Week 19 - Osteology of the Lower Limb Flashcards
What is the only bone in the thigh and the longest bone in the body?
The femur
The femur serves as a critical structural component in the human body.
What are the three parts of the femur?
- Proximal
- Shaft
- Distal
What joint does the proximal aspect of the femur articulate with?
The acetabulum of the pelvis to form the hip joint.
What are the two bony processes found in the proximal femur?
- Greater trochanter
- Lesser trochanter
What is the function of the head of the femur?
Articulates with the acetabulum of the pelvis to form the hip joint.
What is the angle of projection of the neck of the femur to the shaft?
Approximately 135 degrees.
What muscles attach to the greater trochanter?
- Gluteus medius
- Gluteus minimus
- Piriformis
- Vastus lateralis
What can cause an avulsion fracture of the greater trochanter?
Forceful contraction of the gluteus medius.
What is the location and function of the lesser trochanter?
Projects from the posteromedial side of the femur; site of attachment for iliopsoas.
What is the intertrochanteric line?
A ridge of bone that runs in an inferomedial direction on the anterior surface of the femur.
What ligament attaches at the intertrochanteric line?
The iliofemoral ligament.
What is the intertrochanteric crest?
A ridge of bone connecting the two trochanters located on the posterior surface of the femur.
What is the clinical relevance of neck of femur fractures?
Common in the elderly due to low energy falls; more prevalent in women.
What are the two main groups of neck of femur fractures?
- Intracapsular
- Extracapsular
What is the typical consequence of an intracapsular neck of femur fracture?
Potential damage to the medial femoral circumflex artery leading to avascular necrosis.
What is the linea aspera?
Roughened ridges of bone on the posterior surface of the femoral shaft.
What does the medial border of the linea aspera become proximally?
The pectineal line.
What is the distal end of the femur characterized by?
The presence of medial and lateral condyles.
What articulates with the medial and lateral condyles of the femur?
The tibia and patella.
What is the intercondylar fossa?
A deep notch on the posterior surface of the femur between the two condyles.
What ligaments attach at the intercondylar fossa?
- Anterior cruciate ligament (ACL)
- Posterior cruciate ligament (PCL)
True or False: The medial epicondyle is larger than the lateral epicondyle.
True.
Fill in the blank: The distal femur has rounded areas called _______.
[medial and lateral condyles]
What can cause a fracture of the femoral shaft?
Typically a high energy injury; can occur in the elderly due to low energy falls.
What is a common type of fracture for the femoral shaft?
Spiral fracture.
What neurovascular structures are at risk with a closed femoral shaft fracture?
- Femoral nerve
- Femoral artery
What is the location of the patella?
The patella is located at the front of the knee joint, within the patellofemoral groove of the femur.
The patella is commonly referred to as the kneecap.
What type of bone is the patella classified as?
The patella is classified as a sesamoid type bone.
It is the largest sesamoid bone in the body.
What are the attachments of the patella?
The superior aspect is attached to the quadriceps tendon and the inferior aspect to the patellar ligament.
This positioning plays a crucial role in its function.
What is the shape of the patella?
The patella has a triangular shape, with anterior and posterior surfaces.
The apex is situated inferiorly while the base forms the superior aspect.
What connects the apex of the patella to the tibial tuberosity?
The apex of the patella is connected to the tibial tuberosity by the patellar ligament.
What are the two facets of the posterior surface of the patella?
- Medial facet
- Lateral facet
The medial facet articulates with the medial condyle of the femur, and the lateral facet articulates with the lateral condyle.
What are the two main functions of the patella?
- Leg extension
- Protection
Leg extension enhances the leverage of the quadriceps tendon, while protection guards the knee joint from trauma.
What is patellar dislocation?
Patellar dislocation occurs when the patella is displaced out of the patellofemoral groove.
It accounts for around 3% of knee injuries.
What are the common causes of patellar dislocation?
Patellar dislocation is commonly caused by high force impact on the patella or forceful sudden twisting of the knee.
In which sports is patellar dislocation more common?
- Football
- Rugby
- Ice hockey
These sports often involve sudden movements that can lead to injury.
What typically causes patellar fractures?
Patellar fractures usually result from direct trauma to the bone or sudden contraction of the quadriceps muscle.
In which demographic are patellar fractures more common?
Patellar fractures are more common in males, particularly in the 20-50 age range.
What happens when the patella fractures into fragments?
The proximal fragment is displaced superiorly by the quadriceps tendon, and the distal fragment is pulled inferiorly by the patellar ligament.
What is the main bone of the lower leg known as?
The tibia
It is commonly referred to as the shin.
What are the two ends of the tibia that articulate at the knee and ankle joints called?
Proximal and distal ends
What is the second largest bone in the body?
The tibia
What are the widened ends of the proximal tibia called?
Medial and lateral condyles
What is the flat surface formed by the condyles of the tibia?
Tibial plateau
What structure do the tibial condyles articulate with?
Femoral condyles
What is located between the condyles of the proximal tibia?
Intercondylar eminence
What are the projections on either side of the intercondylar eminence called?
Medial and lateral intercondylar tubercles
What is the main site of attachment for ligaments and menisci of the knee joint?
Intercondylar eminence
What shape is the shaft of the tibia?
Prism-shaped
What are the three surfaces of the tibial shaft?
Anterior, posterior, and lateral
What is the anterior border of the tibia known for?
Palpable subcutaneously down the anterior surface of the leg as the shin
What marks the proximal aspect of the anterior border of the tibia?
Tibial tuberosity
What is the posterior surface of the tibia marked by?
Soleal line
What muscle originates from the soleal line of the tibia?
Soleus muscle
What is the lateral border of the tibia also known as?
Interosseous border
What does the interosseous border of the tibia give attachment to?
Interosseous membrane
What is intraosseous access used for?
Vascular access in emergency settings
Where are the two main sites for intraosseous access in the tibia?
Anteromedial surface, proximal to the medial malleolus
What are the complications of intraosseous access?
- Osteomyelitis
- Iatrogenic fracture
- Compartment syndrome
What structure assists with weight-bearing at the distal end of the tibia?
Medial malleolus
What does the medial malleolus articulate with?
Tarsal bones
What is the groove on the posterior surface of the tibia for?
Tendon of tibialis posterior
What is the fibular notch on the tibia?
Where the fibula is bound to the tibia
What are the two main types of tibial fractures?
- High energy trauma
- Low energy trauma or insufficiency fractures
Where do fractures of the tibia most commonly occur?
Shaft of the tibia
What are fractures of the proximal tibia known as?
Tibial plateau fractures
What classification is used for tibial plateau fractures?
Schatzker classification
What is a common cause of medial malleolus fractures?
Ankle being twisted inwards (over-inversion)
What type of fracture can occur at the medial malleolus?
Spiral fracture
True or False: Fractures of the medial malleolus occur in isolation.
False
What is the primary function of the fibula?
To act as an attachment for muscles, not as a weight-bearer.
Name the three main articulations of the fibula.
- Proximal tibiofibular joint
- Distal tibiofibular joint
- Ankle joint
What does the proximal tibiofibular joint articulate with?
The lateral condyle of the tibia.
What does the distal tibiofibular joint articulate with?
The fibular notch of the tibia.
What does the ankle joint articulate with?
The talus bone of the foot.
What is located on the posterior and lateral surface of the fibular neck?
The common fibular nerve.
How many surfaces does the fibular shaft have?
Three surfaces.
Fill in the blank: The anterior surface of the fibular shaft faces the _______.
[anterior compartment of the leg]
What is the lateral malleolus?
The distal continuation of the lateral surface of the fibula.
True or False: The lateral malleolus is less prominent than the medial malleolus.
False.
What are the two main ways in which fractures of the fibula occur at the ankle?
- Forced external rotation of the ankle
- Twisting of the foot outwards (eversion)
What type of fracture occurs due to forced external rotation of the ankle?
Spiral fracture of the lateral malleolus.
What type of fracture occurs due to eversion of the foot?
Transverse fracture of the lateral malleolus.
What is the main function of the bones of the foot?
Provide mechanical support for soft tissues and withstand body weight.
How are the bones of the foot categorized?
Into three groups: Tarsals, Metatarsals, Phalanges.
How many tarsal bones are there?
Seven.
What are the three groups of tarsal bones?
- Proximal group
- Intermediate group
- Distal group.
Which bones comprise the proximal tarsal group?
- Talus
- Calcaneus.
What is the largest tarsal bone?
Calcaneus.
What are the three articulations of the talus?
- Ankle joint
- Subtalar joint
- Talonavicular joint.
What does the calcaneus support?
The weight of the body as the heel hits the ground.
What is the clinical relevance of fractures of the talus?
Can lead to avascular necrosis due to disturbed blood supply.
What is the main cause of calcaneal fractures?
Axial loading from falls.
How many metatarsals are there?
Five.
What is the structure of each metatarsal?
Consists of a head, neck, shaft, and base.
What are the three main mechanisms of metatarsal fractures?
- Direct blow
- Stress fracture
- Excessive inversion.
What bones do the phalanges consist of?
Proximal, intermediate, and distal phalanges.
How many phalanges does the great toe have?
Two (proximal and distal).
What are the regions of the foot?
- Hindfoot
- Midfoot
- Forefoot.
What is the tuberosity on the navicular bone used for?
Attachment of part of the tibialis posterior tendon.
What shape are the cuneiform bones?
Wedge-shaped.
What is a common site for stress fractures in the metatarsals?
Necks of the second and third metatarsals.
Fill in the blank: The proximal tarsal bones are the _______ and the _______.
Talus, Calcaneus.
True or False: The talus has muscles that originate from or insert onto it.
False.
What can be a consequence of a calcaneal fracture?
Arthritis of the sub-talar joint.
What are the names of the tarsal bones?
- Calcaneus
- Talus
- Navicular
- Cuboid
- Cuneiforms
