FEMUR ANATOMY

GENERAL STRUCTURE

The femur is the longest and strongest bone in the human body, characterized as a long bone with a central shaft and two ends. It plays a vital role in weight-bearing and movement, with its proximal end connecting to the hip joint, its body supporting muscular attachments, and its distal end forming part of the knee joint.

Body (Shaft)

• The femur shaft is a long, cylindrical, and slightly curved structure
• Connects the upper and lower ends of the femur
• Supports weight-bearing and facilitates movement
• Notable features include the linea aspera
  • A ridge located on the back of the shaft
  • Serves as an attachment site for muscles

Proximal Epiphysis

• It is the upper part of the femur
• Forms part of the hip joint

Distal Epiphysis

• It is the lower part of the femur
• Forms part of the knee joint

PROXIMAL EPIPHYSIS OF THE FEMUR

The Proximal Epiphysis is the upper part of the femur. It plays a crucial role in connecting to the hip joint, supports mobility and stability, and describes the following structures:

Head of the Femur

• Structure
  • Round, ball-like, spherical shape
  • Forms more than half of a sphere
• Orientation
  • Points slightly upwards and towards the body's center
• Function
  • Fits into the acetabulum (hip socket) for smooth hip joint movement
• Feature: Fovea for the Ligament of the Head
  • Small depression on the surface of the head
  • Location: Slightly below and behind the center
  • Function: Attachment site for a ligament that stabilizes the hip joint

Neck of the Femur

• Structure
  • Narrow, flattened region
• Function
  • Connects the head of the femur to its body
  • Forms an angle with the femur's body for proper hip movement and stability

Greater Trochanter

• Structure
  • Large, irregular bony prominence
  • Projects upwards and outwards from the femur
• Function
  • Major attachment point for several muscles involved in hip and thigh movement
• Feature: Trochanteric Fossa
  • Location: Inner surface of the greater trochanter
  • Function: Attachment point for a tendon aiding hip movement

Lesser Trochanter

• Structure
  • Smaller, cone-shaped projection
  • Located at the junction of the femur's body and neck, towards the back
• Function
  • Attachment point for muscles like the psoas major, aiding hip flexion

Intertrochanteric Line

• Location
  • Front surface of the femur
  • Runs downward and inward from the greater trochanter to the lesser trochanter
• Function
  • Marks the boundary between the neck and body of the femur
  • Provides attachment points for muscles and ligaments

Intertrochanteric Crest

• Location
  • Back surface of the femur
  • Runs diagonally between the greater and lesser trochanters
• Function
  • Provides an area for muscle attachment
  • Serves as a key anatomical landmark

Quadrate Tubercle

• Location
  • Along the intertrochanteric crest, about halfway between the greater and lesser trochanters
• Function
  • Attachment point for the Quadratus femoris muscle, aiding in hip stabilization

BODY OF THE FEMUR

The shaft of the femur is almost cylindrical for most of its length, broadening above its midpoint and flattening near the distal end. It describes the following structures:

Linea Aspera

• Location
  • Longitudinal ridge running down the posterior surface
• Function
  • Attachment point for muscles like adductors and quadriceps
• Features
  • Medial Lip - Defines the inner margin; attachment site for the vastus medialis muscle
  • Lateral Lip - Forms the outer edge; attachment site for the vastus lateralis muscle

Pectineal Line

• Location
  • Extends upwards from the linea aspera toward the lesser trochanter
• Function
  • Attachment site for a muscle
  • Transitions into the anterior part of the femur, blending with the intertrochanteric line

Gluteal Tuberosity

• Location
  • Upper posterior part of the femur, rising toward the base of the greater trochanter
• Function
  • Attachment point for the gluteus maximus muscle
  • Supports hip extension and movement

Popliteal Surface

• Location
  • Triangular area at the distal posterior end, bordered by diverging edges of the linea aspera
• Function
  • Related to muscle and ligament attachments near the knee joint

Medial Supracondylar Line

• Location
  • Descends from the medial lip of the linea aspera to the medial condyle
• Function
  • Attachment site for muscles
  • Provides structural support

Lateral Supracondylar Line

• Location
  • Extends from the lateral lip of the linea aspera to the lateral epicondyle
• Function
  • Provides muscle attachment points
  • Defines the contour of the femur's lower posterior part

DISTAL EPIPHYSIS OF THE FEMUR

The lower part of the femur is located distally and serves as the connection to the knee joint. It features structures that articulate with the tibia and patella, and describes the following structures:

Medial Condyle

• Structure
  • Prominent, rounded projection on the lower, inner side of the femur
  • Extends further back than the lateral condyle
• Function
  • Articulates with the tibia to form part of the knee joint
• Features
  • Medial Epicondyle - Located above the medial condyle; attachment point for a ligament
  • Adductor Tubercle - Small, raised area on the medial condyle; attachment point for a muscle involved in thigh adduction

Lateral Condyle

• Structure
  • Broader and more anterior than the medial condyle
• Function
  • Articulates with the tibia to form part of the knee joint
• Features
  • Lateral Epicondyle - Located above the lateral condyle; attachment point for a ligament connecting the femur to the fibula
  • Groove for Popliteus Muscle - Oblique, deep groove on the back of the lateral condyle; passage for the popliteus muscle, separated from the articular surface by a rounded ridge

Patellar Surface

• Location
  • Front of the femur, between the medial and lateral condyles
• Function
  • Smooth, shallow depression that articulates with the patella
  • Allows smooth movement during knee flexion and extension

Intercondylar Fossa

• Location
  • Deep notch on the posterior side of the femur, between the condyles
• Function
  • Houses attachment points for the cruciate ligaments, essential for knee stability

Intercondylar Line

• Location
  • Ridge running across the back of the femur, above the intercondylar fossa
• Function
  • Connects to the posterior margin of the patellar surface
  • Serves as a boundary for the intercondylar fossa