Muscles Flashcards
What are the functions of muscles?
Movement - skeleton, intestines (peristalsis), heart
Static support
Heat production
What are the types of muscle?
Skeletal
Heart
Smooth
Where can you find the skeletal muscle and what does it do?
Attached to tendon
Locomotion
Voluntary control
Where can you find cardiac muscle and what does it do?
Myocardium
Involved in blood circulation
Involuntary control
Where can you find cardiac muscle and what does it do?
Myocardium
Involved in blood circulation
Involuntary control
Where can you find smooth muscle and what does it do?
Walls of vessels and organs
Move substances and restrict flow
Involuntary control
What is the epimysium of the skeletal muscle?
A layer of dense irregular connective tissue surrounds the skeletal muscle
What is the perimysium of the skeletal muscle?
A layer of connective tissue that surrounds s bundle of muscle fibres
What is the endomysium of the skeletal muscle?
A layer of connective tissue that surrounds an individual muscle fibre
What is a tendon?
A tendon is a fibrous connective tissue that attaches muscle to bone.
What is a ligament?
A ligament is a fibrous connective tissue that attaches bone to bone.
What is aponeurosis?
A sheet of pearly white fibrous tissue that takes the place of a tendon in flat muscles having a wide area of attachment.
Lay flat in the abdomen, covering the abdominal wall
Mainly made up of collagen fibres
Where can you find aponeurosis?
Aponeuroses are connective tissues found on the surface of pennate muscles and are in close association with muscle fascicles.
What is a parallel muscle?
Fascicles that run parallel to one another, and the contraction of these muscle groups act as an extension of the contraction of a single muscle fibre.
What is a pennate muscle?
A muscle with fascicles that attach obliquely (in a slanting position) to its tendon. These types of muscles generally allow better stabilization and force production but less flexibility.
Features of tendons and aponeuroses
Dense fibrous connective tissue
Do not shorten
Can alter force direction
Some muscles share a common tendon
What joints do muscles act on?
The joints they pass over
Some muscles pass over more than one joint
What are examples of muscles working together?
Elbow joint
Shoulder joint
Hand
How do muscles in the elbow joint work together?
Flexors and extensors working in opposition
How do shoulder joint muscles work together?
Stabilised by joint action of rotator cuff muscles
What are muscle compartments?
Compartments are groupings of muscles, nerves, and blood vessels in your arms and legs.
What covers muscle compartments and what is its role?
Fascia.
The role of the fascia is to keep the tissues in place, and, therefore, the fascia does not stretch or expand easily
What nerves supply muscles?
Muscles of the same compartment usually supplied by the same nerve
Example: Radial nerve supplies all extensors in the upper limb
Where do axial muscles originate from?
Axial muscles originate from the trunk and head
Where do appendicular muscles originate from?
Appendicular muscles originate from limbs and stabilise the movement of pectoral and pelvic girdles
What is the role of anterior muscle compartments of the arm?
Anterior muscle compartment of the arm - flexor muscles
What is the role of anterior muscle compartments of the arm?
Posterior muscle compartments of the arm - extensor muscles
What supplies muscles of the same compartment?
Muscles of the same compartment are supplied by the same nerve
What supplies all extensor muscles of the upper limb?
Radial nerve supplies the posterior compartment of the arm and forearm
What are the flexors of the arm?
Biceps brachii
Brachialis
Coracobrachialis
What are the extensors of the arm?
Triceps brachii
What supplies flexor muscles of the upper arm?
Musculocutaneous nerve
What supplies all flexor muscles of the forearm?
Median and ulner nerves
What supplies the whole upper limb?
A network of nerves called the brachial plesxus
What is the brachial plexus?
The brachial plexus is a network of nerves that gives rise to all the motor and sensory nerves of the upper extremity.
Where does the brachial plexus originate from?
This plexus arises from the anterior rami of spinal nerves C5-T1 that undergo several mergers and splits into trunks and divisions, until they finally give rise to their terminal branches.
What are some branches of the brachial plexus?
The musculocutaneous, axillary, radial, median and ulnar nerves.
Where can the brachial plexus be found?
Under the clavicle in a diagonal line
How is the brachial plexus organised?
‘Rugby Teams Don’t Cover Bruises’
(standing for: Roots, Trunks, Divisions, Cords, Branches)
How do flexor and extensor muscle groups work?
In pairs
What is an agonist muscle?
Prime mover/muscle that contracts
What is an antagonist muscle?
Muscle that relaxes
What is a fixator muscle?
Muscle that stabalises
What is a synergist muscle?
A muscle that augments the action of the agonist
When flexing the elbow, what muscles act as the agonist, antagonist, fixator and synergist?
Agonist: bicep
Antagonist: tricep
Fixator: deltoid
Synergist: Brachialis
What side of the forearm is responsible for pronation?
Anterior
What side of the forearm is responsible for supination?
Posterior
How many flexors and pronators are in the forearm?
8 - act to flex the wrist and digits
How many extensors and supinators are in the forearm?
10 - act to extend the wrist and digits
What muscle is responsible for the flexion of the forearm?
Brachioradialis
What muscle is part of the posterior compartment of the forearm?
Brachioradialis
Give a summary of the upper limb muscle compartments
Upper Arm:
Flexors - anterior portion, musculocutaneous nerve
Extensors - posterior portion, radial nerve
Forearm:
Flexors - anterior portion, median and ulnar nerve
Extensors - posterior portion, radial nerve
What are the three gluteal muscles?
Gluteus maximus
Gluteus medius
Gluteus minimus
What do gluteal muscles act on?
Hip joint
What is the role of the gluteus maximus?
Extension of the hip joint and lateral rotation
What is the role of the gluteus medius and minimus?
Abduction of the hip joint and medial rotation
What physical movements do the gluteus maximus help with?
Getting up from a chair
Walking
Running
Climbing stairs
What nerve innervates the gluteal muscles?
Sciatic nerve
What are the three compartments of the thigh?
Anterior
Posterior
Medial
What is the posterior muscle group of the thigh, what nerve is it innervated by and what is its role?
Hamstrings
Sciatic Nerve
Flexion of knee
What is the posterior muscle group of the thigh, what nerve is it innervated by and what is its role?
Quadriceps
Femoral Nerve
Extension of Knee
What is the medial muscle group of the thigh, what nerve is it innervated by and what is its role?
Adductors
Obturator nerve
Adduction of thigh at hip joint
What are the muscles that make up the hamstrings?
Semitendinosus, semimembranosus, and biceps femoris muscles
What are the muscles that make up the quadriceps?
Rectus femoris, the vastus lateralis, the vastus intermedius, and the vastus medialis.
What are the muscles that make up the adductor muscles of the thigh?
Gracilis, obturator externus, adductor brevis, adductor longus and adductor magnu
Why are extensors and flexors on different sides in the thighs and the arm?
During weeks 6-8 of fetal development, the upper limb rotates laterally while the lower limb rotates laterally
What are the three compartments of the leg muscles?
Anterior
Posterior
Lateral
What are leg muscles innervated by?
Sciatic nerve
What are the anterior leg muscles and what is their role?
Dorsiflexion that are responsible for (dorsi)flexion on the ankle joint
What is the posterior leg muscle and what is their role of posterior leg muscles?
Plantarflexors which are responsible for the extension of the ankle joint
What are the lateral muscles of the leg muscles and what do they do?
Evertors which help with eversion of the foot at the ankle joint
Summary of the lower limb
Thigh:
Extensors: anterior, quadriceps, femoral nerve
Flexors: posterior, hamstrings, sciatic nerve
Adductors: medial, adductor, obturator nerve
Leg:
Sciatic nerve
Dorsiflexion: anterior, flexion at ankle joint
Plantarflexors: posterior, extension at ankle joint
Evertors: Lateral, eversion at ankle joint
What are the intrinsic muscles of the hand?
Thenar and hypothenar group
Thenar group - control movement of thumb
Hypothenar group - control movement of pinky finger
Overall, muscles of the hand are used for precision
What are the intrinsic muscles of the foot do?
Support walking and maintain arch of the foot
What muscle abducts the arm?
Deltoid
