Week 4 Anatomy - muscular system Flashcards
Explain the skeletal muscle organisation
- Tendon: connective tissue that anchors muscle to bone
- Fasciles: bundles of muscle fibres
Explain muscle attachments
- Origin: proximal attachment
- Insertion: distal attachment
- Cross at least one joint
- on opposing bones
- During contraction, muscle insertion movest towards the origin
Explain the components and types of muscle actions
Agonist: prime mover (generates movement)
Antagonist: opposes agonist (slows movement)
Synergist: assist agonist
Isometric contraction: muscle tone changes (resisting gravity) e.g. plank
Isotonic contraction: muscle length changes e.g. bicep curl
- Concentric (agonist): muscle shortens
- Eccentric (antagonist): muscle lengthens
Explain fascicle arrangemet
- Number of fibres/fasciles in a cross-sectionarea = muscle power
- Parrallel pattern = more length, less power
- Pennate and convergent = less length, more power
What are the muscles of facial expression?
- Occipitofrontalis
- Obicularis oculi
- Obicularis oris
- Buccinator
Parts/tendon/action of Occipitofrontalis
- Frontal and occipital bellies
- Tendon: epicranial aponeurosis
- Action: pulls scalp posteriorly and elevates eyebrow
Action of muscles of facial expression
- Obicularis oculi: closes/narrows eye
- Obicularis oris: closes/compresses lips
- Buccinator: compresses cheek against teeth
What are the muscles of mastication?
- Temporalis
- Masseter
Origin/Insertion/Action of Temporalis
Origin: temporal bone (fossa)
Insertion: mandible
Action: closes jaw (elevates and retracts mandible in)
Origin/Insertion/Action of Masseter
Origin: zygomatic bone (arch)
Insertion: mandible
Action: closes jaw (elevates and protracts mandible out)
Origin/Insertion/Action of the muscle of the neck
Sternocleidomastoid (SCM)
Origin: sternum (manubrium) and clavicle
Insertion: temporal bone (mastoid process)
Action: flexes head bilateraly, rotates head unilateraly
Action of the muscles of the back
Erector spinae group
Action: extension of trunk (bilateral), lateral flexion of trunk (unilateral)
What are the muscles, tendons and actions of the abdominal wall?
- External oblique
- Internal oblique
Action: lateral flexion of trunk, compression of abdominal wall, contralateral rotation of trunk (EO), ipsilateral rotation of trunk (IO) - Transverse abdominus: compression of abdominal wall
- Rectus abdominus: flexion of trunk, compression of abdominal wall
- Tendon: linea alba, rectus sheath
What are the muscles of the shoulder girdle?
- Pectoralis major
- Trapezius
- Deltoid
- Latissimus dorsi
- Teres major
Origin/Insertion/Action of Pectoralis major
Origin: clavicle, sternum, costal cartilage (1-6)
Insertion: proximal humerus (lateral lip of IT groove)
Action: Flexion, adduction, medial rotation
Origin/Insertion/Action of Trapezius
Origin: occipital bone, spinous process
Insertion: clavicle, scapula (acromiun and spine)
Action: elevation-depression, retraction, upward rotation of scapula
Origin/Insertion/Action of Latissimus dorsi
Origin: spinous process, ribs, thoracolumbar fascia
Insertion: Proximal humerus (floor of IT groove)
Action: Extension, adduction, medial rotation of arm
Origin/Insertion/Action of Delotoid
Origin: clavicle, scapula (acromion and spine)
Insertion: deltoid tuberosity of humerus
Action: Flexion and medial rotation (anterior), abduction past 15 degress, extension and lateral rotation (posterioir) of arm
Origin/Insertion/Action of Teres major
Origin: inferior amd lateral border of scapula
Insertion: Proximal humerus (medial lip of groove)
Action: Extension, adduction, medial rotation of arm
- synergist of latissimus dorsi
What are the muscles of the rotator cuff?
- Supraspinatus
- Infraspinatus
- Teres minor
- Subscapularis
Origin/Insertion/Action of Supraspinatus
Origin: supraspinous fossa
Insertion: greater tubercule of humerus
Action: abduction of arm (15 degrees)
Origin/Insertion/Action of Infraspinatus
Origin: Infraspinous fossa
Insertion: greater tubercle of humerus
Action: lateral rotation of arm
Origin/Insertion/Action of Teres minor
Origin: lateral border of scapula
Insertion: greater tubercle of humerus
Action: lateral rotation of arm
Origin/Insertion/Action of Subscapularis
Origin: subscapular fossa
Insertion: lesser tubercle of humerus
Action: medial rotation of arm
