3400 Lab Exam 4

Gluteus maximus

Proximal Attachment (O): Ilium posterior to posterior gluteal line; dorsal surface of sacrum and coccyx; sacrotuberous ligament

Distal Attachment (I): Most fibers end in iliotibial tract, which inserts into lateral condyle of tibia; some fibers insert on gluteal tuberosity.

Nerve: Inferior gluteal nerve (L5, S1, S2)

Action: Extends hip joint (especially from flexed position) and assists in lateral rotation; fixes hip joint and assists in rising from sitting position

Gluteus medius

Proximal Attachment (O): External surface of ilium between anterior and posterior gluteal lines

Distal Attachment (I): Lateral surface of greater trochanter of femur

Nerve: Superior gluteal nerve (L5, S1)

Action: Abduct and medially rotate hip joint; keep pelvis level when ipsilateral limb is weight bearing and advance opposite (unsupported) side during its swing phase.

Gluteus minimus

Proximal Attachment (O): External surface of ilium between anterior and inferior gluteal lines

Distal Attachment (I): Anterior surface of greater trochanter of femur

Nerve: Superior gluteal nerve (L5, S1)

Action: Abduct and medially rotate hip joint; keep pelvis level when ipsilateral limb is weight bearing and advance opposite (unsupported) side during its swing phase.

Tensor fascia latae

Proximal Attachment (O): Anterior superior iliac spine; anterior part of iliac crest

Distal Attachment (I): Iliotibial tract, which attaches to lateral condyle of tibia

Nerve: Superior gluteal nerve (L5, S1)

Action: Abduct and medially rotate hip joint; keep pelvis level when ipsilateral limb is weight bearing and advance opposite (unsupported) side during its swing phase.

Gracilis

Proximal Attachment (O): Body and inferior ramus of pubis

Distal Attachment (I): Superior part of medial surface of tibia (as part of pes anserinus)

Nerve: Obturator nerve (L2, L3)

Action: Adducts hip joint; flexes knee joint, medially rotating it when flexed

Sartorius

Proximal Attachment (O): Anterior superior iliac spine and superior part of notch inferior to it

Distal Attachment (I): Superior part of medial surface of tibia (as part of pes anserinus)

Nerve: Femoral nerve (L2, L3)

Action: Flexes, abducts, and lateral rotates hip joint; flexes knee joint (medially rotates leg when knee joint is flexed)

Piriformis

Proximal Attachment (O): Anterior surface of sacrum; sacrotuberous ligament

Distal Attachment (I): Superior border of greater trochanter of femur

Nerve: Branches of anterior rami of S1 and S2

Action: Laterally rotate extended hip joint and abduct hip joint when flexed; stabilize hip joint

Gemellus superior

Proximal Attachment (O): Ischial spine

Distal Attachment (I): Medial surface of greater trochanter (trochanteric fossa) of femurb

Nerve: same nerve supply as obturator internus (Nerve to obturator internus (L5, S1))

Action: Laterally rotate extended hip joint and abduct hip joint when flexed; stabilize hip joint

Gemellus inferior

Proximal Attachment (O): Ischial tuberosity

Distal Attachment (I): Medial surface of greater trochanter (trochanteric fossa) of femur

Nerve: same nerve supply as quadratus femoris (Nerve to quadratus femoris (L5, S1))

Action: Laterally rotate extended hip joint and abduct hip joint when flexed; stabilize hip joint

Obturator internus

Proximal Attachment (O): Pelvic surface of obturator membrane and surrounding bones

Distal Attachment (I): Medial surface of greater trochanter (trochanteric fossa) of femur

Nerve: Nerve to obturator internus (L5, S1)

Action: Laterally rotate extended hip joint and abduct hip joint when flexed; stabilize hip joint

Obturator externus

Proximal Attachment (O): Margins of obturator foramen and obturator membrane

Distal Attachment (I): Trochanteric fossa of femur

Nerve: Obturator nerve (L3, L4)

Action: Laterally rotates hip joint; stabilizes hip joint

Quadratus femoris

Proximal Attachment (O): Lateral border of ischial tuberosity

Distal Attachment (I): Quadrate tubercle on intertrochanteric crest of femur and area inferior to it

Nerve: Nerve to quadratus femoris (L5, S1)

Action: Laterally rotates hip jointc; stabilizes hip joint

Biceps femoris

Proximal Attachment (O):

• Long head: ischial tuberosity

• Short head: linea aspera and lateral supracondylar line of femur

Distal Attachment (I): Lateral side of head of fibula. Tendon is split at this site by fibular collateral ligament of knee.

Nerve:

• Long head: tibial division of sciatic nerve (L5, S1, S2)

• Short head: common fibular division of sciatic nerve (L5, S1, S2)

Action: Flexes knee joint and laterally rotates it when flexed; long head extends hip joint (e.g., accelerating mass during first step of gait and when rising from sitting position).

Semimembranosus

Proximal Attachment (O): Ischial tuberosity

Distal Attachment (I): Posterior part of medial condyle of tibia. Reflected attachment forms oblique popliteal ligament (to lateral femoral condyle).

Nerve: Tibial division of sciatic nerve part of tibia (L5, S1, S2)

Action: Extend hip joint; flex knee joint and medially rotate it when flexed. When hip and knee joints are flexed (as when sitting), these muscles can extend trunk at hip joint (to rise).

Semitendinosus

Proximal Attachment (O): Ischial tuberosity

Distal Attachment (I): Superior part of media surface of tibia (as part of pes anserinus)

Nerve: Tibial division of sciatic nerve part of tibia (L5, S1, S2)

Action: Extend hip joint; flex knee joint and medially rotate it when flexed. When hip and knee joints are flexed (as when sitting), these muscles can extend trunk at hip joint (to rise).

Rectus femoris

Proximal Attachment (O): Anterior inferior iliac spine and ilium superior to acetabulum

Distal Attachment (I): Via common tendinous (quadriceps tendon) and independent attachments to base of patella; indirectly via patellar ligament to tibial tuberosity; medial and lateral vasti also attach to tibia and patella via aponeuroses (medial and lateral patellar retinacula).

Nerve: Femoral nerve (L2, L3, L4)

Action: Extends knee joint; rectus femoris also steadies hip joint and helps iliopsoas flex hip joint.

Vastus lateralis

Proximal Attachment (O): Greater trochanter and lateral lip of linea aspera of femur

Distal Attachment (I): Via common tendinous (quadriceps tendon) and independent attachments to base of patella; indirectly via patellar ligament to tibial tuberosity; medial and lateral vasti also attach to tibia and patella via aponeuroses (medial and lateral patellar retinacula).

Nerve: Femoral nerve (L2, L3, L4)

Action: Extends knee joint; rectus femoris also steadies hip joint and helps iliopsoas flex hip joint.

Vastus intermedius

Proximal Attachment (O): Anterior and lateral surfaces of shaft of femur

Distal Attachment (I): Via common tendinous (quadriceps tendon) and independent attachments to base of patella; indirectly via patellar ligament to tibial tuberosity; medial and lateral vasti also attach to tibia and patella via aponeuroses (medial and lateral patellar retinacula).

Nerve: Femoral nerve (L2, L3, L4)

Action: Extends knee joint; rectus femoris also steadies hip joint and helps iliopsoas flex hip joint.

Vastus medialis

Proximal Attachment (O): Intertrochanteric line and medial lip of linea aspera of femur

Distal Attachment (I): Via common tendinous (quadriceps tendon) and independent attachments to base of patella; indirectly via patellar ligament to tibial tuberosity; medial and lateral vasti also attach to tibia and patella via aponeuroses (medial and lateral patellar retinacula).

Nerve: Femoral nerve (L2, L3, L4)

Action: Extends knee joint; rectus femoris also steadies hip joint and helps iliopsoas flex hip joint.

Adductor brevis

Proximal Attachment (O): Body and inferior ramus of pubis

Distal Attachment (I): Pectineal line and proximal part of linea aspera of femur

Nerve: Obturator nerve and branch of anterior division (L2, L3, L4)

Action: Adducts hip joint and, to some extent, flexes it

Adductor longus

Proximal Attachment (O): Body of pubis inferior to pubic crest

Distal Attachment (I): Middle third of linea aspera of femur

Nerve: Obturator nerve and branch of anterior division (L2, L3, L4)

Action: Adducts hip joint

Adductor magnus

Proximal Attachment (O):

• Adductor part: inferior ramus of pubis and ramus of ischium

• Hamstring part: ischial tuberosity

Distal Attachment (I):

• Adductor part: gluteal tuberosity, linea aspera, and medial supracondylar line

• Hamstring part: adductor tubercle of femur

Nerve:

• Adductor part: obturator nerve (L2, L3, L4) and branches of posterior division

• Hamstring part: tibial part of sciatic nerve (L4)

Action:

• Adducts hip joint

• Adductor part: flexes hip joint

• Hamstring part: extends hip joint

Pectineus

Proximal Attachment (O): Superior ramus of pubis

Distal Attachment (I): Pectineal line of femur, just inferior to lesser trochanter

Nerve: Femoral nerve (L2, L3); may receive a branch from obturator nerve

Action: Adducts and slightly flexes hip joint; assists with lateral rotation

Popliteus

Proximal Attachment (O): Lateral surface of lateral condyle of femur and lateral meniscus

Distal Attachment (I): Posterior surface of tibia and superior to soleal line

Nerve: Tibial nerve (L4, L5, S1)

Action: Weakly flexes knee joint and unlocks it by rotating femur 5° on fixed tibia; medially rotates tibia of unplanted limb

Plantaris

Proximal Attachment (O): Inferior end of lateral supracondylar line of femur; oblique popliteal ligament

Distal Attachment (I): Posterior surface of calcaneus via calcaneal tendon

Nerve: Tibial nerve (S1, S2)

Action: Weakly assists gastrocnemius in plantarflexing ankle joint

Gastrocnemius

Proximal Attachment (O):

• Lateral head: lateral aspect of lateral condyle of femur

• Medial head: popliteal surface of femur; superior to medial condyle

Distal Attachment (I): Posterior surface of calcaneus via calcaneal tendon

Nerve: Tibial nerve (S1, S2)

Action: Plantarflexes ankle joint when knee joint is extended; raises heel during walking; flexes knee joint

Soleus

Proximal Attachment (O): Posterior aspect of head and superior quarter of posterior surface of fibula; soleal line and middle third of medial border of tibia; tendinous arch extending between the bony attachments

Distal Attachment (I): Posterior surface of calcaneus via calcaneal tendon

Nerve: Tibial nerve (S1, S2)

Action: Plantarflexes ankle joint independent of position of knee; stabilizes ankle joint

Tibialis posterior

Proximal Attachment (O): Interosseous membrane; posterior surface of tibia inferior to soleal line; posterior surface of fibula

Distal Attachment (I): Tuberosity of navicular, cuneiform, cuboid, and sustentaculum tali of calcaneus; bases of 2nd, 3rd, and 4th metatarsals

Nerve: Tibial nerve (L4, L5)

Action: Plantarflexes ankle joint; inverts foot; maintains medial longitudinal arch

Flexor digitorum longus

Proximal Attachment (O): Medial part of posterior surface of tibia inferior to soleal line; by a broad tendon to fibula

Distal Attachment (I): Bases of distal phalanges of lateral four digits

Nerve: Tibial nerve (S2, S3)

Action: Flexes lateral four digits; plantarflexes ankle joint; supports longitudinal arches of foot

Flexor hallucis longus

Proximal Attachment (O): Inferior two thirds of posterior surface of fibula; inferior part of interosseous membrane

Distal Attachment (I): Base of distal phalanx of great toe (hallux)

Nerve: Tibial nerve (S2, S3)

Action: Flexes great toe at all joints; weakly plantarflexes ankle joint; supports medial longitudinal arch of foot

Tibialis anterior

Proximal Attachment (O): Lateral condyle and superior half of lateral surface of tibia and interosseous membrane

Distal Attachment (I): Medial and inferior surfaces of medial cuneiform and base of 1st metatarsal

Nerve: Deep fibular nerve (L4, L5)

Action: Dorsiflexes ankle joint and inverts subtalar joint

Extensor digitorum longus

Proximal Attachment (O): Lateral condyle of tibia and superior three quarters of medial surface of fibula and interosseous membrane

Distal Attachment (I): Middle and distal phalanges of lateral four digits

Nerve: Deep fibular nerve (L5, S1)

Action: Extends lateral four digits and dorsiflexes ankle joint

Extensor hallucis longus

Proximal Attachment (O): Middle part of anterior surface of fibula and interosseous membrane

Distal Attachment (I): Dorsal aspect of base of distal phalanx of great toe (hallux)

Nerve: Deep fibular nerve (L5, S1)

Action: Extends great toe and dorsiflexes ankle joint

Peroneus longus (fibularis longus)

Proximal Attachment (O): Head and superior two thirds of lateral surface of fibula

Distal Attachment (I): Base of 1st metatarsal and medial cuneiform

Nerve: Superficial fibular nerve (L5, S1, S2)

Action: Everts subtalar joint and weakly plantarflexes ankle joint

Peroneus brevis (fibularis brevis)

Proximal Attachment (O): Inferior two thirds of lateral surface of fibula

Distal Attachment (I): Dorsal surface of tuberosity on lateral side of base of 5th metatarsal

Nerve: Superficial fibular nerve (L5, S1, S2)

Action: Everts subtalar joint and weakly plantarflexes ankle joint

Peroneus Tertius (fibularis tertius)

Proximal Attachment (O): Inferior third of anterior surface of fibula and interosseous membrane

Distal Attachment (I): Dorsum of base of 5th metatarsal

Nerve: Deep fibular nerve (L5, S1)

Action: Dorsiflexes ankle joint and aids in eversion of subtalar joint

Flexor digitorum brevis

Proximal Attachment (O): Medial tubercle of tuberosity of calcaneus; plantar aponeurosis; intermuscular septa

Distal Attachment (I): Both sides of middle phalanges of lateral four digits

Nerve: Medial plantar nerve (L5, S1)

Action: Flexes lateral four digits at MTP and IP joints

Abductor digiti minimi

Proximal Attachment (O): Medial and lateral tubercles of tuberosity of calcaneus; plantar aponeurosis; intermuscular septa

Distal Attachment (I): Lateral side of base of proximal phalanx of 5th digit

Nerve: Lateral plantar nerve (S1–S3)

Action: Abducts and flexes little toe (5th digit) at MTP and IP joints

Abductor hallucis

Proximal Attachment (O): Medial tubercle of tuberosity of calcaneus; flexor retinaculum; plantar aponeurosis

Distal Attachment (I): Medial side of base of proximal phalanx of 1st digit

Nerve: Medial plantar nerve (L5, S1)

Action: Abducts and flexes 1st digit (great toe, hallux) at metatarsophalangeal (MTP) and interphalangeal (IP) joints

Adductor hallucis

Proximal Attachment (O):

• Oblique head: bases of metatarsals 2–4

• Transverse head: plantar ligaments of metatarsophalangeal (MTP) joints

Distal Attachment (I): Tendons of both heads attach to lateral side of base of proximal phalanx of 1st digit.

Nerve: Deep branch of lateral plantar nerve (S1–S3)

Action: Traditionally said to adduct 1st digit; assists in maintaining transverse arch of foot by pulling metatarsals medially

Flexor digiti minimi brevis

Proximal Attachment (O): Base of 5th metatarsal

Distal Attachment (I): Base of proximal phalanx of 5th digit

Nerve: Superficial branch of lateral plantar nerve (S1–S3)

Action: Flexes proximal IP joint of 5th digit, thereby assisting with flexion of digit

Flexor hallucis brevis

Proximal Attachment (O): Plantar surfaces of cuboid and lateral cuneiforms

Distal Attachment (I): Both sides of base of proximal phalanx of 1st digit

Nerve: Medial plantar nerve (L5, S1)

Action: Flexes proximal interphalangeal (IP) joint of 1st digit

Quadratus plantae

Proximal Attachment (O): Medial surface and lateral margin of plantar surface of calcaneus

Distal Attachment (I): Posterolateral margin of tendon of flexor digitorum longus

Nerve: Lateral plantar nerve (S1–S3)

Action: Assists flexor digitorum longus in flexing lateral four digits at MTP and IP joints

Psoas minor

Proximal Attachment (O): Sides of T12–L1 vertebrae and intervertebral discs

Distal Attachment (I): Pectineal line and iliopubic eminence via iliopectineal arch

Nerve: Anterior rami of lumbar nerves (L1, L2)

Action: Act conjointly in flexion and lateral rotation of hip joint and in stabilizing this joint when standing

Psoas major

(Posterior Abdominal Wall)

Superior Attachment (O): Transverse processes of lumbar vertebrae; sides of bodies of T12–L5 vertebrae and intervening intervertebral discs

Inferior Attachment (I): By a strong tendon to lesser trochanter of femur

Nerve: Anterior rami of lumbar nerves L1, L2, and L3

Action: Acting inferiorly with iliacus, it flexes the thigh; acting superiorly, it flexes the vertebral column laterally; it is used to balance the trunk; when sitting, it acts inferiorly with the iliacus to flex the trunk

Iliacus

(Posteiror abdominal wall)

Superior Attachment (O): Superior two thirds of iliac fossa, ala of sacrum, and anterior sacro-iliac ligaments

Inferior Attachment (I): Lesser trochanter of femur and shaft inferior to it and to psoas major tendon

Nerve: Femoral nerve (L2-L4)

Action: Flexes thigh and stabilizes hip joint; acts with psoas major

Extensor digitorum Brevis

Proximal Attachment (O): Calcaneus (floor of tarsal sinus); interosseous talocalcaneal ligament; stem of inferior extensor retinaculum

Distal Attachment (I): Long extensor tendons of three intermediate digits (toes 2–4)

Innervation: Deep fibular nerve (L5 or S1, or both)

Action: Aids the extensor digitorum longus in extending the three intermediate toes at the metatarsophalangeal (MTP) and interphalangeal joints

Extensor hallucis brevis

Proximal Attachment (O): Calcaneus (floor of tarsal sinus); interosseous talocalcaneal ligament; stem of inferior extensor retinaculum

Distal Attachment (I): Dorsal aspect of base of proximal phalanx of great toe (digit 1)

Innervation: Deep fibular nerve (L5 or S1, or both)

Action: Aids the extensor hallucis longus in extending the great toe at the MTP joint

Lumbricals

Proximal Attachment (O): Tendons of flexor digitorum longus

Distal Attachment (I): Medial aspect of expansion over lateral four digits

Innervation:

• Medial one: medial plantar nerve (L5–S1)

• Lateral three: lateral plantar nerve (S1–S3)

Action: Flex proximal IP joint; extend middle and distal IP joints of lateral four digits

Plantar Interossei (3)

Proximal Attachment (O): Plantar aspect of medial sides of shafts of metatarsals 3–5

Distal Attachment (I): Medial sides of bases of phalanges of 3rd–5th digits

Innervation: Lateral plantar nerve (S1–S3)

Action: Adduct and flex digits 3–5 at MTP joints

Dorsal Interossei (4)

Proximal Attachment (O): Adjacent sides of shafts of metatarsals 1–5

Distal Attachment (I):

• 1st: medial side of proximal phalanx of 2nd digit

• 2nd–4th: lateral sides of 2nd–4th digits

Innervation: Lateral plantar nerve (S1–S3)

Action: Abduct and flex digits 2–4 at MTP joints