10.7: Appendicular Muscles of the Pelvic Girdle and Lower Limbs

By the end of this section, you will be able to:

• Identify the appendicular muscles of the pelvic girdle and lower limb
• Identify the movement and function of the pelvic girdle and lower limb

The appendicular muscles of the lower body position and stabilize the pelvic girdle, which serves as a foundation for the lower limbs. Comparatively, there is much more movement at the pectoral girdle than at the pelvic girdle. There is very little movement of the pelvic girdle because of its connection with the sacrum at the base of the axial skeleton. The pelvic girdle is less range of motion because it was designed to stabilize and support the body.

Muscles of the Thigh

What would happen if the pelvic girdle, which attaches the lower limbs to the torso, were capable of the same range of motion as the pectoral girdle? For one thing, walking would expend more energy if the heads of the femurs were not secured in the acetabula of the pelvis. The body’s center of gravity is in the area of the pelvis. If the center of gravity were not to remain fixed, standing up would be difficult as well. Therefore, what the leg muscles lack in range of motion and versatility, they make up for in size and power, facilitating the body’s stabilization, posture, and movement.

Gluteal Region Muscles That Move the Femur

Most muscles that insert on the femur (the thigh bone) and move it, originate on the pelvic girdle. The psoas major and iliacus make up the iliopsoas group. Some of the largest and most powerful muscles in the body are the gluteal muscles or gluteal group. The gluteus maximus is the largest; deep to the gluteus maximus is the gluteus medius, and deep to the gluteus medius is the gluteus minimus, the smallest of the trio (Figure \(\PageIndex{1}\) and Table \(\PageIndex{1}\)).

Figure \(\PageIndex{1}\): Hip and Thigh Muscles. The large and powerful muscles of the hip that move the femur generally originate on the pelvic girdle and insert into the femur. The muscles that move the lower leg typically originate on the femur and insert into the bones of the knee joint. The anterior muscles of the femur extend the lower leg but also aid in flexing the thigh. The posterior muscles of the femur flex the lower leg but also aid in extending the thigh. A combination of gluteal and thigh muscles also adduct, abduct, and rotate the thigh and lower leg. (Image credit: "Gluteal Muscles that Move the Femur" by Openstax is licensed under CC BY 4.0)

Table \(\PageIndex{1}\): Gluteal Region Muscles That Move the Femur

Prime Mover	Origin	Insertion	Movement	Target	Target Motion Direction
Iliopsoas group
Iliacus	Iliac fossa; iliac crest; lateral sacrum	Lesser trochanter of femur	Raises knee at hip, as if performing knee attack; assists lateral rotators in twisting thigh (and lower leg) outward; assists with bending over, maintaining posture	Femur	Thigh: flexion; lateral rotation Torso: flexion
Psoas major	Lumbar vertebrae (L1 - L5); thoracic vertebrae (T12)	Lesser trochanter of femur	Raises knee at hip, as if performing knee attack; assists lateral rotators in twisting thigh (and lower leg) outward; assists with bending over, maintaining posture	Femur	Thigh: flexion; lateral rotation Torso: flexion
Gluteal Group
Gluteus maximus	Dorsal ilium; sacrum; coccyx	Gluteal tuberosity of femur; iliotibial tract	Lower knee and moves thigh back, as when getting ready to kick a ball	Femur	Extension
Gluteus medius	Lateral surface of ilium	Greater trochanter of femur	Opens thighs, as when doing a split	Femur	Abduction
Gluteus minimus	External surface of ilium	Greater trochanter of femur	Brings thighs back together	Femur	Abduction
Tensor fascia lata	Anterior aspect of iliac crest; anterior superior iliac spine	Iliotibial tract	Assists with raising the knee at hip and opening thighs; maintains posture by stabilizing the iliotibial tract, which connects to the knee	Femur	Flexion; abduction
Lateral Rotators
Inferior gemellus	Ischial tuberosity	Greater trochanter of femur	Twists thigh (and lower leg) outward; maintains posture by stabilizing hip joint	Femur	Lateral rotation
Obturator externus	Outer surfaces of obturator membrane, pubis, and ischium; margins of obturator foramen	Trochanteric fossa of posterior femur	Twists thigh (and lower leg) outward; maintains posture by stabilizing hip joint	Femur	Lateral rotation
Obturator internus	Inner surface of obturator membrane; greater sciatic notch; margins of obturator foramen	Greater trochanter in front of piriformis	Twists thigh (and lower leg) outward; maintains posture by stabilizing hip joint	Femur	Lateral rotation
Piriformis	Anterolateral surface of sacrum	Greater trochanter of femur	Twists thigh (and lower leg) outward; maintains posture by stabilizing hip joint	Femur	Lateral rotation
Quadratus femoris	Ischial tuberosity	Trochanteric crest of femur	Twists thigh (and lower leg) outward; maintains posture by stabilizing hip joint	Femur	Lateral rotation
Superior gemellus	Ischial spine	Greater trochanter of femur	Twists thigh (and lower leg) outward; maintains posture by stabilizing hip joint	Femur	Lateral rotation
Adductors
Adductor brevis	Body of pubis; inferior ramus of pubis	Linea aspera above adductor longus	Brings thighs back together; assists with raising knee	Femur	Adduction; flexion
Adductor longus	Pubis near pubic symphysis	Linea aspera	Brings thighs back together; assists with raising knee	Femur	Adduction; flexion
Adductor magnus	Ischial rami; pubic rami; ischial tuberosity	Linea aspera; adductor tubercle of femur	Brings thighs back together; assists with raising knee and moving thigh back	Femur	Adduction; flexion; extension
Pectineus	Pectineal line of pubis	Lesser trochanter to linea aspera of posterior aspect of femur	Opens thighs; assists with raising the knee and turning the thigh (and lower leg) inward	Femur	Adduction; flexion; medial rotation

The tensor fascia latae is a thick, squarish muscle in the superior aspect of the lateral thigh. It acts as a synergist of the gluteus medius and iliopsoas in flexing and abducting the thigh. It also helps stabilize the lateral aspect of the knee by pulling on the iliotibial tract (band), making it taut. Deep to the gluteus maximus, the piriformis, obturator internus, obturator externus, superior gemellus, inferior gemellus, and quadratus femoris laterally rotate the femur at the hip.

The adductor longus, adductor brevis, and adductor magnus can both medially and laterally rotate the thigh depending on the placement of the foot. The adductor longus flexes the thigh, whereas the adductor magnus extends it. The pectineus adducts and flexes the femur at the hip as well. The pectineus is located in the femoral triangle, which is formed at the junction between the hip and the leg and also includes the femoral nerve, the femoral artery, the femoral vein, and the deep inguinal lymph nodes.

Thigh Muscles That Move the Femur, Tibia, and Fibula

Deep fascia in the thigh separates it into medial, anterior, and posterior compartments (Figure \(\PageIndex{1}\) and Table \(\PageIndex{2}\)). The muscles in the medial compartment of the thigh are responsible for adducting the femur at the hip. Along with the adductor longus, adductor brevis, adductor magnus, and pectineus, the strap-like gracilis adducts the thigh in addition to flexing the leg at the knee.

Table \(\PageIndex{2}\): Thigh Muscles That Move the Femur, Tibia, and Fibula

Prime Mover	Origin	Insertion	Movement	Target	Target Motion Direction
Medial Compartment of Thigh
Gracilis	Inferior ramus; body of pubis; ischial ramus	Medial surface of tibia	Moves back of lower legs up toward buttocks, as when kneeling; assists in opening thighs	Femur; tibia/fibula	Thigh: adduction Lower leg: flexion
Anterior Compartment of Thigh: Quadricepts Femoris Group
Rectus femoris	Anterior inferior iliac spine; superior margin of acetabulum	Patella; tibial tuberosity	Moves lower leg out in front of body, as when kicking; assists in raising knee	Femur; tibia/fibula	Thigh: flexion Lower leg: extension
Sartorius	Anterior superior iliac spine	Medial aspect of proximal tibia	Moves back of lower legs up and back toward the buttocks, as when kneeling; assists in moving thigh diagonally upward and outward as when mounting a bike	Femur; tibia/fibula	Thigh: flexion; abduction; lateral rotation Lower leg: flexion
Vastus intermedius	Proximal femur shaft	Patella; tibial tuberosity	Moves lower leg out in front of body, as when kicking	Tibia/fibula	Extension
Vastus lateralis	Greater trochanter; intertrochanteric line; linea apera	Patella; tibial tuberosity	Moves lower leg out in front of body, as when kicking	Tibia/fibula	Extension
Vastus medialis	Linea aspera; intertrochanteric line	Patella; tibial tuberosity	Moves lower leg out in front of body, as when kicking	Tibia/fibula	Extension
Posterior Compartment of Thigh: Hamstring Group
Biceps femoris	Ischial tuberosity; linea aspera; distal femur	Head of fibula; lateral condyle of tibia	Moves back of lower legs up and back toward the buttocks, as when kneeling; moves thigh down and back; twists the thigh (and lower leg) outward	Femur; tibia/fibula	Thigh: extension; lateral rotation Lower leg: flexion
Semimembranosus	Ischial tuberosity	Medial condyle of tibia; lateral condyle of femur	Moves back of lower legs up and back toward the buttocks, as when kneeling; moves thigh down and back; twists the thigh (and lower leg) outward	Femur; tibia/fibula	Thigh: extension; medial rotation Lower leg: flexion
Semitendinosus	Ischial tuberosity	Upper tibial shaft	Moves back of lower legs up and back toward the buttocks, as when kneeling; moves thigh down and back; twists the thigh (and lower leg) outward	Femur; tibia/fibula	Thigh: extension; medial rotation Lower leg: flexion

The muscles of the anterior compartment of the thigh flex the thigh and extend the leg. This compartment contains the quadriceps femoris group, which actually comprises four muscles that extend and stabilize the knee. The rectus femoris is on the anterior aspect of the thigh, the vastus lateralis is on the lateral aspect of the thigh, the vastus medialis is on the medial aspect of the thigh, and the vastus intermedius is between the vastus lateralis and vastus medialis and deep to the rectus femoris. The tendon common to all four is the quadriceps tendon (patellar tendon), which inserts into the patella and continues below it as the patellar ligament. The patellar ligament attaches to the tibial tuberosity. In addition to the quadriceps femoris, the sartorius is a band-like muscle that extends from the anterior superior iliac spine to the medial side of the proximal tibia. This versatile muscle flexes the leg at the knee and flexes, abducts, and laterally rotates the leg at the hip. This muscle allows us to sit cross-legged.

The posterior compartment of the thigh includes muscles that flex the leg and extend the thigh. The three long muscles on the back of the knee are the hamstring group, which flexes the knee. These are the biceps femoris, semitendinosus, and semimembranosus. The tendons of these muscles form the popliteal fossa, the diamond-shaped space at the back of the knee.

Muscles That Move the Feet and Toes

Similar to the thigh muscles, the muscles of the leg are divided by deep fascia into compartments, although the leg has three: anterior, lateral, and posterior (Figure \(\PageIndex{2}\) and Table \(\PageIndex{3}\)).

Figure \(\PageIndex{2}\): Muscles of the Lower Leg. The muscles of the anterior compartment of the lower leg are generally responsible for dorsiflexion, and the muscles of the posterior compartment of the lower leg are generally responsible for plantar flexion. The lateral and medial muscles in both compartments invert, evert, and rotate the foot. (Image credit: "Muscles of the Leg that Move the Foot and Toes" by Openstax is licensed under CC BY 4.0)

Table \(\PageIndex{3}\): Muscles That Move the Feet and Toes

Prime Mover	Origin	Insertion	Movement	Target	Target Motion Direction
Anterior Compartment of Leg
Extensor digitorum longus	Lateral condyle of tibia; proximal portion of fibula; interosseous membrane	Middle and distal phalanges of toes 2 - 5	Raises the sole of the foot off the ground, as when preparing to foot-tap; extends toes	Foot; toes 2 - 5	Foot: dorsiflexion Toes: extension
Extensor hallucis longus	Anteromedial fibula shaft; interosseous membrane	Distal phalanx hallux (big toe)	Raises the sole of the foot off the ground, as when preparing to foot-tap; extends the big toe	Foot; big toe	Foot: dorsiflexion Big toe: extension
Tibialis anterior	Lateral condyle and upper tibial shaft; interosseous membrane	Interior surface of medial cuneiform; first metatarsal bone	Raises the sole of the foot off the ground as when preparing to foot-tap; bends the inside of the foot upwards, as when catching your balance while falling laterally toward the opposite side as the balancing foot	Foot	Dorsiflexion; inversion
Lateral Compartment of Leg
Fibularis (peroneus) brevis	Distal fibula shaft	Proximal end of fifth metatarsal	Lowers the sole of the foot to the ground as when foot-tapping or jumping; bends the inside of the foot downward, as when catching your balance while falling laterally toward the same side as the balancing foot	Foot	Plantar flexion; eversion
Fibularis longus	Upper portion of lateral fibula	First metatarsal; medial cuneiform	Lowers the sole of the foot to the ground as when foot-tapping or jumping; bends the inside of the foot downward, as when catching your balance while falling laterally toward the same side as the balancing foot	Foot	Plantar flexion; eversion
Posterior Compartment of Leg: Superficial Muscles
Gastrocnemius	Medial and lateral condyles of femur	Posterior calcaneus	Lowers the sole of the foot to the ground, as when foot-tapping or jumping; assists in moving the back of the lower legs up and back toward the buttocks	Foot; tibia/fibula	Foot: plantar flexion Tibia/fibula: flexion
Plantaris	Posterior femur above lateral condyle	Calcaneus or calcaneus tendon	Lowers the sole of the foot to the ground, as when foot-tapping or jumping; assists in moving the back of the lower legs up and back toward the buttocks	Foot; tibia/fibula	Foot: plantar flexion Tibia/fibula: flexion
Soleus	Superior tibia; fibula; interosseous membrane	Posterior calcaneus	Lowers the sole of the foot to the ground, as when foot-tapping or jumping; maintains posture while walking	Foot	Plantar flexion
Tibialis posterior	Superior tibia; fibula; interosseous membrane	Several tarsals and metatarsals 2 - 4	Lowers the sole of the foot to the ground, as when foot-tapping or jumping	Foot	Plantar flexion
Posterior Compartment of Leg: Deep Muscles
Flexor digitorum longus	Posterior tibia	Distal phalanges of toes 2 - 5	Lowers the sole of the foot to the ground, as when foot-tapping or jumping; bends the inside of the foot upward and flexes toes	Foot; toes 2 - 5	Foot: plantar flexion; inversion Toes: flexion
Flexor hallucis longus	Midshaft of fibula; interosseous membrane	Distal phalanx of hallux (big toe)	Flexes big toe	Foot; big toe	Foot: plantar flexion Big toe: flexion
Popliteus	Lateral condyle of femur; lateral meniscus	Proximal tibia	Moves the back of the lower legs up and back toward buttocks; assists in rotation of the leg at the knee and thigh	Tibia/fibula	Tibia/fibula: flexion Thigh and lower leg: medial and lateral rotation

The muscles in the anterior compartment of the leg: the tibialis anterior, a long and thick muscle on the lateral surface of the tibia, the extensor hallucis longus, deep under it, and the extensor digitorum longus, lateral to it, all contribute to raising the front of the foot when they contract. The fibularis tertius, a small muscle that originates on the anterior surface of the fibula, is associated with the extensor digitorum longus and sometimes fused to it, but is not present in all people. Thick bands of connective tissue called the superior extensor retinaculum (transverse ligament of the ankle) and the inferior extensor retinaculum, hold the tendons of these muscles in place during dorsiflexion.

The lateral compartment of the leg includes two muscles: the fibularis longus (peroneus longus) and the fibularis brevis (peroneus brevis). The superficial muscles in the posterior compartment of the leg all insert onto the calcaneal tendon (Achilles tendon), a strong tendon that inserts into the calcaneal bone of the ankle. The muscles in this compartment are large and strong and keep humans upright. The most superficial and visible muscle of the calf is the gastrocnemius. Deep to the gastrocnemius is the wide, flat soleus. The plantaris runs obliquely between the two; some people may have two of these muscles, whereas no plantaris is observed in about seven percent of other cadaver dissections. The plantaris tendon is a desirable substitute for the fascia lata in hernia repair, tendon transplants, and repair of ligaments. There are four deep muscles in the posterior compartment of the leg as well: the popliteus, flexor digitorum longus, flexor hallucis longus, and tibialis posterior.

The foot also has intrinsic muscles, which originate and insert within it (similar to the intrinsic muscles of the hand). These muscles primarily provide support for the foot and its arch, and contribute to movements of the toes (Figure \(\PageIndex{3}\) and Table \(\PageIndex{4}\)). The principal support for the longitudinal arch of the foot is a deep fascia called plantar aponeurosis, which runs from the calcaneus bone to the toes (inflammation of this tissue is the cause of “plantar fasciitis,” which can affect runners. The intrinsic muscles of the foot consist of two groups. The dorsal group includes only one muscle, the extensor digitorum brevis. The second group is the plantar group, which consists of four layers, starting with the most superficial.

Figure \(\PageIndex{3}\): Intrinsic Muscles of the Foot. The muscles along the dorsal side of the foot (a) generally extend the toes while the muscles of the plantar side of the foot (b, c, d) generally flex the toes. The plantar muscles exist in three layers, providing the foot the strength to counterbalance the weight of the body. In this diagram, these three layers are shown from a plantar view beginning with the bottom-most layer just under the plantar skin of the foot (b) and ending with the top-most layer (d) located just inferior to the foot and toe bones. (Image credit: "Intrinsic Muscles of the Foot" by Openstax is licensed under CC BY 4.0)

Table \(\PageIndex{4}\): Intrinsic Muscles in the Foot

Prime Mover	Origin	Insertion	Movement	Target	Target Motion Direction
Dorsal Group
Extensor digitorum brevis	Calcaneus; extensor retinaculum	Base of proximal phalanx of big toe; extensor expansions on toes 2 - 5	Extends toes 2 - 5	Toes 2 - 5	Extension
Plantar Group: Layer 1
Abductor digiti minimi	Calcaneal tuberosity	Proximal phalanx of toe 5 (pinky toe)	Abducts and flexes toe 5	Toe 5	Abduction; flexion
Abductor hallucis	Calcaneal tuberosity; flexor retinaculum	Proximal phalanx of hallux (big toe)	Abducts and flexes big toe	Big toe	Abduction; flexion
Flexor digitorum brevis	Calcaneal tuberosity	Middle phalanx of toes 2 - 4	Flexes toes 2 - 4	Middle toes	Flexion
Plantar Group: Layer 2
Lumbricals	tendons of flexor digitorum longus	Medial side of proximal phalanx of toes 2 - 5	Extends toes 2 - 5 at the interphalangeal joints; flexes the small toes at the metatarsophalangeal joints	Toes 2 - 5	Extension; flexion
Quadratus plantae	Medial and lateral sides of calcaneus	Tendon of flexor digitorum longus	Assists in flexing toes 2 - 5	Toes 2 - 5	Flexion
Plantar Group: Layer 3
Adductor hallucis	Bases of metatarsals 2 - 4; fibularis longus tendon sheath; ligament across metatarsophalangeal joints	Base of proximal phalanx of hallux (big toe)	Adducts and flexes big toe	Big toe	Adduction; flexion
Flexor digiti minimi brevis	Base of metatarsal 5; tendon sheath of fibularis longus	Base of proximal phalanx of toe 5 (pinky toe)	Flexes pinky toe	Pinky toe	Flexion
Flexor hallicus brevis	Lateral cuneiform; cuboid bones	Base of proximal phalanx of hallux (big toe)	Flexes big toe	Big toe	Flexion
Plantar Group: Layer 4
Dorsal interossei	Sides of metatarsals	Both sides of toe 2; for each other toe, extensor expansion over first phalanx on side opposite toe 2	Abducts and flexes middle toes at metatarsophalangeal joints; extends middle toes at interphalangeal joints	Middle toes	Abduction; flexion; extension
Plantar interossei	Side of each metatarsal that faces metatarsal 2 (absent from metatarsal 2)	Extensor expansion on first phalanx of each tow ( except on 2) on side facing toe 2	Abducts toes 3 - 5; flexes proximal phalanges and extends distal phalanges	Small toes	Abduction; flexion; extension

Concept Review

The pelvic girdle attaches the legs to the axial skeleton. The hip joint is where the pelvic girdle and the leg come together. The hip is joined to the pelvic girdle by many muscles. In the gluteal region, the psoas major and iliacus form the iliopsoas. The large and strong gluteus maximus, gluteus medius, and gluteus minimus extend and abduct the femur. Along with the gluteus maximus, the tensor fascia lata muscle forms the iliotibial tract. The lateral rotators of the femur at the hip are the piriformis, obturator internus, obturator externus, superior gemellus, inferior gemellus, and quadratus femoris. On the medial part of the thigh, the adductor longus, adductor brevis, and adductor magnus adduct the thigh and medially rotate it. The pectineus muscle adducts and flexes the femur at the hip.

The thigh muscles that move the femur, tibia, and fibula are divided into medial, anterior, and posterior compartments. The medial compartment includes the adductors, pectineus, and the gracilis. The anterior compartment comprises the quadriceps femoris, quadriceps tendon, patellar ligament, and the sartorius. The quadriceps femoris is made of four muscles: the rectus femoris, the vastus lateralis, the vastus medius, and the vastus intermedius, which together extend the knee. The posterior compartment of the thigh includes the hamstrings: the biceps femoris, semitendinosus, and the semimembranosus, which all flex the knee.

The muscles of the leg that move the foot and toes are divided into anterior, lateral, superficial- and deep-posterior compartments. The anterior compartment includes the tibialis anterior, the extensor hallucis longus, the extensor digitorum longus, and the fibularis (peroneus) tertius. The lateral compartment houses the fibularis (peroneus) longus and the fibularis (peroneus) brevis. The superficial posterior compartment has the gastrocnemius, soleus, and plantaris; and the deep posterior compartment has the popliteus, tibialis posterior, flexor digitorum longus, and flexor hallucis longus.

Review Questions

Q. The large muscle group that attaches the leg to the pelvic girdle and produces extension of the hip joint is the ________ group.

A. gluteal

B. obturator

C. adductor

D. abductor

Answer

Answer: A

Q. Which muscle produces movement that allows you to cross your legs?

A. the gluteus maximus

B. the piriformis

C. the gracilis

D. the sartorius

Answer

Answer: D

Q. What is the largest muscle in the lower leg?

A. soleus

B. gastrocnemius

C. tibialis anterior

D. tibialis posterior

Answer

Answer: B

Q. The vastus intermedius muscle is deep to which of the following muscles?

A. biceps femoris

B. rectus femoris

C. vastus medialis

D. vastus lateralis

Answer

Answer: B

Critical Thinking Questions

Q. Which muscles form the hamstrings? How do they function together?

Answer

A. The biceps femoris, semimembranosus, and semitendinosus form the hamstrings. The hamstrings flex the leg at the knee joint.

Q. Which muscles form the quadriceps? How do they function together?

Answer

A. The rectus femoris, vastus medialis, vastus lateralis, and vastus intermedius form the quadriceps. The quadriceps muscles extend the leg at the knee joint.

Glossary

adductor brevis

muscle that adducts and medially rotates the thigh

adductor longus

muscle that adducts, medially rotates, and flexes the thigh

adductor magnus

muscle with an anterior fascicle that adducts, medially rotates and flexes the thigh, and a posterior fascicle that assists in thigh extension

anterior compartment of the leg

region that includes muscles that dorsiflex the foot

anterior compartment of the thigh

region that includes muscles that flex the thigh and extend the leg

biceps femoris

hamstring muscle

calcaneal tendon

(also, Achilles tendon) strong tendon that inserts into the calcaneal bone of the ankle

dorsal group

region that includes the extensor digitorum brevis

extensor digitorum brevis

muscle that extends the toes

extensor digitorum longus

muscle that is lateral to the tibialis anterior

extensor hallucis longus

muscle that is partly deep to the tibialis anterior and extensor digitorum longus

femoral triangle

region formed at the junction between the hip and the leg and includes the pectineus, femoral nerve, femoral artery, femoral vein, and deep inguinal lymph nodes

fibularis brevis

(also, peroneus brevis) muscle that plantar flexes the foot at the ankle and everts it at the intertarsal joints

fibularis longus

(also, peroneus longus) muscle that plantar flexes the foot at the ankle and everts it at the intertarsal joints

fibularis tertius

small muscle that is associated with the extensor digitorum longus

flexor digitorum longus

muscle that flexes the four small toes

flexor hallucis longus

muscle that flexes the big toe

gastrocnemius

most superficial muscle of the calf

gluteal group

muscle group that extends, flexes, rotates, adducts, and abducts the femur

gluteus maximus

largest of the gluteus muscles that extends the femur

gluteus medius

muscle deep to the gluteus maximus that abducts the femur at the hip

gluteus minimus

smallest of the gluteal muscles and deep to the gluteus medius

gracilis

muscle that adducts the thigh and flexes the leg at the knee

hamstring group

three long muscles on the back of the leg

iliacus

muscle that, along with the psoas major, makes up the iliopsoas

iliopsoas group

muscle group consisting of iliacus and psoas major muscles, that flexes the thigh at the hip, rotates it laterally, and flexes the trunk of the body onto the hip

iliotibial tract

muscle that inserts onto the tibia; made up of the gluteus maximus and connective tissues of the tensor fasciae latae

inferior extensor retinaculum

cruciate ligament of the ankle

inferior gemellus

muscle deep to the gluteus maximus on the lateral surface of the thigh that laterally rotates the femur at the hip

lateral compartment of the leg

region that includes the fibularis (peroneus) longus and the fibularis (peroneus) brevis and their associated blood vessels and nerves

medial compartment of the thigh

a region that includes the adductor longus, adductor brevis, adductor magnus, pectineus, gracilis, and their associated blood vessels and nerves

obturator externus

muscle deep to the gluteus maximus on the lateral surface of the thigh that laterally rotates the femur at the hip

obturator internus

muscle deep to the gluteus maximus on the lateral surface of the thigh that laterally rotates the femur at the hip

patellar ligament

extension of the quadriceps tendon below the patella

pectineus

muscle that abducts and flexes the femur at the hip

pelvic girdle

hips, a foundation for the lower limb

piriformis

muscle deep to the gluteus maximus on the lateral surface of the thigh that laterally rotates the femur at the hip

plantar aponeurosis

muscle that supports the longitudinal arch of the foot

plantar group

four-layered group of intrinsic foot muscles

plantaris

muscle that runs obliquely between the gastrocnemius and the soleus

popliteal fossa

diamond-shaped space at the back of the knee

popliteus

muscle that flexes the leg at the knee and creates the floor of the popliteal fossa

posterior compartment of the leg

region that includes the superficial gastrocnemius, soleus, and plantaris, and the deep popliteus, flexor digitorum longus, flexor hallucis longus, and tibialis posterior

posterior compartment of the thigh

region that includes muscles that flex the leg and extend the thigh

psoas major

muscle that, along with the iliacus, makes up the iliopsoas

quadratus femoris

muscle deep to the gluteus maximus on the lateral surface of the thigh that laterally rotates the femur at the hip

quadriceps femoris group

four muscles, that extend and stabilize the knee

quadriceps tendon

(also, patellar tendon) tendon common to all four quadriceps muscles, inserts into the patella

rectus femoris

quadricep muscle on the anterior aspect of the thigh

sartorius

band-like muscle that flexes, abducts, and laterally rotates the leg at the hip

semimembranosus

hamstring muscle

semitendinosus

hamstring muscle

soleus

wide, flat muscle deep to the gastrocnemius

superior extensor retinaculum

transverse ligament of the ankle

superior gemellus

muscle deep to the gluteus maximus on the lateral surface of the thigh that laterally rotates the femur at the hip

tensor fascia lata

muscle that flexes and abducts the thigh

tibialis anterior

muscle located on the lateral surface of the tibia

tibialis posterior

muscle that plantar flexes and inverts the foot

vastus intermedius

quadricep muscle that is between the vastus lateralis and vastus medialis and is deep to the rectus femoris

vastus lateralis

quadricep muscle on the lateral aspect of the thigh

vastus medialis

quadricep muscle on the medial aspect of the thigh

Contributors and Attributions

• OpenStax Anatomy & Physiology (CC BY 4.0). Access for free at https://openstax.org/books/anatomy-and-physiology