Anatomy of Muscular System - Lower Extremity

Muscular SystemLower Extremity

Reynaldo V. Lopez, M.D.Senior Lecturer, Department

of AnatomyAUF School of Medicine

Muscles that Move the Femur at the Hip Joint

The ball-and-socket hip joint, with its 3 axes of rotation is capable of:

1. Flexion & extension2. Abduction & adduction3. Medial & lateral

rotation

Muscles that Move the Femur at the Hip Joint

The flexors of the hip are the:

1. Psoas major2. Iliacus* these muscles

are considered together as the iliopsoas

Muscles that Move the Femur at the Hip Joint

The extensors of the hip are the:

1. Gluteus maximus2. Hamstring

muscles• Semitendinosus• Semimembranosu

s• Biceps femoris

Muscles that Move the Femur at the Hip Joint

The abductors/medial rotators of the hip are the:

1. Gluteus medius2. Gluteus

minimus3. Tensor fasciae

latae

Muscles that Move the Femur at the Hip Joint

The adductors of the hip are the:

1. Adductor longus2. Adductor brevis3. Adductor magnus

Muscles that Move the Femur at the Hip Joint

The lateral rotators of the hip are the:

1. Piriformis2. Obturator externus3. Obturator internus4. Superior and

inferior gemellus5. Quadratus femoris

Muscles that Move the Femur at the Hip Joint

Muscles that Move the Femur at the Hip Joint

Muscles that Act at the Knee Joint

The knee is a hinge joint capable of flexion & extension, with a slight amount of medial & lateral rotation when not fully extended.

Muscles that Act at the Knee Joint

The flexors of the knee are the:

1. Biceps femoris2. Semitendinosus3. Semimebranosus4. Sartorius5. Gracilis6. Popliteus

Muscles that Act at the Knee Joint

The extensors of the knee are the:

1. Rectus femoris2. Vastus lateralis3. Vastus

intermedius4. Vastus medialis

Muscles that Act at the Knee Joint

Muscles that Act at the Knee Joint

Muscles that Act at the Knee Joint

Muscles of the Leg

Fascia lata of the leg surrounds muscles Tightly binds muscles Prevents swelling during exercise Aids venous return Divides leg into three compartments

Tendons are held in place by: Extensor, fibular, and flexor retinacula

Muscle movement at ankle and intertarsal joints

Muscles that Move the Foot

The ankle joint is a hinge joint capable of plantarflexion & dorsiflexion.

Muscles that Move the Foot

The plantarflexors of the ankle located at the posterior compartment are the:

1. Superficial muscles Triceps surae

Gastrocnemius Soleus

Muscles that Move the Foot

The plantarflexors of the ankle located at the posterior compartment are the:

2. Deep muscles Popliteus Peroneus longus Peroneus brevis Tibialis posterior

Muscles that Move the Foot

Muscles that Move the Foot

The dorsiflexors of the ankle located at the anterior compartment are the:

1. Tibialis anterior2. Extensor digitorum

longus3. Extensor hallucis longus4. Peroneus tertius

Muscles that Move the Foot

These muscles continue on to insert into the toes:

1. Extensor digitorum longus

2. Extensor hallucis longus

Muscles that Move the Foot

Muscles that Move the Foot

The movements of eversion of the foot (turning so the sole faces outward) & inversion (turning so the sole faces inward) use the subtalar axis.

Muscles that Move the Foot

The invertors are the:1. Tibialis anterior ) tendons pass on the2. Tibialis posterior ) great-toe side

The evertors are the:1. Peroneus longus ) tendons pass on the 2. Peroneus brevis ) little-toe side of the 3. Peroneus tertius ) subtalar axis

Muscles of the Lateral Compartment

Peroneus longus

Peroneus brevis

Peronius tertius

Muscles of the Lateral Compartment

Muscles of the Toes

There are 4 basic muscle layers of the foot. The first layer contains the:

1. Abductor hallucis (abducts the great toe)

2. Flexor digitorum brevis (flexes 2nd phalanges of the 4 small toes)

3. Abductor digiti minimi (abducts the small toe)

Muscles of the Toes

The second layer contains the:

1. Quadratus plantae (flex the terminal phalanges of the 4 small toes)

2. Lumbricals (flex the proximal phalanges & extend the distal phalanges of the 4 small toes)

Muscles of the Toes

The third layer contains the:

1. Flexor hallucis brevis (flexes the proximal phalanx of the great toes)

2. Adductor hallucis (adducts the great toe)

3. Flexor digiti minimi brevis (flexes the proximal phalanx of the little toe)

Muscles of the Toes

The fourth layer contains the:

1. 4 Dorsal interossei (abduct 2nd, 3rd, & 4th toes & flex the proximal & extend the distal phalanges)

2. 3 Plantar interossei (adduct the 3rd, 4th & 5th toes)