Lab #6: Mammal Bones - Hindlimb Flashcards
(22 cards)
The mammalian hindlimb includes: (5)
(1) Pelvis
(2) Femur
(3) Tibia
(4) Fibula
(5) Metatarsal
Mammalian hindlimb play a crucial role in …
locomotion
Reminder: animal + order
Dog = Carnivora (terrestrial)
Seal = Carnivora (marine)
Caribou/muskox = Artiodactyla
Pelvic girdle is formed by ….
2 innominates (fuse with age)
-> also known as ‘os coxae’
-> articulates with either side of the sacrum
Each innominate is formed by…
the fusion of 3 bones:
-> ilium
-> ischium
-> pubis
=> Together, these bones comprise a cup-shaped socket called the acetabulum
What is the proximal bone of the hindlimb?
Femur
The femur connects the …. to the ….
pelvis, lower leg
The head of the femur articulates with the …. to form the ….
acetabulum, hip joint
Hip joint utility (2)
Important for (1) hindlimb movement + (2) weight transfer during locomotion
Lateral to the femoral head is the …
greater trochanter
What’s the greater trochanter?
Prominent projection where several powerful muscles attach
-> Part of the femur
What’s the difference between a femur of a running mammal (e.g. caribou/dog) vs marine mammal?
-> Terrestrial: femur long and straight with pronounced trochanters
-> Marine: femur shortened and thickened, adapted to flipper-based swimming
The distal end of the femur widens into … that articulate with the … and patella to form the …
two condyles (medial and lateral), tibia and patella, knee joint
Tibia particularity
LARGER, weight-bearing bone of the lower hindlimb
The proximal end of the tibia features a …
broad articular surface for the femoral condyles
The distal end of the tibia articulates with the …
tarsals
What is the fibula?
Slender (mince) bone that runs parallel to the tibia
How is the fibula in most carnivores?
The fibula remains SEPARATE but thin, contributing minimally to weight bearing
How is the fibula in artiodactyls?
Fibula often highly reduced or partially fused to the tibia and may exist as a mere splinter of bone
How is the fibula in marine mammals?
Tibia & fibula fuse together over time into a single structure called the crural bone
Crural bone function
Provides greater stability and strength to the ankle joint and lower leg, which is key for efficient swimming and locomotion in water
How are artiodactyls metatarsals?
They are fused into a single, elongated bone = the cannon bone
-> Extends from the distal tarsals to the proximal phalanges
