Neurovascular Structures of the Thigh

EXTREMITY ANATOMY: Neurovascular Structures of the Thigh

Femoral Nerve

  • Definition: A major nerve serving the thigh, arising from the lumbar plexus.

  • Nerve Roots: L2-L4.

  • Composition: Largest branch of the lumbar plexus.

  • Location & Pathway:

    • Forms in the psoas muscle located in the abdomen.

    • Passes beneath the mid-part of the inguinal canal.

    • In the femoral triangle, it divides into terminal branches that innervate the anterior thigh muscles.

    • Sends articular branches to both the hip and knee joints.

  • Associated Nerves:

    • Subcostal nerve (T12)

    • Iliohypogastric nerve (L1)

    • Ilioinguinal nerve (L1)

    • Lateral femoral cutaneous nerve (L2-L3)

    • Femoral nerve (L2-L4)

    • Genitofemoral nerve (L1-L2)

    • Obturator nerve (L2-L4)

Femoral Triangle

  • Components:

    • Femoral nerve

    • Femoral artery

    • Femoral vein

    • Muscles: Psoas major, Iliacus, Pectineus, Adductor Longus, Sartorius, Rectus Femoris.

Saphenous Nerve

  • Definition: A branch of the femoral nerve.

  • Pathway:

    • A distal extension of the femoral nerve.

    • Passes through the adductor canal alongside the femoral artery and vein.

    • Proximal to the adductor hiatus, it passes between the sartorius and gracilis muscles.

  • Function: Supplies sensory innervation to the anterior-medial aspect of the knee and foot.

Nerve to Vastus Medialis

  • Definition: A branch of the femoral nerve.

  • Pathway: Runs with the femoral vessels.

  • Function: Innervates the vastus medialis muscle.

Obturator Nerve

  • Definition: A major nerve serving the medial thigh region.

  • Nerve Roots: L2-L4.

  • Location & Pathway:

    • Passes between the medial border of the psoas muscle and the lateral border of the iliac vessels to enter the obturator foramen.

    • Splits into anterior and posterior branches; adductor brevis lies in between.

  • Innervation:

    • Anterior branch innervates:

    • Adductor longus

    • Adductor brevis

    • Gracilis

    • Pectineus (sometimes)

    • Posterior branch innervates:

    • Obturator externus

    • Adductor magnus (specifically the adductor portion).

Femoral Artery

  • Definition: A continuation of the external iliac artery extending beyond the inguinal ligament.

  • Branches: Distal to the inguinal ligament, it gives rise to:

    1. Superficial epigastric artery

    2. Superficial (and sometimes deep) circumflex iliac artery

    3. Superficial and deep external pudendal arteries

  • Pathway:

    • Descends along the adjacent border of the iliopsoas and pectineus.

    • Bisects the femoral triangle; at the apex, it enters the adductor canal deep to the sartorius muscle.

    • After passing through the adductor hiatus, it becomes the popliteal artery.

Branches of the Femoral Artery

  1. Superficial Circumflex Iliac Artery: Arises 1-3 cm below inguinal ligament.

  2. Superficial Epigastric Artery.

  3. Deep artery of thigh (Profunda Femoris).

  4. Lateral Circumflex Femoral Artery.

  5. Medial Circumflex Femoral Artery.

  6. Perforating Arteries that supply the adductor magnus, hamstrings, and vastus lateralis.

Obturator Artery

  • Definition: Usually arises from the internal iliac artery.

  • Incident: Approximately 20% of individuals have an enlarged pubic branch of the inferior epigastric artery replacing the obturator artery.

  • Supplies:

    • Obturator externus

    • Pectineus

    • Adductors

    • Gracilis

  • Pathway:

    • Enters the medial compartment of the thigh through the obturator foramen.

    • Splits into anterior and posterior branches surrounding the adductor brevis; the posterior branch supplies the femoral head.

Venous Structures

Femoral Vein

  • Definition: A continuation of the popliteal vein.

  • Pathway:

    • Ascends in the adductor canal posterior to the femoral artery.

    • Enters the femoral sheath lateral to the adductor canal.

    • Becomes the external iliac vein at the inguinal ligament.

Deep Vein of the Thigh

  • Definition: Formed by the union of the deep perforating veins, which joins the femoral vein inferior to the inguinal ligament.

  • Connection: Great saphenous vein joins this vein distal to the inguinal ligament.

Neural Structures of the Gluteal Region and Posterior Thigh

Cluneal Nerves

  • Definition: Sensory nerves of the gluteal region.

  • Branches:

    • Superior Cluneal Nerves: Cutaneous branches of posterior rami of L1-3; serve the superior buttock above the iliac crest.

    • Middle Cluneal Nerves: Cutaneous branches of posterior rami of S1-3; exit through sacral foramen, serve adjacent areas.

    • Inferior Cluneal Nerves: Cutaneous branches of posterior rami of S2-3; exit inferior border of the gluteus maximus, ascend to the greater trochanter.

Deep Gluteal Nerves

  • Definition: Branches of the sacral plexus; exit via the greater sciatic foramen, primarily below the piriformis except for the superior gluteal nerve.

  • Nerve Types:

    • Superior Gluteal Nerve: Arises from anterior rami of L4-5; innervates gluteus medius, gluteus minimus, and tensor of the fascia lata.

    • Inferior Gluteal Nerve: Arises from anterior rami of L5-S2; innervates gluteus maximus.

Sciatic Nerve

  • Definition: The largest nerve in the body.

  • Formation: Formed by the anterior & posterior divisions of L4-S3.

  • Pathway:

    • Converges at the inferior border of the piriformis, emerges as a band ~2 cm wide.

    • Passes beneath the gluteus maximus midway between the greater trochanter and ischial tuberosity resting on the ischium.

  • Function: Supplies the posterior thigh muscles (not the short head of biceps femoris), continues to supply all leg & foot muscles and their sensation.

  • Anatomical Relationships: Lateral to the sciatic nerve are superior & inferior gluteal nerves, vessels, and pudendal nerve.

Arteries of the Gluteal Region and Posterior Thigh

  • Internal Iliac Artery Branches:

    • Superior gluteal artery

    • Inferior gluteal artery

    • Internal pudendal artery

  • Superior Gluteal Artery:

    • Exits pelvis via the greater sciatic foramen & divides into superficial and deep branches for gluteal muscles and surrounding tissues.

Internal Pudendal Artery

  • Definition: Arises from internal iliac artery.

  • Function: Supplies skin of external genitalia and perineal muscles; enters gluteal region via greater sciatic foramen.