Muscular overview Flashcards
What is smooth muscle?
Involuntary muscle that cannot be consciously controlled.
Found in blood vessels where ‘vaso-constriction and vaso-dilation’ cause changes in blood flow.
What is cardiac muscle?
Highly specialised muscle found only in the heart. It has characteristics of both cardiac and skeletal muscles.
Involuntary.
What is skeletal muscle?
Muscle that is under conscious control, allowing voluntary movement.
Various shapes allow for different amounts of force production.
What are the types of skeletal muscles?
Fusiform, Convergent (Triangular), Parallel/strap, and Pennate.
Pennate has three subcategories: Unipennate, Bipennate, and Multipennate.
Describe fusiform muscles.
Long, parallel fibres typically involved in movement over a large range, with tendons on either side.
Describe convergent (triangular) muscles.
Origin is typically wider than insertion, allowing for large production of forces.
Describe parallel/strap muscles.
Muscles that run parallel to each other, typically long and more suited for endurance rather than strength.
What is unipennate muscle?
One row of muscle fibres arranged diagonally into a tendon on one side only.
What is bipennate muscle?
Two rows of muscle fibres arranged diagonally into a tendon on either side, resembling a feather.
What is multipennate muscle?
Multiple rows of muscle fibres converging into a central tendon.
What is the origin of the trapezius muscle?
Occipital aspect of skull, nuchal ligament, spinous processes of C7 –T12.
What is the action of the trapezius muscle?
Elevates, depresses, retracts, rotates, and fixes scapula; extends neck.
What is the origin of the levator scapulae muscle?
Upper spine (C1 –C4).
What is the action of the levator scapulae muscle?
Elevates, retracts, and rotates scapula; laterally flexes neck.
What is the action of the rhomboids (major & minor)?
Major - retracts, rotates, and fixes scapula; Minor - retracts slightly, elevates, rotates, and fixes scapula.
What is the origin of the latissimus dorsi muscle?
T7 –L5, sacrum, and iliac crest.
What is the action of the latissimus dorsi muscle?
Adducts, flexes, and extends the arm.
What is the origin of the teres major muscle?
Lateral border of scapula.
What is the action of the teres major muscle?
Adducts, extends, and medially rotates the arm.
What is the action of the erector spinae muscle?
Extends the vertebral column; Iliocostalis also laterally flexes and rotates the vertebral column.
What is the origin of the quadratus lumborum muscle?
Iliac crest & lower lumbar vertebrae.
What is the action of the quadratus lumborum muscle?
Laterally flexes vertebral column & depresses the 12th rib.
What is the origin of the sternocleidomastoid muscle?
Upper sternum (manubrium) and medial clavicle.
What is the action of the sternocleidomastoid muscle?
One contracting alone laterally flexes & rotates on the same side; two together cause neck extension.
What is the origin of the pectoralis major muscle?
Clavicle, sternum, & upper 6 ribs (costal cartilages).
What is the action of the pectoralis major muscle?
Adducts, flexes, & medially rotates arm; extends arm from flexed position.
What is the origin of the serratus anterior muscle?
1st to 9th ribs.
What is the action of the serratus anterior muscle?
Rotates & protracts scapula; elevates ribs.
What is the origin of the pectoralis minor muscle?
3rd to 5th ribs.
What is the action of the pectoralis minor muscle?
Depresses scapula or elevates ribs.
What is the origin of the external intercostals?
Inferior margin of each rib.
What is the action of the external intercostals?
Inspiration - elevates ribs.
What is the origin of the internal intercostals?
Superior margin of each rib.
What is the action of the internal intercostals?
Expiration - depresses ribs.
What is the origin of the diaphragm?
Xiphoid process, cartilage of last 7 ribs, lateral aspect of L1-L4.
What is the action of the diaphragm?
Inspiration – depresses floor of thorax.
What is the origin of the supraspinatus muscle?
Supraspinous fossa of scapula.
What is the action of the supraspinatus muscle?
Abducts arm.
What is the origin of the infraspinatus muscle?
Infraspinous fossa of scapula.
What is the action of the infraspinatus muscle?
Extends and laterally rotates arm.
What is the origin of the teres minor muscle?
Lateral border of scapula.
What is the action of the teres minor muscle?
Extension and laterally rotates arm.
What is the origin of the subscapularis muscle?
Subscapular fossa.
What is the action of the subscapularis muscle?
Flexion and medial rotation of the arm.
What is the origin of the anterior head of the deltoid muscle?
Lateral portion of the anterior aspect of the clavicle.
What is the action of the anterior head of the deltoid muscle?
Adduction, flexion, and internal rotation.
What is the origin of the lateral head of the deltoid muscle?
Lateral portion of the acromion process.
What is the action of the lateral head of the deltoid muscle?
Adduction.
What is the origin of the posterior head of the deltoid muscle?
Inferior portion of the spine of scapula.
What is the action of the posterior head of the deltoid muscle?
Adduction, extension, and external rotation.
What is the origin of the triceps brachii muscle?
Long head – lateral border of scapula; Lateral head – lateral and posterior surface of humerus; Medial head – posterior humerus.
What is the action of the triceps brachii muscle?
Extends forearm; extends and adducts arm.
What is the origin of the biceps brachii muscle?
Long head – supraglenoid tubercle; Short head – coracoid process.
What is the action of the biceps brachii muscle?
Shoulder: Long head triggers flexion and abduction; Short head does flexion, adduction, and medial rotation; Elbow flexion.
What is the origin of the coracobrachialis muscle?
Coracoid process of scapula.
What is the action of the coracobrachialis muscle?
Adducts and flexes the shoulder joint.
What is the origin of the brachialis muscle?
Middle of the anterior shaft of humerus.
What is the action of the brachialis muscle?
Flexes forearm.
What is the origin of the pronator teres muscle?
Coronoid process of ulna.
What is the action of the pronator teres muscle?
Pronates forearm.
What is the origin of the pronator quadratus muscle?
Ulna.
What is the action of the pronator quadratus muscle?
Pronates forearm.
What is the origin of the brachioradialis muscle?
Lateral epicondyle of humerus.
What is the action of the brachioradialis muscle?
Flexes forearm.
What is the action of the wrist flexors?
Flexes wrist.
What is the action of the wrist extensors?
Extends wrist.
What is the origin of the supinator muscle?
Lateral epicondyle of humerus.
What is the action of the supinator muscle?
Supinates forearm.
What is the origin of the rectus abdominus muscle?
Pubic crest & pubic symphysis.
What is the action of the rectus abdominus muscle?
Flexes vertebral column; compresses abdomen.
What is the origin of the transverse abdominus muscle?
7th to 12th costal cartilages, iliac crest, and inguinal ligament.
What is the action of the transverse abdominus muscle?
Compresses abdomen.
What is the origin of the internal oblique muscle?
Outer edge of the middle two thirds of the iliac crest.
What is the action of the internal oblique muscle?
Bilateral contraction compresses the abdomen (lumbar flexion); unilateral contraction ipsilaterally rotates the torso.
What is the origin of the external oblique muscle?
5th to 12th ribs.
What is the action of the external oblique muscle?
Flexes and contralaterally rotates the thoracic spine.
