Block 5 Origins/Insertions/Function/Innervation/Compartments/Blood Supply

Iliopsoas

Chief Hip Flexor, Inserts on Lesser Trochanter

Psoas major

Origin: Superficial; T12-L4 and associated intervertebral disks (lateral surfaces)

Deep; L1-L5 vertebrae (transverse processes)

Insertion: Lesser trochanter

Innervation: Direct branches from the lumbar plexus (L2-L4)

Function: flexion and external rotation of hip; helps lumbar spine contract unilaterally and bilaterally

Iliacus

Origin: on iliac fossa

Insertion: lesser trochanter

Innervation: femoral n. (L2-4)

Function: flexion and external rotation of hip; helps lumbar spine contract unilaterally and bilaterally

Gluteal Muscles

• Major extensor of the thigh

• Medial and lateral rotation and abduction

• Gluteus Medius is a common IM injection site in the adult

Gluteus maximus (Chief Extensor)

Origin- sacrum, illium, thoracolumbar fascia, Sacro tuberous ligament

Insertion- upper fibers: iliotibial tract

Lower fibers: gluteal tuberosity

Function- entire muscle extends and externally rotates the hip in sagittal and coronal planes

Upper fibers: abduction

Lower fibers- adduction

Innervation- inferior gluteal

Gluteus Medius

Origin: Ilium

Insertion: Greater trochanter of the femur

Function: Adducts the hip, Stabilizes the pelvis in the coronal plane

Anterior: Flexion/Internal

Posterior: External Rotation/Extension

Innervation: Superior gluteal nerve

Gluteus Minimus

Origin: Ilium

Insertion: Greater Trochanter of the femur

Function: Adducts the hip, Stabilizes the pelvis in the coronal plane

Anterior: Flexion/Internal

Posterior: External Rotation/Extension

Innervation: Superior gluteal nerve

Tensor fascia latae

Origin: Anterior superior iliac spine

Insertion: Iliotibial tract

Function: Tenses fascia lata, Moves the hip joint (abduction, flexion, and internal rotation)

Innervation: Superior gluteal nerve

Piriformis

Origin: Pelvic surface of the sacrum

Insertion: Apex of the greater trochanter of the femur

Function: Moves the hip joint (external rotation, abduction, and extension), Stabilizes the hip joint

Innervation: Direct branches from the sacral plexus (S1-S2)

Obturator internus

Origin: Inner surface of the obturator membrane

Insertion: Medial surface of the greater trochanter

Function: Moves the hip joint (external rotation, adduction, and extension)

Innervation: Direct branches from the sacral plexus (L5-S1)

Superior and inferior gemellus

Origin:

Superior gemellus- Ischial spine

Inferior gemellus- Ischial tuberosity

Insertion: medial surface of the greater trochanter

Function: Moves the hip joint (external rotation, adduction, and extension)

Innervation: Direct branches from the sacral plexus (L5-S1)

Quadratus femoris

Origin: Lateral border of the Ischial tuberosity

Insertion: Intertrochanteric crest of the femur

Function:

-External rotation and adduction of the hip joint

Innervation: Direct branches from the sacral plexus (L5-S1)

Anterior Compartment of the Thigh

• Primarily extensors of the leg at the knee

• Sartorius and rectus femoris secondarily flex the thigh at the hip

• All innervate by the femoral nerve

• Blood supplied by the femoral artery

Sartorius (seatbelt muscle)

Origin- anterior superior iliac spine

Insertion-medial to tibial tuberosity

function - secondary flex the thigh at the hip; abduction external rotation

Knee joint: flexion and internal rotation

Innervated by femoral nerve

Quadratus femoris (Group of 4 muscles)

Includes: rectus femoris, vastus medialis, vastus lateralis, vastus intermedius

rectus femoris

Origin- anterior iliac spine

Insertion- medial to the tibial tuberosity

Function- hip joint: abduction and external rotation

Knee joint- flexion and internal rotation

Innervation- femoral

vastus medialis

Origin- linea aspera

Insertion- both sides of tuberosity on the medial and lateral condyles

function- knee joint extension

Innervation- femoral

vastus lateralis

Origin- linea aspera

Insertion- both sides of the tuberosity on the medial and lateral condyles

Function- knee joint extension

Innervation- femoral

vastus intermedius

Origin- femoral shaft

Insertion- tibial tuberosity

Function knee joint extension

Innervation- femoral nerve

Medial Compartment of the Thigh: Superficial

• Primarily adductors of the thigh at the hip

• Most can secondarily flex and/or rotate the thigh

• Most are innervated by the obturator nerve

• Blood supplied by the obturator and deep femoral arteries

Pectineus

Origin- pecten pubis

Insertion- femur

Function- hip joint: adduction, external rotation and slight flexion, Stabilizes the pelvis in the coronal and sagittal planes

Innervation- femoral, obturator

Adductor brevis

Origin- inferior pubic ramus

Insertion- femur

Function- hip joint adduction and flexion, extension, stabilizes the pelvis in the coronal sagittal planes

innervation - obturator

Adductor longus

Origin- superior pubic ramus and anterior side of the symphysis

Insertion- femur

Function- Hip joint adduction and flexion, extension, stabilizes the pelvis in the coronal and sagittal planes

Innervation- obturator

Gracilis

Origin- inferior pubic ramus below the symphysis

Insertion- tibia

Innervation- obturator

Function- hip joint: adduction and flexion

Knee joint: flexion and internal rotation

Medial Compartment of the Thigh: Deep

Obturator externus

Adductor minimus and magnus

Obturator externus

Origin-outer surface of the obturator membrane and its bony boundaries

Insertion- trochanteric fossa of the femur

Function- hip joint: adduction and external rotation, Stabilizes the pelvis in the sagittal planes

Innervation- obturator nerve

Adductor magnus

Origin: Inferior pubic ramus, ischial ramus, and ischial tuberosity

Insertion: Deep part (fleshy insertion): Medial lip of the linea spine; Superficial part (tendinous insertion): adductor tubercle of the femur

Innervation: Deep part: Obturator nerve; Superficial part: Tibial nerve

Function: adduction, extension and slight flexion of hip joint; stabilizes the pelvis in the coronal and sagittal planes

Adductor Minimus

Origin: Inferior pubic ramus

Insertion: Medial lip of the linea aspera

Innervation: Obturator nerve

Function: adduction, extension and slight flexion of the hip joint

Posterior Compartment of the Thigh

Hamstrings

•Biceps femoris, Semitendinosus Semimembranosus, and Adductor magnus

• All innervated by tibial branch of sciatic nerve

Characteristics

• Originate from ischial tuberosity

• Innervated by tibial nerve

• Flexors (strong) of the knee joint

• Extensors (weak) of hip joint

• Insert around bones of the knee joint

Biceps Femoris

Origin:

-Long Head: Ischial Tuberosity, Sacrotuberous Ligament

-Short Head: Lateral Lip of the linea aspera in the middle third of the femur

Insertion: Head of Fibula

Innervation:

-Long Head: Tibial N.

-Short Head: Common Fibular N.

Function:

-Long Head: extension at hip, stabilizes the pelvis in sagittal plane

- Flexion and external rotation at Knee

-Short Head: Flexion and external rotation at Knee

semitendinosis

Origin: Ischial Tuberosity

Insertion: Medial Tibial Condyle, oblique popliteal ligament, popliteus fascia

Innervation: Tibial N.

Function: extension at hip, stabilizes the pelvis in sagittal plane

- Flexion and external rotation at Knee

semimembranosis

Origin: Ischial Tuberosity and Sacrotuberous ligament (common head with long head of biceps femoris)

Insertion: Medial to tibial tuberosity in pes anserinus

Innervation: Tibial N.

Function: extension at hip, stabilizes the pelvis in sagittal plane

- Flexion and external rotation at Knee

Posterior Compartment of the Leg: Superficial

gastrocnemius, soleus, plantaris

Triceps surae

gastrocnemius and soleus

gastrocnemius

Origin; femur (medial and lateral epicondyles)

Insertion; calcaneal tuberosity via the achilles tendon

Innervation; tibial nerve (S1,S2)

Function- talocrural joint: plantar flexion; knee joint: flexion (gastrocnemius)

soleus

Origin; fibula (head and neck, posterior surface), tibia (soleal line via a tendinous arch)

Insertion- calcaneal tuberosity via the Achilles tendon

Innervation- tibial nerve (S1,S2)

Function; talocrural joint: plantar flexion; Knee joint: flexion

Plantaris

Origin; femur (lateral epicondyle, proximal to lateral head of gastrocnemius)

Insertion; calcaneal tuberosity

Inervation; tibial nerve

Function; negligible, may prevent compression of posterior leg musculature during knee flexion

Posterior Compartment of the Leg: Deep

popliteus, tibialis posterior, flexor digitorum longus, flexor hallucis longus

Tibialis posterior

Origin: interosseous membrane, adjacent borders of tibia and fibula

Insertion: Navicular tuberosity: Cuneiforms (medial, intermediate, and lateral); 2nd to 4th metatarsals (bases)

Innervation: Tibial n

Function: plantar flexion of talocrural joint; inversion of subtalar joint; supports the longitudinal and transverse arches

Flexor digitorum longus

Origin: Tibia (middle third of posterior surface)

Insertion: 2nd to 5th distal phalanges (bases)

Innervation: Tibial n

Function: plantar flexion of talocrural joint; inversion of subtalar joint; plantar flexion of MTP and IP joints of the 2nd to 5th toes

Flexor hallucis longus

Origin: Fibula (distal two thirds of posterior surface), adjacent interosseous membrane

Insertion: 1st distal phalanx (base)

Innervation: Tibial n (L5-S2)

Function: plantar flexion of talocrural joint; inversion of subtalar joint; plantar flexion of MTP and IP joints of the 2nd to 5th toes; supports the medial longitudinal arch

Popliteus

Origin: Lateral femoral condyle, posterior horn of the lateral meniscus

Insertion: Posterior tibial surface (above the origin at the soleus)

Innervation: Tibial n.

Function: flexion and internal rotation of knee joint

Anterior Compartment of the Leg

• Extensors of the foot at the ankle and extensors of the toes

• Innervated by the deep fibular nerve

• Blood supplied by the anterior tibial artery

Tibialis anterior

Origin: tibia, interosseous membrane and superficial crural fascia

Insertion: medial cuneiform, first metatarsal

Innervation: deep fibular n.

Function: dorsiflexion of talocrural joint; inversion of subtalar joint

Extensor hallucis longus

Origin: fibula, interosseous membrane

Insertion: 1st toe

Innervation: deep fibular n.

Function: dorsiflexion of talocrural joint; active in both eversion and inversion of subtalar joint; extends the MTP and IP joints of the big toe

Extensor digitorum longus

Origin: fibula, tibia and interosseous membrane

Insertion: 2nd to 5th toes

Innervation: deep fibular n.

Function: dorsiflexion of talocrural joint and eversion of subtalar joint

Fibularis tertius

Origin: distal fibula

Insertion: 5th metatarsal

Innervation: deep fibular n.

Function: dorsiflexion of talocrural joint and eversion of subtalar joint

Lateral Compartment of the Leg

• Eversion of the foot, with weak plantar flexion of the ankle

• Innervated by the superficial fibular nerve

• Blood supplied by the fibular artery

Fibularis longus

Origin: fibula

Insertion: medial cuneiform, 1st metatarsal

Innervation: superficial fibular n.

Function: plantar flexion of talocrural joint; eversion of subtalar joint; supports the transverse arch of the foot

Fibularis Brevis

Origin: fibula, intermuscular septa

Insertion: 5th metatarsal

Innervation: superficial fibular n.

Function: plantar flexion of talocrural joint; eversion of subtalar joint

Blood supply of anterior compartment of thigh

Femoral artery

Blood supply of medial compartment of thigh

Obturator and deep femoral arteries

Blood supply of posterior compartments of leg

Posterior tibial artery

Blood supply of anterior compartment muscles

Anterior tibial artery

Blood supply of lateral compartment of leg

Fibular artery

Intrinsic Dorsum

Extensor digitorum brevis

Extensor hallucis brevis

Extensor digitorum brevis

Innervation: deep fibular n.

Function: extension of the MTP and PIP joints of the 2nd to 4th toes

Extensor hallucis brevis

Innervation: deep fibular n.

Function: extension of the MTP joints of the 1st toe

Superficial Sole (1st Layer)

abductor hallucis, flexor digitorum brevis, abductor digiti minimi

Abductor hallucis

Innervation: medial plantar n.

Function: flexion and abduction of the 1st toe; supports the longitudinal arch

Flexor digitorum brevis

Innervation: medial plantar n.

Function: flexes the MTP and PIP joints of the 2nd to 5th toes; supports the longitudinal arch

Abductor digiti minimi

Innervation: lateral plantar n.

Function: flexes the MTP and PIP joints of the 2nd to 5th toes; supports the longitudinal arch

Deep Sole (2nd and 3rd Layers)

quadratus plantae, lumbricals, flexor hallucis brevis, adductor hallucis, flexor digiti minimi brevis, opponens digiti minimi

Quadratus plantae

Innervation: lateral plantar n.

Function: redirects and augments the pull of flexor digitorum longus

Lumbricals

Innervation: 1st lumbrical: medial plantar n.; 2nd and 4th lumbrical: lateral plantar n.

Function: flexes the MTP joints of 2nd to 5th toes; extension of IP joints of 2nd to 5th toes; adducts the 2nd to 5th toes toward the big toe

Flexor hallucis brevis

Innervation: medial head: medial plantar, lateral head: lateral plantar n.

Function: flexes the first MTP joint; supports the longitudinal arch

Adductor hallucis

Innervation: lateral plantar n., deep branch

Function: flexes the first MTP joint; adducts big toe; supports transverse arch of the transverse head; supports longitudinal arch of oblique head

Flexor digiti minimi brevis

Innervation: lateral plantar n., superficial branch

Function: flexes the MTP joint of the little toe

Opponens digiti minimi

Innervation: lateral plantar n., superficial branch

Function: pulls the 5th metatarsal in plantar and medial direction

Deep Sole (4th Layer)

plantar interossei

dorsal interossei

Plantar interossei

Innervation: lateral plantar n.

Function: flexes the MTP joints of 3rd to 5th toes; extension of IP joints of 3rd to 5th toes; adducts 3rd to 5th toes toward 2nd toe

Dorsal interossei

Innervation: lateral plantar n.

Function: flexes the MTP joints of 2nd to 4th toes; extension of IP joints of 2nd to 4th toes; abducts 3rd and 4th toes from 2nd toe