LAB 3 : (C.) Human Leg Muscle

Size: Major indicates the larger of the psoas muscles.

Location: A major muscle associated with the loin/lower back and hip region.

Psoas major

Location: A muscle associated with the ilium, the large upper portion of the hip bone.

Iliacus

Action and Location: A muscle that tenses (tensor) the fascia (fasciae) on the lateral/wide part of the thigh (latae).

Tensor fasciae latae

Location: A strong band running from the ilium of the hip toward the tibia of the lower leg.

Structure: A tract/band, rather than a typical muscle.

Iliotibial tract (Iliotibial band)

Shape and Location: A long, thin, strap-like muscle that runs diagonally across the front of the thigh, from the lateral hip toward the medial knee.

Action: Helps flex, abduct, and laterally rotate the thigh and flex the knee.

Sartorius

Location: A relatively short muscle located in the upper/medial thigh, near the pectineal region of the pubic bone.

Action: Helps adduct and flex the thigh.

Pectineus

Action and Location: A muscle that adducts the thigh, pulling it toward the body's midline.

Size: Longus indicates a longer adductor muscle.

Location: Located in the medial thigh.

Adductor longus

Action and Size: A muscle that adducts the thigh and is large (magnus).

Location: A large muscle occupying much of the medial thigh.

Adductor magnus

Shape and Size: A slender, thin muscle running along the medial thigh.

Action: Helps adduct the thigh and flex the knee.

Gracilis

Location and Fiber Direction: A muscle running straight (rectus) down the femur/thigh (femoris).

Group: One of the four quadriceps muscles.

Action: Extends the knee and also assists in flexing the hip.

Rectus femoris

Location: A large quadriceps muscle on the lateral/outer side of the thigh.

Group: One of the four quadriceps muscles.

Action: Extends the knee.

Vastus lateralis

Location: A quadriceps muscle on the medial/inner side of the thigh.

Group: One of the four quadriceps muscles.

Action: Extends the knee.

Vastus medialis

Location: A strong band located below the patella (kneecap).

Structure: Connects the patella to the tibia and continues the quadriceps tendon mechanism.

Patellar ligament

Location: A muscle located on the lateral surface of the hip, between the gluteus maximus and the deeper gluteal muscles.

Size/Group: Medius indicates the middle gluteal muscle.

Action: Primarily abducts the thigh and helps stabilize the pelvis.

Gluteus medius

Shape: A pear-shaped muscle.

Location: Located deep in the gluteal region, running from the sacrum toward the femur.

Action: Laterally rotates the thigh and helps stabilize the hip.

Piriformis

Size: Maximus indicates the largest of the gluteal muscles.

Location: The large, superficial muscle forming much of the buttock.

Action: Primarily extends and laterally rotates the thigh.

Gluteus maximus

Group: A two-headed (bi-) muscle of the femur/thigh (femoris).

Location: Located on the posterior/lateral thigh.

Action: Flexes the knee and assists with hip extension.

Biceps femoris

Shape/Structure: A hamstring with a relatively long, cord-like tendon (tendinosus) extending toward the medial side of the knee.

Location: Posteromedial thigh.

Group: One of the three hamstring muscles.

Semitendinosus

Shape/Structure: A hamstring with a broad, flattened membranous tendon (membranosus).

Location: Located on the posteromedial thigh, deep to/near the semitendinosus.

Group: One of the three hamstrings.

Semimembranosus

Shape and Location: A large, superficial two-headed muscle forming much of the calf.

Group: One of the major muscles of the posterior lower leg.

Action: Plantarflexes the foot and assists with knee flexion.

Gastrocnemius

Location: A broad, flat muscle located deep to the gastrocnemius in the posterior lower leg.

Shape: Broad and relatively flat, forming much of the deeper calf.

Action: Plantarflexes the foot.

Soleus

Location: A thick tendon connecting the gastrocnemius/soleus region to the calcaneus (heel bone).

Structure: A tendon, not a muscle.

Achilles tendon (Calcaneal tendon)

Action and Location: A muscle that extends the digits/toes (digitorum).

Size: Longus indicates a long muscle.

Location: Located in the anterior lower leg.

Extensor digitorum longus

Location: A small muscle located behind the knee, in the popliteal region.

Action: Helps unlock the knee and assists with knee rotation.

Popliteus

Location: A muscle located along the front/anterior side of the tibia.

Action: Dorsiflexes and inverts the foot.

Tibialis anterior

Location: A muscle running along the lateral side of the fibula/lower leg.

Size: Longus indicates a long fibularis muscle.

Action: Everts and plantarflexes the foot.

Fibularis longus

Location: A muscle on the lateral side of the lower leg, associated with the fibula.

Size: Brevis indicates that it is the shorter fibularis muscle.

Action: Everts the foot.

Fibularis brevis

Action and Location: A muscle that flexes the digits/toes (digitorum).

Size: Longus indicates a long muscle.

Location: Located in the posterior lower leg.

Flexor digitorum longus

Location: A muscle located posterior to the tibia in the deep posterior compartment of the lower leg.

Action: Helps plantarflex and invert the foot.

Tibialis posterior

Action and Location: A muscle that flexes the hallux/big toe (hallucis).

Size: Longus indicates a long muscle.

Location: Located in the posterior lower leg.

Flexor hallucis longus