The muscles of the thigh are responsible for various movements, including flexion, extension, abduction, and adduction of the hip and knee joints. These muscles can be broadly categorized into anterior (quadriceps), medial (adductors), posterior (hamstrings), and lateral (tensor fasciae latae) compartments. These muscles collectively contribute to the complex movements of the hip and knee joints, providing stability and support during various activities. Understanding their anatomy and function is essential for healthcare professionals involved in orthopedics, rehabilitation, and sports medicine.

1. Dr / Ahmed Salah Ashour(Ph.D.)
Associate professor of human anatomy
Dr.Ahmedashour@gmu.ac.ae
USMLE Clinical Anatomy

2. Case report

3. A young soccer player was diagnosed with
myositis ossificans 6 weeks after a muscle strain
in the right quadriceps muscles. Radiographic and
sonographic investigations initially helped to
confirm diagnosis and later supported clinical
improvement.
Calcifications along the medial
border of the proximal femur

4. MUSCLES OF
THE THIGH

5. The muscles of the thigh are responsible
for various movements, including flexion,
extension, abduction, and adduction of the
hip and knee joints. These muscles can be
broadly categorized into anterior
(quadriceps), medial (adductors), posterior
(hamstrings), and lateral (tensor fasciae
latae) compartments. These muscles
collectively contribute to the complex
movements of the hip and knee joints,
providing stability and support during
various activities. Understanding their
anatomy and function is essential for
healthcare professionals involved in
orthopedics, rehabilitation, and sports
medicine.

7. Muscles of front of thigh

8. Quadriceps Sartorius
Front of thigh
Three vasti Rectus femoris

9. Quadriceps muscle

10. The quadriceps femoris (resemble a 4-leaflet flower with only one stem) ,
commonly referred to as the quadriceps, is a group of four muscles located at the
front of the thigh. These muscles play a crucial role in knee extension and are
essential for various lower limb movements, including walking, running, jumping,
and standing up from a sitting position.
The four muscles that make up the quadriceps are:
1) Rectus Femoris
2) Vastus Lateralis
3) Vastus Medialis
4) Vastus Intermedius

11. THREE VASTI
1. Vastus medialis
2. Vastus lateralis
3. Vastus intermedius
• Origin
- Vastus medialis (Back of femur)
- Vastus lateralis (Back of femur)
- Vastus intermedius (Front of femur)
• Insertion
Patella – patellar ligament -- patellar tuberosity
• Nerve supply
Femoral n.
• Action
Extension of knee joint

12. • Origin
Front and sides of upper of shaft of femur
VASTUS INTERMEDIUS
Front and sides of upper of shaft of femur

13. Vastus
Lateralis
Intermeudius
medialis
Rectus femoris
Vastus
Lateralis
medialis
Patella
patellar ligament
patellar tuberosity

14. • Origin
Lower part of trochanteric line.
Base of lesser trochanter.
Spiral line.
Medial lip of linea aspera.
Medial supracondlar line.
VASTUS MEDIALIS
trochanteric line
lesser trochanter
Spiral line
Medial lip of linea aspera
Medial supracondlar line.

15. • Origin
Upper part of trochanteric line.
Base of greater trochanter .
Lateral lip of gluteal tuberosity
Lateral lip of linea aspera.
VASTUS LATERALIS
trochanteric line
GREATER trochanter
Gluteal tuberosity
Lateral lip of linea aspera

16. RECTUS FEMORIS
• Origin
a)Straight head: anterior Inferior iliac spine
b)Reflected head: groove above the acetabulum.
• Insertion
Patella – patellar ligament -- patellar tuberosity
anterior Inferior iliac spine
groove above the acetabulum
Patella
patellar tuberosity

17. • Nerve supply
Femoral nerve
• Action
Extension of knee
Flexion of hip

18. Vastus
Lateralis
Intermeudius
medialis
Rectus femoris
Vastus
Lateralis
medialis
Patella
patellar ligament
patellar tuberosity

19. Sartorius

20. • Origin
Anterior superior iliac spine
• Insertion
Upper part of medial surface of tibia (SGS)
SARTORIUS
Anterior superior iliac spine
Upper part of medial surface of tibia (SGS)

21. Sartorius (lateral)
Gracilis (intermeidate)
Semitendinosus (medial)

22. • Nerve supply
Femoral nerve
• Action
Abduction
Flexion of hip joint
Lateral rotation. Rectus femoris
Vastus
Lateralis
medialis
sartorius

23. Sartorius
Abduction of hip joint
Flexion of hip joint
Lateral rotation of hip joint.

24. Medial surface of thigh
+ + pectineus

25. Three adductors Pectineus
Medial of thigh
Gracilis

26. Three adductors

27. The adductor muscles refer to a
group of muscles in the inner
thigh that are responsible for
bringing the thigh towards the
midline of the body. The adductor
muscles include the:
1) Adductor longus
2) Adductor brevis
3) Adductor magnus

28. Adductor longus
Adductor magnus Adductor brevis
Gracilis

29. • Origin
Front of pubis body
• Insertion
Middle 1/3 of linea aspera
• Nerve supply
Anterior branch of obturator nerve
ADDUCTOR LONGUS
Front of pubis body
linea aspera

30. Adductor longus

31. obturator nerve
Posterior division
Anterior division
Adductor longus
Adductor brevis
Adductor magnus

32. ADDUCTOR BREVIS
Anterior surface of body of pubis
Inferior ramus of pubis
lesser trochanter
linea aspera
• Origin
Anterior surface of body of pubis
Inferior ramus of pubis
• Insertion
Back of femur a line from lesser
trochanter to linea aspera
• Nerve supply
Anterior branch of obturator nerve

33. Adductor longus
Adductor brevis

34. obturator nerve
Posterior division
Anterior division
Adductor longus
Adductor brevis
Adductor magnus

35. • Origin
pubic part: inferior ramus of
pubis
Ischial part ischial: ramus and
lower lateral of ischial
tuberosity
ADDUCTOR MAGNUS
inferior ramus of pubis
ischial ramus
ischial tuberosity

36. Adductor longus
Adductor brevis
Adductor magnus

37. • insertion
1- Pubic part:
a)Medial lip of gluteal tuberosity
b)Linea aspera and medial supra condylar ridge.
2- Ischial part: adductor tubercle
• Nerve supply
Pubic part posterior division of obturator nerve
Ischial part sciatic nerve
gluteal tuberosity
Linea aspera
adductor tubercle
medial supra condylar ridge

38. obturator nerve
Adductor magnus

39. Adductor magnus
sciatic nerve

40. Gracilis

41. • Origin
Body of pubis.
Inferior ramus of pubis.
• insertion
Upper part of medial surface of tibia
(SGS)
• Nerve supply
Anterior division of obturator nerve
Body of pubis.
Inferior ramus of pubis
Upper part of medial surface of tibia (SGS)

42. Adductor longus
Adductor brevis
Gracilis
Adductor magnus

43. Sartorius (lateral)
Gracilis (intermeidate)
Semitendinosus (medial)

44. Pectineus

45. • Origin:
Superior ramus of pubis
• Insertion:
Pectineal line of femur
• Nerve supply:
Femoral nerve
Superior ramus of pubis
Pectineal line

46. Pectineus

47. Actions of the three adductors:
The three adductors and gracilis produces adduction of hip
The ischial part of adductor magnus flex the knee and extend the hip.
The gracilis flex the hip joint

48. Three adductors + gracilis Ischial part of add. magnus Gracilis

49. Muscles of back of thigh

50. Two [semi] muscles Biceps femoris
Back of thigh [Hamstring]
Medial Lateral

51. Biceps femoris
Semi-tendinosus
Semi-membranosus

52. • Origin
a)long head: from lower and medial part of
the upper half of ischial tuberosity with
semitendinosus.
b)Short head: from lateral lip of linea aspera
and lateral supracondylar line
BICEPS FEMORIS
lower and medial part of
the upper half of ischial
tuberosity
lateral lip of linea aspera
and lateral supracondylar
line

53. • Insertion
Head of fibula
• Nerve supply
Sciatic
• Action
Flexion and lateral rotation of knee.
Extension of hip.
lower and medial part of
the upper half of ischial
tuberosity
lateral lip of linea aspera
and lateral supracondylar
line
Head of fibula

55. • Origin
from lower and medial part of the
upper half of ischial tuberosity with
long head biceps
• Insertion
Upper part of medial surface of tibia
(SGS) with sartorius and gracilis
SEMITENDINOSUS
lower and medial part of
the upper half of ischial
tuberosity

56. Sartorius (lateral)
Gracilis (intermeidate)
Semitendinosus (medial)

57. A
B
C D
A.SEMI-TENDINOSUS + LONG HEAD BI-CEPS
B.SEMI-MEMBRANOSUS
C.SUB-CUTANEOUS
D.ADDUCTOR MAGNUS

58. • Nerve supply
Sciatic
• Action
Flexion and medial rotation of knee.
Extension of hip.
Sciatic

60. • Origin
Upper and lateral of ischial tuberosity
• Insertion
Groove on the back of medial condyle of
tibial
SEMI-MEMBRANOSUS
Upper and lateral of
ischial tuberosity
back of medial condyle
of tibial

61. • Nerve supply
Sciatic
• Action
Flexion and medial rotation of knee.
Extension of hip.
Sciatic

63. The hamstrings test
by having the supine patient flex the limb 90° at the hip and knee and then further
flexing the knee against resistance.
Clinical Insight

64. Sartorius muscle
is the longest muscle in the human body.
Because it crosses 2 joints, it acts on both of
them (hip and knee).
However, despite its length, the sartorius is not
a particularly strong muscle.
Clinical Insight

65. Rectus Femoris test
Rectus Femoris acts in concert with the
other 3 muscles of the quadriceps
femoris and is tested clinically by
having the patient extend the leg,
flexed at the knee, against resistance.
Clinical Insight

66. Obturator nerve injury
The obturator nerve may become compressed by the
muscles of the medial compartment of the thigh,
causing weakness and/or atrophy with
thigh adduction.
Clinical Insight

67. Adductor test
The adductor muscles may be tested
collectively by asking a patient in the supine
position (on the back) whose lower limb is
extended to adduct the limb while one holds
the ankle to provide resistance to this
movement.
Clinical Insight

68. SGS stabilization
Gracilis, along with the sartorius and
semitendinosus, helps stabilize the medial
aspect of the extended knee (while the tensor
fasciae latae and the iliotibial tract do this on
the lateral side of the extended knee). The
gracilis is the weakest of the medial adductor
group of muscles.
Clinical Insight

69. Pes anserinus
The pes anserinus is the
conjoined tendon of
the sartorius, gracilis,
and semitendinosus.
It acts as the insertion of all three
muscles. This patient’s symptoms
indicate involvement of a different
muscle.
Clinical Insight

70. Hamstring test
The hamstrings are collectively tested by having the supine patient flex the limb 90°
at the hip and knee and then further flexing the knee against resistance.
Clinical Insight

71. Formative Quiz

72. Q1. Which muscle is primarily responsible for extending the thigh and is commonly
used in a surgical procedure to harvest a tendon for grafting in the reconstruction of
the anterior cruciate ligament (ACL)?
a) Rectus femoris
b) Sartorius
c) Biceps femoris
d) Semitendinosus

73. Q2. A 35-year-old male presents to the emergency department with complaints of
severe pain, numbness, and weakness in his right leg. He reports that the symptoms
began suddenly while he was lifting heavy boxes at work. On examination, he has
decreased sensation along the lateral aspect of his foot and toes, weakness in ankle
dorsiflexion and plantar flexion, and diminished reflexes in the affected leg. Straight
leg raise test is positive on the right side. Damage to the sciatic nerve can lead to
weakness in which of the following thigh muscles?
a) Hamstring
b) Adductor longus
c) Gracilis
d) Tensor fasciae latae

74. Q3. The iliotibial (IT) band, a fibrous band of tissue running down the lateral aspect
of the thigh, provides attachment points for which muscle?
a) Vastus medialis
b) Adductor magnus
c) Gluteus maximus
d) Semitendinosus

75. Q4. Which muscle of the thigh is responsible for adduction of the thigh and is often
involved in muscle strains seen in athletes, especially during kicking sports?
a) Vastus lateralis
b) Adductor longus
c) Pectineus
d) Gluteus medius

76. Q5. In a femoral hernia, a loop of the intestine protrudes through the femoral canal,
which is located just below the inguinal ligament. Which muscle forms the posterior
wall of the femoral canal?
a) Pectineus
b) Adductor magnus
c) Iliopsoas
d) Psoas major

77. Q6 25-year-old track athlete comes to the clinic because of right groin pain and
lower extremity weakness for the past 2 months. He notes worsening of symptoms
with exercise. On examination, the patient has atrophy of the medial compartment
of the right thigh with weakened adduction.
Injury to which of the following nerves is the most likely cause of this patient’s
presentation?
Femoral nerve
Inferior gluteal nerve
Obturator nerve
Sciatic nerve
Tibial nerve

78. Q1. d) Semitendinosus
Q2. a) Hamstring
3Q. c) Gluteus maximus
Q4. b) Adductor longus
Q5. d) Psoas major
Q6 Obturator nerve

79. List of Texts and Recommended Readings
• Last's Anatomy, Regional and Applied. Chummy S. Sinnatamby. 12th edition 2011, ISBN:13 - 978 0 7020 3394 0
(Available in ClinicalKey: https://www.clinicalkey.com/#!/browse/book/3-s2.0- C2009060533X)
• Estomih Mtui, Gregory Gruener and Peter Dockery. Fitzgerald's Clinical Neuroanatomy and Neuroscience. 7th
edition; 2016, ISBN: 13 - 978-0-7020- 6727-3 (Available in ClinicalKey:
https://www.clinicalkey.com/#!/browse/book/3-s2.0- C20130134113
• Drake, Richard L. Gray's Anatomy for Students, Third Edition, Elsevier Saunders 2015. ISBN-13: 978-0702051319
(Available in ClinicalKey: https://www.clinicalkey.com/#!/browse/book/3- s2.0-C20110061707).
• Sobotta Atlas of Human Anatomy. F. Paulsen. Vol.1, 15th Edition; 2013, ISBN: 9780702052514 (Available in
ClinicalKey: https://www.clinicalkey.com/#!/content/book/3- s2.0-B9780702052514500067)
• Sobotta Atlas of Human Anatomy. F. Paulsen. Vol.2, 15th Edition; 2013, ISBN:13 - 978-0-7020-5252-1 (Available in
ClinicalKey: https://www.clinicalkey.com/#!/browse/book/3- s2.0-C20130046919)

80. Recap