Study Notes on the Bones of the Lower Limb

Bones of the Lower Limb

• Overview of the Lower Limb

  • The lower limbs are divided into three primary regions:

  • Thigh (Upper Leg)

  • Lower Leg

  • Foot

  • Key Bones in Each Region:

  • Thigh: Femur (single bone)

  • Lower Leg: Tibia and Fibula (pair of bones)

  • Foot:

    • Tarsal Bones: 7

    • Metatarsal Bones: 5

    • Phalanges: 14 (singular: phalanx)

  • Major Functional Joints:

  • Knee Joint

  • Ankle Joint

  • Numerous minor joints are present between individual bones within these regions.

Femur

• Overview:

  • The femur is the single bone located in the thigh region.

• Articulation:

  • The head of the femur articulates with the acetabulum of the Os coxa (hip bone) to form the hip joint.

• Anatomical Features:

  • Fovea Capitis:

  • A small, rough pit located at the center of the head of the femur.

  • Functions as the attachment point for the ligament of the head of the femur.

  • Neck of the Femur:

  • Contains two bony projections:

    • Greater Trochanter: Large lateral bony projection.

    • Lesser Trochanter: Smaller, posteromedial projection.

  • Intertrochanteric Line: Located on the anterior surface between the greater and lesser trochanters.

  • Intertrochanteric Crest: Located on the posterior surface between the greater and lesser trochanters.

  • Gluteal Tuberosity:

  • Rough bulge of bone inferior and lateral from the intertrochanteric crest.

  • Serves as the attachment point for the gluteus maximus muscle.

  • Linea Aspera:

  • A ridge of bone running along the anterior shaft of the femur.

  • Functions as an attachment point for thigh muscles.

  • Distal End Features:

  • Lateral Epicondyle of the Femur

  • Medial Epicondyle of the Femur

  • Condyles:

    • Lateral Condyle of the Femur: Articulates with the tibia at the knee joint.

    • Medial Condyle of the Femur: Articulates with the tibia at the knee joint.

  • Intercondylar Fossa: Deep pit located on the posterior surface between the two condyles.

  • Patellar Surface: Shallow depression located on the distal anterior surface where the patella articulates.

Tibia

• Overview:

  • The tibia is the larger of the two bones of the crus (lower leg).

• Articulating Surfaces:

  • Articular surfaces of the medial condyle

  • Articular surface of the lateral condyle: Collectively referred to as the tibial plateau.

• Intercondylar Eminences:

  • Two small bony points found between the medial and lateral condyles on the tibial plateau.

• Bulges Below the Plateau:

  • Medial Condyle of the Tibia

  • Lateral Condyle of the Tibia

• Proximal Fibula:

  • Located just distal to the lateral condyle of the tibia.

• Tibial Tuberosity:

  • Prominent bulge on the anterior surface of the proximal tibia where the patellar ligament attaches.

• Distal Features:

  • Medial Malleolus:

  • An obvious inferior bulge of bone found on the medial aspect at the distal end.

  • Marks where the tibia brackets the talus (a tarsal bone) to form part of the ankle joint.

  • Distal Tibiofibular Joint:

  • The lateral surface of the distal tibia has a curved appearance that accommodates the distal fibula.

Fibula

• Overview:

  • The fibula is the smaller and thinner of the two bones in the crus, located laterally to the tibia.

• Proximal Feature:

  • Head of the Fibula: Found at the proximal end.

• Distal Feature:

  • Lateral Malleolus: Located at the distal end of the fibula, contributes to the ankle joint.

Bones of the Foot

• Overview:

  • The foot comprises small bones that are best studied in an intact, articulated manner.

• Tarsal Bones:

  • The ankle is formed by seven tarsal bones.

  • Key Tarsal Bones:

  • Calcaneus (largest, forms the heel):

    • Contains the calcaneal tuberosity, where the calcaneal tendon (Achilles tendon) attaches.

  • Talus: Bracketed by the distal ends of the tibia and fibula, sits above the calcaneus.

  • Navicular: Located anterior to the talus.

  • Four Lateral Tarsals:

    • Medial Cuneiform

    • Intermediate Cuneiform

    • Lateral Cuneiform

    • Cuboid

• Metatarsal Bones:

  • Five elongated metatarsal bones connect the tarsal bones of the ankle to the bones of the toes.

  • Numbering: Begins medially as metatarsal 1 through 5.

• Phalanges:

  • The toes contain a total of 14 phalanges (bones of the toes).

  • Phalanges Composition:

  • Digit 1 (Hallux): contains 2 phalanges (proximal and distal).

  • Digits 2 through 5 contain 3 phalanges each: proximal, middle, and distal.

Practical Instructions

• Lab Activity:

  • Obtain a right or left femur, patella, tibia, fibula, and an articulated foot.

  • Ensure correct identification of right or left bones with the help of lab partners or an articulated skeleton for reference.