Lower limb anatomy originals Flashcards
What are the three groups of ligaments around ankle joint?
-Lateral collateral ligamentous complex
-Deltoid ligament (medial ligament)
-Syndesmosis
What ligaments comprise the deltoid ligament? What is it otherwise known as? What is primary action?
-Also known as medial ligament
-Primary action is to avoid over eversion of foot
-Deep part: anterior tibio-talar
-Superficial part: posterior tibiotalar, tibio-calcaneal, tibio-navicular
What ligaments comprise lateral collateral ligamentous complex?
-Anterior and posterior talofibular ligaments
-Calcaneofibular ligament
What are the terminal branches of sciatic nerve?
-Tibial nerve
-Common peroneal nerve
What is the root value of the tibial nerve?
L4-S3
Name muscles innervated by tibial nerve, what is its sensory distribution?
Posterior compartment
Superficial:
-Plantaris
-Gastrocnemius
-Soleus
Deep:
-Flexor hallucis longus
-Flexor digitorum longus
-Tibialis posterior
-All muscles on sole of foot (via medial and lateral plantar nerves)
-Popliteus
Note: sensory distribution of tibial nerve is sole of foot
-Name muscles of posterior compartment of leg
-How are they divided?
Superficial:
-Soleus
-Gastrocnemius
-Plantaris
Deep:
-Popliteus
-Flexor hallucis longus
-Flexor digitorum
-Tibialis posterior
Intermuscular septum
What is arterial and nerve supply of flexor compartment lower leg?
Posterior tibial artery
Tibial nerve
Define compartment syndrome and describe its pathophysiology
-Raised pressure within osseo-fascial compartment of sufficient magnitude to result in myo-neural necrosis
-Inter-muscular septae of limbs are strong + resistant to stretch, therefore any rise in insterstitial fluid pressure can compress muscles and nerves resulting in microvascular injury
-Prompt diagnossi is essential to prevent irreversible damage to limb and significant morbidity
Blood supply to head and neck of femur (simplified)
-Medial (dominant) and lateral circumflex arteries from profunda femoris, from femoral artery
-Artery of ligamentum teres (from obturator artery)
Name muscles of lateral (peroneal) compartment
-Peroneus longus
-Peroneus brevis
What are the branches of the external iliac artery?
-Inferior epigastric
-Deep circumflex iliac
-Continues as femoral artery
Describe course of femoral artery
-External iliac becomes femoral when it crosses inguinal ligament and enters femoral triangle
-In femoral triangle gives off profunda femoris which gives off 3 main branches
—-> perforating branches
—-> medial circumflex femoral artery
—-> lateral circumflex femoral artery
-Runs through adductor canal
-Becomes popliteal artery when it leaves adductor hiatus
-Popliteal artery terminates by dividing into anterior tibial artery and tibioperoneal trunk
-Tibioperoneal trunk becomes:
–> posterior tibial artery
–> Peroneal artery
Which artery supplies lateral (peroneal) compartment?
-Superiorly by perforating branches atnerior tibial, inferiorly by perforating branches of peroneal
-Peroneal artery lies within deep posterior compartment, not within peroneal compartment
What is the innervation of the lateral compartment?
Superficial peroneal (fibular) nerve, branch of common peroneal
Name extracapsular ligaments of hip
-Iliofemoral
-Pubofemoral
-Ischiofemoral
Describe attachments of pubo-femoral ligament (and action)
Arises from superior pubic rami, inserts into intertrochanteric line (resists extension and abduction)
Describe attachments of iliofemoral ligament, action
-Y shaped and twisted
-Arises from anterior inferior iliac spine, bifurcates and is inserted at each end of trochanteric line (resists hyperextension)
Ischio-femoral attachments and action
Arises from ischium and inserts into base of greater trochanter (limits hyper extension)
Describe overall role of extracapsular ligaments of hip, and which is strongest
-All three strengthen capsule and prevent excessive ROM of hip joint
-Iliofemoral is strongest
Name muscles that make up quadriceps
Vastus medialis
Vastus lateralis
Vastus intermedius
Rectus femoris
What is innervation of quadriceps femoris?
Femoral nerve L2-L4
Describe garden classification of intracapsular # of femoral neck
1: Incomplete undisplaced
2: Complete, undisplaced
3: Complete with partial displacement
4: Complete with total displacement
What are the main flexors of the hip (and other contributors)
-Psoas
-Iliacus
Other contributors:
-Pectineus
-Rectus femoris
-Sartorius
-Adductor longus
What is nerve supply to main hip flexors?
-Psoas major: ventral rami L1, L2 spinal nerves with small contribution from L3
-Iliacus, rectus femoris and sartorius: femoral nerve (L2-L4)
How many intrinsic layers of muscles are there on plantar aspect of foot?
4
Name muscles that make up first layer of plantar aspect of foot
-Abductor hallucis
-Flexor digitorum brevis
-Abductor digiti minimi
Name nerve which innervates dorsal + plantar interossei. Where does it originate?
Lateral plantar nerve (branch of tibial nerve)
Name cutaneous innervation to medial aspect foot
Saphenous nerve
Note: sural nerve supplies sensation to lateral foot
What is the sensory distribution of the of foot?
Sole of foot
-Lateral 1.5 digits: lateral plantar nerve (from tibial nerve)
-Medial 3.5 digits: medial plantar nerve (tibial nerve)
-Small portion lateral foot: sural nerve
-Small portion medial foot: saphenous nerve
-Calcaneal region: tibial nerve
Dorsum:
-Superficial peroneal nerve except dorsal first webspace
-First webspace: deep peroneal nerve
-Small part lateral foot: sural nerve
What are key signs and symptoms of compartment syndrome?
-Key feature: severe pain out of proportion to injury, aggravated by passive muscle stretch
-Sensory loss within distribution of nerves within compartment
6 Ps
-Pain
-Pallor
-Pulselessness
-Paralysis
-Perishing cold
-Paraesthesia
Name some common causes compartment syndrome
-Trauma
-Fractures
-Haemorrhage
-Burns
-Tight POP cast
-Toxins (e.g. snake venom)
How would you manage compartment syndrome?
-Immediate surgical decompression of fascial compartments (fasciotomy)
-Wound is closed at later stage
-Intracompartment pressures can be measured, although the condition is a clinical diagnosis
Describe measurement of compartment pressures
-Intracompartmental pressures can be measured with specific devices
-A difference of 30mmhg or less between diastolic pressure and intracompartmental pressure is recommended threshold for fasciotomy
Name the tarsal bones
Proximal: talus and calcaneus
Intermediate: navicular
Distal: cuboid and 3 cuneiforms (lateral, intermediate, medial)
How are ankle fractures classified?
Weber A: below distal tibio-fibular joint (syndesmosis)
Weber B: At level of syndesmosis
Weber C: Above level of syndesmosis
What is clinical relevance of weber classification?
-Fractures at or above level of syndesmosis (B+C) are likely to produce unstable ankle
-Therefore more likely to require ORIF
-Isolated Weber A # can be managed conservatively in POP cast
What is the course of the sciatic nerve
-Originates from lumbosacral plexus via L4-S3 nerve roots
-Enters gluteal region via greater sciatic foramen
-Emerges inferior to piriformis
-In posterior thigh: gives branches to hamstrings and hamstring part of adductor magnus
-At apex of popliteal fossa, bifurcates to form common fibular (peroneal) and tibial nerves
What is the innervation of anterior compartment?
-Deep peroneal (fibular) nerve, one of two terminal branches of common peroneal nerve
What is main action of muscles in anterior compartment? what are the other actions?
-Help in dorsiflexion of ankle and extension of toes
-Tibialis anterior also contributes to inversion of foot and peroneus tertius helps in eversion of foot at subtalar joint
Describe cruciate anastamosis
Formed by:
-Inferior gluteal artery
-Lateral and medial circumflex artery
-First perforating artery from profunda femoris
-Posterior branch obturator artery
Describe trochanteric anastamosis
Formed by:
-Superior and inferior gluteal artery
-Medial and lateral circumflex arteries
Muscles which attach to greater trochanter of femur
GT is distal insertion of following muscles:
-Lateral surface: gluteus medius
-Anterior surface: Gluteus minimus
-Superior border: piriformis
-medial surface: gemelli superior and inferior, obturator internus
Popliteal fossa contents medial to lateral
Popliteal arttery
Popliteal vein
Tibial nerve
Common peroneal nerve
Name the contents of popliteal fossa
Superficial to deep:
-Common peroneal nerve
-Tibial nerve
-small saphenous vein (empties into popliteal)
-Popliteal vein
-Popliteal artery
-Tendon of popliteus laterally
-Capsule of knee joint
Note: superiorly, popliteal fossa contains sciatic nerve only (before it divides)
Name boundaries of popliteal fossa
-Supero-medial: semimebranosus and semitendinosus
-Supero-lateral: Biceps femoris
-Infero-medial: medial head gastrocnemius
-Inferio-lateral: Lateral head gastrocnemius
-Roof: popliteal fascia, subcutaneous tissue, skin
-Floor: Popliteal surface of femur, capsule of knee joint, popliteus
What are the salient differences between medial and lateral menisci?
-Different shape
-Lateral more mobile
-Popliteus tenon runs between joint capsule and lateral meniscus
Describe medial vs lateral meniscus shape
Medial meniscus: elongated “C” shaped structure (tibial surface larger on medial side)
Lateral meniscus: smaller and more circular in shape
Describe medial vs lateral meniscus mobility
Medial meniscus is attached to medial collateral ligament and joint capsule + is therefore less mobile
Lateral meniscus has no attachment to lateral collateral ligament or joint capsule and is therefore more mobile
Name contents of hunter’s canal. What is the fate of the nerves in hunter’s canal?
Vessels
Superficial femoral artery
-Femoral vein
Nerves
-Saphenous nerve
-Nerve to vastus medialis
-Terminal division of obturator nerve
-Deep lymphatics
Note: nerves to not exit through hunter’s canal. Saphenous nerve perforates gracilis and sartorius to run in superficial fascia along with long saphenous vein
Nerve to vastus medialis lies in hunter’s canal where it supplies vastus medialis but does not exit canal
Action of gluteal muscles
Gluteus maximus: extends and externally rotates thigh. Supports extended knee through iliotibial tract, has key role in standing from sitting, walking up stairs, running
Gluteus medius and minimus: abduct and medially rotate thigh. Play important role during walking to stabilise unsupported side of pelv
Describe lateral rotators of thigh
Lateral rotators of thigh (piriformis, obturator internus + externus, gemelli superior + inferior + quadratus femoris) are covered by inf half gluteus maximus and help stabilise hip
Name borders lesser sciatic foramen
Anterior: tuberosity of ischium
Superior: spine of ischium, sacrospinous ligament
Posterior: sacrotuberous ligament
How can be fractures of femoral neck be classified?
-Intracapsular and extracapsular
-Intracapsular are at greater risk of AVN due to nature of blood supply
-Extracapsular can be further subdivided into intertrochanteric and sub trochanteric
What is the management of neck of femur fractures?
Intracapsular
-Undisplaced: fixation of head with pinning (unless old and comorbid)
Displaced:
Nice criteria thr vs hemi:
- 1. Can walk outside with one stick or less
-2. Not confused: amts 7 or above
-3. Fit for operation
Intertrochanteric –> DHS
Reverse oblique: IM nail
Subtrochanteric –> IM nail
Name structures passing through greater sciatic foramen above piriformis
-Superior gluteal nerve
-Superior gluteal artery and vein
Structures passing through greater sciatic foramen below piriformis
-Inferior gluteal vessels
-Inferior gluteal nerve
-Internal pudendal artery
-Pudendal nerve
-Sciatic nerve
-Posterior cutaneous nerve of thigh
-Nerve to quadratus femoris
-Nerve to obturator internus
Greater sciatic foramen borders
-Superior: anterior sacroiliac ligament
-Posteromedial: Sacrotuberous ligament (posterior in both)
-Anterolateral: greater sciatic notch of ilium
-Inferior: sacrospinous ligament and ischial spine
What are origins of superior and inferior gluteal arteries?
-Superior and inferior gluteal arteries originate from internal iliac artery
-Superior gluteal artery i a continuation of posterior division of internal iliac
-Inferior gluteal artery is one of the two terminal branches anterior division of internal iliac
Why is short head of biceps not a true hamstring?
-Does not cross hip joint
-True hamstrings arise from ischial tuberosity, short head arises from linea aspera and lateral supracondylar line of femur
What is hunter’s canal? What is its purpose?
-Also known as subsartorial or adductor canal
-It is an aponeurotic sheath located in middle anteromedial thigh
-Lies deep to sartorius extending from apex of femoral triangle to adductor hiatus (opening in adductor magnus)
-Canal provides intermuscular passage for femoral vessels to reach popliteal fossa
Borders hunter’s canal
Lateral: vastus medialis
Posterior: adductor longus, adductor magnus
Anterior: sartorius
Contents of femoral sheath
Encloses proximal parts femoral artery, vein and femoral canal. NOT femoral nerve
Contents of femoral triangle
Lateral to medial:
-Femoral nerve and branches
-Femoral artery and branches
-Femoral vein and proximal tributaries
-Femoral canal and lymph nodes
Boundaries of femoral triangle
Lateral: medial border sartorius
Medial: medial border adductor longus
Superior: inguinal ligament
Floor: iliacus, psoas major, pectineus
Roof: skin, subcutaneous tissue, fascia lata
What is the arrangement of structures you would encounter during arthroscopic surgery to knee from anterior approach?
Anterior to posterior:
-Transverse meniscal ligament (stretches across anterior horns medial and lateral menisci)
-Anteiror horn medial meniscus
-Anterior cruciate ligament
-Anterior horn lateral meniscus
-Posterior horn lateral meniscus
-Posterior horn medial meniscus
-Posterior cruciate ligament
Describe retinacular arterial supply to hip joint
-Femoral artery –> medial and lateral circumflex
-Lateral circumflex –> transverse branch –> ascending and descending branches
-Ascending branch (ascending cervical arteries) travel towards femoral head
-Medial circumflex: main supply for weight bearing dome, therefore significant
Describe supply of artery of ligamentum teres to head and neck of femur
Internal iliac –> obturator –> artery of ligamentum teres
-Supplies variable proportion of femoral head
Extracapsular ring of anastomosis
Ascending cervical vessels contribute to extracapsular ring of anastomosis at base of femoral neck
Which arteries supply head and neck of femur?
-Retinacular (from medial/lateral circumflex)
-Artery of ligamentum teres (from obturator artery)
-Interosseous blood supply
-Extracapsular ring (ascending cervical arteries)
-Perforating arteries: from profunda femoris
Sensory innervation lower leg
Medial lower leg:
-Saphenous nerve
-Lateral lower leg: sural nerve
-Anterior: superficial peroneal
-1st webspace: deep peroneal
-Sole of foot: tibial nerve
