanter and neck of femur; the pubic symphysis, body and superior and inferior rami of the pubis; the ramus
of the ischium and the ischial tuberosity; femoral angiograms and venograms and know major branches of the femoral
artery as seen on an angiogram; inguinal lymphangiogram

4. Dr. Akram Jaffar
Dr.AkramJaffar
Superficial thigh structures
• The fat of the front of the thigh contains:
– Cutaneous nerves
– Termination and tributaries of the great
saphenous vein
– Cutaneous branches of the femoral artery
– Lymphatic vessels and nodes.

5. Dr. Akram Jaffar
Dr.AkramJaffar
Inguinal ligament
• The lower border of the aponeurosis of
the external oblique muscle.
• Extends between the anterior superior
iliac spine and the pubic tubercle. External oblique
aponeurosis
Inguinal lig.
Pubic tubercle
ASIS

6. Dr. Akram Jaffar
Dr.AkramJaffar
Cutaneous nerves
• Subcostal nerve (T12)
• Ilioinguinal nerve (L1)
• Femoral branch of the genitofemoral
nerve (L1 & L2)
• Cutaneous branch of the obturator nerve
• Medial and intermediate cutaneous
nerves of the thigh (branches of the
femoral nerve L2, 3 & 4)
• Lateral cutaneous nerve of the thigh
which is a separate branch of the lumbar
plexus (L2 & 3).
intermediate
cutaneous n. of thigh
Femoral of genitofemoral
medial
cutaneous n. of thigh
Cut. Br. obturator n.
Ilioinguinal n.
Lat. cutaneous n. of thigh
Subcostal n.

7. Dr. Akram Jaffar
Dr.AkramJaffar
Lateral cutaneous nerve of the thigh
• Enters the thigh by passing through or beneath the inguinal ligament just medial to the
anterior superior iliac spine
• Meralgia parasthetica
– Pressure on the nerve at this site by protrusion of the abdomen in fat people may
lead to tingling sensation on the lateral side of the thigh at the region of distribution
of this nerve.
Lat. cutaneous n. of thigh
ASIS
Inguinal lig.
Lat. cutaneous n. of thigh
area of distribution

8. Dr. Akram Jaffar
Dr.AkramJaffar
Femoral triangle
• Location:
– Supero-medial part of the front of the thigh.
• Boundaries:
– Superiorly (base of the triangle):
• Inguinal ligament
– Laterally:
• medial border of sartorius muscle
– Medially:
• medial border of adductor longus muscle
• Therefore, adductor longus muscle lies in the floor
of the triangle.
– The apex
• where the medial border of sartorius and adductor
longus meet.
• The floor of the triangle (from medial to lateral)
– adductor longus, pectineus, psoas major, iliacus.
– The floor is gutter-shaped since all the muscles forming
the floor pass to the posterior aspect of the femur.
• Roof:
– Skin, superficial and deep fascia of the thigh.
Inguinal lig.
sartorius
Adductor longus
pectineus
Psoas major
iliacus

9. Dr. Akram Jaffar
Dr.AkramJaffar
Femoral triangle
• Contents:
– femoral nerve, artery, and vein
(from lateral to medial) and their
branches and tributaries
– Superficial and deep inguinal lymph
nodes.
Femoral n.
Femoral a.
Femoral v.
Inguinal L.N.

10. Dr. Akram Jaffar
Dr.AkramJaffar
Saphenous opening
• Gap in the top of the stocking of the fascia lata.
• Located 4cm inferolateral to the pubic tubercle.
• Has a sharp crescentic falciform margin.
• Closed by sieve-like cribriform fascia.
• Allows the passage of
– Lymphatic vessels from superficial  deep inguinal lymph nodes.
– Great saphenous vein and its tributaries.
Great saphenous v.
Femoral v..
Pubic tubercle
Falciform margin

11. Dr. Akram Jaffar
Dr.AkramJaffar
• As in the upper limb, the venous return in
the lower limb is by way of
• Superficial veins
• Lie in the superficial fascia
• Not accompanied by
corresponding arteries.
• Play a major role in temperature
regulation
• Deep veins
• Lie deep to the deep fascia
• Accompany arteries .
Venous return in the lower limb

12. Dr. Akram Jaffar
Dr.AkramJaffar
• A vein leaves each side of the
dorsal arch.
• Preaxial veins
• The great (long) saphenous vein
in the lower limb, and the
cephalic vein in the upper limb,
leave the preaxial side of the
dorsal venous arch.
• Run to the root of the limb.
• Pierce the deep fascia to open
into the main vein of the limb
(the femoral vein in the lower
limb and the axillary vein in the
upper limb).
Pre-axial and post-axial veins

13. Dr. Akram Jaffar
Dr.AkramJaffar
• Post axial veins:
• The small saphenous vein in the lower
limb and the basilic vein in the upper
limb drain the post axial side of the
dorsal venous arch.
• Pierce the deep fascia proximal to the
root of the limb
• Join the popliteal vein and the venae
comitantes of the brachial artery
respectively
Pre-axial and post-axial veins

14. Dr. Akram Jaffar
Dr.AkramJaffar
• The word "saphenous" is an Arabic derivation of the word
"‫"صافن‬ which means standing because it does not pulsate.
• Begins at the medial end of the dorsal venous arch of the
foot and passes anterior to the medial malleolus of the tibia
• The vein in front of the medial malleolus is accompanied by
a cutaneous nerve (the saphenous nerve), this relation
should be remembered so that not to injure the nerve while
cutting down for the vein
The great saphenos vein

15. Dr. Akram Jaffar
Dr.AkramJaffar
• Ascends to the medial aspect of the
knee about a hand’s breadth posterior
to the medial border of the patella
• Ascends to the saphenous opening
where it perforates the cribriform
fascia to end in the femoral vein; this
point is located about three-five
centimeters below and lateral to the
pubic tubercle.
The great saphenos vein

16. Dr. Akram Jaffar
Dr.AkramJaffar
• Before piercing the deep fascia, the
saphenous vein receives tributaries,
which correspond to the superficial
branches of the femoral artery.
• The superficial and deep external
pudendal veins drain the external
genitalia and are responsible for vulval
varicosity, which may accompany
varicosity of the great saphenous vein.
• Lateral and anterior cutaneous
veins.
Superficial epigastric
Superficial
circumflex iliac
Superficial & deep
External pudendal
Tributaries of the great saphenous vein
Lateral &
anterior
cutaneous vv.

17. Dr. Akram Jaffar
Dr.AkramJaffar
Tributaries of the great saphenous vein
• Accessory saphenous vein
– From the medial and posterior
aspect of the thigh.
– Often communicates with the small
saphenous vein.
Accessory saphenous v.
Accessory saphenous v.
Accessory saphenous v.
small saphenous v.

18. Dr. Akram Jaffar
Dr.AkramJaffar
• The small saphenous vein begins posterior to the
lateral malleolus
• Ascends lateral to the tendo calcaneus.
• Inclines medially to the midline of the calf
• Passes between the heads of the gastrocnemius
• Pierces the deep fascia (popliteal fascia)
• Terminates in the popliteal vein above the knee
joint in the popliteal fossa.
• The vein behind the lateral malleolus is
accompanied by a cutaneous nerve (the sural
nerve).
The small (short or external) saphenous vein

19. Dr. Akram Jaffar
Dr.AkramJaffar
Perforating (communicating) veins
• Penetrate the deep fascia from the
superficial to the deep vein.
• Contain valves that allow unidirectional flow
of blood from the surperficial to the deep
vein.
• Are compressed when muscles contract and
pressure increases in the deep fascia.
• Muscle contraction propel blood in the deep
veins toward the heart.

20. Dr. Akram Jaffar
Dr.AkramJaffar
Mechanisms of venous return
Arterial
pulsation
help
compress
and blood in
the veins

21. Dr. Akram Jaffar
Dr.AkramJaffar
Varicose veins
• Dilated and tortuous superficial veins.
• Results from incompetent valves in the
perforating veins.

22. Dr. Akram Jaffar
Dr.AkramJaffar
Lymphatic drainage of the lower limb
• Superficial inguinal lymph nodes:
• Arrangement:
– T-shape, one row of nodes runs parallel
to and below the inguinal ligament, while
the other row is arranged vertically
along the great saphenous vein.
Superficial
Inguinal LN
(horizontal gp)
Superficial
Inguinal LN
(vertical gp)
Great saphenous v
Inguinal lig.

23. Dr. Akram Jaffar
Dr.AkramJaffar
Lymphatic drainage of the lower limb
• Superficial inguinal lymph nodes:
• Drainage area:
– Superficial tissues (everything
superficial to the deep fascia)
– Lower limb (including the buttocks)
except posterolateral part of the calf
(drains to popliteal lymph nodes)
– Lower abdominal wall below the
umbilicus.
– External genitalia (excluding the testes).
– Perineum, the lower part of anal canal
and vagina
– Cornu of the uterus by means of
lymphatics that follow the round
ligament.
Superficial
Inguinal LN
(horizontal gp)
Superficial
Inguinal LN
(vertical gp)
Great saphenous v
popliteal LN
Inguinal lig.

24. Dr. Akram Jaffar
Dr.AkramJaffar
Lymphatic drainage of the lower limb
• Deep inguinal lymph nodes: Three
of four nodes. Lie medial to the
femoral vein, one being in the
femoral canal.
• Drainage area:
– Deep lymphatics that
accompany the femoral vessels
from the popliteal fossa
– Glans penis (or clitoris).
– Efferent lymphatics from the
superficial inguinal nodes that
pass through the cribriform
fascia.
• Efferent vessels from the deep
inguinal lymph nodes pass through
the femoral canal to enter the
external iliac group of lymph nodes.
External iliac LN
Deep inguinal LN
Femoral a & v
Femoral ring
Deep inguinal LN
Superficial
Inguinal LN
External iliac LN
Femoral ring
Cribriform fascia

25. Dr. Akram Jaffar
Dr.AkramJaffar
Inguinal lymphangiogram

26. Dr. Akram Jaffar
Dr.AkramJaffar
• Funnel-shaped fascial prolongation
of extraperitoneal fascia
(transversalis fascia anteriorly and
iliac fascia posteriorly)
• Extends beneath the inguinal
ligament.
• Terminates by fusing with the
adventitia of the femoral vessels
about 4cm inferior to the inguinal
ligament.
Femoral sheath
Inguinal lig
Femoral a.
Femoral v.
Femoral sheath
Extraperitoneal fascia

27. Dr. Akram Jaffar
Dr.AkramJaffar
Femoral sheath
• In the abdomen, the aorta and its
branches, the inferior vena cava and
its tributaries lie within the
extraperitoneal fascia; while spinal
nerves lie behind it
• Thus, the vessels which pass from the
abdominal cavity into the thigh must
pierce the fascial envelope while the
femoral nerve does not do so and is
thus located outside the femoral
sheath.
Femoral a.
Femoral v.
Femoral sheath
Extraperitoneal fascia
Femoral n.
Femoral n.
Extraperitoneal fascia
peritoneum
psoas fascia
transversalis fascia
Femoral a.

28. Dr. Akram Jaffar
Dr.AkramJaffar
Femoral sheath
• The femoral sheath is pierced
– Anteriorly: femoral branch of the genitofemoral nerve (to supply skin over the
femoral triangle).
– Medially: great saphenous vein as it joins the femoral vein.
Femoral of genitofemoral n.
Great saphenous v.
Femoral v..
Great saphenous v.
Femoral v..

29. Dr. Akram Jaffar
Dr.AkramJaffar
Femoral sheath
• The femoral sheath is subdivided
by two fascial septa into three
compartments:
– Lateral compartment for the
femoral artery
– Intermediate compartment for
the femoral vein
– Medial compartment called
the femoral canal
Femoral a.
Femoral v.
Femoral sheath
Femoral canal

30. Dr. Akram Jaffar
Dr.AkramJaffar
Femoral canal
• Medial compartment of the femoral
sheath.
• Allows the femoral vein to expand
• Contains lymph vessels, a lymph
node, and connective tissue.
• Conical in shape, widest at its
abdominal end which is called the
femoral ring.
L.N. of cloquet
Femoral v.
Lymph vessel
Femoral ring

31. Dr. Akram Jaffar
Dr.AkramJaffar
Lacunar ligament
• Triangular ligament.
• Extends horizontally backwards
from the medial end of the inguinal
ligament to the pectineal line on
the pubis.
• Has a crescentic free lateral edge.
• Forms the medial margin of the
femoral ring.
Femoral ring
Lacunar lig.
Inguinal lig.
Pectineal line

32. Dr. Akram Jaffar
Dr.AkramJaffar
Femoral ring
• Boundaries:
– Laterally: femoral
vein
– Posteriorly: superior
ramus of the pubis
covered by
pectineus muscle
– Medially: lacunar
ligament
– Anteriorly: inguinal
ligament.
Femoral ring
Lacunar lig.
Inguinal lig.
Pectineal line
Femoral v.

33. Dr. Akram Jaffar
Dr.AkramJaffar
Femoral ring
• The femoral ring is closed by
extraperitoneal tissue called the femoral
septum which is pierced by lymph
vessels connecting the deep inguinal
with external iliac lymph nodes.
Deep inguinal L.Ns
External iliac L.Ns
Femoral ring
Lymph vessel

34. Dr. Akram Jaffar
Dr.AkramJaffar
Femoral hernia
• The femoral ring is a weak area in the anterior
abdominal wall and allows the formation of a femoral
hernia.
• Hernia through the femoral ring.
• ♀ > ♂ because the femoral ring is larger owing to the
greater breadth of the female pelvis.
Femoral hernia
intestine
Femoral hernia

35. Dr. Akram Jaffar
Dr.AkramJaffar
Femoral hernia
• Strangulation may occur due to the rigid
boundaries of the femoral ring especially the
lacunar ligament.
• Initially the hernia is located within the femoral
canal and is thus small, but it can enlarge by
passing through the saphenous opening into
the subcutaneous tissue of the thigh.
Femoral hernia
Saphenous opening

36. Dr. Akram Jaffar
Dr.AkramJaffar
Femoral hernia
• The saphenous opening lies below the
point of attachment of superficial fascia of
the anterior abdominal wall to fascia lata;
therefore a femoral hernia emerging from
the saphenous opening (contrary to an
inguinal hernia) can never come to lie
within the space beneath Scarpa’s fascia
of the anterior abdominal wall.
• Thus a femoral hernia is always felt below
the inguinal ligament and can never
become very large since it emerges into
ordinary subcutaneous tissue.
Femoral hernia
inguinal hernia
Scarpa fascia
Inguinal lig.
cSaphenous opening
Femoral hernia

37. Dr. Akram Jaffar
Dr.AkramJaffar
Femoral artery
• Direct continuation of the external
iliac artery.
• enters the thigh deep to the
inguinal ligament, half way
between the anterior superior iliac
spine and the pubic tubercle.
• Pulsations can be felt in the
femoral triangle 2-3cm inferior to
midpoint of the inguinal ligament
(ASIS-Pubic tubercle).
• The head of the femur lies
posterior to the artery, separated
from it by psoas major muscle.
External iliac a.
Femoral a.

38. Dr. Akram Jaffar
Dr.AkramJaffar
Femoral artery
• Occupies the lateral compartment of
the femoral sheath.
• The femoral vein is medial to the
artery, but at the apex of the triangle
the vein spirals to become posterior to
the artery.
• Branches in the femoral triangle:
– Cutaneous branches: small
branches distributed to the lateral
thigh, lower abdomen, and
external genitalia
– Deep femoral a.: largest branch, is
the chief artery of the thigh.
Superficial circumflex iliac a.
Superficial epigastric a.
Superficial external
pudendal a.
Deep external
pudendal a.
Profunda femoris a.
Femoral v.

39. Dr. Akram Jaffar
Dr.AkramJaffar
Profunda femoris artery
• Arises from the lateral side of the
femoral artery, within the femoral
triangle.
• Spirals to pass posterior to the femoral
artery and vein.
• Leaves the femoral triangle between
pectineus and adductor longus
muscles.
Profunda femoris a.
Femoral a.

40. Dr. Akram Jaffar
Dr.AkramJaffar
Branches of the profunda femoris artery
• lateral and medial circumflex
femoral arteries:
– given in the femoral triangle
– encircle the shaft of the femur.
• Perforating branches:
– Four.
– Perforate the muscles they
meet.
– The fourth is the termination of
the vessel.
– The upper two arise in the
femoral triangle
Femoral a.
Lat. Circumflex
Femoral a.
Med. Circumflex
Femoral a.
Profunda
femoris a.
Ascending Br.
Transverse Br.
Descending Br.
perforating Br.
Femoral a.
Profunda
femoris a.

41. Dr. Akram Jaffar
Dr.AkramJaffar
Profunda femoris artery
• Lateral circumflex artery:
– Passes laterally between the
branches of the femoral nerve.
– Leaves the femoral triangle beneath
sartorius.
– Breaks up into three branches:
ascending, transverse, and
descending. The descending branch
slopes downward accompanied by
the nerve to vastus lateralis.
• Medial circumflex artery:
– Passes posteriorly.
– Leaves the femoral triangle between
psoas major and iliacus.
– Breaks into ascending and
transverse branches.
Descending Br.
n. to vastus laterlais
Femoral n.
Lat. Circumflex
Femoral a.
sartorius

42. Dr. Akram Jaffar
Dr.AkramJaffar
Trochanteric anastomosis
• Provides the main source of blood for the supply of the head of the femur.
• Lies near the trochanteric fossa, hence the name.
• Formed by the anastomosis of the descending branch of the superior gluteal artery
and the ascending branch of the lateral and medial circumflex femoral arteries. The
inferior gluteal artery usually participating by an anastomotic branch.
Lat. circumflex femoral a.
Med. circumflex femoral a.
Sup. gluteal a.
Trochanteric fossa

43. Dr. Akram Jaffar
Dr.AkramJaffar
Cruciate anastomosis
• Located at the level of the lesser
trochanter.
• Cruciform in shape hence the name.
• The transverse limb is formed by the
transverse branches of the medial and
lateral circumflex femoral arteries.
• The vertical limb is formed by a
descending branch from the inferior
gluteal artery (from internal iliac artery)
and an ascending branch from the first
perforating artery.
Lat. circumflex femoral a.
Med. circumflex femoral a.
Profunda femoris a.
Perforating a.
Femoral a.

44. Dr. Akram Jaffar
Dr.AkramJaffar
Occlusion of the femoral artery
• Anastomosis of branches of the femoral artery with
other arteries that cross the hip joint may supply blood
to the lower limb.
Perforating a.
Medial circumfelx
femoral a.
Lateral circumfelx
femoral a.
Inferior glutea a.
Superior glutea a.
4th
perforator
Popliteal a.

45. Dr. Akram Jaffar
Dr.AkramJaffar
Compression of the femoral artery
• Just inferior to the midpoint of the
inguinal ligament (midway between
ASIS & pubic tubercle).
• Pressing posteriorly against superior
pubic ramus, psoas major and femoral
head.
Femoral a.
Psoas major
Head of femur
ASIS
Inguinal lig.
Pubic
tubercle

46. Dr. Akram Jaffar
Dr.AkramJaffar
Cannulation of the femoral artery
• Inferior to the midpoint of the inguinal
ligament.
• A slender catheter is passed into the
femoral artery  external iliac a. 
common iliac a.  aorta  coronary
arteries or left ventricle.
catheter
aorta
Coronary a.
Femoral a.
Common
iliac a.
External
iliac a.
aorta

47. Dr. Akram Jaffar
Dr.AkramJaffar
Femoral angiogram
Femoral a.
Profunda femoris a.
Lat. circumflex a.
Femoral a.
perforating Br.

48. Dr. Akram Jaffar
Dr.AkramJaffar
Femoral vein
• Ends posterior to the inguinal
ligament where it becomes the
external iliac vein.
• Its tributaries correspond to the
branches of the femoral artery.
• It also receives the great saphenous
vein into which the cutaneous veins of
the inguinal region drain.
Femoral v.
Great saphenous v.

49. Dr. Akram Jaffar
Dr.AkramJaffar
Femoral venogram
• Valves form an essential
part of the venous pumping
mechanisms returning
blood from the lower limbs
against gravity

50. Dr. Akram Jaffar
Dr.AkramJaffar
Femoral nerve
• Is the nerve of the anterior
compartment of the thigh.
• Branch of the lumbar
plexus in the abdomen
(L2, 3, & 4).
Femoral n.

51. Dr. Akram Jaffar
Dr.AkramJaffar
Femoral nerve
• Enters the thigh deep to the inguinal
ligament lateral to the femoral artery
and outside the femoral sheath
• Lies on iliacus.
• An inch distal to the femoral sheath
it breaks up into a number of
branches through which pass the
lateral circumflex femoral artery.
Femoral n.
iliacus
Lat. Circumflex
Femoral a.

52. Dr. Akram Jaffar
Dr.AkramJaffar
Branches of the femoral nerve
• Muscular branches:
– Sartorius
– Four heads of quadriceps femoris.
– May also supply pectineus, which is also
supplied by the obturator nerve.
– Iliacus is supplied by the femoral nerve in
the iliac fossa.
• Articular branches:
– The nerve to rectus femoris sends an
articular branch to the hip joint.
– The nerve to vastus medialis sends an
articular branch to the knee joint.
• Cutaneous branches:
– Medial and intermediate cutaneous nerves
of the thigh
– saphenous nerve, which becomes
cutaneous in the leg and foot.

53. Dr. Akram Jaffar
Dr.AkramJaffar
Femoral nerve block
• Two cm inferior to the inguinal ligament
and lateral to the femoral artery.
• Inserting the needle results in a twitch
of quadriceps femoris muscle.
• Results in loss of sensation in the
anterio-medial thigh and saphenous
nerve distribution (medial leg), as well
as quadriceps muscle relaxation