G: Scapular & Pectoral Flashcards
What is the action of the deltoid muscle?
Primary: abduct humerus
Secondary: Flex, extend, & rotate humerus
Deltoid nurovasculature?
Axillary nerve (C5, C6)
posterior circumflex humeral vessels
Teres major muscle actions?
Medially rotate and extend humerus
Teres major nurovasculature?
Lower (inferior) subscapular nerve (C5-C7)
subscapular vessels
Supraspinatus muscle action?
Abducts humerus for the first 15 degrees
Supraspinatus muscle nurovasculature?
Suprascapular nerve (C5, C6)
suprascapular vessels and dorsal scapular vessels.
Infraspinatus muscle action?
Laterally rotates the humerus
Infraspinatus muscle nurovasculature?
Suprascapular nerve (C5, C6)
suprascapular vessels and subscapular vessels
Teres minor muscle actions?
Lateral rotation of the humerus
Teres minor muscle nurovasculature
Axillary nerve (C5, C6)
suprascapular vessels and subscapular vessels.
Subscapularis muscle actions?
Medial rotation of the humerus.
Subscapularis muscle nurovasculature?
Upper and lower subscapular nerves
subscapular vessels
What provides the outer muscular support of the shoulder region?
Deltoid muscle
What muscles provide the inner rotator cuff support of the shoulder region.
SITS
Supraspinatus: superior
Infraspinatus: lateral
Teres minor: lateral/slightly inferior
Subscapularis: medial/slightly inferior
What is found in the subacromial bursa?
Lubricating synovial fluid
Does the subacromial bursa communicate with the joint capsule?
No. It is superior to the supraspinatus muscle
What happens to the subacromial bursa with age?
May join with joint capsule as supraspinatus tendon degenerates.
What are the borders of the quadrangular space?
Superior = teres minor Inferior = teres major Medial = long head of triceps brachii Lateral = surgical neck of humerus
What passes through the quadrangular space?
Axillary nerve and posterior circumflex humeral vessels
What are the borders of the triangular space?
Superior: Teres minor
Inferior: teres major
Lateral: long head of triceps brachii
What passes through the triangular space?
Circumflex scapular vessels
What are the borders of the triangular interval?
Superior = teres major Medial = long head of triceps brachii Lateral = lateral head of triceps brachii
What passes through the triangular interval?
Radial nerve and deep brachial artery (aka profunda brachial artery)
How do the suprascapular nerve and artery differ in their paths?
Nerve: runs UNDER superior transverse scapular ligament and THRU suprascapular notch
Artery: runs OVER sup trans scap lig and ABOVE suprascapular notch
What muscles do the suprascapular nerve and artery supply?
Supraspinatus and infraspinatus
What cervical nerves supply the suprascapular nerve?
Ventral rami of C5-C6
What cervical rami supple the dorsal scapular nerve?
Ventral ramus of C5
What muscles do the dorsal scapular nerve and deep transverse cervical artery supply?
Levator scapulae & rhomboid muscles
What nerve runs with the deep transverse cervical artery?
Dorsal scapular nerve
What nerve runs along the transverse cervical artery?
Accessory nerve (CN XI) after descending through the neck.
T/F: Superficial transverse cervical artery runs deep to the trapezius muscle?
True
What muscle do the accessory nerve and transverse cervical artery supply?
Trapezius muscle
What muscle do the upper and lower subscapular nerves and subscapular artery supply?
All: subscapularis muscle
Lower subscapularis nerve & subscapularis artery: teres major
What is the reasoning for collateral circulation?
Ensures adequate blood supply to UL in event of insufficient flow through axillary artery
Where is the ligature for the collateral circulation of the scapular region?
On the axial artery between the thyrocervical truck and subscapular artery
Is the sternum part of the pectoral girdle?
NO
What are the three functions of the clavicle bone?
- Holding UL free from trunk for max range of motion
- Provide attachments for muscles
- Transmit forces from UL -> axial skeleton
What bone connects the clavicle to the humerus?
Scapula
What ribs do the scapula span vertically?
2nd - 7th
What are the three joints of the shoulder complex?
- Sternoclavicular
- Acromioclavicular
- Glenohumeral
What is the action of the pectoralis major muscle?
Adducts and medially rotates humerus
What is the nurovasculature for the pectoralis major muscle?
medial and lateral pectoral nerve
Thoracoacrominal vessels
What is the action of pectoralis minor muscle?
Protracts scapular
What is the neurovascular supply of the pectoralis minor muscle?
Medial pectoral nerve
Thoracoacromial vessels
What major artery does the lateral thoracic artery branch from?
Axillary artery (deep to pec minor)
What does the lateral thoracic artery supply?
Lateral thorax, lateral pec region, lateral breast
What major artery does the internal thoracic artery branch from?
Subclavian artery
What does the internal thoracic artery supply?
Anterior thorax, medial pec region, medial breast
What major artery does the thoracoacromial artery branch from?
Axillary artery (under pec minor)
What are the four branches of the thoracoacromial artery?
Pectoral artery - upper pec region
Clavicular artery - clavicle region
Acromial artery - upper shoulder region
Deltoid artery - lower shoulder region
What vertebral levels give rise to the cutaneous nerves of the pectoral regions?
T1-T6
What ventral vertebral rami give rise to the medial pectoral nerve?
C8-T1
What muscle(s) does the medial pectoral nerve innervate?
Pectoralis minor and part of pec major
What ventral vertebral rami give rise to the lateral pectoral nerve?
C5-C7
What muscle does the lateral pectoral nerve innervate?
Pectoralis major
Which pectoral nerve pierces the pectoralis minor muscle?
Medial pectoral nerve
What ventral vertebral rami give rise to the long thoracic nerve?
C5-C7
What muscle does the long thoracic nerve supply?
Serratus anterior superficially
What nerve can be damaged during a mastectomy resulting in a “winged scapula”?
Long thoracic nerve
