Lower Limb

Laboratory Overview

  • Only two weeks left of lab.
  • Last lab learning will focus on the entire inferior limb.
  • Important to study the interactive atlas for lab due to potential unanticipated muscle learning in earlier labs (Monday and Tuesday labs may not cover all muscles in advance).

Exam Details

  • Next week is the final practical exam in lab.
  • Open reviews or open labs will be held this weekend for self-learning through hands-on experience with lab pieces.
  • Checklist pages containing structures to identify in lab are available for print (electronic devices not allowed in exam).

Importance of Comprehensive Study

  • Students should familiarize themselves with structures beyond those taught directly in lab, emphasizing a holistic understanding of anatomy.

Inferior Limb Muscle Anatomy

Anterior Thigh Compartment

  • Complete focus on anterior thigh muscles before final practical.
  • Final muscle taught in this segment is the sartorius muscle.
Sartorius Muscle
  1. Attachments:
    • Proximal: Anterior superior iliac spine of the os coxa (front of hip).
    • Distal: Medial to the tibial tuberosity (forming an anatomical pulley at the knee).
  2. Topography:
    • Diagonal course across the thigh, wrapping from anterior lateral to medial posterior around the knee.
  3. Actions:
    • Knee: Flexion (notable due to anterior compartment classification, unusual action compared to quadriceps).
    • Hip: Flexion and lateral rotation (due to corkscrew shape).
Summary of Anterior Compartment Muscles
  • Six muscles total, all with a primary attachment to the tibial tuberosity, except sartorius.
  • Collective action: Knee extension, and hip flexion for those crossing the hip joint.

Posterior Thigh Compartment (Hamstrings)

  1. Biceps Femoris

    • Two heads (long and short).
    • Attachments:
      • Long head: Ischial tuberosity.
      • Short head: Distal half of the linea aspera of the femur, both attaching distally to the head of the fibula.
    • Actions: Extends hip, flexes knee.

  2. Semimembranosus

    • Attachments:
      • Proximal: Ischial tuberosity.
      • Distal: Posterior medial condyle of the tibia.
    • Actions: Extends hip, flexes knee.

  3. Semitendinosus

    • Attachments:
      • Proximal: Ischial tuberosity.
      • Distal: Medial to the tibial tuberosity.
    • Actions: Extends hip, flexes knee.
Anatomical Connections
  • Palpation exercise to identify tendons in the popliteal fossa.
  • Clinical relevance: ACL repairs often utilize hamstring tendons; regeneration of the semitendinosus tendon post-surgery is common (80% regrowth rate).

Topography of the Inferior Limb

Femoral Triangle

  • Boundaries:
    • Inguinal ligament (superior boundary).
    • Sartorius muscle (medial boundary).
    • Adductor longus (medial border).
  • Contents:
    • Femoral nerve, artery, and vein (superficial as they run below the inguinal ligament).
    • Great saphenous vein running medially.
    • Inguinal lymph nodes.
  • Clinical relevance: Accessibility of pulse points; significance in trauma scenarios (e.g., hemorrhage control).

Adductor Canal

  • Boundaries:
    • Adductor longus (superior), adductor magnus (inferior), sartorius (roof).
  • Veins and arteries transition from femoral to popliteal at the adductor hiatus.

Popliteal Fossa

  • Boundaries:
    • Gastrocnemius (inferior), biceps femoris (lateral), semimembranosus (medial).
  • Contains popliteal artery and vein, and small saphenous vein coming from the posterior knee.

Knee Anatomical Pulleys

  • Muscles forming tripod:
    • Sartorius (anterior compartment), semitendinosus (posterior), gracilis (medial compartment).
    • All attach medial to the tibial tuberosity, creating a significant mechanism to facilitate knee flexion.

Ankle Joint and Foot Muscle Actions

Ankle Joint (Talocrural Joint)

  • Articulating bones: Talus, tibia, and fibula.
  • Movements: Dorsiflexion (moving upward) and plantarflexion (moving downward).
  • Class: Hinge joint.

Intertarsal Joints

  • Movements: Inversion (turning foot medially) and eversion (turning foot laterally).

Metatarsophalangeal and Interphalangeal Joints

  • Actions include abduction, adduction, flexion, and extension for digits.
  • Like fingers, but reference for abduction/adduction is the second toe.
  • Interphalangeal Joints: Hinge joints allowing only flexion and extension abilities.

Final Notes

  • Review materials, practice anatomical palpation, and prepare for practical exams focusing on these structures and their actions.