7.3 Muscles and Movements of the Limbs Flashcards
What are all of the classifications/shapes that a muscle can be?
- Convergent
- Circular
- Unipennate
- Bipennate
- Multipennate
- Parallel
- Fusiform
What is the function of and an example of circular muscle?
Function:
- Sphincter muscles that allow the opening and closing of orifices
Example(s):
- Orbicular oris (mouth)
What are the features, function and some examples of the different types of pennate muscle?
Features and function:
- Fibres at an angle to the muscle’s line of action
- High fibre density
- Rotate as they shorten
- Result in a lot of power being generated across the joint
- Unipennate = only one side has the diagonal fibres (looks like a quill)
- Bipennate = two sides have the diagonal fibres
- Multipennate = multiple groups of diagonal fibres
Examples:
- Unipennate, extensor digitorum longus
- Bipennate, rectus femoris
- Multipennate, deltoid muscle
What are the features, function and example(s) of parallel muscles?
Features and function:
- Fibres align themselves parallel to the line of action of the muscle
- Usually long muscles
- Bring about larger but typically weaker movements than pennate muscles
Examples:
- Sartorius
- Sternocleidomastoid
What are the features, function and example(s) of fusiform muscles?
Features and function:
- Spindle-shaped
- Has a ‘muscle belly’ that is wider than the points of origin and insertion
- Provides a large range of motion/larger than other shapes of muscle
Examples:
- Biceps brachii
What are the features, function and examples of convergent muscle?
Features and function: - Triangular/fan- shaped muscles - Wide origins - Narrow insertions -> this results in high risk of tear or damage - Wide variation of fibre angles in muscles allows for multiple actions across joints Examples: - Pectoralis major
What is the origin of a muscle?
An area of a bone to which the muscle is attached via a tendon, but this region won’t move during the muscle’s action
What is the insertion of a muscle?
An area of a bone to which the muscle is attached via a tendon, but this region will move during the muscle’s action
Practice drawing out the diagram of a muscle insertion
Do it! Diagram is from Tom Cosker’s muscle and movement lecture
- Over how many joints are the biceps and gastrocnemius active over?
Both are active over 2 joints
- Where does the biceps insert?
Into the coracoid process (9 things insert into here, don’t mention this unless you can name all of them!)
What is a bursa?
A small fluid filled sac that cushions and reduces friction at a joint, will exist between two tissues that could grate over each other
What is an enthesis?
The name for where a muscle attaches to a bone, referring exactly to the connective tissue between a tendon and a bone (can be cartilaginous or fibrocartilaginous)
How is surface area increased at entheses?
The bone has a rough surface to increase the area articulating with the calcified fibrocartilage of the enthesis
Where is the fibrocartilage in a enthesis/insertion/origin calcified, and where is it now?
- On bursal side of tendon/further from the bone: un-mineralised
- On the bursal side of the bone/closer to the bone: calcified
Revise movements of joints
See set of flash cards on joints
What is the definition of a muscle agonist (with example)?
An agonist is the muscle that provides the primary force driving the joint to perform the movement in question
For example:
- Elbow flexion, agonist = biceps brachii
What is the definition of a muscle antagonist (with example)?
An antagonist is a muscle that opposes the agonist, providing some resistance to the agonist muscle and may reverse the movement in question. May also stabilise action of agonist.
For example:
- Elbow flexion, antagonist = triceps brachii
What is the definition of a muscle synergist (with example)?
A synergist is a muscle that assists the agonist muscle in performing the movement in question
For example:
- Elbow flexion, synergist = brachialis
What rough muscle group carries out flexion of the hip?
Anterior muscle group, e.g. psioas major (innervated by L1-L3 anterior rami), iliacus, pectineus, rectus femoris
What nerve innervates the hip flexor compartment?
Anterior thigh muscle compartment, innervated by the femoral nerve
What rough muscle group carries out extension of the hip?
Posterior thigh muscle compartment, e.g. gluteus maximus and the hamstrings
What nerves innervate the hip extensor compartment?
Posterior thigh muscle compartment, gluteus maximus by the inferior gluteal nerve, the hamstrings by the sciatic nerve
What rough muscle group carries out abduction of the hip?
Muscles on the lateral aspect of the joint, e.g. gluteus medius, gluteus minimus and tensor fasciae latae
