POSTERIOR COMPARTMENT OF
THIGH
OBJECTIVES
By the end of this lecture students should know:
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The muscles of posterior compartment of the thigh
The arterial supply of posterior compartment of thigh
The greater and cruciate anastomosis at the back of thigh
The venous drainage of back of thigh
The nerve supply of posterior compartment of thigh
Clinical conditions effecting the back of thigh
MUSCLES OF POSTERIOR COMPARTMENT
 All the muscles are known as the Hamstrings
 ALL arise from the ischial tuberosity
 The hamstrings are:
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Biceps femoris (long head)
Semimembranosus
Semitendinosus
 The hamstring muscles flex the leg upon the thigh
 Taking their fixed point from below, these muscles serve to
support the pelvis upon the head of the femur
 Draw the trunk directly backward, as in raising it from the
stooping position or in feats of strength, when the body is thrown
backward in the form of an arch.
Complete flexion of the hip cannot be effected unless the knee-joint is
also flexed, on account of the shortness of the hamstring muscles.
NERVE SUPPLY:
The muscles of this region are supplied by the fourth and fifth lumbar
and the first, second, and third sacral nerves
BICEPS FEMORIS(biceps):
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The Biceps femoris (Biceps) is situated on the posterior and lateral aspect of the
thigh.
ORIGIN:
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It has two heads of origin;
The long head arises from the lower and inner impression
on the back part of the tuberosity of the ischium, by a
tendon common to it and the Semitendinosus, and from
the lower part of the sacrotuberous ligament;
The short head, arises from the lateral lip of the linea
aspera, between the Adductor magnus and Vastus
lateralis, extending up almost as high as the insertion of
the Glutæus maximus; from the lateral prolongation of the
linea aspera to within 5 cm. of the lateral condyle; and from the lateral
intermuscular septum.
The fibers of the long head pass laterally to end in an aponeurosis which covers
the posterior surface of the muscle, and receives the fibers of the short head
INSERTION:
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This aponeurosis contracts into a tendon, which is inserted into the lateral side of
the head of the fibula, and by a small slip into the lateral condyle of the tibia.
At its insertion the tendon divides into two portions, which embrace the fibular
collateral ligament of the knee-joint.
From the posterior border of the tendon a thin expansion is given off to the fascia
of the leg.
The tendon of insertion of this muscle forms the lateral hamstring
The common peroneal nerve descends along its medial border.
NERVE SUPPLY:
 Short head: supplied by the common peroneal nerve
 Long head: tibial nerve
ACTIONS:
When the knee is semiflexed, the Biceps femoris in
consequence of its oblique direction rotates the leg
slightly outward
VARIATIONS:
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The short head may be absent
Additional heads may arise from the ischial
tuberosity, the linea aspera, the medial
supracondylar ridge of the femur or from various
other parts.
A slip may pass to the Gastrocnemius.
THE SEMITENDINOSUS
The Semitendinosus, (great length of its tendon of insertion), is
situated at the posterior and medial aspect of the thigh.
ORIGIN:
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Arises from the lower and medial impression on the
tuberosity of the ischium, by a tendon common to it and the
long head of the Biceps femoris
It also arises from an aponeurosis which connects the
adjacent surfaces of the two muscles
The muscle is fusiform and ends a little below the middle of
the thigh in a long round tendon which lies along the medial
side of the popliteal fossa
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It then curves around the medial condyle of the tibia and passes over the tibial
collateral ligament of the knee-joint, from which it is separated by a bursa
INSERTION:
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It is inserted into the upper part of the medial surface of the
body of the tibia, nearly as far forward as its anterior crest.
 At its insertion it gives off from its lower border a prolongation
to the deep fascia of the leg and lies behind the tendon of the
Sartorius, and below that of the Gracilis, to which it is united.
 A tendinous intersection is usually observed about the middle of
the muscle.
NERVE SUPPLY:
Tibial nerve
ACTIONS:
When the knee is semiflexed, the Semitendinosus rotate the leg inward, assisting the
Popliteus
THE SEMIMEMBRANOSUS
The Semimembranosus so called from its membranous tendon of origin
situated at the back and medial side of the thigh.
ORIGIN:
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It arises by a thick tendon from the upper and outer
impression on the tuberosity of the ischium, above
and lateral to the Biceps femoris and
Semitendinosus.
The tendon of origin expands into an aponeurosis,
which covers the upper part of the anterior surface of
the muscle
INSERTION:
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From this aponeurosis muscular fibers arise, and converge to
another aponeurosis which covers the lower part of the
posterior surface of the muscle and contracts into the tendon
of insertion.
It is inserted mainly into the horizontal groove on the
posterior medial aspect of the medial condyle of the tibia
FIBROUS EXPANSIONS OF THE TENDON OF INSERTION:
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The tendon of insertion gives off certain fibrous expansions:
One, passes upward and laterally to be inserted into the back part of the lateral
condyle of the femur, forming part of the oblique popliteal ligament of the kneejoint
Second is continued downward to the fascia which covers the Popliteus muscle
A few fibers join the tibial collateral ligament of the joint and the fascia of the leg.
The muscle overlaps the upper part of the popliteal vessels.
NERVE SUPPLY:
Tibial nerve
ACTIONS:
Assist semitendinosus (and popliteus) in internal rotation of leg
VARIATIONS:
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It may be reduced or absent, or double
May arise mainly from the sacrotuberous ligament
May give off a slip to the femur or Adductor magnus.
The tendons of insertion of the two preceding muscles form the medial
hamstrings.
ADDUCTOR MAGNUS (HAMSTRING PART)
ORIGIN: ischial tuberosity
INSERTION: adductor tubercle of femur
NERVE SUPPLY: tibial nerve
ACTIONS: extends thigh
ARTERIES OF THE POSTERIOR COMPARTMENT OF THIGH
The arteries of the posterior compartment of the thigh arise from two major
arteries:
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inferior gluteal (upper posterior compartment)
perforating branches of the profunda femoris
THE PROFUNDA FEMORIS ARTERY (A. PROFUNDA FEMORIS; DEEP
FEMORAL ARTERY)
A branch of the femoral artery arising, from 2 to 5 cm below the inguinal ligament.
COURSE:
Lateral to the femoral artery
and the femoral vein
behind femoral artery
medial side of the femur
downward behind the Adductor
longus
ends at the lower third of the thigh in a small terminal
branch, the fourth perforating artery, which pierces the Adductor
magnus, and is distributed on the back of the thigh to the hamstrings.
RELATIONS:
Posteriorly:
 Iliacus
 Pectineus
 Adductor brevis
 Adductor magnus.
Anteriorly:
 Separated from the femoral artery by the femoral and
profunda veins above
 The Adductor longus below.
Laterally:
 The origin of the Vastus medialis
 The femur.
SURGICALLY IMPORTANT PECULARITIES:
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It can arise(more often) from 2.25 to 5 cm. below the inguinal ligament;
In a few cases the distance can be less than 2.25 cm.;
Occasionally the distance between the origin of the vessel and the inguinal ligament
exceeds 5 cm
More rarely, opposite the ligament; and very rarely above the inguinal ligament,
from the external iliac.
BRANCHES:
 Medial circumflex femoral artery
 Lateral circumflex femoral artery
 Four perforating arteries
 Highest genicular artery
IMPORTANT ANASTOMOSIS: The trochanteric and the Cruciate anastomosis
provide important connection between the internal iliac and femoral arteries
TROCHANTERIC ANASTOMOSIS:
Provides main supply to the head of femur via:
 Superior gluteal artery
 Inferior gluteal artery
 Medial circumflex femoral artery
 Lateral circumflex femoral artery
CRUCIATE ANASTOMOSIS:
 Inferior gluteal artery
 Medial circumflex femoral artery
 Lateral circumflex femoral artery
 Fourth perforating artery(Branch of profunda femoris artery)
NERVES OF BACK OF THIGH
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The Lateral Femoral Cutaneous
Nerve (n. cutaneus femoralis
lateralis; external cutaneous nerve)
arises from the dorsal divisions of L2
and L3.
It emerges from the lateral border of
the Psoas major about its middle,
passes under the inguinal ligament
into the thigh, where it divides into
two branches, and anterior and a
posterior
The anterior branch is distributed to
the skin of the anterior and lateral
parts of the thigh, as far as the knee.
The posterior branch pierces the
fascia lata, innervates the lateral and
posterior surfaces of the thigh, supplying the skin from the level of the greater
trochanter to the middle of the thigh.
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The Posterior Femoral Cutaneous Nerve (n. cutaneus femoralis posterior;
small sciatic nerve) is distributed to the skin of the perineum and posterior
surface of the thigh and leg.
It arises partly from the dorsal divisions of the first and second, and from the
ventral divisions of the second and
third sacral nerves
Issues from the pelvis through the greater
sciatic foramen below the Piriformis.
It then descends beneath the Glutæus
maximus with the inferior gluteal
artery, and runs down the back of the
thigh beneath the fascia lata, and over the
long head of the Biceps femoris to the
back of the knee
Its branches are all cutaneous
Distributed to the gluteal region, the
perineum, and the back of the thigh and
leg.
The branches to the back of the thigh and leg consist of numerous filaments
derived from both sides of the nerve, and distributed to the skin covering the back
and medial side of the thigh, the popliteal fossa, and the upper part of the
back of the leg
PATELLAR PLEXUS:
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Anterior branch of the lateral cutaneous nerve of thigh
Intermediate cutaneous nerve of thigh
Medial cutaneous nerve of thigh
Infrapatellar branch of the saphenous nerve
SCIATIC NERVE (L4, L5, S1, S2, S3):
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The Sciatic (n. ischiadicus; great sciatic nerve) supplies nearly the whole of the
skin of the leg, the muscles of the back of the thigh, the leg
and the foot.
It is the largest nerve in the body, measuring 2 cm. in
breadth, and is the continuation of the flattened band of the
sacral plexus.
It passes out of the pelvis through the greater sciatic
foramen, below the Piriformis muscle
COURSE:
 It descends between the greater trochanter of the femur and the tuberosity of
the ischium, and along the back of the thigh to about its lower third, where it
divides into two large branches, the tibial and common peroneal nerves.
SURGICALLY IMPORTANT PECULARITIES:
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The division of sciatic nerve into Tibial and Common Peroneal nerve may take
place at any point between the sacral plexus and the lower third of the thigh.
When it occurs at the plexus, the common peroneal nerve usually pierces the
Piriformis
RELATIONS:
Upper part
ANTERIORLY:
 The posterior surface of the ischium
 The nerve to the Quadratus femoris
 The Obturator internus
 The superior and inferior Gemelli
 The Quadratus femoris
POSTERIORLY:
 The posterior femoral cutaneous nerve and
the inferior gluteal artery
 The Gluteus maximus
Lower part:
ANTERIORLY:
 The Adductor magnus
POSTERIORLY:
 The long head of the Biceps femoris.
BRANCHES:
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The articular branches supply the hip joint
Muscular branches:
1. COMMON PERONEAL NERVE:
 At the back of thigh supplies the short head of biceps
femoris
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THE TIBIAL NERVE
larger
Arises from the anterior branches of L4, L5 and S1, S2, S3.
It descends along the back of the thigh and through the middle of
the popliteal fossa, to the lower part of the Popliteus muscle,
where it passes with the popliteal artery beneath the arch of the
Soleus.
 Tibial nerve supplies:
o Biceps femoris (long head)
o Semitendinosus
o Semimembranosus
o Adductor magnus.