Adductor Canal and Obturator Nerve Quiz

Medial Thigh Anatomy

• The medial thigh comprises muscles, nerves, and vascular structures.
• Revision of the anatomy including muscles, adductor canal & hiatus, neural structures, blood supply, and venous drainage is outlined.
• Aims to study muscle origins, courses, insertions, and actions, nerve locations, actions, and the blood supply and venous return mechanisms for the region.
• The medial compartment contains muscles like adductor longus, gracilis, adductor magnus, adductor brevis, and pectineus.
• The adductor canal is a channel passing through structures, including femoral artery, vein, saphenous nerve, lymph vessels, and nerves for vastus muscles. It starts at the inferior apex of the femoral triangle and ends at the adductor hiatus.
• Key borders include sartorius, adductor longus & magnus, and vastus medialis & intermedius.
• Gracilis originates from the pubic body and inserts on the medial surface of the tibia, just posterior to the sartorius. Its action is hip adduction, knee flexion, and medial rotation of the leg, innervated by the obturator nerve (L2-L3).
• Pectineus originates from the pectineal surface of the superior pubic ramus and insertion between the lesser trochanter and linea aspera. Action is hip adduction. Innervated by femoral nerve (L2-L3), possibly also obturator nerve.
• Adductor longus originates from the pubic crest, inserting on the linea aspera, and middle third of the femur. It's action is hip adduction and innervated by the obturator nerve (L2-L4).
• Adductor brevis originates from the body and inferior ramus of the pubis, inserting on linea aspera and upper part of the femur; action is adduction of the thigh, innervated by the obturator nerve (L2-L4).
• Adductor magnus originates from the ischiopubic ramus and ischial tuberosity, its insertion being the adductor portion and posterior femur from gluteal tuberosity and medial supracondylar ridge, and hamstring portion and adductor tubercle. It ADDucts the thigh and extends the thigh at the hip. Innervated by obturator (L3 & L4) and sciatic (L4 & L5) nerves
• The adductor canal and hiatus are key structures for blood vessels and nerves in the medial thigh area.
• Nerve supply to medial thigh muscles mainly comes from the obturator nerve (L2-L4).
• The obturator nerve gives both anterior and posterior divisions, and sometimes an accessory branch. Branches provide innervation to muscles and skin.

Vascular Structures

• Arterial supply is shared between profunda femoris, medial femoral circumflex, lateral femoral circumflex, and four perforating arteries.
• The profunda femoris is the largest, arising on the lateral side of the femoral artery below the inguinal ligament. Branches pass through pectineus and adductor brevis before passing medial to the femoral artery and vein, and behind the adductor longus tendon, and onto the adductor magnus. Perforating branches lie between the edges of the femur and tendinous insertion of adductor magnus.
• The obturator artery arises from the internal iliac artery, accompanying the obturator nerve through the canal, branching into medial and lateral branches supplying muscles and the hip joint.
• Both profunda femoris and obturator veins collect blood and drain into the femoral and internal iliac veins respectively.

Nerve Supply

• Sensory (cutaneous) nerves in the region come from two main nerves supplying skin of the medial thigh: the obturator nerve and medial femoral cutaneous nerve (a branch of femoral nerve). A little of the ilioinguinal nerve.
• Problems with the nerves in this area could lead to pain, paresthesia, loss of sensation, and loss of hip adduction.

Summary of Learning Objectives

• Learn the names of medial thigh muscles and their actions
• Learn the names of the nerves, and identify which nerves supply specific muscles and innervate the medial thigh skin.
• Understand the vascular structures associated with the medial thigh (arteries and veins).