Lower Limb 2 - Muscles, Nerves & Vessels

What are the 3 compartments of the lower limb?

1. Anterior

2. Posterior

3. Medial (thigh) OR lateral (leg)

Label the following diagram

Name 3 regions of continuous fascial tissue

• Iliotibial tract

• Fascia lata

• Deep fascia of leg

Label the following diagram

What are the 2 key anterior muscles of the pelvic girdle & where do they attach?

• Iliacus + psoas major → iliopsoas

• Combined attachment onto lesser trochanter of the femur

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What is the role of the iliopsoas muscle?

• Main hip flexors

• Deep; come from inside the abdomen & converge towards the femur

• Any thigh muscles which cross vertically over the hip & attach to the pelvic bone produce flexion

What are the 3 key posterior muscles of the pelvic girdle & what is their role?

• Gluteus maximus: hip extensor

• Gluteus medius & gluteus minimus: hip abductors

Where does the gluteus maximus attach?

To the side near the greater trochanter

What happens when the gluteus minimus & gluteus medius contract?

• Prevention of excessive pelvic tilt during swing phase on opposite side

• Gives a relatively neutral pelvis during gait

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What are the anterior thigh muscles?

• Sartorius: comes off anterior superior iliac spine

• Quadriceps (distally converge into 1 - blend @ the patella)

  • Vastus medialis: doesn’t cross over pelvis → NOT Involved in thigh flexion

  • Vastus lateralis: doesn’t cross over pelvis → NOT involved in thigh flexion

    • deep to ITB

  • Vastus intermedius

  • Rectus femoris: thigh flexion

Label the following diagram

What muscles make up the posterior thigh compartment?

Hamstrings:

• Semitendinous

  • Medial

  • Blends fibres as a long, thick tendon

• Semimembranous

  • Medial

    • Blends fibres as a broad membrane

• Biceps femoris (long & short heads)

  • Lateral

What is the role of the hamstrings?

• Crosses the posterior aspect of the hip & knee joints → hip extension & knee flexion

• Knee rotation

Which component of the hamstrings will only function at the knee?

Biceps femoris short head

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What muscles make up the medial compartment of the thigh & where do they attach?

• Adductor muscles

• Anchor to the pubic & ischial bones

What type of structures pass through adductor muscles?

Major artery & vein (travel posteriorly through adductor muscles

• Important for staying on the flexor side of joints

• Located posteriorly by the time they are at the knee (supply blood to the muscles facilitating these movements)

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What types of muscles make up the anterior compartment of the leg & what do they all have in common?

• Dorsiflexors & toe extensors

• All cross anteriorly → all involved in dorsiflexion

What types of muscles make up the lateral compartment of the leg & what do they all have in common at the ankle?

• Evertors

• All cross posterior to the joints

  • Very week in plantar flexion

  • Strongly pull foot into eversion

What types of muscles make up the superficial posterior compartment of the leg & what do they all have in common at their distal attachment?

• Plantar flexors

• Important for long & short distances (have fast & slow twitch fibres)

• All converge into calcaneal tendon/Achilles’ heel

  • Far away from joint → strong & powerful movement

What types of muscles make up the deep posterior compartment of the leg & where do they cross?

• Plantar flexors & toe flexors

• Cross posterior to the joint

  • Much closer to the bones

  • Some blend to tarsals & some blend to toes

  • Very close to medial malleolus

Where are intrinsic foot muscles found & what are the 3 major groups?

• Found primarily on the plantar side of the foot

• Major groups:

  • Hallucis muscles: 1st digit

  • Digiti minimi muscles: 5th digit

  • Central muscles: varied attachments & functions

Label the following diagram of the lower limb neural overview

What do the lumar & lumbarsacral plexi supply?

The lower limb, in addition to compartments of the pelvis & lower abdomen

For the obturator nerve, state:

• Where it receives input from

• Where it travels

• Where it leaves

• What it splits into & where it supplies

• Receives input from L2-L4 anterior rami

• Travels medial to psoas major

• Leaves pelvis via obturator canal

• Splits into 2 branches → supply medial compartment of thigh

For the sciatic nerve, state:

• Where it receives input from

• Where it forms

• Where it leaves

• What is supplies

• What it splits into

• Receives input from L4-S3 anterior rami

• Forms within pelvis

• Leaves posteriorly via greater sciatic foramen

  • Inferior to piriformis

• Supplies the lower limb muscles

  • Posterior compartments of the thigh

  • All leg compartments

  • All foot muscles

• Splits into 2 nerves in a common sheath;

  • Tibial nerve

  • Common fibular nerve