shoulder and brachial plexus Flashcards
what are functions of the pectoral girdle
attachment of the upper limb to the trunk
attachment site for upper limb muscles
allows upper limb to be mobile
-moves scapula freely
scapula-anterior
subscapular fossa
attachment site for subscapularis muscle
scapula-anterior
coracoid process
attachment site for biceps brachii, pectoralis major and corachobrachialis muscle
scapula -posterior
articulation with the humerus
intrinsic shoulder muscles
deltoid and teres major
intrinsic shoulder muscles
deltoid
origin: lateral third of clavicle, acromion, and spine of scapula
insertion: deltoid tuberosity of humerus
action: arm abduction
innervation: axillary nerve
intrinsic shoulder muscles
teres major
origin: posterior scapula surface at inferior angle
insertion: lesser tubercule on anterior humerus
action: adducts and medially rotates the humerus, and extends
innervation: lower subscapular nerve
rotator cuff muscles, primary function, attachment, and innervation
supraspinatus
infraspinatus
teres minor
subscapularis
primary function: reinforce the joint capsule and hold the humeral head in place
attachment: attach from the scapula to the head of the humerus
innervation: brachial plexus
rotator cuff muscles functions:
supraspinatus: assists the deltoid with arm abduction
infraspinatus: laterally rotates the arm
teres minor: laterally rotates the arm
subscapularis: medially rotates and abducts the arm
glenohumeral joint: shoulder joint
articulation:
ligaments
articulation: between the lateral humeral head and shallow glenoid cavity
ligaments: coracohumeral ligament and coraco-acromial ligament,glenohumeral ligament
glenohumeral joint
coracohumeral ligament
reinforces the capsule superiorlygl
glenohumeral joint
coracoacromial ligament
prevents the superior displacement of the lateral head
synovial bursae
provide cushioning and reduce friction between bones, tendons, and muscles around glenohumeral joint
abductors of the humerus
deltoid
supraspinatus, needs to start first
adductors of the humerus
teres minor
lat dorsi
pectoralis pajor
upward rotators of the scapula: medial side drops and joint cavity goes up
descending and ascending portions of trapezius
serratus anterior
downward rotators of the scapula: joint cavity goes down
rhomboids
levator scapulae
lat dorsi
pectoralis major
retractors of the scapula
middle part of traps
rhomboids
lat dorsi
protractors of scapula
serratus anterior
pectoralis minor
what is the brachial plexus formed by
formed by union of ventral rami spinal nerves C5-T1
describe the brachial plexus
- roots (C5,C6,C7,C8,T1)
- 3 trunks: superior, middle, inferior; each has a anterior and posterior region
- anterior and poster divisions of trunks
- divisions unite to form lateral cord : superior and middle trunks, medial cord: anterior division of inferior trunk, and posterior cord: posterior divisions of all cords unite.
- terminal branches: musculotaneous, median nerve, ulnar nerve, axillary nerve, radial nerve
the brachial plexus is divided into parts by the clavicle:
-supraclavicular: arising from roots and trunks
-infraclavicular: arising from the cords
terminal branches
musculotaneus nerve
-from: lateral cord
innervates: bicep, anterior arm
terminal branches
median nerve
from: from medial and lateral cord
innervates: anterior forearm and thenar
terminal branches
ulnar nerve
from: medial cord
innervates: 2 muscles in forearm and hypthenar muscles. forearm: flexor carpi ulnaris and lateral side of flexor digitorum profundus
terminal branches
axillary nerve
from: posterior cord
innervates: deltoid muscle
terminal branches
radial nerve
from: posterior cord
innervates:. triceps brachii posterior compartment
dermatome
ara of skin supplied by a single cord level or a certain peripheral nerve.
what terminal branch nerves forms a M
musculotaneous, median, and ulnar nerve
