Appendicular Muscles of the Pelvic Girdle and Lower Limbs

Learning Objectives

  • 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 1 and Table 1).

The left panel shows the superficial pelvic and thigh muscles, the center panel shows the deep pelvic and thigh muscles. The right panel shows the posterior view of the pelvic and thigh muscles. Figure 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.


Table 1. Gluteal Region Muscles That Move the Femur
Movement Target motion direction Prime mover Origin Insertion
Iliopsoas group
raises the knee at the hip, as if performing a knee attack; it also assists the lateral rotators in twisting the thigh (and lower leg) outward, and assists with bending over and maintaining posture thigh: flexion and lateral rotation;

torso: flexion
psoas major lumbar vertebrae (L1 through L5) and thoracic vertebra (T12) lesser trochanter of femur
raises the knee at the hip, as if performing a knee attack; it also assists the lateral rotators in twisting the thigh (and lower leg) outward, and assists with bending over and maintaining posture thigh: flexion and lateral rotation;

torso: flexion
iliacus iliac fossa, iliac crest, and lateral sacrum lesser trochanter of femur
Gluteal group
lowers the knee and moves the thigh back, as when getting ready to kick a ball extension gluteous maximus  dorsal ilium, sacrum, and coccyx gluteal tuberosity of femur; iliotibial tract
opens the thigh, as when doing a split abduction gluteus medius  lateral surface of the ilium greater trochanter of femur
brings the thighs back together abduction gluteus minimus  external surface of the ilium greater trochanter of femur
assists with raising the knee at the hip and opening the thighs; it also maintains posture by stabilizing the iliotibial track, which connects to the knee flexion; abduction tensor fascia lata  anterior aspect of the iliac crest and the anterior superior iliac spine iliotibial tract
Lateral rotators
twists the thigh (and lower leg) outward; it also maintains posture by stabilizing the hip joint  lateral rotation piriformis  anterolateral surface of the sacrum greater trochanter of femur
twists the thigh (and lower leg) outward; it also maintains posture by stabilizing the hip joint lateral rotation obturator internus  inner surface of the obturator membrane, the greater sciatic notch, and the margins of the obturator foramen greater trochanter in front of piriformis
twists thigh (and lower leg) outward; maintains posture by stabilizing hip joint lateral rotation obturator externus outer surfaces of obturator membrane, pubic, and ischium; margins of obturator foramen trochanteric fossa of posterior femur
twists the thigh (and lower leg) outward; it also maintains posture by stabilizing the hip joint lateral rotation superior gemellus  ischial spine greater trochanter of femur
twists the thigh (and lower leg) outward; it also maintains posture by stabilizing the hip joint lateral rotation inferior gemellus  ischial tuberosity  greater trochanter of femur
twists the thigh (and lower leg) outward; it also maints posture by stabilizing the hip joint lateral rotation quatratus femoris  ischial tuberosity trochanteric crest of femur
Adductors
brings the thighs back together; it also assists with raising the knee adduction; flexion adductor longus  pubis near the pubic symphysis linea aspera
brings the thighs back together; it also assists with raising the knee adduction; flexion adductor brevis  body of the pubis and in the inferior ramus of the pubis linea aspera above adductor longus
 brings the thighs back together; it also assists with raising the knee and moving the thigh back adduction; flexion; extension adductor magnus  ischial rami, the pubic rami, and the ischial tuberosity linea aspera; adductor tubercle of femur
opens the thigh; with raising the knee and turning the thigh (and lower leg) inward adduction; flexion; medial rotation pectineus  pectineal line of the pubis lesser trochanter to linea aspera of posterior aspect of femur
The tensor fascia lata 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 piriformisobturator internus, obturator externussuperior gemellusinferior gemellus, and quadratus femoris laterally rotate the femur at the hip.

The adductor longusadductor 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 (see Figure 1 and Table 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 2. Thigh Muscles That Move the Femur, Tibia, and Fibula
Movement Target Target motion direction Prime mover Origin Insertion
Medial compartment of thigh
moves the back of the lower legs up toward the buttocks, as when kneeling; it also assists in opening the thighs femur; tibia/fibula tibia/fibula: flexion;

thigh: adduction
 gracilis inferior ramus, the body of the pubis, and the ischial ramus medial surface of tibia
Anterior compartment of the thigh: Quadriceps femoris group
 moves the lower leg out in front of the body, as when kicking; it also assists in raising the knee femur; tibia/fibula tibia/fibula: extension;

thigh: flexion
 rectus femoris anterior inferior iliac spine and in the superior margin of the acetabulum patella; tibial tuberosity
moves the lower leg out in front of the body, as when kicking tibia/fibula extension vastus lateralis greater trochanter, the intertrochanteric line, and the linea aspera patella; tibial tuberosity
moves the lower leg out in front of the body, as when kicking tibia/fibula extension vastus medialis linea aspera and the intertrochanteric line patella; tibial tuberosity
moves the lower leg out in front of the body, as when kicking tibia/fibula extension vastus intermedius proximal femur shaft patella; tibial tuberosity
moves the back of the lower legs up and back toward the buttocks, as when kneeling; it also assists in moving the thigh diagonally upward and outward as when mounting a bike femur; tibia/fibula tibia: flexion;

thigh: flexion, abduction, lateral rotation
sartorius anterior superior iliac spine medial aspect of proximal tibia
Posterior compartment of the thigh: Hamstring group
moves the back of the lower leg up and back toward the buttocks, as when kneeling; it also moves the thigh down and back and twists the thigh (and lower leg) outward femur; tibia/fibula tibia/fibula: flexion;

thigh: extension, lateral rotation
biceps femoris  ischial tuberosity, linea aspera, and distal femur head of fibula; lateral condyle of tibia
moves the back of the lower legs up toward the buttocks, as when kneeling; it also moves the thigh down and back and twists the thigh (and lower leg) inward femur; tibia/fibula tibia/fibula: flexion;

thigh: extension, medial rotation
semitendinosus  ischial tuberosity upper tibial shaft
moves the back of the lower legs up and back toward the buttocks, as when kneeling; it also moves the thigh down and back and twists the thigh (and lower leg) inward femur; tibia/fibula tibia/fibula: flexion;

thigh: extension, medial rotation
semi-membranosus  ischial tuberosity medial condyle of tibia; lateral condyle of femur
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 2 and Table 3).

The left panel shows the superficial muscles that move the feet and the center panel shows the posterior view of the same muscles. The right panel shows the deep muscles of the right lower leg. Figure 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.


Table 3. Muscles That Move the Feet and Toes
Movement Target Target motion direction Prime mover Origin Insertion
Anterior compartment of the leg
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 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; extends the big toe foot; big toe foot: dorsiflexion;

big toe: extension
extensor hallucis longus anteromedial fibula shaft and interosseous membrane distal phalanx of big toe
raises the sole of the foot off the ground, as when preparing to foot-tap; extends the toes foot; toes 2–5 foot: dorsiflexion;

toes: extension
extensor digitorum longus lateral condyle of the tibia, the proximal portion of the fibula, and the interosseous membrane middle and distal phalanges of toes 2–5
Lateral compartment of the leg
lowers the sole of the foot to the ground, as when foot-tapping or jumping; it also bends the inside of the foot downwards, as when catching your balance while falling laterally toward the same side as the balancing foot foot plantar flexion and eversion fibularis longus upper portion of the lateral fibula first metatarsal; medial cuneiform
lowers the side of the foot to the ground, as when foot-tapping or jumping; it also 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 and eversion fibularis (peroneus) brevis distal fibula shaft proximal end of fifth metatarsal
Posterior compartment of leg: Superficial muscles
lowers the sole of the foot to the ground, as when foot-tapping or jumping; it also assists in moving the back of the lower legs up and back toward the buttocks foot; tibia/fibula foot: plantar flexion;

tibia/fibula: flexion
gastrocnemius medial and lateral condyles of the femur posterior calcaneus
lowers the sole of the foot the ground, as when foot-tapping or jumping; it also maintains posture while walking foot plantar flexion soleus superior tibia, fibula, and interosseous membrane posterior calcaneus
lowers the sole of the foot to the ground, as when foot-tapping or jumping; it also 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 the lateral condyle calcaneus or calcaneus tendon
lowers the sole of the foot to the ground, as when foot-tapping or jumping foot plantar flexion tibialis posterior superior tibia and fibula and in the interosseous membrane several tarsals and metatarsals 2–4
Posterior compartment of the leg: Deep muscles
moves the back of the lower legs up and back toward the buttocks; it also assists in rotation of the leg at the knee and thigh tibia/fibula tibia/fibula: flexion;

thigh and lower leg: medial and lateral rotation
popliteus lateral condyle of the femur and the lateral meniscus proximal tibia
lowers the sole of the foot to the ground, as when foot-tapping or jumping; it also bends the inside of the foot upward and flexes the toes foot; toes 2–5 foot: plantar flexion and inversion;

toes: flexion
flexor digitorum longus posterior tibia distal phalanges of toes 2–5
flexes the big toe big toe; foot big toe: flexion;

foot: plantar flexion
flexor hallicis longus midshaft of fibula; interosseous membrane distal phalanx of big toe
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 popliteusflexor digitorum longusflexor 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 3 and Table 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.

This figure shows the muscles of the foot. The top panel shows the lateral view of the dorsal muscles. The bottom left panel shows the superficial muscles of the left sole, the center panel shows the intermediate muscles of the left sole, and the right panel shows the deep muscles of the left sole. Figure 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.


Table 4. Intrinsic Muscles in the Foot
Movement Target Target motion direction Prime mover Origin Insertion
Dorsal group
extends toes 2 through 5 toes 2–5 extension extensor digitorum brevis calcaneus; extensor retinaculum base of proximal phalanx of big toe; extensor expansions on toes 2–5
Plantar group (layer 1)
abducts and flexes the big toe big toe adduction; flexion abductor hallucis calcaneal tuberosity; flexor retinaculum proximal phalanx of big toe
flexes toes 2 through 4 middle toes flexion flexor digitorum brevis calcaneal tuberosity middle phalanx of toes 2–4
abducts and flexes the small toe toe 5 abduction; flexion abductor digiti minimi calcaneal tuberosity proximal phalanx of little toe
Plantar group (layer 2)
assists in flexing toes 2 through 5 toes 2–5 flexion quadratus plantae  medial and lateral sides of the calcaneus tendon of flexor digitorum longus
extend toes 2 through 5 at the interphalangeal joints; they also flex the small toes at the metatarsophalangeal joints toes 2–5 extension; flexion lumbricals tendons of the flexor digitorum longus medial side of proximal phalanx of toes 2–5
Plantar group (layer 3)
flexes the big toe big toe flexion flexor hallucis brevis lateral cuneiform and in the cuboid bones base of proximal phalanx of big toe
adducts and flexes the big toe big toe adduction; flexion adductor hallucis bases of metatarsals 2 through 4, in the fibularis longus tendon sheath, and in the ligament across the metatarsophalangeal joints base of proximal phalanx of big toe
flexes the small toe little toe flexion flexor digiti minimi brevis base of metatarsal 5 and in the tendon sheath of the fibularis longus base of proximal phalanx of little toe
Plantar group (layer 4)
abducts and flexes the middle toes at the metatarsophalangeal joints; it also extends the middle toes at the interphalangeal joints middle toes abduction; flexion; extension dorsal interossei sides of the metatarsals both sides of toe 2; for each tother to, extensor expansion over first phalanx on side opposite toe 2
abducts toes 3 through 5; it also flexes the proximal phalanges and extends the distal phalanges small 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 toe (except toe 2) on side facing toe 2

Self-Check Questions

Take the quiz below to check your understanding of the Appendicular Muscles of the Pelvic Girdle and Lower Limbs:

http://oea.herokuapp.com/assessments/206

Licenses and Attributions

More Study Resources for You

Show More