Limbs 3 Flashcards
What are the two major regions of the lower limb?
- gluteal region (buttock and hip)
- free lower limb (thigh, leg and foot)
What is the leg?
The area between the knee and the ankle
What is the gluteal region homologous to in the upper limb?
The pectoral girdle
What is the knee joint homologous to in the upper limb?
The elbow joint
Why do the homologous actions between the upper and lower limb appear so different?
Developmental differences in the arrangement of muscle groups
How does flexion differ between the elbow and knee joints?
- elbow = anterior movement
- knee = posterior movement
Why does the flexion in the knee and elbow joints differ?
- upper and lower limb buds extend laterally in early limb development
- at 7-8 weeks the lower limbs rotate medially just below the hip (permanent pronation)
- results in anterior structres becoming posterior and vice versa
What is the outcome of rotation in the developing lower limb?
- anterior dermatomes have twisted oblique fields rather than straight
- extensor muscles are anterior and flexors are posterior
What are the bones of the buttock/hip?
Pelvic girdle
What are the bones of the thigh?
Femur and patella
What are the bones of the leg?
Tibia and fibula
What are the bones of the foot?
Tarsals, metatarsals and phalanges
Which bones form the pelvic girdle?
- the hip bones (x2)
- sacrum
What are the three bones which fuse to form each hip bone?
- ilium
- ischium
- pubis
What is the joint which articulates the hips bones and the sacrum?
Sacro-iliac joint
What is the joint between the two hip bones?
Pubic symphysis
What is the timescale for fusion of the hip bones?
- begins ~15 years
- finished by early 20s
Where do the three bones of the hip bone meet?
Triradiate cartilage
What do the three bones of the hip form around the triradiate cartilage?
Acetabullum (socket of the hip joint)
What is the obturator foramen?
Round opening between the interior and exterior of the pelvis, covered by the obturator membrane
What does the femur articulate with?
- pelvis proximally
- tibia distally
What is the linea aspera?
- ridge running through the posterior surface of the femur
- attachment site for a number of muscles
Why do the knees sit close together under the pelvis and why is this important?
- femoral head and neck are at an angle while the distal end is horizontal
- thighs are inferomedially oblique
- allows for efficient bipedal standing and walking
Label this diagram of the proximal femur
- pectineal line
- lesser trochanter
- trochanteric crest
- head
- neck
- greater trochanter
- gluteal tuberosity
- linea aspera
Label this diagram of the distal femur
- medial epicondyle
- medial condyle
- intercondylar fossa
- lateral condyle
- lateral epicondyle
Which of the two bones of the leg is larger and weight-bearing?
The tibia
What does the tibia articulate with?
- femur proximally
- talus tarsal bone distally
What is the tibial plateau?
Widened proximal end of tibia
What is the medial malleolus?
Distal end of the tibia
Which bone of the leg is primarily used for muscle attachment?
Fibula