Ch. 20: Femoral triangle/Vessels and nerves of A/M thigh

Question 1

Boundaries of Femoral Triangle

Answer 1

1. Superior: Inguinal ligament
2. Medial: lateral border of adductor longus
3. Lateral: medial border of sartorius
4. Roof: fascia lata (deep fascia)
5. Pectineus, iliopsoas

Question 2

Contents of femoral triangle

Answer 2

NAVL: from lateral to medial

1. femoral nerve as it divides into cutaneous and motor branches
   * femoral n. courses laterally in a groove formed by iliacus and psoas major muscle joining
2. femoral artery with branches
3. Femoral veing
4. Lymphatics

NOTE: femoral a. and v. are ensheathed in a prolongation of transversalis fascia from abdomen called “femoral sheath” … Femoral N. is NOT located in this sheath

Question 3

Femoral Hernia

Answer 3

• occurs when gut protrudes from within the abdomen through the entrance of the femoral ring: an area at the opening of the femoral canal, located medial to the femoral v.

Question 4

Adductor Canal

Answer 4

• connects fmoral triangle with popliteal fossa
• begins at apex of femoral triangle and passes inferiorly until it reaches opening in adductor magnus tendon (adductor hiatus) which communicates with popleal fossa

Question 5

Boundaries of adductor canal

Answer 5

Anteromedially: sartorius (forms roof over canal) and vastoadductor membrane

Anterolaterally: vastus medialis

Posteriorly: adductor longus superiorly, adductor magnus inferiorly

Question 6

What does adductor canal contain?

Answer 6

1. Femoral artery (artery is lateral to vein anteriorally and medial to vein posteriorally - goes into the canal and out the hiatus)
2. femoral vein
3. motor nerve to the vastus medialis (from femoral n.)
4. saphenous n. (from femoral n.)

NOTE: as the femoral a. and v. descend to enter the adductor canal, the femoral a. comes to lie anterior to the femoral vein. the nerves that enter the adductor canal DO NOT exit the adductor hiatus. the nerve to vastus medialis pierces that muscle while in the canal, and the saphenous n. pierces the medial wall (vasoadductor membrane) of the adductor canal to become cutaneous. Aslo, the descending genicular a. branches from the femoral a. while in the canal and accompanies the saphenous n.

Question 7

Where is the femoral a. located?

Answer 7

• it is a continuation of the external iliac a. inferior to inguinal ligament
• superiorly in thigh it lies in the femoral triangle
• inferiorly in thigh it lies in adductor canal

NOTE: in the femoral triangle, the femoral a. lies LATERAL to the vein. As the pair descend in the thigh, the artery comes to lie ANTERIOR to the vein within the adductor canal. This will place the femoral a. in a more protected position within the popliteal fossa, directly adjacent to the posterior surface of the femur (covered by popliteus m.) and deep popliteal v.

Question 8

What are the branches of the femoral a?

Answer 8

1. superficial circumflex iliac a.
2. superficial epigastric a.
3. superficial external pudendal a.
4. deep external pudendal a.

(these are part of the units with abdomen and perineum)

5. deep(profunda femoral a.)

• lateral femoral artery (transverse and descending and ascending)
• medial circumflex femoral a.
• perforating aa.

6. descending genicular a.

• articular branch
• saphenous branch

Question 9

Deep Femoral A.

Answer 9

• arises from femoral a. posterolaterally, courses behind femoral a. parallel to femur b/w adductor longus and adductor brevis/magnus muscle
  1. Lateral Femoral Circumflex a.
• Ascending: deep to tensor fascia lata muscle
• Transverse: winds around femur within vastus lateralis muscle to anastomose with branches of medial femoral circumflex a, inferior gluteal a. and first perforating a. (cruciate anastamosis)
• Descending: descends on surface of vastus lateralis and participates with genicular anastomosis

2. Medial Femoral Circumflex a. dives b/w psoas and pectineus, supplies adductor muscles and deep glutial area (cruciate anastamosis)
3. Perforating aa. arise from lateral surface of deep femoral a. pierce adductor magnusand pass posterior to femur wihtin vastus lateralis

Question 10

Descending genicular a

Answer 10

• arises from femoral a. before it passes through adductor hiatus and divides into:

1. articular branch (penetrates vastus medialis and participates in genicular anastamosis)
2. saphenous branch (pierves vastoadductor membrane with saphenous n. and goes to subcutaneous areas of upper medial portion of leg)

Question 11

femoral vein

Answer 11

continuation of popliteal v. superior to adductor hiatus

• receives tributaries of femoral a. and the greater saphenous vein in the femoral triangle

Question 12

Obturator a.

Answer 12

• branch of internal iliac a.
• passes from pelvic cavity to thigh via obturator canal - remains deep in obturator externus muscle

Branches:

• Anterior
• Posterior: provides branches to acetabulum

obturator vein: parallels course of artery

Question 13

femoral n.

Answer 13

L2,3,4

• exits pelvis passing deep to inguinal ligament in groove between iliacus and psoas major
• passes through femoral triangle LATERAL to femoral vessels
• provides motor to pectineus, sartorius, rectus femoris, vastus muscles and articularis genu

–>two branches of femoral n. enter adductor canal; motor branch of vastus medialis and SAPHENOUS NERVE (L4)- its terminal branch pierces vastoadductor membrane (along with saphenous branch of descending genicular a.) and descends medially with greater saphenous v. to provide cutaneous sensation to medial portion of leg and foot and posterior portion of dorsum of foot

Question 14

Obturator N.

Answer 14

L2,3,4

• exits pelvis by passing through obturator canal
• devides into two branches at adductor brevis (“brevis sandwich):

1. Anterior division: adductor longus, brevis, gravilis and sometime pectineus
2. Posterior division: obturator externus muscle, portion of adductor magnus