pectoral region and brachial plexus Flashcards
clavicle helps _____ from the upper limb to the axial skeleton
transmit shock
most frequently fractured bone in the body
clavicle
80% of adult fractures are through the ______ of the bone
middle 1/3
is a clavicular fracture clinically obvious?
yes
shoulder on affected side of a clavicular fracture is usually _____ than other side
lower…
the SCM elevates the proximal fragment
most frequently broken bone during labor/delivery
clavicle
joints of clavicle
sternoclavicular joint
acromioclavicular joint
only true articulation between the upper limb and the axial skeleton
sternoclavicular joint
motion at the SC joint
about 60 degrees
costoclavicular ligament
anchors sternal end of the clavicle to the 1st rib
FOOSH
falling on an outstretched hand/arm
intra-articular fibrocartilagenous disc acts as shock absorber
ligaments of the AC joint
acromioclavicular ligament - provides strength to the joint capsule
coracoclavlicular extrinsic ligaments- trapezoid and conoid ligaments unite coracoid process and to clavicle
situations where AC injuries are common
football/hockey
acromioclavicular injuries are graded according to the _____ of ligamentous damage
severity
1st degree tear
stretch or minor tear of the AC ligament but it is still intact
2nd degree AC tear
a rupture of AC ligament with subluxation of the joint
3rd degree
severe injuries where both the AC and the coracoclavicular ligaments are torn
shoulder separation
referes to the separation of the clavicle with the shoulder and acromion
piano sign
3rd degree injury - AC dislocation with prominent clavicle
anterior thoracoappendicular muscles
pectoralis major
pectoralis minor
subclavius
serratus anterior
origin of pectoralis major
coracoid process of clavicle and 3-5th ribs sternocostal
insertion of pectoralis major
inserts into the bicipital groove of the humerus
innervation of the pectoralis major
medial and lateral pectoral nerves
action of pectoralis major
medially rotates, adducts, flexes the arm
Pectoralis minor insertion
coracoid process
pectoralis minor function
stabilizes the scapula against the thoracic wall
also accessory respiratory muscle
origin of pectoralis minor
anterior surface of 3rd-5th ribs
innervation of the pectoralis minor
medial pectoral nerve
pectoralis minor forms a bridge over these major neuromuscular structures entering the arm
axillary artery
axillary vein
brachial plexus
the ________ is a continuation of the subclavian artery as it passes the lateral margin of the 1st rib
brachial? artery
provides vascular supply to the pectoral girdle and shoulder region
axillary artery
this muscle divides the axillary artery into three parts
pectoralis minor
generally there are ___ branches that arise from the axillary artery
6
1st part of axillary artery has one branch
superior thoracic artery
1st and 2nd intercostal space between ribs
2nd part of axillary artery has two branches
thoracoacromial trunk - divides into 4 branches (deltoid, acromial, pectoral, clavicular)
lateral thoracic artery - pectoral muscles and breast
3rd part of axillary artery has three branches
subscapular (largest)
anterior humeral circumflex (around surgical neck)
posterior humeral circumflex (around surgical neck)
many axillary arterial branches contribute to a large __________ that provides collateral circulation around the scale/muscles
anastomotic arcade
subscapular artery
longest branch that supplies the muscles and anastomoses around the scapula, gives rise to the thoracodosal and scapular circumflex artery in the triangular space
anterior and posterior humeral circumflex
help vascularize the humerus and surrounding muscles (posterior goes through the quadrangular space)
collateral circulation of axillary artery
numerous blood vessels anastomose around the scapula and can convey blood to the arm, invade the axillary artery ever is blocked/thrombosis
large nerves network that innervates the upper extremity and all its associated musculature
brachial plexus
5 segments of the brachial plexus
roots trunks divisions cords branches
Real Truckers Drink Cold Beer to MARMU
roots of brachial plexus
ventral rami of C5 to T1 spinal nerves
trunks of the brachial plexus
superior - C5 and C6
middle - C7
inferior - C8 and T1
divisions of the brachial plexus
each trunk divides into an anterior and posterior division
anterior divisions of the brachial plexus
eventually forms nerves that innervate muscles in flexor (anterior) compartments of the upper limb
posterior divisions of the brachial plexus
combine and eventually form nerves that innervate muscles in extensor (posterior) compartments of the upper limb
cords of brachial plexus
3 cords that are named in relation to the axillary artery
lateral cord
medial cord
posterior cord
lateral cord of the brachial plexus
both anterior divisions of superficial and middle trunk
medial cord
the anterior division of the inferior trunk
posterior cord
the posterior portion of all 3 trunks (superior, medial and inferior)
branches of the brachial plexus
MARMU
musculocutaneous axillary nerve radial nerve median nerve ulnar nerve
the lateral cord gives rise to the _______ and the lateral root of the _____ nerve
musculocutaneous
median
musculocutaneous nerve
innervates flexors of the arm
ulnar nerve
intrinsic muscles of the hand and some forearm flexors
axillary nerve
innervates deltoid and teres minor
musculocutaneous nerve roots
C5,6,7
axillary nerve roots
C5,6
radial nerve roots
C5,6,7,8, T1
median nerve roots
C5, C6, C7, C8, T1
radial nerve
innervates extensors of the arm and forearm (from the posterior cord and division)
median nerve
innervates most forearm flexors and thumb muscles
________ nerves all innervate muscles that adduct and medially rotate the arm
subscapular nerves
sub scapular nerves
upper scapular (c5, c6)
middle (thoracodorsal) subscapular (c6,7,8)
lower sub scapular (c5, c6)
The ______ and the ______ pass between the anterior and middle scalene muscles in the cervical region
roots of the plexus and the subclavian artery
the deep fascia that surrounds the scalene muscles in the neck is called the
prevertebral fascia
the prevertebral fascia becomes the _____ is it extends laterally, forming a tubular sheath that surrounds the _______ and ______
axillary sheath
brachial plexus
axillary artery
