Skeletal muscles are attached to bones and allow voluntary movement. They consist of bundles of cells called muscle fibers. Muscle fibers contain protein filaments of actin and myosin that slide past each other, causing contraction. Muscles are arranged in antagonistic pairs around joints to enable movement. The muscular system includes three layers of skeletal muscles - superficial, intermediate and deep muscles of the forearm that flex the hand. Extensor muscles on the back of the forearm extend the hand. Intrinsic hand muscles control fine finger movements. Nerves stimulate muscle contraction while blood vessels supply muscles with oxygen and nutrients.

1. MUSCULAR SYSTEM
Skeletal muscle

2. Skeletal Muscle
• Skeletal muscles are muscles which are attached to the skeleton.
• 40% of human body mass
• Skeletal muscles are mainly responsible for locomotion, and voluntary
contraction and relaxation.

3. Structure of Skeletal muscles
• Cell structure
– Muscles cells contain many nuclei
– The plasma membrane→ sarcolemma
– The cytoplasm→ sarcoplasm
– Length
– ranges from 0.1cm to more the 30cm in length
– Diameter
– ranges from 0.001cm to 0.01cm in diameter

4. Structure of skeletal muscle
• Muscles are made of bundles of muscle fibers that are held together
by connective tissue

5. Cont…
 Epimysium: This is the connective
tissue wrap just under the deep fascia
that surrounds the entire muscle
 Perimysium: This connective tissue
surrounds each individual fascicle
(bundle of muscle fibers).
 Endomysium: This is the connective
tissue wrapped around each individual
muscle cell (fiber).

7. Structure of Skeletal muscles
• The myofibril consists of protein chains called
myofilaments
– Myofilaments have a symmetrical, alternating pattern of
thick and thin elements.

8. Skeletal Muscle Myosin
• Thick myofilament
• consists of a large number of bundled myosin molecules aligned in
overlapping arrays.

9. Skeletal Muscle Actin
• The thin myofilament (F-actin, filamentous actin)
– made up of two helically intertwined chains of G-actin (globular actin) units.
• Other proteins that bind to the actin molecules:
• Tropomyosin
• The Troponin complex→ made up of three members

10. MUSCLE ARRANGEMENTS
• Muscles are arranged around
the skeleton to bring
movements.
• Two general types of
arrangements
oOpposing (antagonists)
o Cooperative (synergists)

11. Synergistic Muscles
• Synergistic muscles are those
with the same function, or
those that work together to
perform a particular function.
• biceps brachii flexes the
forearm.
• Brachioradialis and brachialis
also flexes the forearm.

12. Naming Skeletal Muscles
1-Direction of Muscle
Fibers Relative to the
Midline
• RECTUS: parallel to the
midline
• Eg: Rectus Abdominus
• TRANSVERSE:
perpendicular to midline
• Eg: Transverse Abdominus
• OBLIQUE: diagonal to
midline
• Eg: External Oblique

13. 2. Location
• Structure near which
muscle is found
• FRONTALIS near FRONTAL
bone
• OCCIPITALIS near OCCIPITAL
bone

14. 3. Size
• Relative Size of Muscle
• MAXIMUS: largest
• Gluteus Maximus
• MEDIUS: middle
• Gluteus Medius
• MINIMUS: smallest
• Gluteus Minimus
• LONGUS: longest
• Fibularis Longus
• BREVIS: short
• Fibularis Brevis
• TERTIUS: shortest
• Fibularis Tertius

15. 4. Number of Origins
• Number of tendons of
origin
• BICEPS: Two
• Biceps Brachii
• Biceps Femoris
• TRICEPS: Three
• Triceps Brachii
• QUADRICEPS: Four
• Quadriceps Femoris

16. 5. Shape
Relative Shape of the Muscle
• DELTOID: triangular shape
• TRAPEZIUS: trapezoid shape
• SERRATU: saw-toothed
• RHOMBOIDEUS: rhomboid
shape
• TERES: round

18. • Pennate (penniform) muscle is a muscle with fascicles that attach obliquely to its tendon.
allow better stabilization and force production but less flexibility.

20. Muscles of facial expression
• Are located within the layers of superficial fascia.
• Developed from the mesoderm of the 2nd pharyngeal arch,
• Innervated by facial nerve.
• Functionally, they perform an all important function of non-verbal
communication in addition to closing and opening the orifices in the region of
of face.
Grouped into:
(a) muscles of the scalp,
(b) muscles of the external ear
(c) muscles of the eyelid
(d) the nasal muscles
(e) the oral muscles.

29.  Platysma is a large, thin sheet of
muscle in the superficial fascia of the
neck.
 It arises below the clavicle in the upper
part of the thorax and ascends through
the neck to the mandible.
 At this point, the more medial fibers
insert on the mandible, whereas the
lateral fibers join with muscles around
the mouth.
 Platysma tenses the skin of the neck
and can move the lower lip and
corners of the mouth down.
Platysma

30. FACIAL MUSCLES AND EMOTIONAL EXPRESSIONS
The facial muscles responsible for important emotional expressions are presented in Table 3.3.

32. Muscles of the neck

39. Blood supply of face and neck

41. Nerve supply of muscles of the face

42. Nerve supply of
muscles of the
neck

43. Muscle of pectoral region

47. Posterior Axioappendicular Muscles
• Attach the superior appendicular skeleton to the axial skeleton
• Divided into three groups
• Superficial (extrinsic shoulder) muscles :
• trapezius and
• latissimus dorsi
• Deep (extrinsic shoulder) muscles :
• levator scapulae and
• rhomboids
• Scapulohumeral (intrinsic shoulder) muscles:
• deltoid, teres major, and
• the four rotator cuff muscles (supraspinatus, infraspinatus, teres minor, and
subscapularis)

52. Scapulohumeral(intrinsic shoulder) Muscles
• Six muscles
• Deltoid
• Teres major
• Supraspinatus
• Infraspinatus
• Subscapularis
• Teres minor
• Short muscles that pass from scapula to humerus
• Act on glenohumeral joint

55. Rotator Cuff Muscles (SITS)
• Teres Minor
• External Rotation
• Subscapularis
• Internal Rotation
• Supraspinatus
• Abduction
• Infraspinatus
• External Rotation

57. MUSCLES OF THE UPPER LIMB
• MUSCLES OF THE ARM
• MUSCLES OF THE FOREARM
• MUSCLES OF THE HAND

58. MUSCLES OF THE ARM
Anterior (flexor ) group
• Coracobrachialis
• Biceps brachi
• Long head
• Short head
• Brachialis
Posterior(extensor)group
• Triceps Brachai
• long head
• Lateral head
• medial head
• Anconeus

59. Coracobrachialis
• an elongated muscle in the superomedial part of the arm
• Origin: coracoid process of the scapula
• Insertion: medial shaft of the humerus at about its middle part
• Innervation : musculocutaneous nerve, C5,6,(C7)
• Action: flexes the humerus and assists to adduct the humerus

60. Coracobrachialis

61. Biceps brachii
• Although the biceps is located in the arm it
has no attachment to the humerus
• Origin:
- long head- supraglenoid tubercle
-short head- tip of the coracoid process of
the scapula
• Insertion: radial tuberosity
• Innervation: musculocutaneous nerve, C5,6
• Action : Supinates forearm and when it is
supine flexes forearm

62. • is the main flexor of the forearm
• Origin: lower 1/2 of anterior humerus,
both intermuscular septa
• Insertion: ulnar tuberosity and ulnar
coronoid process
• Innervation :musculocutaneous nerve,
C5,6
• Action : elbow flexion (prime mover)
Brachialis

63. Triceps brachi
• The main extensor of the forearm
• Because the long head of the triceps crosses the shoulder joint, it also
aids in extension and adduction of the arm.
Origin:
- long head - infraglenoid tubercle of the scapula
- lateral head - upper half of the posterior surface of the shaft of the
humerus
- medial head - posterior shaft of humerus, distal to radial groove (deep
to the long & lateral heads)
Insertion: olecranon process
• Innervation: radial nerve, C6,7
• Action: chief extensor of forearm

64. Anconeus
• small triangular muscle and is on the
lateral part of the posterior aspect of
the elbow.
• Origin: posterior surface of the
lateral epicondyle of the humerus
• Insertion: lateral aspect of olecranon
• Innervation: radial nerve, C6,7
• Action :assists triceps in extension of
elbow

65. Cubital fossa
• Shallow triangular depression on anterior surface of the elbow
• Boundaries
• Superiorly, an imaginary line connecting the medial and lateral
epicondyles
• Medially, pronator teres
• Laterally, brachioradialis
• Floor
• brachialis and supinator muscles
• Roof
• the continuity of brachial and antebrachial (deep) fascia, reinforced by
the bicipital aponeurosis, subcutaneous tissue and skin

66. • Contents
• Brachial artery and branches, radial and ulnar arteries
• Accompanying veins of the arteries
• Biceps brachii tendon
• Median nerve
• Radial nerve, dividing into its superficial and deep
branches
• Median cubital vein
• Medial and lateral cutaneous nerves of the forearm

69. • The flexor muscles are arranged in three layers:
1. Superficial layer
• Pronartor teres
• Flexor carpi radialis
• Palmaris longus
• Flexor carpi ulnaris
 These muscles are attached to the medial epicondyle of the
humerus , the common flexor attachment.

72. 2. Intermediate layer_ consists of one muscle
• Flexor digitorum superficialis
3. Deep layer- three muscles
• Flexor digitorum profundus
• Flexor pollicis longus
• Pronator quadrates

73. Pronator teres
• Most lateral of the superficial muscles
• Its lateral border forms the medial
boundary of the cubital fossa.
• Origin:
- humeral head: medial epicondyle via
the common flexor tendon (CFT)
,medial intermuscular septum
- ulnar head - coronoid process of ulna
• Insertion: lateral aspect of radius at the
middle of the shaft (pronator
tuberosity)
• Innervation : median nerve, C6,7
• Action: pronates forearm & weakly
flexes the elbow

74. Flexor carpi radialis
• a long fusiform muscle located
medial to the pronator teres
• Its tendon is a good guide to the
radial artery, which lies lateral to it
• Origin :Medial epicondyle of
humerus
• Insertion: base of 2nd metacarpal
• Innervation: median nerve
• Action: flexes and abducts hand

75. Palmaris longus
• has a short belly and long cord-
like tendon that is a useful guide
to the median nerve
• Oirgin: Medial epicondyle of
humerus
• Insertion: distal half of flexor
retinaculum and palmar
aponeurosis
• Innervation: median nerve
• Action: flexes hand and tenses
palmar aponeurosis

76. Flexor carpi ulnaris
• This is the most medial of the
superficial flexor muscles in the
forearm.
• It has 2 heads of proximal
attachment, between which the
ulnar nerve passes distally in the
forearm
• Origin: humeral head -Medial
epicondyle of humerus
• Ulnar head-medial aspect of
olecranon
• Insertion: pisiform, hook of hamate
and base of 5th metacarpal
• Innervation: ulnar nerve
• Action: flexes and adducts hand

77. Flexor Digitorum Superficialis
• The median nerve and ulnar artery enter
the forearm by passing its humeroulnar and
radial heads.
• Near the wrist, gives 4 tendons which are
enclosed (along the 4 tendons of FDP) in a
common flexor synovial sheath.
• Origin: humeroulnar head-medial
epicondyle and coronoid process
• Radial head-superior half of anterior
border
• Insertion: shafts of middle phalanges of
medial 4 fingers
• Innervation: median nerve
• Action: flexes middle phalanges at PIP

78. Flexor Digitorum profundus
• It is the only one that can flex the
DIP joints of the digits
• Origin: proximal ¾ of medial and
anterior surface of ulna and IO
membrane
• Insertion: bases of distal phalanges
of 2nd -5th fingers
• Innervation: median nerve (lateral
two heads) and ulnar nerve (medial 2
heads)
• Action: flexes distal phalanges

79. Flexor pollicis longus
• Lies lateral to the FDP ,where it covers the
anterior surface of radius
• The only muscle that flexes the IP joint of the
thumb
• Its flat tendon passes deep to the flexor
retinaculum, enveloped in its own synovial
sheath
• Origin: anterior surface of radius and adjacent
IO membrane
• Insertion: base of distal phalanx of thumb
• Innervation: median nerve
• Action: flexes phalanges of 1st digit (thumb)

80. Pronator quadratus
• The deepest muscle in the anterior
group
• Origin: distal quarter of the ulna
• Insertion: distal quarter of the radius
• Innervation: median nerve
• Action: pronates forearm

81. Extensor Muscles of the Forearm
• are in the posterior (extensor-supinator) compartment of the forearm.
• All extensors are innervated by muscular and deep branches of the
radial nerve.
• The extensor tendons are held in place in the wrist region by the
extensor retinaculum.

82. Superficial layer of extensors
• Include:
• Brachioradialis,
• Extensor Carpi radialis longus,
• Extensor Carpi radialis brevis,
• Extensor Digitorum,
• Extensor digiti minimi,
• Extensor carpi ulnaris

83. Deep layer
• Supinator
• Extensor indicis
• Abductor Pollicis longus
• Extensor pollicis logus
• Extensor pollicis brevis

85. MUSCLES OF THE HAND
• The intrinsic muscles of the hand are located in five compartments:
1. Thenar muscles in the thenar compartment
• Abductor pollicis brevis
• Flexor pollicis brevis
• Opponens pollicis
2. Adductor pollicis in the adductor compartment
3. Hypothenar muscles in the hypothenar compartment:
• Abductor digiti minimi ,
• Flexor digiti minimi brevis, and
• Opponens digiti minimi.
4. Lumbricals in the central compartment with long flexor tendons
5. The interossei lie in separate interosseos compartments between the metacarpals

89. Muscle Origin Insertion Innervation Main action
Palmar
Interossei
(3)
Palmar surface
of 2nd, 4thand
5thmetacarpals.
As unipennate
muscles
Dorsal
aponeurosis
of the 2nd,
4th and 5th
fingers.
Ulnar nerve Adduction of the 2nd,
4th and 5th fingers,
Flexion of the
corresponding
metacarpo-phlangeal
joint, and extension
of the
interphalangeal joints.
Dorsal
interossei
(4)
Adjacent sides
of two
metacarpals as
bipennate
muscles
Dorsal
aponeurosis
of 2nd - 4th
fingers
Ulnar nerve Abduction of the 2nd,
3rd and 4th fingers,
Flexion of the
corresponding
metacarpo-phalangeal
joint, and extension
of the
interphalangeal joints

92. Muscles of the anterior abdominal wall

93. 93

94. 1. External Oblique Muscle
• Largest & most superficial
flat muscle
• Fibers run inferiomedially
Origin:-
- external surface of 5th -12th
ribs
• Insertion:-
- linea alba
- outer lip of iliac crest
- anterior superior iliac spine
- pubic tubercle and pubic
crest
94

95. Cont…
Innervation:-
- Anterior rami of lower six thoracic spinal nerves (T7 to T12)
Blood supply:-
- lower intercostal arteries, deep circumflex iliac artery and
iliolumbar artery.
Action:-
- unilateral contraction tilt the trunk
- bilateral contraction flexes the trunk
- elevation of the pelvis
- compression of the abdomen
- expiration or defecation
- fixation of the trunk during carrying
95

96. 2. Internal Oblique Muscle
• Intermediate of the three flat
abdominal wall
• Muscle fibers run superomedially
Origin: - thoracolumbar fascia
- lateral 2/3rd of inguinal
ligament
- anterior 2/3rd of iliac crest
- anterior superior iliac spine
Insertion:- linea alba
- lower border of 10th-12th
ribs
- pubic crest & pectineal line
96

97. Cont….
Innervation:-
- Anterior rami of lower six thoracic spinal nerves
(T7 to T12)
- iliohypogastric nerve
- ilioinguinal nerve
Blood supply:- Subcostal arteries
Action:-
- unilateral contraction tilt & rotate on the side
- bilateral contraction flexes the trunk
- elevation of the pelvis
- compression of the abdomen
- expiration or defecation
- fixation of the trunk 97

98. 3. Transversus Abdominis Muscle
• The innermost of the three flat
muscles
• run more or less transversely
• B/n internal oblique &
transversus abdominis
muscles, there is neurovascular
bundle
Origin:-
- internal surface of 7th-12th
costal cartilages
- thoracolumbar fascia
- inner lip of iliac crest
- lateral 1/3rd of inguinal
ligament
98

99. Cont….
Insertion:-
- linea alba
- pubic crest
- pectineal line
- fused part of aponeurosis (conjoint tendon)
Innervation:-
- Anterior rami of lower six thoracic spinal nerves (T7 to
T12)
- ilioinguinal nerve & iliohypogastric nerve
Blood supply:- Subcostal arteries
Action:-
- compress & support abdominal viscera
- increase intra-abdominal pressure
99

100. 4. Rectus Abdominis Muscle
• A long, broad, strap-like muscle
• Principal vertical muscle of anterior abdominal
wall
• Paired rectus muscles are separated by linea
alba
• Wider superiorly & narrow inferiorly
• Has three or more tendinous intersections
• Enclosed by the rectus sheath
100

101. Origin:-
- upper surface of pubic (symphysis,
and crest)
Insertion:-
- xiphoid process & 5th-7th costal
cartilage
Innervation:-
- Anterior rami of lower seven
thoracic spinal nerves (T6 to T12)
- Blood supply:- inferior and superior
epigastric arteries
Action:-
- tenses the abdominal wall
- flexes trunk & increase intra-
abdominal pressure
- elevate pelvis & expiration or
defecation
101

102. The Lower Limb-muscle

103. Ligaments Of The Gluteal Region
The two important ligaments in the gluteal
region are
The sacrotuberous ligament
It connects the back of the sacrum to the
ischial tuberosity.
The sacrospinous ligament.
It connects the back of the sacrum to the
ischial spine
They stabilize the sacrum and prevent its
rotation at the sacroiliac joint by the weight of
the vertebral column.

104. Foramina of the gluteal region
The two important foramina in the gluteal region are
The greater sciatic foramen
The lesser sciatic foramen.
Greater Sciatic Foramen
The greater sciatic foramen is formed by the greater sciatic notch of the hip
bone and the sacrotuberous and sacrospinous ligaments.
It provides an exit from the pelvis into the gluteal region.
The following structures exit through the foramen:
Piriformis muscle
Sciatic nerve
Posterior cutaneous nerve of the thigh
Superior and inferior gluteal nerves
Nerves to the obturator internus and quadratus femoris
Pudendal nerve
Superior and inferior gluteal arteries and veins
Internal pudendal artery and vein

106. Lesser Sciatic Foramen
The lesser sciatic foramen is formed by the lesser sciatic notch
of the hip bone and the sacrotuberous and sacrospinous
ligaments.
It provides an entrance into the perineum from the gluteal
region.
Its presence enables nerves and blood vessels that have left the
pelvis through the greater sciatic foramen above the pelvic floor
to enter the perineum below the pelvic floor.
The structures pass through the foramen are:
Tendon of obturator internus muscle
Nerve to obturator internus
Pudendal nerve
Internal pudendal artery and vein

107. Muscles of the gluteal region
• Organized into 2 layers: superficial and deep
Superficial layer:consists of
• Gluteus maximus,
• Gluteus medius
• Gluteus minimus and
• The tensor of the fascia lata
• All have proximal attachments to the posterolateral
(external) surface and margins of the ala of the ilium and are
mainly extensors, abductors, and medial rotators of the thigh

108. Deep layer:
• piriformis,
• obturator internus,
• superior and inferior gemilli, and
• quadratus femoris
• all have distal attachments on or adjacent to the
intertrochanteric crest of the femur.
• These muscles are lateral rotators of the thigh but they also
stabilize the hip joint, working with the strong ligaments of
the hip joint to steady the femoral head in the acetabulum

109. Gluteus maximus
Origin
Outer surface of ilium(
posterior gluteal line), sacrum,
coccyx, Sacrotuberous
ligament
Insertion
Iliotibial tract and gluteal
tuberosity of femur
Nerve Supply
Inferior gluteal nerve L5; S1,
2
Action
Extends and Laterally rotates
hip joint
Through iliotibial tract, it
extends knee joint

110. Gluteus medius
Origin
Outer surface of ilium(
between posterior and
anterior gluteal line)
Insertion
Lateral surface of greater
trochanter of femur
Nerve Supply
Superior gluteal nerve
L5;S1
Action
Abducts thigh at hip joint
Tilts pelvis when walking
to permit opposite leg to
clear ground

111. Gluteus minimus
Origin
External surface of ilium between
inferior and anterior gluteal lines
Insertion
Linear facet on the antero-lateral
aspect of the greater trochanter
Nerve Supply
Superior gluteal nerve (L4,L5,S1)
Action
Abducts femur at hip joint
Holds pelvis secure over stance leg
and prevents pelvic drop on the
opposite swing side during walking
Medially rotates thigh

112. • Injury to Superior Gluteal
Nerve
• When a person who has
suffered a lesion of the
superior gluteal nerve is
asked to stand on one leg,
the pelvis on the
unsupported side descends
indicating that the gluteus
medius and minimus on the
supported side are weak or
non-functional
• Trendelenburg test

113. Tensor fasciae latae
Origin
Lateral aspect of crest of
ilium between anterior
superior iliac spine and
tubercle of the crest
Insertion
Iliotibial tract of fascia
lata
Nerve Supply
Superior gluteal nerve
(L4,L5,S1)
Action
Stabilizes the knee in
extension

114. • Common Sites of IM injections
 Deltoid region
 Gluteal region
 Anterolateral thigh
The gluteal region is a common site for
intramuscular (IM) injection of drugs.
It is important to be aware of the extent
of the gluteal region and the safe region
for giving injections.
Injections into the buttock are safe in
the superolateral quadrant of the
buttock or superior to a line extending
from the PSIS to the superior border of
the greater trochanter.

115. Piriformis
Origin
Anterior surface of
sacrum between anterior
sacral foramina
Insertion
Medial side of superior
border of greater
trochanter of femur
Nerve Supply
Branches from (S1,S2)
Action
Laterally rotates the
extended femur at hip joint
Abducts flexed femur at
hip joint

116. Obturator internus
Origin
Anterolateral wall of true
pelvis; deep surface of
obturator membrane and
surrounding bone
Insertion
Medial side of greater
trochanter of femur
Nerve Supply
Nerve to obturator
internus (L5,S1)
Action
Laterally rotates the
extended femur at hip joint
Abducts flexed femur at
hip joint

117. Gemellus superior
Origin
External surface of ischial spine
Insertion
Along length of superior
surface of the obturator internus
tendon and into the medial side
of greater trochanter of femur
with obturator internus tendon
Nerve Supply
Nerve to obturator internus
(L5,S1)
Action
Laterally rotates the extended
femur at hip joint
Abduction of flexed femur at
hip joint

118. Gemellus inferior
Origin
Upper aspect of ischial tuberosity
Insertion
Along length of inferior surface
of the obturator internus tendon
and into the medial side of greater
trochanter of femur with obturator
internus tendon
Nerve Supply
Nerve to quadratus femoris
(L5,S1)
Action
Laterally rotates the extended
femur at hip joint
Abducts flexed femur at hip joint

119. Quadratus femoris
Origin
Lateral aspect of the
ischium just anterior to the
ischial tuberosity
Insertion
Quadrate tubercle on the
intertrochanteric crest of
the proximal femur
Nerve Supply
Nerve to quadratus
femoris (L5,S1)
Action
Laterally rotates femur at
hip joint

120. The Thigh

121. • The thigh is divided into three compartments
by intermuscular septa between the posterior
aspect of the femur and the fascia lata:
• The anterior compartment of thigh
contains muscles that mainly extend the
leg at the knee joint.
• The posterior compartment of thigh
contains muscles that mainly extend the
thigh at the hip joint and flex the leg at the
knee joint.
• The medial compartment of thigh consists
of muscles that mainly adduct the thigh at
the hip joint.
Cross section of left thigh

122. Superficial Fascia of the Thigh
• The membranous layer of the superficial
fascia of the anterior abdominal wall
extends into the thigh and is attached to
the deep fascia (fascia lata) about a
finger breadth below the inguinal
ligament.
• The fatty layer of the superficial fascia
on the anterior abdominal wall extends
into the thigh and continues down over
the lower limb without interruption.

123. Deep Fascia of the Thigh (Fascia Lata)
• The deep fascia encloses the thigh
like a trouser leg and at its upper end
is attached to the pelvis and the
inguinal ligament.
• On its lateral aspect, it is thickened &
is called the iliotibial tract.
• In the gluteal region, the deep fascia
forms sheaths, which enclose the
tensor fasciae latae and the gluteus
maximus muscles.
• In front of the thigh just below the
inguinal ligament, the deep fascia has
a gap & is called as the saphenous
opening.
• It transmits the great saphenous vein,
some small branches of the femoral
artery, and lymph vessels.

124. Femoral Triangle
• The femoral triangle is a triangular depressed
area situated in the upper part of the medial
aspect of the thigh just below the inguinal
ligament.
Boundaries:
• Superiorly:
• The inguinal ligament
• Laterally:
• The sartorius muscle
• Medially:
• The adductor longus muscle
• Floor
• It is gutter shaped and formed from lateral to
medial by the iliopsoas, the pectineus, and the
adductor longus.

126. • Roof
• Is formed by the skin and
fasciae of the thigh.
• Contents
• The terminal part of the
femoral nerve and its
branches.
• The femoral sheath,
• The femoral artery and its
branches.
• The femoral vein and its
tributaries.
• The deep inguinal lymph
nodes.

127. Femoral Sheath
• The femoral sheath is a
downward protrusion into the
thigh of the fascial envelope
lining the abdominal walls.
• Its anterior wall is continuous
above with the fascia
transversalis, and its posterior
wall with the fascia iliaca.
• The sheath surrounds the
femoral vessels and
lymphatics about 2.5 cm
below the inguinal ligament.
• The femoral sheath is adherent
to the walls of the blood
vessels and inferiorly blends
with the tunica adventitia of
these vessels.

128. • The femoral sheath is divided into three compartments
by septa.
• The femoral artery occupies the lateral
compartment of the sheath.
• The femoral vein occupies the intermediate
compartment.
• The lymph vessels the most medial compartment.
The femoral canal
• It is the small medial compartment of the femoral
sheath.
• It is about 1.3 cm long.
• Its upper opening of femoral canal is called the
femoral ring.
• The femoral ring is closed by a condensation of
extraperitoneal tissue called as the femoral septum.

129. Femoral hernia

130. Adductor Canal
• The adductor canal is an
intermuscular cleft situated on the
medial aspect of the middle third of
the thigh beneath the sartorius
muscle.
• It commences(begins) above at the
apex of the femoral triangle and
ends below at the opening in the
adductor magnus.
• It is triangular in cross section & has
three walls.
• Anteromedial wall
• A posterior wall
• A lateral wall.

131. • The anteromedial wall
• sartorius muscle and fascia.
• The posterior wall
• the adductor longus and magnus
muscles.
• The lateral wall
• the vastus medialis.
• Contents:
• The terminal part of the femoral
artery.
• The femoral vein.
• The deep lymph vessels.
• The saphenous nerve.
• The nerve to the vastus medialis
• The terminal part of the obturator
nerve.

132. Thigh
• Thigh muscles are organized into 3 compartments by
intermuscular septa
• Anterior or extensor compartment: This is composed of
the quadriceps femoris, iliopsoas, sartorius, and pectineus,
as well as the femoral artery, vein, and nerve, and the
lateral femoral cutaneous nerve.
• Medial or adductor compartment: This contains the
gracilis, adductor longus, brevis, magnus, and obturator
externus muscles along with the obturator artery, vein, and
nerve, and the profunda femoris artery.
• Posterior or flexor compartment: This includes the
biceps femoris, semitendinosus, and semimembranosus, a
portion of the adductor magnus muscle, branches of the
profunda femoris artery, the sciatic nerve, and the
posterior femoral cutaneous nerve.

133. Muscles of the Anterior
Compartment of the
Thigh
Sartorius
• Origin
• Anterior superior iliac spine
• Insertion
• Upper medial surface of
shaft of tibia
• Nerve Supply
• Femoral nerve L2, 3
• Action
• Flexes, abducts, laterally
rotates thigh at hip joint
• Flexes and medially rotates
leg at knee joint

134. Iliacus
• Origin
• Iliac fossa of hip bone
• Insertion
• With psoas major into lesser
trochanter of femur
• Nerve Supply
• Femoral nerve L2,3
• Action
• Flexes thigh on trunk
• If thigh is fixed, it flexes the
trunk on the thigh as in sitting
up from lying down

135. Psoas major
• Origin
• Transverse processes, bodies, and
intervertebral discs of the 12th
thoracic to 5th lumbar vertebrae
• Insertion
• With iliacus into lesser trochanter
of femur
• Nerve Supply
• Lumbar plexus L1, 2,3
• Action
• Flexes thigh on trunk
• If thigh is fixed, it flexes the trunk
on thigh as in sitting up from lying
down

136. Pectineus
• Origin
• Superior ramus of pubis
• Insertion
• Oblique line extending from base of
lesser trochanter to linea aspera on
posterior aspect of proximal femur
• Nerve Supply
• Femoral nerve L2,3
• Action
• Flexes and adducts thigh at hip
joint

137. Quadriceps Femoris.
Rectus femoris
• Origin
• Straight head:
• Anterior inferior iliac spine
• Reflected head:
• Ilium above acetabulum
• Insertion
• Quadriceps tendon into patella, then
via ligamentum patellae into
tubercle of tibia.
• Nerve Supply
• Femoral nerve L2, 3, 4
• Action
• Extension of leg at knee joint
• Flexes thigh at hip joint

138. Vastus lateralis
• Origin
• Lateral part of intertrochanteric
line, margin of greater trochanter,
lateral margin of gluteal
tuberosity, lateral lip of the linea
aspera.
• Insertion
• Quadriceps tendon into patella,
then via ligamentum patellae into
tubercle of tibia
• Nerve Supply
• Femoral nerve L2, 3, 4
• Action
• Extension of leg at knee joint

139. Vastus medialis
• Origin
• Medial part of
intertrochanteric line,
pectineal line, medial lip of
the linea aspera, medial
supracondylar line
• Insertion
• Quadriceps tendon into
patella, then via ligamentum
patellae into tubercle of tibia.
• Nerve Supply
• Femoral nerve L2, 3, 4
• Action
• Extension of leg at knee
joint; stabilizes patella

140. Vastus intermedius
• Origin
• Upper 2/3rd of the anterior and lateral surfaces of shaft of femur
• Insertion
• Quadriceps tendon into patella, then via ligamentum patellae into
tubercle of tibia
• Nerve Supply
• Femoral nerve L2, 3, 4
• Action
• Extension of leg at knee joint; articularis genus retracts synovial
membrane

141. The Medial Compartment of the Thigh
• Collectively called adductor group
• Attach from the pubis and ischium to the linea aspera
• Adductor muscles are
• Adductor magnus
• Adductor longus
• Adductor brevis
• Gracilis
• Obturator externus
All are supplied by obturator nerve except hamstring part of
adductor magnus
Three layers
• Superficial - gracilis and adductor longus
• Middle - adductor brevis
• Deep - adductor magnus & obturator externus

142. Gracilis
• Origin
• Inferior ramus of pubis, ramus of
ischium
• Insertion
• Upper part of shaft of tibia on
medial surface
• Nerve Supply
• Obturator nerve L2,3
• Action
• Adducts thigh at hip joint
• Flexes leg at knee joint

143. Adductor longus
• Origin
• Body of pubis, medial to pubic
tubercle
• Insertion
• Linea aspera on the middle
1/3rd of the femur.
• Nerve Supply
• Obturator nerve L2, 3, 4
• Action
• Adducts thigh at hip joint and
assists in lateral rotation

146. Adductor brevis
• Origin
• External surface of the pubis
& Inferior ramus of pubis
• Insertion
• Posterior surface of shaft of
femur or the upper 1/3rd of
the linea aspera
• Nerve Supply
• Obturator nerve L2, 3, 4
• Action
• Adducts thigh at hip joint
and assists in lateral rotation

147. Adductor magnus
• Origin
• Adductor part
• Inferior ramus of pubis, ramus of ischium,
• Hamstring part
• Ischial tuberosity.
• Insertion
• Posterior surface of shaft of femur, linea aspera,
medial supracondylar ridge.
• Adductor tubercle of femur
• Nerve Supply
• Adductor portion: obturator nerve
• Hamstring portion: sciatic nerve L2, 3, 4
• Action
• Adducts thigh at hip joint and assists in lateral
rotation
• Hamstring portion extends thigh at hip joint

148. Obturator externus
• Origin
• Outer surface of obturator
membrane and pubic and
ischial rami
• Insertion
• Medial surface of greater
trochanter
• Nerve Supply
• Obturator nerve L3, 4
• Action
• Laterally rotates thigh at hip
joint

149. The posterior compartment of Thigh
• Three of the four muscles in posterior thigh are hamstrings
• Semitendinosus
• Semimembranosus
• Biceps femoris (long head)

150. Hamstring muscles
•They share common features
• Arise from ischial tuberosity
• Insert into tibia or fibula
• Innervated by the tibial division of sciatic nerve
• the short head of the biceps femoris fail to meet any of these
condition innervation comes from the lateral (fibular) division
whereas branches to other hamstrings arise from the medial (tibial)
division
•Extend hip and flex knee joint
•The semimembranosus and semitendinosus also
rotate the leg medially, being attached to the medial
head of the tibia

151. Biceps femoris
• Origin
• Long head:
• Ischial tuberosity
• Short head:
• Linea aspera, lateral supracondylar ridge
of shaft of femur
• Insertion
• Head of fibula
• Nerve Supply
• Long head:
• Tibial portion of sciatic nerve- L5; S1,2
• Short head:
• Common peroneal portion of sciatic
nerve
• Action
• Flexes and laterally rotates leg at knee joint;
long head also extends thigh at hip joint

152. Semitendinosus
• Origin
• Ischial tuberosity
• Insertion
• Upper part of medial surface of
shaft of tibia
• Nerve Supply
• Tibial portion of sciatic nerve L5;
S1,2
• Action
• Flexes and medially rotates leg at
knee joint; extends thigh at hip
joint

153. Semimembranosus
• Origin
• Ischial tuberosity
• Insertion
• Medial condyle of tibia
• Nerve Supply
• Tibial portion of sciatic nerve L5;
S1,2
• Action
• Flexes and medially rotates leg at
knee joint
• Extends thigh at hip joint

154. The Popliteal Fossa

155. • The popliteal fossa is a diamond
shaped intermuscular space
situated at the back of the knee.
• The fossa is most prominent
when the knee joint is flexed.
• Contents
• The popliteal vessels
• The small saphenous vein
• The common peroneal and
tibial nerves
• The posterior cutaneous nerve
of the thigh
• The genicular branch of the
obturator nerve
• Loose connective tissue, and
lymph nodes

156. Boundaries
• Laterally:
• The biceps femoris above and the
lateral head of the gastrocnemius and
plantaris below
• Medially:
• The semimembranosus and
semitendinosus above and the medial
head of the gastrocnemius below.)
• The anterior wall or floor
• Formed by the popliteal surface of the
femur, the posterior ligament of the
knee joint, and the popliteus muscle.
• The roof
• Formed by skin, superficial fascia,
and the deep fascia of the thigh.

157. Popliteus Muscle
• Origin:
• The lateral surface of the lateral condyle of the femur
by a rounded tendon and by a few fibers from the
lateral meniscus.
• Insertion:
• To the posterior surface of the tibia, above the soleal
line.
• The muscle arises within the capsule of the knee
joint, and its tendon separates the lateral meniscus
from the lateral ligament of the joint.
• It emerges through the lower part of the posterior
surface of the capsule of the joint to pass to its
insertion.
• Nerve supply:
• Tibial nerve.
• Action:
• Medial rotation of the tibia on the femur or, if the
foot is on the ground, lateral rotation of the femur on
the tibia.

158. The Leg

159. Fascial Compartments of the Leg
• The deep fascia surrounds the leg and is
continuous above with the deep fascia of
the thigh.
• Below the tibial condyles, it is attached
to the periosteum on the anterior and
medial borders of the tibia.
• The anterior & posterior inter muscular
septa together with the interosseous
membrane, divide the leg into three
compartments—
• The anterior compartment
• The lateral compartment
• The posterior compartment
• Each having its own muscles, blood
supply, and nerve supply.

160. Retinacula of the Ankle
• The retinacula are thickenings of
the deep fascia that keep the long
tendons around the ankle joint in
position and act as pulleys.
• The retinacula around the leg are:
• Superior Extensor Retinaculum
• Inferior Extensor Retinaculum
• Flexor Retinaculum
• Superior Peroneal Retinaculum
• Inferior Peroneal Retinaculum

161. • Structures that pass anterior to the extensor retinacula from
medial to lateral
• Saphenous nerve
• The great saphenous vein
• Superficial peroneal nerve (medial and lateral branches)
• Structures that pass beneath or through the extensor retinacula
from medial to lateral
• Tibialis anterior tendon
• Extensor hallucis longus tendon
• Anterior tibial artery with venae comitantes
• Deep peroneal nerve
• Extensor digitorum longus tendons
• Peroneus tertius

164. • Flexor Retinaculum
• The flexor retinaculum
extends from the medial
malleolus downward and
backward to be attached to
the medial surface of the
calcaneum.
• Structures that Pass behind
the Medial Malleolus beneath
the Flexor Retinaculum From
Medial to Lateral
• Tibialis posterior tendon
• Flexor digitorum longus
• Posterior tibial artery with
venae comitantes
• Tibial nerve
• Flexor hallucis longus

165. • Superior Peroneal Retinaculum
• connects the lateral malleolus to
the lateral surface of the
calcaneum.
• It binds the tendons of the
peroneus longus and brevis to the
back of the lateral malleolus.
• Inferior Peroneal Retinaculum
• binds the tendons of the peroneus
longus and brevis muscles to the
lateral side of the calcaneum.

166. Muscles of anterior compartment
of leg
Tibialis anterior
• Origin
• Lateral surface of shaft of tibia and
interosseous membrane
• Insertion
• Medial cuneiform and base of 1st
metatarsal bone
• Nerve Supply
• Deep peroneal nerve L4, 5
• Action
• Extends foot at ankle joint
• Inverts foot at subtalar and
transverse tarsal joints
• Holds up medial longitudinal arch
of foot

167. Extensor digitorum longus
• Origin
• Upper half of anterior surface of shaft
of fibula
• Insertion
• Extensor expansion of lateral four
toes
• Nerve Supply
• Deep peroneal nerve L5; S1
• Action
• Extends toes
• Extends foot at ankle joint

168. Peroneus tertius
• Origin
• Lower half of anterior surface
of shaft of fibula
• Insertion
• Base of 5th metatarsal bone
• Nerve Supply
• Deep peroneal nerve L5; S1
• Action
• Extends foot at ankle joint
• Everts foot at subtalar and
transverse tarsal joints

169. Extensor hallucis longus
• Origin
• Anterior surface of shaft of
fibula
• Insertion
• Base of distal phalanx of great
toe
• Nerve Supply
• Deep peroneal nerve L5; S1
• Action
• Extends big toe
• Extends foot at ankle joint
• Inverts foot at subtalar and
transverse tarsal joints

170. The Lateral Compartment Of The Leg

171. Peroneus longus
• Origin
• Lateral surface of shaft of fibula
• Insertion
• Base of 1st metatarsal and the medial
cuneiform
• Nerve Supply
• Superficial peroneal nerve L5; S1, 2
• Action
• Plantar flexes foot at ankle join
• Everts foot at subtalar and
transverse tarsal joints
• Supports lateral longitudinal and
transverse arches of foot

172. Peroneus brevis
• Origin
• Lateral surface of shaft of fibula
• Insertion
• Base of 5th metatarsal bone
• Nerve Supply
• Superficial peroneal nerve L5; S1,
2
• Action
• Plantar flexes foot at ankle joint;
everts foot at subtalar and
transverse tarsal joint; supports
lateral longitudinal arch of foot

173. The posterior of the Leg

174. Gastrocnemius
• Origin
• Lateral head from lateral
condyle of femur
• Medial head from above
medial condyle
• Insertion
• Via tendocalcaneus into
posterior surface of
calcaneum
• Nerve Supply
• Tibial nerve S1, 2
• Action
• Plantar flexes foot at ankle
joint
• Flexes knee joint

175. Plantaris
• Origin
• Lateral supracondylar ridge
of femur
• Insertion
• Posterior surface of
calcaneum
• Nerve Supply
• Tibial nerve S1, 2
• Action
• Plantar flexes foot at ankle
joint
• Flexes knee joint

176. Soleus
• Origin
• Soleal line, medal border of
tibia Shafts of fibula
• Insertion
• Via tendo calcaneus into
posterior surface of calcaneum
• Nerve Supply
• Tibial nerve S1, 2
• Action
• Together with gastrocnemius
and plantaris is powerful
plantar flexor of ankle joint
• Provides main propulsive force
in walking and running

177. Flexor digitorum longus
• Origin
• Posterior surface of shaft of
tibia
• Insertion
• Bases of distal phalanges of
lateral four toes
• Nerve Supply
• Tibial nerve S2, 3
• Action
• Flexes distal phalanges of
lateral four toes
• Plantar flexes foot at ankle
joint
• Supports medial and lateral
longitudinal arches of foot

178. Flexor hallucis longus
• Origin
• Posterior surface of shaft of fibula
• Insertion
• Base of distal phalanx of big toe
• Nerve Supply
• Tibial nerve S2, 3
• Action
• Flexes distal phalanx of big toe
• Plantar flexes foot at ankle joint
• Supports medial longitudinal arch
of foot

179. Tibialis posterior
• Origin
• Posterior surface of shafts of tibia and
fibula and interosseous membrane
• Insertion
• Tuberosity of navicular bone and
other neighboring bones
• Nerve Supply
• Tibial nerve L4, 5
• Action
• Plantar flexes foot at ankle joint
• Inverts foot at subtalar and transverse
tarsal joints
• Supports medial longitudinal arch of
foot

180. The Foot

181. • Deep Fascia
• The plantar aponeurosis is a triangular
thickening of the deep fascia that
protects the underlying nerves, blood
vessels, and muscles.
• Its apex is attached to the medial and
lateral tubercles of the calcaneum.
• The base of the aponeurosis divides into
five slips that pass into the toes.

182. Muscles of the Sole of the Foot
The muscles of the sole are conveniently described in four layers from the inferior layer superiorly.
• First layer:
• Abductor hallucis
• Flexor digitorum brevis
• Abductor digiti minimi
• Second layer:
• Quadratus plantae
• Lumbricals
• Flexor digitorum longus tendon
• Flexor hallucis longus tendon
• Third layer:
• Flexor hallucis brevis
• Adductor hallucis
• Flexor digiti minimi brevis
• Fourth layer:
• Interossei
• Peroneus longus tendon
• Tibials posterior tendon

183. Abductor hallucis
• Origin
• Medial tuberosity of calcaneum
and flexor retinaculum
• Insertion
• Base of proximal phalanx of big
toe
• Nerve Supply
• Medial plantar nerve S2, 3
• Action
• Flexes and abducts big toe; braces
medial longitudinal arch

184. Flexor digitorum brevis
• Origin
• Medial tubercle of calcaneum
• Insertion
• Four tendons to four lateral
toes—inserted into borders of
middle phalanx; tendons
perforated by those of flexor
digitorum longus
• Nerve Supply
• Medial plantar nerve S2, 3
• Action
• Flexes lateral four toes;
braces medial and lateral
longitudinal arches

185. Abductor digiti minimi
• Origin
• Medial and lateral tubercles
of calcaneum
• Insertion
• Base of proximal phalanx of
fifth toe
• Nerve Supply
• Lateral plantar nerve S2, 3
• Action
• Flexes and abducts fifth toe;
braces lateral longitudinal
arch

186. Second Layer
Quadratus plantae
• Origin
• Medial and lateral sides of
calcaneum
• Insertion
• Tendon of flexor digitorum
longus
• Nerve Supply
• Lateral plantar nerve S2, 3
• Action
• Assists flexor digitorum longus
in flexing lateral four toes

187. Lumbricals
• Origin
• Tendons of flexor digitorum
longus
• Insertion
• Dorsal extensor expansion
• Bases of proximal phalanges
of lateral four toes
• Nerve Supply
• First lumbrical by medial
plantar nerve
• 2nd ,3rd & 4th by lateral plantar
nerve S2, 3
• Action
• Extends toes at interphalangeal
joints

188. Third Layer
Flexor hallucis brevis
• Origin
• Cuboid, lateral cuneiform, tibialis
posterior insertion
• Insertion
• Medial tendon into medial side of base of
proximal phalanx of big toe
• Lateral tendon into lateral side of base of
proximal phalanx of big toe
• Nerve Supply
• Medial plantar nerve S2, 3
• Action
• Flexes metatarsophalangeal joint of big
toe
• Supports medial longitudinal arch

189. Adductor hallucis
• Origin
• Oblique head from bases of 2nd,
3rd, and 4th metatarsal bones;
transverse head from plantar
ligaments
• Insertion
• Lateral side of base of proximal
phalanx of big toe
• Nerve Supply
• Deep branch lateral plantar nerve
S2, 3
• Action
• Flexes metatarsophalangeal joint of
big toe
• Holds together metatarsal bones

190. Flexor digiti minimi brevis
• Origin
• Base of 5th metatarsal
bone
• Insertion
• Lateral side of base of
proximal phalanx of little
toe
• Nerve Supply
• Lateral plantar nerve S2, 3
• Action
• Flexes
metatarsophalangeal joint
of little toe

191. Fourth Layer
Dorsal Interossei(4)
• Origin
• Adjacent sides of metatarsal bones
• Insertion
• Bases of proximal phalanges & dorsal
extensor expansion
• First:
• Medial side of second toe
• Remainder:
• Lateral sides of second, third, and
fourth toes
• Nerve Supply
• Lateral plantar nerve S2, 3
• Action
• Abduction of toes
• Flexes metatarsophalangeal joints and
extends interphalangeal joints

192. Plantar interossei(3)
• Origin
• Inferior surfaces of 3rd, 4th, and
5th metatarsal bones
• Insertion
• Medial side of bases of proximal
phalanges of lateral three toes
• Nerve Supply
• Lateral plantar nerve S2, 3
• Action
• Adduction of toes; flexes
metatarsophalangeal joints and
extends interphalangeal joints

193. Extensor digitorum brevis
• Origin
• Anterior part of upper surface of the
calcaneum and from the inferior
extensor retinaculum
• Insertion
• By four tendons into the proximal
phalanx of big toe and long extensor
tendons to second, third, and fourth
toes
• Nerve supply
• Deep peroneal nerve S1, S2
• Action
• Extends toes