Lab 5 Flashcards
What is flexion?
A decrease in a joint angle
What is extension?
An increase in a joint angle
What is the order of bones in a bird’s leg from proximal to distal?
Femur Knee Shank (Fibula & tibiotarsus) Intertarsal joint Tarso-metatarsus Phalanges
What is the order of bones in a human’s leg from proximal to distal?
Femur Knee Tibia (with small fibula) Ankle Tarsals Metatarsals Phalanges
What colours does masson’s trichrome stain skeletal muscle, collagen, nuclei and bone?
Skeletal muscle = Red
Collagen = Green
Bone = red/pink in some places, blue/green in others
Nuclei = brown/black
How good is the blood supply to the tendon?
Quite avascular
In how many directions does collagen withstand tension?
2 directions, but one plane.
How does the arrangement of collagen in the tendon change as it nears bone?
In purely the tendon, it is quite parallel, with about 20 fibres per bundle
As it nears the bone it becomes wavy and irreguar
What is the difference between chicken and human RBCs?
Chicken RBCs have nuclei
How are sharpey’s fibres formed?
Osteoblasts secrete osteoid onto collagen fibres already projecting into bone, calcifying it.
What shape are muscle fibres in cross section?
Polyhedral
What happens to the coarse collagen fibres in the tendon as they near the muscle?
They blend at the myotendinous junction, becoming attached to the sarcolemma
What are the muscles of the chicken thigh from lateral to medial?
Lateral iliotibular muscle –> Iliofibular muscle –> Lateral knee flexor muscle –> medial knee flexor muscle
Which muscle has a sling surrounding its tendon?
The iliofibular muscle
What is superficial fascia?
The soft, weak layer of CT directly underlying the skin.
Where is the origin vs. insertion of the lateral iliotibial muscle?
Origin is ileum of pelvis
Insertion is tibiotarsus of shank
What is the corresponding muscle to the iliotibial muscle in humans?
The gluteus maximus
Where does the iliofibular muscle insert?
The fibula
What does the sling do?
Prevents the iliofibular muscle from bowstringing
What is the corresponding muscle to the iliofibular muscle in humans?
The biceps femoris
What is the corresponding muscle to the sling of the chicken leg in humans?
The short head of the biceps femoris
Where is the lateral knee flexor?
It forms the posterior muscle of the thigh
Where is the gastrocnemius muscle?
Below the knee of the chicken
Where do the medial and lateral knee flexor muscles combine?
In their combined aponeurosis, culminating in a tendon that inserts on the tibiotarsis
What is the anatomy of the combined knee flexor aponeurosis?
It is in two parts: A large anterior part inserts on the tibiotarsus, while the smaller posterior part joins a fibrous fascia on the medial surface of the shank, becoming a large tendon on the posterior side of the intertarsal joint
What is the equivalent of the posterior knee flexor tendon in humans?
The achilles tendon
What is the origin of the knee flexor muscles?
In the pelvis, posterior to the head of the femur.
The lateral knee flexor muscle origin is dorsal to that of the medial
Where is the lateral knee flexor accessory muscle and how do we identify it?
It joins the anterior edge of the lateral knee flexor distally, with fibres at right angles to the axis of the thigh
What is the function of the lateral knee flexor accessory muscle?
It prevents the lateral knee flexor from bowstringing
What happens to the hip joint when the iliofibular muscle contracts?
The hip joint extends
What happens to the hip joint when the long head of the biceps femoris contracts?
The hip joint extends
What happens to the hip joint when the short head of the biceps femoris contracts?
Nothing
What happens to the knee joint when the iliofibular muscle contracts?
The knee joint flexes
What are the hamstring muscles of the human thigh?
The biceps femoris, semimembranous and semitendinosus muscles
What are biarticulate muscles?
The cross two joints (usually hip and knee)
Why is it easier to bend forward in a crouch than with the legs straight?
The hamstrings become less taut when the knees are bent due to their origin and insertions being closer together
What are the phases in walking?
Heel strike Foot flat Mid-stance Push off Toe off Mid swing Heel strike
Which phases of walking do the hamstrings contract in?
Heel strike, to decelerate the step and reduce impact.
Some action during right foot flat for balance
They also prevent excessive hip flexion.
What are the equivalent muscles in the human to the medial and lateral knee flexors?
The semimembranous and semitendinous muscles.
