Download Anterior and Medial Thigh Muscles/Actions

Anterior and Medial Thigh
Muscles/Actions
Anterior Compartment
Muscles
Iliopsoas (iliacus, psoas major/minor)
Iliac crest, vertebrae (T12-L5)  lesser trochanter
Action
Main:
-Major flexor of the hip
Other:
-Flex trunk if hip fixed (sit up)
-Eccentrically resists acceleration while walking
down hill
-Maintain lumbar lordosis
-Balance trunk while sitting
-Initial and mid-swing
Sartorius
Main:
-Flex hip
Other:
-ABducts
-ER thigh
-Flex knee
-IR leg
Pectineus
Main:
-Flex hip
Other:
-ADduction
-ER
ASIS  medial tibia
Superior ramus  pectineal line on post. Femur
Quadriceps
Distally all attach to quadriceps tendon  patella  patellar ligament  tibial tuberosity
Most important function:
-Receive weight during loading response (flat foot)
-Projection (jumping)
Rectus Femoris
Main:
AIIS 
-Flex thigh
-Extend knee
Other:
-Accelerate thigh during swing phase
Vastus Lateralis
Main:
-Extend knee
Vastus Intermedius
Main:
-Extend knee
Vastus Medialis
Main:
-Extend knee
Posterior femur 
Anterior femur 
Posterior femur 
OVERALL:
 Anterior compartment flexes the hip and extends the knee
o If a muscle flexes hip then that means they cross the hip joint
o If a muscle extends the knee then they cross the knee joint
o If the muscle does both… then crosses both joints!
Medial Compartment
Muscle
Obturator externus
Obturator membrane  greater trochanter
Action
-ER of femur
-Only muscle in medial compartment that does
not ADduct the thigh!
Pectineus
-See above
Adductor Longus
-Flex thigh (<70°)
-Extend thigh (>70° until reaches 70° again)
Adductor Brevis
-Flex thigh (<70°)
-Extend thigh (>70° until reaches 70° again)
Adductor Magnus
Adductor Part
-Flexes thigh
Hamstrings Part
-Extends thigh
Inferior ramus  linea aspera
Inferior ramus  linea aspera
Adductor Part:
Inferior ramus  linea aspera
Hamstrings Part:
Ischial tuberosity  linea aspera
Gracilis
Pubic symphysis and inferior ramus  medial tibia
-IR of femur
OVERALL:
 All of the muscles in the medial compartment do ADduction
o Table above just includes the oddball movements

Obturator externus and gracilis minimize vertical shifts during walking (keep
the hip level)
Innervation
Motor:
Lumbar Plexus
-
Anterior rami T12-L4
Anterior compartment of thigh
Sacral Plexus
- Anterior rami L4-S3
-Posterior compartment of thigh
Anterior compartment of thigh innervated by femoral nerve (L2-L4) EXCEPT:
 Anterior rami of L1-L2 = psoas major and minor
 Pectineus can be innervated by femoral nerve but ALSO obturator nerve
o This is b/c it is in both anterior and medial compartment
Medial compartment of the thigh innervated by the obturator nerve (L2-L4)
EXCEPT:
 Pectineus… see above
 Adductor magnus
o Adductor part (flex thigh) = obturator n.
o Hamstrings part (extend thigh) = tibial divison of sciatic n.
Sensory:
Vasculature
Great and small saphenous v.  femoral v.  external iliac v. (becomes this at
inguinal ligament)
Clinical Relevance


Fascial lines are important as guidelines for surgery.
o Thigh region has two… lateral and medial intermuscular septum
o
Psoas Abscess
o Abdominopelvic infections (Spinal TB/enteritis (Crohn’s))
o May be mistaken for femoral/inguinal hernia
o Infection can pierce through fascia and spread causing severe referred
hip/thigh/knee pain



Rectus Femoris Strain
o Rapid contraction following stretch (ex: soccer kick) = anterior hip
pain
o So basically, if you contract if too hard during swing phase.
Femoral Triangle
o Superior border = inguinal ligament
o Lateral border = Sartorius m.
o Medial border = adductor longus m.
o Floor = iliopsoas/pectineus
o Roof = fascia lata
o Femoral Sheath (protects vessels from inguinal ligament during hip
movements)
o Femoral n. is in the femoral triangle but NOT in the femoral sheath!!
 Lateral compartment = femoral a.
 Intermediate compartment = femoral v.
 Medial compartment (femoral canal) = lymphatic
 Lymphatics don’t take up the whole space in the
femoral canal… leads to potential femoral hernia
Femoral Hernias

o
o Abdominal contents can herniate through the femoral ring into the
femoral canal and come out through the saphenous v. opening.
o More common in female’s b/c they have wider pelvis’s leading to a
wider femoral ring.
Femoral Artery
o Can take pulse… if pulse is weak then could signify an occluded artery.

o Catheters can also be inserted here and run all the way up to the
heart.

Gluteal Region
Muscles/Actions
Superficial Layer
Muscles
Actions
Tensor Fascia Latae
-AB
-IR
Gluteus Maximus
-Extend thigh
-ER
Gluteus Medius
-AB
-IR
Gluteus Minimus
-AB
-IR
ASIS  IT band  lat. Tibia
Ilium, sacrum, coccyx  IT band, gluteal tuberosity
Ilium  lateral greater trochanter
Ilium  anterior greater trochanter
Deep layer
Muscles
Piriformis
Anterior sacrum  greater trochanter
Superior gemellus
Ischial spine  greater trochanter
Obturator internus
Obturator membrane  greater trochanter
Inferior gemellus
Ischial tuberosity  greater trochanter
Quadratus femoris
Ischial tuberosity  greater trochanter
Actions
All do ER and AB!
QF is the strongest lateral rotator of the thigh

Triceps Coxae made up of superior gemellus, obturator internus, and inferior
gemellus
OVERALL
 Mainly muscles of the superficial gluteal region AB and IR EXCEPT:
o Gluteus maximus ER and extends
 ALL muscles of the deep gluteal region AB and ER and distally attach to the
greater trochanter.
Innervation

Alternative routes of the sciatic n.
Motor
Superificial layer is mainly innervated by the superior gluteal n. EXCEPT:
 Gluteus maximus is innervated by the inferior gluteal n.
Deep layer:
 Ventral rami of S1, S2 = piriformis m.
 N. to obturator internus = superior gemelli and obteratur internus mm.
 N. to quadratus femoris = inferior gemelli and quadratus femoris mm.
Sensory
Clunial nerves
 Superior = top half from sacrum over to tubercle of iliac crest
 Middle = skin over sacrum
 Inferior = bottom half down to greater trochanter

Ligaments

Greater Foramen
-Greater sciatic notch made up of
sacrospinous ligament
Muscles
-Piriformis m.
Nerves
-Superior and inferior gluteal nn.
-Pudendal n.
Arteries
-Superior and inferior gluteal aa.
-Pudendal a.

Lesser Foramen
-Lesser sciatic notch made up of
sacrospinous and sacrotuberous
ligament
Muscles
-Obterator internus m.
Nerves
-Pudendal n.
Arteries
-Pudendal a.
Note that pudendal n. and a. go through both of the foramen!
Joint Capsule of the Hip





Iliofemoral ligament
o Anterior and superior
o Prevents hyperextension of thigh
Pubofemoral ligament
o Anterior and inferior
o Prevents over ABduction
Ischiofemoral ligament
o Posterior
o Prevents hyperextension… but is the weakest ligament of the joint
capsule
o If torn then can get a posterior dislocation of the hip
Ligament to head of femur
o Carries artery to head of femur
 Obturator a.  acetabular branch  a. to head of femur

Bursa
Trochanteric
-Largest
-B/w gluteus maximus and
greater trochanter
Ischial
- B/w gluteus maximus and
ischial tuberosity
Gluteofemoral
-B/w IT band and vastus
lateralis
Clinical Relevance



Damage to the ligament of the head of the femur
o Can cause avascular necrosis of the femoral head b/c carries artery to
head of femur.
Piriformis Syndrome
o “Fat Wallet Syndrome”
o Peripheral neuritis of sciatic nerve due to impingement by piriformis
m.
o Associated w/ low back pain and pain that radiates down the
posterior leg.
Trendelenburg Test
o
o Positive if hip on leg in swing phase drops b/c gluteus medius and
minimus are weak and not able to AB the hip up.
o Can be from an injury to the superior gluteal n., fracture of greater
trochanter (where gluteus medius/minimus attach), or dislocation of
the hip joint.
Posterior Thigh
Muscles/Actions
Posterior Compartment (Hamstrings)
Muscles
Biceps Femoris
Long Head
Ischial tuberosity  head of fibula
Short Head
Linea aspera  head of fibula
Semitendinosus
Ischial tuberosity  superior medial tibia
Semimembranosus
Ischial tuberosity  posterior medial epicondyle tibia
Part of the distal attachment forms the oblique
popliteal ligament!!
Actions
All of the extend the hip EXCEPT:
-Short head of bicep femoris
ALL of them flex the knee!
If lower limb fixed:
-Extend the trunk (prevent forward falling)
When Knee is 90°:
-Semitendinosus and semimembranosus: IR knee
-Biceps femoris: ER knee (can rotate laterally
more than medially)
Gait:
-Eccentrically contract during terminal swing to
decelerate quadriceps (hip flex/knee extension)
OVERALL:
 The hamstrings extend the thigh and flex then knee but cannot do both
motions to maximum contraction simultaneously!
o If in full thigh extension then cannot fully flex the knee
o If in full knee flexion then cannot full extend the thigh
Innervation
OVERALL:
o Hamstrings are innervated by the tibial division of the sciatic EXCEPT:
o Short head of biceps femoris is innervated by the fibular division of
the sciatic nerve
Clinical Relevance

Pes Anserinus
o “S sandwich”
o Sartorius, Gracilis, Semitendinosus

o
Hamstring Strain
o Usually happens in sprinting when there is rapid lengthening of
hamstring during terminal swing
 Basically, violently slowing down the hamstrings during a
sprint vs. the quads are forcefully springing you forward
Avulsion Fracture of Ischial Tuberosity

o
o Hamstrings fully lengthened (thigh flexed and leg extended)
o Still an eccentric motion here… same basic mechanics leading to
injury as hamstring strain
Cruciate Anastomosis

o
o Composed of lateral and medial circumflex femoral aa., inferior gluteal
a., and the first perforating a. of profunda femoris.
o If there is a blockage in the external iliac a. and proximal part of the
femoral a. then blood can reach the popliteal a. through the Cruciate
anastomosis.
o Bypass route is:
o Internal iliac a.  inferior gluteal a.  1st perforating branch 
descending branch of lateral circumflex femoral a.  superior lateral
genicular a.  popliteal a.
Popliteal Fossa
Borders:
o Lateral border = Biceps Femoris
o Medial Border = Semitendinosus/Semimembranosus
o Inferior border = Gastrocnemius
o Roof = skin and popliteal deep fascia (continuous w/ fascia lata and crural
fascia)
o Floor = femur, knee joint capsule, popliteus muscle
Contents:
o Popliteal a. and v.
o Sciatic n. bifurcates into common fibular n. and tibial n.
o Tibial n. goes straight through the middle of the popliteal fossa
o Common fibular n. follows the tendon of biceps femoris m. and curls
around the fibular head.
 Can easily get injured if fracture fibula
o Small/short saphenous vein  popliteal vein  femoral vein
Neurovasculature
Saphenous n., femoral a. and v.  adductor canal (saphenous n. pierces through and
leaves)  adductor hiatus  popliteal a. and v. dive through adductor hiatus to
posterior side  now in popliteal fossa  popliteal a. bifurcates to anterior and
posterior
Genicular branches arise off of the popliteal a. and form anastomoses around the
knee.
Clinical Relevance
o Hot spot for injury and lots of problems as a result
o Acts as a passage for surgeons to get to the knee
o Small/short saphenous v. serves as a landmark that makes it easier to find
the tibial n.
o You follow this vein and the sural n. to find key structures during
surgeries
o You can take the popliteal a. pulse in the popliteal fossa
o Popliteal fascia is extremely tough and does not expand to pressure easily =
severe pain if abscess/tumor present
o Baker’s (popliteal) cyst
o Protrusion of the bursa b/w semimembranosus tendon and medial
head of grastrocnemius
o Arteriovenous Fistula (AVF)
o Abnormal connection b/w artery and vein
o Can happen from injuries involving the knee joint or during surgery
o Shunts blood from artery to vein  blood is not getting to leg  can
cause necrosis of the leg and foot
o AVF also results in a venous aneurysm (bulging) of the popliteal v.
Knee and Leg
Muscles/actions
Anterior Compartment
Muscles
Actions
Tibialis anterior
-Dorsiflexion
Extensor hallucis longus
Tibialis anterior and extensor hallucis longus
also do inversion.
Lateral tibia  medial cuneiform/1st metatarsal
Fibula  1st phalange
Gait:
-Smooth lowering of foot while pulling body over
the foot (heel strike)
-Toe ground clearance (terminal swing)
Extensor digitorum longus
Fibula  2nd-5th phalanges
Fibularis tertius
EDL  5th metatarsal
Lateral Compartment
Fibularis longus
-Eversion
-Weak plantar flexion
Fibularis brevis
Gait:
-Prevents excessive inversion (ankle sprain)
during swing phase
-This holds the medial aspect down during swing
phase
Fibula  1st metatarsal
Fibula  5th metatarsal
Posterior Compartment
Superficial
All muscles distally attach to the Achilles tendon  calcaneal tuberosity
Gastrocnemius
Femoral epicondyles 
Main:
-Plantarflexion
Other:
-Weak knee flexion
Soleus
Soleal line of tibia and fibula 
Plantaris
Femur 
Can’t maximally do both of these actions at once
(like hamstrings)
Strongest plantarflexor
Main:
-Plantarflexion
Other:
-Weak knee flexion
Deep
Popliteus
Lateral femoral condyle  soleal line of tibia
Flexor digitorum longus
Tibia  2nd-5th phalanges
IR tibia to unlock the knee from fully extended
position
Gait:
-Crucial for toe off
Flexor hallucis longus
Fibula  1st phalange
Tibialis posterior
Tibia/fibula  midfoot bones
-Main inverter of leg
-Support medial longitudinal arch
Triceps surae = gastrocnemius and soleus
OVERALL:
o Posterior compartment are the main inverters of the foot
o TA and EHL from the anterior compartment can also invert
o All the posterior compartment muscles plantar flex
o Actions in the table are the oddball movements
o The retinaculum act as a fulcrum for the anterior compartment mm.
Innervation
Anterior compartment is innervated by the deep fibular n.
o Found in b/w tibialis anterior and EDL/EHL
Lateral compartment is innervated by the superficial fibular n.
Posterior compartment is innervated by the tibial n.
Clinical Relevance
o The fascia in your leg is so tight to aid your veins in pumping blood back up
to the heart
o
o Fibularis tertius m. may serve to support ATF ligament, which is
commonly sprained.
o Foot Drop
o Severing the common fibular n. = can’t dorsiflex (deep fibular n.) or
evert the foot (superifical fibular n.)
o Can’t clear toes during swing phase
o Compartment Syndrome
o Deep compartment of the posterior leg happens more often than in
the superficial compartment of the posterior leg.
 Split by the transverse intermuscular septum
o Shin Splints (Medial tibial stress syndrome)
o Microtrauma to periosteum of tibia as soleus m. suddenly
used/overused
o Can also arise from exterional compartment syndrome (muscular
hypertrophy… usually ant. Compartment) and stress fractures
Ankle and Foot
Muscles/Actions
Dorsal Compartment
Muscles
Extensor digitorum brevis
Actions
-Extend the digits
Extensor hallucis brevis
Plantar Compartment
Layer 1
ABductor digiti minimi
-AB 5th digit
Flexor digitorum brevis
-Flex digits 2-5
ABductor hallucis
-AB 1st digit
Layer 2
Quadratus plantae
-Inserts on FDL tendon to help align pull of FDL
Lumbricals
-Flex PIP and extended DIP
Layer 3
Flexor hallucis brevis
-Flex 1st digit
Adductor hallucis
-AD 1st digit
Flexor digiti minimi brevis
- Flex 5th digit
Two distal heads acts as a channel for FHL
Tranverse and oblique head
Interosseous Compartment/Layer 4
Plantar interossei
-AD (PAD) digits 3-5
Dorsal Interossei
-AB (DAB) digits 2-4
3 of them – arise from single metatarsal
4 of them – arise from two metatarsals
Innervation
Motor
Dorsal compartment is innervated by the deep fibular n.

Plantar compartment is innervated by the medial and lateral plantar nerves from
the tibial n.
Medial Plantar n. (purple)
Layer 1:
-Flexor digitorum brevis
-ABductor hallucis
Layer 2:
-1st lumbrical
Layer 3:
-Flexor hallucis brevis
Lateral Plantar n. (pink)
Layer 1:
-ABductor digiti minimi
Layer 2:
-Quadratus plantae
-Lumbricals 2-4
Layer 3:
-ADductor hallucis
-Flexor digiti minimi brevis
Layer 4:
-All the interossei
Sensory

Deep and superficial fibular n. both give rise to dorsal digital nerves.


Medial and plantar nerves both give rise to plantar digital nerves.
Vasculature
Dorsal Compartment
Anterior tibial a.  dorsalis pedis  arcuate and lateral tarsal aa.

Plantar Compartment
Posterior tibial a.  ABductor hallucis m.  medial and lateral plantar aa.
 Lateral plantar a.  plantar arch
All of the neurovasculature to the plantar foot arises under ABductor hallucis m.

Ligaments/Joints/Misc
Hindfoot = talus and calcaneus
Midfoot = cuboid, navicular, and cuneiforms
Forefoot = metatarsals and phalanges

1st metatarsal has 2 sesamoid bones under it to protect the FHL tendon
Plantar fascia/plantar aponeurosis
 Protects the sole of the foot, serves as muscular attachment and maintains
integrity of the arches
 Arises from calcaneal tuberosity
The foot has many segmented bones to adapt to unleveled ground and to absorb
shock so that the rest of the skeleton doesn’t absorb it.
 The foot also acts as a segmented lever to adapt to unleveled ground.
 Toe off involves the deep muscles of the posterior compartment of the leg
and the segmented lever of the foot.

Arches/Arch Supporters
 Medial longitudinal arch
 Lateral longitudinal arch
 Transverse arch

3 major ligaments of the foot:
o Long plantar, short plantar, and spring ligament.
o They support the medial/lateral longitudinal arches
o
o

Spring ligament also supports the head of the talus

Tendons, bones, ligaments, and muscles all help to form the
arches.
TP and FL tendons criss-cross to help support the transverse
arch.

Joints of the Foot/Ankle




Ankle (talocrural) joint can only do dorsiflexion and plantarflexion!
Pronation = dorsiflexion, AB, eversion
Supination = Plantarflexion, Inversion, AD
o “have to get PAID for soup”…. Use your imagination
Toe Movements
Metatarsophalangeal (MTP) Joints
-Flexion/extension
-AB/AD

2nd digit cannot be AB/AD
Interphalangeal (IP) Joints
-Flexion/extension
Subtalar Joint
Composed of two joints that are
anatomically separate but functionally
work together.
Actions:
-Mainly inversion/eversion
-All together do rotation of the foot
(inversion/eversion/AB/AD combined)
Transverse Tarsal Joint
Also composed of two joints.
This joint is where the greatest
movement of the foot occurs.
These joints all form the
transverse arch.
Also known as Choparts joints.
Also known as Lisfranc’s
joints.
Actions:
-where midfoot and forefoot
flex/extend
-inversion/eversion
Actions:
-Flexion/extension
-Adaptation to uneven
surfaces
Lisfranc ligament



Tarsometatarsal
Joints
From medial cuneiform  base of 2nd metatarsal
Crucial to stability of the tarsometatarsal joints.


All pass under the tarsal tunnel (flexor retinaculum)
TP  FDL  TA  TN  FHL
Clinical Relevance




Amputation
o Usually amputate b/w the hindfoot and midfoot at the transverse
tarsal joint
Plantar Fasciitis
o “Painful heel syndrome”… usually point tenderness directly under the
calcaneus
o Pain w/ great toe extension and dorsiflexion
o Overuse injury (running) causing inflammation of fascia
o Repeated tearing of plantar aponeurosis can lead to a calcaneal bone
spur
Foot Infections
o Usually caused by a puncture wound
o Have to be drained to relieve compartment syndrome
o If need a fasciotomy
 Go in on medial side to avoid scaring on weight-bearing side

Pes Planus (flat foot)
o Stuck in pronation when walking
o Flexible flatfeet = arch present when not bearing weight but flat when
walking
 From loose or degenerating ligaments
o Rigid flatfeet = flat when not bearing or bearing weight
 From bone deformity
o Acquired flatfeet = from dysfunction of tibialis posterior
 Usually spring ligament failure

o
Lisfranc Injuries

o
o If injured it affects the entire tarsometatarsal area
Dorsalis pedis
o Can take pulse (right next to tendon of EHL)
o Diminised pulse = possible peripheral a. dz


o
Deep Fibular n. Entrapment (Ski boot syndrome)
o Results in pain in anterior compartment that radiates down to the
space in b/w the 1st and 2nd digits.
Tarsal Tunnel Syndrome
o Space under the flexor retinaculum
o Tibial n. can get entrapped there (like median n. and carpal tunnel),
which causes tingling and numbness on the sole of the foot.
o
Gait Cycle
Gait Cycle
Phase
Heel strike (initial contact)
Main Action
Lower foot to ground
Muscles
Gluteus maximus
(extension/ER)
Tibialis anterior
(dorsiflexion/inversion)
Loading response (foot flat)
Accept body weight
Quadriceps
Gluteus medius and minimus
(AB/IR)
Midstance
Stabilize pelvis
Gluteus medius and minimus
(AB/IR)
Terminal stance (heel off)
Accelerate mass
Triceps surae
(plantarflexion)
Stabilize pelvis
Gluteus medius and minimus
(AB/IR)
Grip floor to clear foot
Flexor hallucis longus
Preswing (toe off)
Flexor digitorum longus
Initial and mid-swing
Terminal swing
Accelerate thigh
Iliopsoas/rectus femoris
(flex thigh)
Clear foot
Tibialis anterior
(dorsiflexion/inversion)
Decelerate thigh
Hamstrings
Extend knee
Quadriceps
Position foot
Tibialis anterior