In-depth detail of the origin, insertion, contraction movements of the muscles of the appendicular skeleton including muscles of the pectoral girdle, shoulder, arms, forearms, hands, pelvic girdle, thigh, legs, feet etc
Appendicular musculature
Monday, 20 September 2021 4:55 PM
Muscle origins, insertions and actions
- Origin
o The attachment at the relative stationary end
- Insertion
o The attachment at the more mobile end
§ General more distal attachment of a muscle
- Bicep
o Inserted into the radius
o Upon contraction produces flexion2 origins at the scapula
o Stationary during movement since action is to move forearm
o Spans elbow and shoulder joint
Upper limb muscles
- Pectoral girdle muscles
o Trapezius
§ Origin
• Occipital bone and vertebral column all the way to thoracic region
• Very large origin
§ Muscle bundles converge into insertion on the scapula and the clavicle
§ Insertion
• Lateral third of the clavicle
• the acromion
• the scapular spine of the scapula
§ 3 parts
• Upper
o Elevates the scapula
o Laterally rotate the scapula upwards
o Laterally flex and rotate neck to opposite side
o Extend the neck
• Middle
o Retracts scapula towards the midline
• lower
o Depress the scapula
o Laterally rotate scapula upwards
o Levator Scapulae
§ Originates at transverse processes of C1-4
§ Inserts at
• medial border of scapula
• Superior angle of scapula
§ Bilateral Contraction
• Elevates scapula
, o Levator Scapulae
§ Originates at transverse processes of C1-4
§ Inserts at
• medial border of scapula
• Superior angle of scapula
§ Bilateral Contraction
• Elevates scapula
§ Unilateral contraction
• Lateral flexion of head
o Rhomboid minor
§ Smaller
§ Origin
• Spinous processes of C7-T1
§ Insertion at medial border of scapula
• Superior to insertion of rhomboid major
§ Contraction - both
• Retract scapula
• Rotate scapula downwards
o Rhomboid major
§ Origin
• Spinous processes of T2-5
§ Inserts at medial border of scapula
§ Same action as above
§ Draws scapula towards the midline – same as trapezius
o Pectoralis minor
§ Covered by Pectoralis major
§ Origin
• Anterior ends of 3rd to 5th rib
§ Insertion is at the coracoid process of scapula
o Depresses and protracting the scapula
§ Shrug
o When scapula is immobilized
§ Involved in inspiration
§ Lifting the thoracic cage
o Serratus anterior
§ Origin
• External surfaces of 4th-9th rib
• includes finger like projections
§ Insertion at the medial border of scapula
§ Protracts scapula – provides punching action
§ Holds scapula close to body
§ Important together with upper fibres with trapezius
• Forms a force couple
- Arm/shoulder joint muscles
o Deltoid
§ Shaped like inverted triangle
§ Origin
• Lateral one third of clavicle, acromion of scapula, scapular spine
§ wraps around to posterior side to scapular spine
§ Anterior, middle or posterior
§ Inserts
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