Ligament	Attachments	Function
Iliofemoral	ASIS and acetabulum → intertrochanteric line (strong, Y-shaped ligament)	Prevents hyperextension
Ischiofemoral	Acetabular rim → circles superiorly and laterally to medial base of greater trochanter	Prevents hyperextension Screws femoral head into acetabulum
Pubofemoral	Pubic ramus → laterally and inferiorly to joint capsule	Tightens during extension and abduction Limits abduction
Transverse acetabular	Joins inferior ends of labrum, crosses acetabular notch	Completes the acetabular ring
Ligament of head of femur	Acetabular notch → fovea of femur (intracapsular but extrasynovial)	Contains artery to head of femur (minute in adults)

Fascial Compartments of the Thigh

• Superficial fascia

• Contains variable amounts of fat

• Cutaneous nerves, such as saphenous and sural

• Superficial veins, such as great and small saphenous

• Lymphatics

• Deep fascia = fascia lata

• Separates subcutaneous tissue from muscles

• Dense strong layer

• Prevents bulging of muscles during contraction, which improves efficiency of pumping blood through veins back to the heart

• Attaches to inguinal ligament, iliac crests, and sacrum superiorly and is continuous with crural fascia inferiorly (see Section 7.4, Lower Limb: Leg)

• Fascial septa from fascia lata divide thigh into three compartments: anterior, medial, and posterior

• Iliotibial tract

• Lateral thickening of fascia lata

• Conjoint aponeurosis of tensor fasciae lata and gluteus maximus muscles

• Attaches to tubercle on lateral condyle of tibia (Gerdy tubercle)

• Saphenous opening in fascia lata

• Deficiency inferior to medial inguinal ligament

• Spanned by cribriform fascia

• Saphenous vein and efferent lymphatic vessels form superficial inguinal nodes, pass through opening and cribriform fascia

Muscles of the Gluteal Region

• Extensor of hip: gluteus maximus

• Also laterally rotates hip

• Through iliotibial tract, extends knee

• Abductors of hip

• Gluteus medius

• Gluteus minimus

• Most important function of these muscles: contract to prevent sagging of unsupported side of hip during locomotion, enabling opposite foot to swing through (e.g., Trendelenburg test)

• Lateral rotators of hip

• Gemelli (superior and inferior)

• Quadratus femoris

• Extensors of knee

• Gluteus maximus

• Tensor fasciae latae

Muscle	Proximal Attachment (Origin)	Distal Attachment (Insertion)	Innervation	Main Actions	Blood Supply
Gluteus maximus	Ilium posterior to posterior gluteal line, dorsal surface of sacrum and coccyx, sacrotuberous ligament	Most fibers end in iliotibial tract that inserts into lateral condyle of tibia; some fibers insert into gluteal tuberosity of femur	Inferior gluteal nerve (L5–S2)	Extends flexed thigh, assists in lateral rotation, and abducts thigh	Inferior gluteal arteries mainly, and superior gluteal arteries occasionally
Gluteus medius	Lateral surface of ilium between anterior and posterior gluteal lines	Lateral surface of greater trochanter of femur	Superior gluteal nerve (L4–S1)	Abducts and medially rotates thigh at hips; steadies pelvis on leg when opposite leg is raised	Deep branch of superior gluteal artery
Gluteus minimus	Lateral surface of ilium between anterior and inferior gluteal lines	Anterior surface of greater trochanter of femur	Superior gluteal nerve (L4–S1)	Abducts and medially rotates thigh at hips; steadies pelvis on leg when opposite leg is raised	Main trunk and deep branch of superior gluteal artery
Piriformis	Anterior surface of sacral segments 2–4, sacrotuberous ligament	Superior border of greater trochanter of femur	Ventral rami of upper L5, S1, S2	Laterally rotates extended thigh, abducts flexed thigh at hip	Superior and inferior gluteal arteries, internal pudendal artery
Obturator internus	Pelvic surface of obturator membrane and surrounding bone	Medial surface of greater trochanter of femur	Nerve to obturator internus (L5–S2)	Laterally rotates extended thigh, abducts flexed thigh at hip	Internal pudendal and obturator arteries
Superior gemellus	Outer surface of ischial spine	Medial surface of greater trochanter of femur	Nerve to obturator internus (L5–S2)	Laterally rotates extended thigh at the hip	Inferior gluteal and internal pudendal arteries
Inferior gemellus	Upper margin of ischial tuberosity	Medial surface of greater trochanter of femur	Nerve to quadratus femoris (L4–S1)	Laterally rotates extended thigh at the hip	Medial circumflex femoral artery
Quadratus femoris	Lateral margin of ischial tuberosity	Quadrate tubercle on intertrochanteric crest of femur	Nerve to quadratus femoris (L4–S1)	Laterally rotates thigh at hip	Medial circumflex femoral artery

Muscles of the Thigh

• Anterior (= extensor) compartment

• Flexors of hip

• Sartorius (also abducts and laterally rotates hip and flexes and medially rotates knee)

• Iliopsoas

• Pectineus (also adducts hip)

• Extensor of knee: quadriceps femoris, composed of

• Rectus femoris (also flexes hip)

• Vastus lateralis

• Vastus intermedius

• Vastus medialis (also stabilizes patella)

Anterior Thigh Muscles

Muscle	Proximal Attachment (Origin)	Distal Attachment (Insertion)	Innervation	Main Actions	Blood Supply
Iliopsoas/ psoas major	Sides of vertebra T12 to L5 and transverse processes of L1–L5	Lesser trochanter of femur	Ventral rami of lumbar spinal nerves 1–3	Flexes thigh at hip and stabilizes the hip	Lumbar branches of iliolumbar artery
Iliacus	Superior 2/3 of iliac fossa, ala of sacrum, and anterior sacro-iliac ligaments	Lesser trochanter of femur and shaft inferior to it, to psoas major tendon	Femoral nerve (L2–L3)	Flexes thigh at hips and stabilizes hip joint, acts with psoas major	Iliac branches of iliolumbar artery
Tensor fasciae latae	Anterior superior iliac spine and anterior part of iliac crest	Iliotibial tract that attaches to lateral condyle of tibia	Superior gluteal nerve (L4–L5)	Abducts, medially rotates, and flexes thigh at hip; helps to keep knee extended	Ascending branch of lateral circumflex femoral artery
Sartorius	Anterior superior iliac spine and superior part of notch below it	Superior part of medial surface of tibia	Femoral nerve (L2–L3)	Abducts, laterally rotates, and flexes thigh; flexes knee joint	Femoral artery
Quadratus femoris	Lateral margin of ischial tuberosity	Quadrate tubercle on intertrochanteric crest of femur	Nerve to quadratus femoris (L4 to S1)	Laterally rotates thigh at hip	Medial circumflex femoral artery
Rectus femoris	Anterior inferior iliac spine and ilium superior to acetabulum	Base of patella and to tibial tuberosity via patellar ligament	Femoral nerve (L2–L4)	Extends leg at knee joint and flexes thigh at hip joint	Profunda femoris and lateral circumflex femoral arteries
Vastus lateralis	Greater trochanter, lateral lip of linea aspera of femur	Base of patella and to tibial tuberosity via patellar ligament	Femoral nerve (L2–L4)	Extends leg at knee joint	Lateral circumflex femoral and profunda femoris arteries
Vastus medialis	Intertrochanteric line, medial lip of linea aspera of femur	Base of patella and to tibial tuberosity via patellar ligament	Femoral nerve (L2–L4)	Extends leg at knee joint	Femoral and profunda femoris arteries
Vastus intermedius	Anterior and lateral surfaces of body of femur	Base of patella and to tibial tuberosity via patellar ligament	Femoral nerve (L2–L4)	Extends leg at knee joint	Lateral circumflex femoral and profunda femoris arteries
Pectineus	Superior ramus of Pubis	Pectineal line of femur	Femoral nerve (L2–L3) and sometimes obturator nerve	Adducts and flexes thigh at hip	Medial circumflex femoral artery, obturator artery

• Medial (= adductor) compartment

• Adductors of hip

• Adductors longus

• Adductor brevis

• Adductor magnus (also assists in lateral rotation of knee)

• Gracilis (also flexes knee)

• Obturator externus—laterally rotates hip

Medial Thigh Muscles

Muscle	Proximal Attachment (Origin)	Distal Attachment (Insertion)	Innervation	Main Actions	Blood Supply
Adductor longus	Body of pubis, inferior to pubic crest	Middle third of linea aspera of femur	Obturator nerve (anterior division) (L2–L4)	Adducts thigh at hip	Profunda femoris and medial circumflex femoral arteries
Adductor brevis	Body and inferior pubic ramus	Pectineal line and proximal part of linea aspera of femur	Obturator nerve (L2–L4)	Adducts thigh at hip, weak hip flexor	Profunda femoris, medial circumflex femoral, and obturator arteries
Adductor magnus	Inferior pubic ramus, ramus of ischium Hamstring part: sciatic nerve (tibial division)	Gluteal tuberosity, linea aspera, supracondylar line; Hamstring part: adductor tubercle of femur	Adductor part: obturator nerve (L2–L4) Hamstring part: tibial nerve (L4)	Adductor part: adducts and flexes thigh; Hamstring part: extends thigh	Femoral, profunda femoris, and obturator arteries
Gracilis	Body and inferior ramus of pubis	Superior part of medial surface of tibia	Obturator nerve (L2–L3)	Adducts thigh, flexes and medially rotates leg	Profunda femoris artery, medial circumflex femoral artery
Obturator externus	Margins of obturator foramen, obturator membrane	Trochanteric fossa of femur	Obturator nerve (L2–L3)	Laterally rotates thigh, stabilizes head of femur in acetabulum	Medial circumflex femoral artery, obturator artery

• Posterior (= flexor) compartment

• Hamstrings

• Biceps femoris—also laterally rotates knee

• Semitendinosus—also medially rotates knee

• Semimembranosus—also medially rotates knee

• Together extend hip (except short head of biceps femoris) and flex knee

• Hamstring part of adductor magnus—extends hip

Posterior Thigh Muscles

Muscle	Proximal Attachment (Origin)	Distal Attachment (Insertion)	Innervation	Main Actions	Blood Supply
Semitendinosus	Upper and medial ischial tuberosity	Superior part of medial surface of tibia	Tibial division of sciatic nerve (L5–S2)	Flexes leg, extends thigh	Perforating branch of profunda femoris and medial circumflex femoral arteries
Semimembranosus	Upper and lateral ischial tuberosity	Posterior part of medial condyle of tibia	Tibial division of sciatic nerve (L5–S2)	Flexes leg, extends thigh	Perforating branch of profunda femoris and medial circumflex femoral arteries
Biceps femoris	Long head: ischial tuberosity Short head: linea aspera and lateral supracondylar line of femur	Lateral side of head of fibula	Long head: sciatic nerve (tibial division) (L5–S2) Short head: sciatic nerve (common fibular division)	Flexes and laterally rotates leg, extends thigh at hip	Perforating branches of profunda femoris, inferior gluteal, and medial circumflex femoral arteries