Exam 3 - Axilla & Brachial Plexus I & II Flashcards
The basilic vein is found near what nerve?
Medial antebrachial cutaneous nerve (in deep brachial fascia)
Function of pectoralis major
Flexes, adducts, medial rotates humerus
Function of pectoralis minor
Draws scapula down and forward, stabilizes it
3 structures of deltopectoral triangle
Cephalic vein, thoracoacromial artery, lateral pectoral nerve
The anterior axillary fold, visible in people with good musculature, is found on the lateral border of what muscle?
Pectoralis major
What nerve passing through the medial wall of the axilla can convey referred pain from the heart?
Lateral cutaneous branch of the 2nd/3rd intercostal nerve (from the intercostobrachial nerve)
The anterior division of the brachial plexus is responsible for _______; the posterior division of the brachial plexus is responsible for _____.
Flexors; extensors
The brachial plexus lies on top of what artery?
Axillary artery
Difficult delivery of a newborn or motorcycle injuries may lead to a lesion of the upper trunk of the brachial plexus. What are the four nerves associated with this type of palsy?
Suprascapular (supraspinatous/infraspinatous); nerve to subclavius (subclavius); musculocutaneous (coracobrachialis, biceps brachii, brachialis); axillary (deltoid, teres minor)
What are four primary symptoms of Erb-Duchenne Palsy (lesion of the upper trunk)?
Upper limb hangs limply (NO abduction); humerus medially rotated (loss of teres major); forearm pronated (loss of biceps brachii); loss of sensation from lateral limb (loss of musculocutaneous nerve)
Lower lesions of the Brachial Plexus are caused by excessive _____ of the arm, often from breech births or a child falling from a height.
abduction
Lower lesions of the brachial plexus often affect the ulnar nerve, which supplies the small muscles of the hand. Avulsion of the C8 and T1 roots will cause:
Hyper extension of metacarpophalangeal joints (knuckles), flexion of interphalangeal joints (fingers)
Lesion of what nerve causes Winged Scapula, impaired abduction of arm, and weakened triceps?
Long thoracic nerve - injured by blows or pressure on posterior triangle.
Name the three passageways where brachial plexus nerves and subclavian vessels may be subject to compression via Thoracic Outlet syndrome.
Interscalene triangle;
Costoclavicular triangle;
Subcoracoid space.
What two (spinal cord) nerve roots are most commonly involved in producing pain and paresthesia in thoracic outlet syndrome?
C8, T1, along ulnar nerve distribution
The chief source of blood to the breast is found in what branch of the axillary artery?
Lateral thoracic artery
A fixed scapula (via the serratus anterior muscle) is crucial in the origin/function of what arm muscle?
Triceps
Which 4 muscles medially rotate the humerus?
Latissimus dorsi; anterior deltoid; teres major; subscapularis
What artery and nerve pair is found in the quadrangular space?
Axillary nerve; posterior circumflex humeral artery
What nerve and artery pair is endangered at the most common site of fractures?
The radial nerve and profunda brachii artery are found in the radial groove, which is in the triangular interval.
Which vessels are found in the triangular space?
Circumflex scapular vessels
Which muscles retract the scapula? What are their associated nerves?
Middle trapezius (CN11); rhomboid muscles(dorsal scapular nerve); levator scapulae (dorsal scapular nerve)
What are the powerful lateral rotators of the humerus?
Teres minor, infraspinatus
The axillary nerve may be damaged in a posterior dislocation of the shoulder. Such an injury may be diagnosed by demonstrating impaired skin sensation over the:
Lower half deltoid muscles
