Muscles of the Pectoral Girdle Flashcards
What are the origins of the Trapezius muscle?
Upper fibres =
- External Occipital Protruberance,
- Superior nuchal line,
- Ligamentum nachae,
- Spinous process of C7
Middle fibres =
-Spinous process of T1 - T5 vertebra
Lower fibres =
-Spinous process of T6-T12 vertebra
What are the INSERTIONS of Trapezius muscles?
Upper fibres =
- Lateral 1/3 of Clavicle
- Acromion Process
Middle fibres =
-Lateral 2/3 of superior border of SPINE of SCAPULA
Lower fibres =
-Medial 1/3 of spine of scapula
What do the upper, middle and lower muscle fibres of Trapezius do?
Upper : Elevates the scapula
Middle : Retract the scapula
Lower : Depress the scapula
What is the nerve supply of trapezius?
Motor : Accessory nerve CNXI
Sensory : anterior rami of C3 and C4
Where does latissimus dorsi attach on the skeleton?
Intertubercular groove (bicipital groove) of the Humerus
What are the actions of latissimus dorsi?
- Extension
- adduction
- flexion from extended position
- Medial / internal rotation of shoulder joint
What are the origins of Levator Scapulae?
Origin = Transverse process of C1 - C4
What are the insertions of Levator Scapulae?
Insertion = Medial border of scapula, superior to level of spine.
What are the origins of Rhomboid Minor?
Origins =
-Spinous process of C7 to T1 vertebra
What are the insertions of Rhomboid Minor?
Insertions =
-medial border of scapula, at the level of the spine of the scapula.
What is the nerve supply of Rhomboid MINOR?
Dorsal Scapular Nerve (C5)
What is the origin of Rhomboid MAJOR?
-Spinous process of T2 - T5
What are the insertions of Rhomboid MAJOR?
Medial border of scapula, inferior to the level of the spine of the scapula
What is the nerve supply of Rhomboid MAJOR?
Dorsal Scapular Nerve (C5)
What is the nerve supply of Levator Scapulae?
Dorsal Scapular Nerve (C5)
What is the function of Rhomboid Major and Minor?
Retract scapula medially and superiorly, used to square shoulders.
what happens if the long thoracic nerve is damage?
winged scapula
What causes winged scapula?
damage to the long thoracic nerve
What is painful arc syndrome?
It is caused by calcific bursitis. Typically develops in males >50years. Caused by inflammation.
Pain during 50-130’ of abduction.
In what direction do 95% of shoulder dislocations occur in?
Anteroinferior direction counts for 95% of all shoulder dislocation.
Inferior dislocation of the shoulder can cause damage to what nerve?
Axillary nerve can be damages in an inferior shoulder dislocation
How does a patient with axillary damage usually present?
Deltoid atrophy.
Area of anaesthesi on arm at poroximal region of humerus.
What are the nerve roots of the musculocutaneous branch of the brachial plexus?
C5-C7
What are the nerve roots of the median nerve?
C6-T1
What are the nerve roots of the ulnar nerve?
C7-T1
What are the nerve roots of the axillary nerve
C5-C6
Radial nerve roots
C5-T1
What muscle initiates abduction of the shoulder joint?
supraspinatus
What muscle is known as the power abductor of the shoulder joint?
Deltoid
What can impair abduction of the shoulder joint?
1) Supraspinatus paralyzation caused by damage to suprascapular nerve (C5,6)
2) Deltoid paralyzation caused by axillary nerve (C5,6) damage. e.g shoulder dislocation or fracture of surgical neck of humerus
Fracture of the neck of humerus can damage what nerve?
Axillary (C5,6)
What are the contents of the quadrangular space?
1) Axillary nerve
2) Posterior circumflex humeral atery and vein
What is Quadrangular Space Syndrom?
Transient blockage of the posterior cirmflex artery and axillary nerve. Presents with shoulder pain and paraesthesia down arm. uncommon condition.
