Anatomy - Muscles and Movement Flashcards
What are the three types of muscle?
Smooth, cardiac and skeletal muscle. Slide 2
What is the order of muscle structure, layer by layer?
Skeletal muscle Fascicle Muscle fibre Myofibril Actin and myosin. Slide 3
Why does skeletal muscle appear ‘striped’ when viewed histologically?
From the overlapping of actin and myosin. Slide 4
What has happened histologically when a muscle is strained?
Some muscle fibres have been torn. Slide 4
There are 5 types of skeletal muscle, what are they?
Flat, fusiform, circular, pennate and quadrate. Slide 5
What does longer muscle fibres allow to happen?
It has a greater potential range of shortening. Therefore a greater potential range of movement produced at the joint. Slide 5
What is a flat skeletal muscle and an example?
With aponeurosis (sheet of fibrous tissue) it is muscle fibres which run parallel. e.g. external oblique muscle. Slide 5
What is a fusiform skeletal muscle and an example?
It is a spindle shaped muscle, round thick muscle belly which tapers at the end, e.g. biceps brachii. Slide 5
What is a circular skeletal muscle and an example?
It is circular muscle, e.g. orbicularis oculi. Slide 5
What is a pennate skeletal muscle and an example?
It is feather like muscle e.g. deltoid. Slide 5
What is a quadrate skeletal muscle and an example?
It is 4 sided and square shaped, e.g. rectus abdominus. Slide 5
How do skeletal muscles move joints?
They have to span the joint and cross it. Slide 6
Do muscles always connect to bone at insertion or origin?
No. Slide 7
Do tendons which are attached to muscle, contract?
No. Slide 8
What is an aponeurosis?
A flattened tendon, usually with flat muscles and attach to soft tissue rather than bone. Slide 8
What does longus and brevis mean?
Longus - long
Brevis - short. Slide 10
What part of the deltoid muscle extends the shoulder?
The posterior fibres move the shoulder back. Slide 11
What part of the deltoid muscle abducts the shoulder?
The middle fibres. Slide 11
What part of the deltoid muscle flexes the shoulder?
The anterior fibres. Slide 11
What does the articular surface of a bone determine?
Determines the possible movement of that joint e.g. shoulder can circumduct due to shallow socket of the glenoid fossa in the scapula. Slide 12
What are the clinical aspects of skeletal muscle?
Testing ability to move, muscle itself and nerves supplying it - can be tested by asking patient to carry out moves or reflexes. Slide 13
What are the two main reflexes for skeletal muscle?
Stretch reflex and the flexion withdrawal reflex. Slide 14
What is the flexion withdrawal reflex?
When we touch something that is potentially dangerous. Slide 14
What are the deep tendon reflexes?
Biceps jerk, triceps jerk, knee jerk and ankle jerk. Slide 15
How are the deep tendon reflexes tested?
A tendon hammer applies a brief sudden stretch to the muscle VIA its tendon. Slide 15
What are the deep tendon reflexes doing when being tested?
Protecting the muscle against overstretching. Slide 15
How do the deep tendon reflexes work?
Sensory nerve detects stretch. The synapse in the spinal cord communicates this to the motor nerves. Then the motor nerve passes the message for the muscle to contract. Slide 16
What is the neuromuscular junction?
The synapse at the end of the motor neuron and the skeletal muscle. Slide 16
What does a normal stretch reflex indicate is functioning normally?
The muscle, sensory nerve, motor nerve, spinal cord connections between the two neuromuscular junctions. Slide 17
What are descending controls from the brain for during stretch reflexes?
Prevents a full leg kick, and a large reaction.
What is muscle paralysis?
It is a muscle without a functioning more nerve supply, it cannot contract and would result in reduced tone (floppy feeling). Slide 18
What is muscle spasticity?
Has an intact and functioning motor nerve, however the descending controls from the brain are not working. So it would have increase tone (feel tight). Slide 18
What is muscle atrophy?
When the muscle ‘wastes’ away and muscle fibres shrink. This is due to inactivity. Slide 19
What is hypertrophy?
Opposite of atrophy. The skeletal muscles enlarge. Slide 20
Where are skeletal muscles found?
In the deep fascia with tough fibrous connective tissue covering it. Slide 21
How is the muscle positioned in the deep fascia?
Separated into compartments by an invaginated deep fascia forming an intermuscular septum.
What is the positives and negatives about the compartmentalisation of muscle?
They usually have a similar function and if there is an infection, it won’t spread. However if there is an infection it tends to spread upwards throughout the compartment. Slide 22
What are the 3 compartments in the thigh?
Anterior, medial and posterior. Slide 23
What are the 3 compartments in the leg?
Anterior, posterior and lateral. Slide 23
What are the 2 compartments of the arm?
Anterior and posterior. Slide 24
What are the 2 compartments of the arm?
Anterior and posterior. Slide 24
What is compartment syndrome?
Since the fascia creates an enclosed space, if there is a swelling or bleeding there, it creates pressure and affects the nerves and muscles. Slide 25
How do you treat a compartment syndrome?
Preform a fasciotomy, which relieves the pressure. Slide 25
Are the muscles that preform coughing, gagging, sneezing etc.. skeletal or smooth muscle?
Skeletal, you are still in control. Slide 26
What details do you need to know for each muscle?
Name, attachments, main actions, nerve supply and how to clinically test it. Slide 27
