Femoral triangle, Anterior and Medial Thigh Flashcards
Adductor Magnus
The adductor magnus is the largest muscle in the medial compartment. It lies posteriorly to the other muscles. Functionally, the muscle can be divided into two parts; the adductor part, and the hamstring part.
Adductor part – Originates from the ischiopubic ramus, attaching to the linea aspera of the proximal femur.
Hamstring part – Originates from the ischial tuberosity and attaches to the adductor tubercle and medial supracondylar line of the femur.
Actions: They both adduct the thigh. The adductor component also flexes the thigh, with the hamstring portion extending the thigh.
Innervation: Adductor part is innervated by the obturator nerve (L2-L4), the hamstring part is innervated by the tibial nerve (L4-S3).
Adductor Longus
The adductor longus is a large, flat muscle. It partially covers the adductor brevis and magnus. The muscle forms the medial border of the femoral triangle.
Attachments: Originates from the pubis, and expands into a fan shape, attaching broadly to the linea aspera of the femur
Actions: Adduction and medial rotation of the thigh.
Innervation: Obturator nerve (L2-L4).
Adductor Brevis
The adductor brevis is a short muscle, lying underneath the adductor longus.
It lies in between the anterior and posterior divisions of the obturator nerve. Therefore, it can be used as an anatomical landmark to identify the aforementioned branches.
Attachments: Originates from the body of pubis and inferior pubic rami. It attaches to the linea aspera on the posterior surface of the femur, proximal to the adductor longus.
Actions: Adduction of the thigh.
Innervation: Obturator nerve (L2-L4).
Obturator Externus
This is one of the smaller muscles of the medial thigh, and it is located most superiorly.
Attachments: It originates from the membrane of the obturator foramen, and adjacent bone. It passes under the neck of femur, attaching to the posterior aspect of the greater trochanter.
Actions: Laterally rotates the thigh.
Innervation: Obturator nerve (L2-L4).
Gracilis
The gracilis is the most superficial and medial of the muscles in this compartment. It crosses at both the hip and knee joints. It is sometimes transplanted into the hand or forearm to replace a damaged muscle.
Attachments: It originates from the inferior rami of the pubis, and the body of the pubis. Descending almost vertically down the leg, it attaches to the medial surface of the tibia, between the tendons of the sartorius (anteriorly) and the semitendinosus (posteriorly).
Actions: Adduction of the thigh at the hip, and flexion of the leg at the knee.
Innervation: Obturator nerve (L2-L4).
What is the fascia lata?
A deep fascial investment of the whole thigh musculature, analogus to a strong extesnible and elasticated stocking
What is the iliotibial tract?
A longitudinal thickening of the fascia lata, which is strengthened posteriorly by fibres from the gluteus maximus.
What is the action of the iliotibial tract?
An extensor, abductor and lateral rotator of the hip with an additional role in providing lateral stabilisation to the knee koint.
What is a femoral hernia?
- Femoral hernias develop when an out-pouching of gastric viscera protrudes through the femoral canal
- The protrusion becomes noticeable when it exits through the saphenous opening within the fascia lata = swelling inferior to the inguinal ligament
Which muscles act as hip flexors?
Pectineus, iliopsoas muscles (iliacus and psoas major) and the sartorius
Pectineus
Origin: Pectineal line of pubis
Insertion: Pectineal line of the femoral shaft, inferior to the lesser trochanter
Innervation: Femoral nerve
Action: Adducts and flexes the hip
Iliacus
Origin: Iliac fossa
Insertion: Lesser trochanter
Innervation: Femoral nerve
Action: Flexion at the hip and assists in lateral rotation
Psoas Major
Origin: Transverse processes of the lumbar vertebrae
Insertion: Lesser trochanter
Innervation: Anterior rami of L1-L3
Action: Flexion at the hip and assists in lateral rotation
Sartorius
Origin: Anterior superior iliac spine
Insertion: Superior medial surface of the tibia
Innervation: Femoral nerve
Action: Flexion, abduction and lateral rotation at the hip. Flexion at the knee joint.
Which muscles make up the quadriceps femoris?
Vastus lateralis, vastus intermedius, vastus medialis and the rectus femoris
Vastus lateralis
Origin: Greater trochanter
Insertion: Patella via the quadriceps femoris tendon
Innervation: Femoral nerve
Action: Extend at the knee joint
Vastus intermedius
Origin: Anterior lateral surface of the femoral shaft
Insertion: Patella via the quadriceps femoris tendon
Innervation: Femoral nerve
Action: Extend at the knee joint
Vastus medialis
Origin: Intertrochanteric line and medial lip of linea aspera
Insertion: Patella via the quadriceps femoris tendon
Innervation: Femoral nerve
Action: Horizontal fibres insert into patella and prevent lateral displacement
Rectus femoris
Origin: Ileum (just superior to the acetabulum)
Insertion: Patella via the quadriceps femoris tendon
Innervation: Femoral nerve
Action: Extend at the knee and flex at the hip joint
Which muscles are the thigh adductors?
Adductor longus
Adductor brevis
Adductor magnus (adductor part and hamstring part)
Gracilis
Obturator Externus
What are the borders of the femoral triangle?
Superior border – Formed by the inguinal ligament, a ligament that runs from the anterior superior iliac spine to the pubis tubercle.
Lateral border – Formed by the medial border of the sartorius muscle.
Medial border – Formed by the medial border of the adductor longus muscle. The rest of this muscle forms part of the floor of the triangle.
Anteriorly, the roof of the femoral triangle is formed by the fascia lata.
Posteriorly, the base of the femoral triangle is formed by the pectineus, iliopsoas and adductor longus muscles.
What are the contents of the femoral traingle?
N: Nerve.
A: Artery.
V: Vein.
E: Empty space (this is important as it allows the veins and lymph vessels to distend, so they can cope with different levels of flow).
L: Lymph canal.
Femoral nerve – Innervates the anterior compartment of the thigh, and provides sensory branches for the leg and foot.
Femoral artery – Responsible for the majority of the arterial supply to the lower limb.
Femoral vein – The great saphenous vein drains into the femoral vein within the triangle.
Femoral canal – A structure which contains deep lymph nodes and vessels.
The femoral artery, vein and canal are contained within a fascial compartment – known as the femoral sheath.
Femoral artery
• Femoral artery is a continuation of the external iliac artery (terminal branch of the abdominal aorta)
• The external iliac becomes the femoral artery when it crosses under the inguinal ligament and enters the femoral triangle
The great saphenous vein
- The great saphenous vein is formed by the dorsal venous arch of the foot, and the dorsal vein of the great toe
- It ascends up the medial side of the leg, passing anteriorly to the medial malleolus at the ankle, and posteriorly to the medial condyle at the knee
- The great saphenous vein terminates by draining into the femoral vein immediately inferior to the inguinal ligament.
Femoral Nerve
- Nerve Roots: L2-L4
- Motor: Innervates the anterior thigh muscles (except psoas major)
- Sensory: Supplies cutaneous branches to the anteromedial thigh (anterior cutaneous branches of the femoral nerve) and the medial side of the leg and
foot (saphenous nerve)
Obturator nerve
- Nerve roots: L2-L4
- Motor: Innervates the medial (adductor) compartment of the thigh – except for
hamstrings part of Adductor Magnus
• Sensory: Cutaneous branch innervates the skin of the medial thigh.
