Muscles of the Hip and Thigh

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Sacrum, sacroiliac and hip joints | Main Anatomy Index | Knee joint

Last updated 30 March 2006

The Anterior Thigh Muscles

This group of muscles consists of the iliopsoas, tensor fasciae latae, sartorius, and quadriceps femoris muscles.

The Iliopsoas Muscles

This powerful muscle is composed of the psoas major and iliacus muscles.

The Psoas Major Muscles (pp. 229, 385-7)

Long, thick, powerful muscle passes from the abdomen to the thigh deep to the inguinal ligament.
The lumbar plexus is imbedded in this muscle.

Proximal attachments are: sides of T12 to L5 vertebrae and intervertebral discs between them.
Distal attachment is: lesser trochanter of femur
Innervation: ventral rami of lumbar nerves (L1, L2, and L3)

The Iliacus Muscle (pp. 386-7)

Large triangular or fan-shaped muscle lies along the lateral side of the psoas major in the pelvis.

Proximal attachments are: iliac crest, iliac fossa, ala of sacrum, and anterior sacroiliac ligaments.
Distal attachments are: tendon of psoas major and body of femur, inferior to lesser trochanter.
Innervation: femoral nerve (L2 and L3)

Action of Iliopsoas Muscle

This composite muscle is the strongest flexor of the thigh at the hip joint.
The iliopsoas muscles are also important antigravity postural muscles, which help to maintain erect posture at the hip joints.
Acting inferiorly, the iliopsoas muscles flex the trunk, as in raising the trunk from the supine position to the sitting position.

Anterior Compartment

Comprises of the quadriceps femoris, sartorius and tensor fasciae latae mm.

The Tensor Fasciae Latae Muscle (p. 386-7)

The Deep Fascia of the Thigh-Fascia lata (p. 385)

Strong, dense, broad (lata: L. broad) layer that invests the muscles of the thigh like an elastic stocking.
It provides a dense tubular sheath for the thigh muscles, which prevents them from bulging excessively when they contract.
Improves the effectiveness of these muscles.

Proximal attachments are: the inguinal ligament, the external lip of the iliac crest, the posterior surface of the sacrum and coccyx, the sacrotuberous ligament, the ischial tuberosity, the margin of the pubic arch, the body of the pubis, and the pubic tubercle.
It is extremely laterally where it runs from the iliac crest to the tibia. This part is known as the iliotibial tract.
The sides don't form a complete stocking. The fascia dives under and connects on the pecten pubis. There is a "loop".
The cribiform fascia is a loose covering of fascia over this loop.
It receives tendinous reinforcements from the tensor fasciae latae and gluteus maximus mm.
Distal end of the iliotibial tract is attached to the lateral condyle of the tibia.

The Muscle

Fusiform muscle, lies on the lateral side of the thigh, enclosed between two layers of the fascia lata, which form its sheath.

Proximal attachments are: anterior superior iliac spine and anterior part of external lip of iliac crest.
Distal attachments are: iliotibial tract that attaches to lateral condyle of tibia.
Innervation: superior gluteal (L4 and L5)

It tightens the fascia lata, thereby enabling the thigh muscles to act with increased power.
It also tightens the iliotibial tract enabling the gluteus maximus muscle to keep the knee joint in the extended position.
In addition, when in the standing position, it steadies the trunk on the thigh and counteracts the posterior pull of the gluteus maximus on the iliotibial tract.

The Sartorius Muscle (p. 386-7)

This narrow, elongated, strap-like muscle is the longest one in the body and is the most superficial muscle in the anterior part of the thigh.
It acts across two joints.
It was given its name because it is used to cross the legs in the tailor's squatting position (L. sartor, a tailor).
Throughout much of its course, this muscle covers the femoral artery as it runs in the adductor canal (subartorial).

Proximal attachments are: ASIS and superior part of notch inferior to it.
Distal attachments are: superior part of medial surface of tibia.
Innervation: femoral nerve (L2 and L3)

During squatting, it flexes, abducts, and laterally rotates the thigh at the hip joint, and it flexes the leg at the knee joint.
Acting inferiorly, it also flexes the trunk on the thigh and rotates the trunk to the opposite side.

The Quadriceps Femoris Muscle (pp. 386-7)

The great extensor muscle of the leg, the biggest muscle in the body.
It covers almost all of the anterior surface and sides of the femur.
It is divided into 4 parts: rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius. (L. vastus, large) and (L. rectus, straight)
The names of the parts of the quadriceps m. indicate their form or location.

The rectus femoris has deep fibres that run straight down the thigh.
Proximal attachments are: AIIS and groove superior to acetabulum.

The vastus lateralis lies on the lateral side of the thigh.
Proximal attachments are: greater trochanter and lateral lip of linea aspera of femur.

The vastus medialis covers the medial aspect of the thigh.
Proximal attachments are: intertrochanteric line and medial lip of linea aspera of femur.

The vastus intermedius is located between the above two mm.
Proximal attachments are: anterior and lateral surfaces of the body of the femur.

The tendons of all of this large muscle unite to form the quadriceps tendon. This broad tendon attaches to and surrounds the patella and then continues as the patellar ligament (ligamentum patellae), which is attached to the tuberosity of the tibia.
Expansions of the aponeuroses of the vasti muscles, called the medial and lateral retinaculum of the patella, insert into the condyles of the tibia.

All parts of the quadriceps, acting through the patella ligament, extend the leg at the knee joint, and through the actions of the rectus femoris, they flex the hip joint. All four parts of this muscle is used during climbing, running, jumping, and rising from a chair.

Gluteal Muscles

The gluteal muscles consist of three glutei mm., gluteus maximus, g. medius, and g. minimus.

The Gluteus Maximus Muscle (pp. 407,411-2,417)

This is the largest, heaviest, and most coarsely fibred muscle in the gluteal region and is one of the largest muscles in the body.
It forms a thick quadrilateral pad over the ischial tuberosity when the thigh is extended.
When the thigh is flexed, the distal border of this muscle moves superiorly, leaving the ischial tuberosity subcutaneous.

Proximal attachments are: external surface of ala of ilium, including iliac crest, dorsal surface of sacrum and coccyx, and sacrotuberous ligament.
Distal attachments are: most fibres end in iliotibial tract; some fibres insert on gluteal tuberosity of femur.
Innervation: inferior gluteal nerve.

A thick flat sheet of muscle, the gluteus maximus slopes inferolaterally from the pelvis across the buttock at a 45 degree angle. Its inferior edge lies just superior to the gluteal fold produced by bulging fat.
The gluteus maximus m., extends the thigh and steadies it. It is the chief extensor of the thigh. When acting with its distal attachment fixed, it is a strong extensor of the pelvis (e.g., when rising from a seated or stooped position).
It also assists with lateral rotation of the thigh.

It is used very little during ordinary walking and is relaxed when one stands still. It acts when force is required, e.g., in running, climbing and similar activities.
As the thigh is being flexed, e.g. during sitting, the gluteus maximus steadies the movement by relaxing gradually.
When acting from its distal attachment, it tilts the superior part of the pelvis posteriorly (when one stands to attention).

Gluteus Medius Muscle (pp. 412, 417)

Most of this thick, fan-shaped or triangular muscle lies deep to the gluteus maximus on the external surface of the ilium.

Proximal attachments are: external surface of ilium between anterior and posterior gluteal lines.
Distal attachments are: lateral surface of greater trochanter of femur.
Innervation: superior gluteal nerve (L5 and S1)

This muscle is an abductor of the hip joint and plays an essential role during locomotion; it is largely responsible for the tilt of the pelvis. When the left muscle pulls the left side of the pelvis down, the right side is prevented from sagging as the right limb is raised during walking. Conversely, the right gluteus muscle permits the left foot to clear the ground during walking.
It also helps to rotate the thigh medially.
Summary: abduct and medially rotate thigh; steady pelvis.

The Gluteus Minimus Muscle (pp. 412, 417)

The fan-shaped or triangular muscle, the smallest of the gluteal muscles, lies deep to the gluteus medius.

Proximal attachments are: external surface of ilium between anterior and inferior gluteal lines.
Distal attachments are: anterior surface of greater trochanter of femur.
Innervation: superior gluteal nerve (L5 and S1)

During locomotion its actions are similar to those of the gluteus medius.
Its anterior fibres help to rotate the thigh medially, more strongly that do those of the gluteus medius.

Pelvitrochanteric Muscles (Lateral Rotators)

The Piriformis Muscle (pp. 412, 417)

This muscle is located partly on the posterior wall of the pelvis minor and partly posterior to the hip joint.
It leaves the pelvis though the greater sciatic foramen to reach its distal attachment to the greater trochanter of the femur.
Because of its position, this narrow, pear-shaped (L. piriform) muscle is landmark of the gluteal region. It is the key to understanding relationships in this area because it determines the names of the blood vessels and nerves; e.g., the superior gluteal vessels and nerve emerge superior to it.
The surface marking of the superior border of the piriformis muscle is indicated by a line joining the skin dimple formed by the posterior superior iliac spine, to the superior border of the greater trochanter of the femur.

Proximal attachments are: anterior surface of sacrum and sacrotuberous ligament.
Distal attachments are: superior border of greater trochanter of femur.
Innervation: branches from ventral rami of S1 and S2

It laterally rotates extended thigh and abducts the flexed thigh; steadies femoral head in acetabulum.

The Obturator Internus Muscle (pp. 412-3, 417)

This thick fan-shaped muscle, like the piriformis, is located partly in the pelvis where it covers most of the lateral wall of the pelvis minor.
It leaves the pelvis through the lesser sciatic foramen to reach its attachment to the greater trochanter of the femur.

Proximal attachments are: pelvic surface of obturator membrane and surrounding bones.
Distal attachments are: medial surface of greater trochanter of femur.
Innervation: nerve to obturator internus (L5 and S1). Note: same as superior gemellus.

The Gamelli Muscles (Superior and Inferior) (pp. 412-413, 417)

The two gemelli muscles are narrow, triangular extrapelvic parts of the obturator internus.
The superior and inferior gemelli arise from the ischial spine and ischial tuberosity, respectively.
The obturator internus and gemelli muscles laterally rotate the extended thigh, abduct it when it is flexed and also help to hold the head of the femur in the acetabulum.
Note: the innervation of inferior gemellus is the nerve to quadratus femoris (L5 and S1)

The Quadratus Femoris Muscle (pp. 413, 417)

This is a short, flat, rectangular muscle.

Proximal attachments are: lateral border of ischial tuberosity.
Distal attachments are: quadrate tubercle on intertrochanteric crest of femur and inferior to it.

Medial Compartment (adductors)

This group of muscles include the pectineus, gracilis and adductor magnus, brevis, and longus muscles.
The obturator nerve (L2, L3, and L4) supplies all adductors of the thigh, except the pectineus.
The femoral nerve (L2 and L3) supplies the pectineus. The "hamstring" part of the adductor magnus is supplied by the sciatic nerve (L4).

The Pectineus Muscle (pp. 393, 399)

This is a short, flat quadrangular muscle.
It forms part of the floor of the femoral triangle.

Proximal attachments are: pecten pubis (pectineal line of pubis).
Distal attachments are: pectineal line of femur.
Innervation: femoral nerve (L2 and L3); may receive a branch from obturator nerve.

It adducts and flexes the thigh.

The Adductor Longus Muscle (pp. 393, 399)

This long adductor is a triangular muscle and is the most anterior muscle in the adductor group.

Proximal attachments are: body of pubis, inferior to pubic crest.
Distal attachments are: middle third of linea aspera of femur.
Innervation: obturator nerve, anterior branch (L2, L3, L4)

It adducts the thigh.

Adductor Brevis Muscle (pp. 393, 399)

This short adductor lies deep to the pectineus and adductor longus mm. and anterior to the adductor magnus.

Proximal attachments are: body and inferior ramus of pubis.
Distal attachments are: pectineal line and proximal part of linea aspera of femur.
Innervation: Obturator (L2, L3, and L4).

It adducts the thigh and to some extent flexes it.

The Adductor Magnus Muscle (pp. 393, 399)

This large adductor is the largest in the muscle adductor group.
It is a composite, triangular muscle and comprises adductor and hamstring parts.
The two portions differ in their attachments, nerve supply, and main actions.

There is a hiatus in the aponeurotic attachment of the adductor magnus to the supracondylar line, called the adductor hiatus. It is located at the junction of the adductor canal and the popliteal fossa, a bout a handbreadth superior to the adductor tubercle of the femur. This opening enables the femoral vessels to pass into the popliteal fossa.

Proximal attachments are: inferior ramus of pubis, ramus of ischium (adductor part), and ischial tuberosity (hamstring part).
Distal attachments are: gluteal tuberosity, linea aspera, medial supracondylar line (adductor part), and adductor tubercle of femur (hamstring part).
Innervation: adductor part, obturator nerve (L2, L3, and L4). Hamstring part, tibial portion of sciatic nerve (L4).

It adducts the thigh; its adductor part also flexes thigh, and its hamstring part extends it.

The Gracilis Muscle (pp. 393, 399)

It is a long, strap-like fusiform muscle that lies along the medial side of the thigh and knee.
The gracilis (L. slender) is the most superficial of the adductor group of muscles and is the weakest member.
It is the only one that crosses the knee joint.

Proximal attachments are: body and inferior ramus of pubis.
Distal attachments are: superior part of medial surface of tibia.
Innervation: obturator nerve (L2, L3).

It laterally rotates the thigh and steadies the head of the femur in the acetabulum.

The Obturator Externus Muscle (pp. 393, 399)

This is a flat, relatively small, fan-shaped muscle is deeply placed in the superomedial part of the thigh.
Its tendon crosses the posterior aspect of the neck of the femur.

Proximal attachments are: margins of obturator foramen and obturator membrane.
Distal attachments are: trochanteric fossa of femur.
Innervation: Obturator nerve (L3 and L4)

It laterally rotates thigh and steadies the head of femur in acetabulum.

Posterior Thigh Muscles (Hamstring Muscles)

Three large (semitendinosus, semimembranosus, and biceps femoris) in the posterior aspect of the thigh are commonly called the hamstring muscles.
They can be made to stand out by flexing the leg against resistance.
The hamstrings have a common proximal attachment to the ischial tuberosity deep to the gluteus maximus, but one of them, the biceps femoris, has an additional attachment to the body of the femur. They also have a common nerve supply from the sciatic nerve.

The hamstring muscles span the hip and knee joints; hence, they are extensors of the thigh and flexors of the leg. Both actions cannot be performed fully at the same time.
The hamstrings descend in the posterior aspect of the thigh and their tendons are visible posterior to the knee.

The Semitendinosus Muscle (pp. 422-3)

As its name indicates, this muscle is half-tendinous. It is fusiform with a long, rounded, cord-like tendon, which begins about two-thirds of the way down the thigh.

Proximal attachments are: ischial tuberosity (common attachment with the semimembranosus and long head of the biceps femoris).
Distal attachments are: medial surface of superior part of tibia.
Innervation: tibial division of sciatic nerve (L5, S1, and S2).

It extends the thigh, flexes the leg and medially rotates when the thigh and leg are flexed. It can extend the trunk.

The Semimembranosus Muscle (pp. 422-3)

This broad muscle is half-membranous.
It is located deep to the semitendinosus muscle.

Proximal attachments are: ischial tuberosity.
Distal attachments are: posterior part of medial condyle of tibia.
Innervation: tibial division of sciatic nerve (L5, S1, and S2)-same as the above.

Its actions are the same as the semitendinosus muscle.

The Biceps Femoris Muscle (pp. 422-3)

A fusiform muscle with two heads, a long and a short.
The rounded tendon of the biceps femoris can easily be seen and felt as it passes the knee to insert into the head of the fibula, especially when the knee is flexed against resistance.
Like the other hamstrings, the long head of the biceps femoris extends the thigh at the hip joint.
Both heads flex the leg at the knee joint and laterally rotate the leg when it is flexed.

Proximal attachments are: long head; ischial tuberosity, short head; lateral lip of linea aspera and lateral supracondylar line.
Distal attachments are: lateral side of head of fibula; tendon is split at this site by fibular collateral ligament of knee joint.
Innervation: long head; tibial division of sciatic nerve (L5, S1, and S2), short head; common fibular (peroneal) division of sciatic nerve (L5, S1, S2).