The Shoulder: Superficial & Deep Structures Flashcards
which group of muscles are described as “the superficial, or extrinsic, muscles of the back that move the upper limb and pectoral girdle”?
posterior axio-appendicular muscles
ID muscle
trapezius
what is the proximal attachment of the trapezius?
-external occiptal protuberance of skull
-nuchal ligament
-spinous processes of vertebrae
what is the distal attachment of the trapezius?
-lateral third of clavicle (anterior)
-acromion
-spine of scapula
what are the actions of the trapezius?
-elevates scapula
-depresses scapula
-retracts scapula
-rotates glenoid fossa superiorly (upward rotation of scapula)
what is the motor innervation of the trapezius?
spinal accessory nerve (CNXI)
what is the sensory innervation of the trapezius? (pain & proprioception)
cervical plexus (C3 & C4)
ID muscle
latissimus dorsi
what is the proximal attachment of the latissimus dorsi?
-spinous processes
-thoracolumbar fascia
-iliac crest
-inferior 3 ribs
what is the distal attachment of the latissimus dorsi?
-floor of intertubercular sulcus of humerus
what are the actions of the latissimus dorsi?
-extends humerus
-adducts humerus
-medially rotates humerus
-raises torso towards arms when climbing or doing a pull-up
what is the motor & sensory innervation of the latissimus dorsi?
thoracodorsal nerve
ID muscle
rhomboid minor
what is the proximal attachment for rhomboid minor?
-nuchal ligament
-spinous processes of vertebrae
what is the distal attachment for rhomboid minor?
medial end of scapular spine
what are the actions of both rhomboid major and rhomboid minor?
retract, elevate, and rotate scapula downward, as well as fix it to thoracic wall
what is the motor & sensory innervation for both rhomboid major and rhomboid minor?
dorsal scapular nerve
ID muscle
rhomboid major
what is the proximal attachment for rhomboid major?
spinous processes of vertebrae
what is the distal attachment for rhomboid major?
medial border of scapula from level of spine to inferior angle
ID muscle
levator scapulae
what is the proximal attachment for levator scapulae?
posterior tubercles of transverse processes of vertebrae
what is the distal attachment for levator scapulae?
-medial border of scapula
-superior angle of scapula
what are the actions of levator scapulae?
-elevates scapula and tilts glenoid fossa inferiorly by rotating scapula (downward rotation)
what is the motor & sensory innervation of levator scapulae?
cervical plexus (C3 & C4) & dorsal scapular nerve
which muscles are innervated by the ventral rami of spinal nerves via branches of the brachial plexus?
muscles of the pectoral region
which muscles are included in the pectoral region?
-pectoralis major
-pectoralis minor
-subclavius
-serratus anterior
ID muscle
pectoralis major
what is the proximal attachment of pectoralis major?
clavicular and sternocostal attachments
-anterior surface of medial 1/2 of clavicle
-anterior surface of sternum and superior costal cartilages
what is the distal attachment of pectoralis major?
-lateral lip of intertubercular sulcus
what are the actions of pectoralis major?
-adducts & medial rotates humerus
-draws scapula anteriorly & inferiorly (via clavicle)
-clavicular portion flexes humerus
-sternal portion can extend humerus while it is in this flexed position
what is the motor & sensory innervation of pectoralis major?
lateral & medial pectoral nerves
ID muscle
pectoralis minor
what is the proximal attachment of pectoralis minor?
-3rd & 5th ribs, near costal cartilages
what is the distal attachment of pectoralis minor?
coracoid process of scapula
what are the actions of pectoralis minor?
-stabilizes scapula by pulling it anteriorly & inferiorly against posterior thoracic wall
what is the motor & sensory innervation of pectoralis minor?
medial pectoral nerve
(usually pierced by this nerve)
ID muscle
serratus anterior
what is the proximal attachment of serratus anterior?
external surfaces of lateral parts of ribs
what is the distal attachment of serratus anterior?
anterior surface of medial border of scapula
what are the actions of serratus anterior?
-protracts scapula
-rotates scapula
-holds scapula against thorax
-allows full abduction of humerus; arms raised above head
what is the motor & sensory innervation of serratus anterior?
long thoracic nerve
ID muscle
subclavius
what is the proximal attachment of subclavius?
junction of 1st rib & its costal cartilage
what is the distal attachment of subclavius?
inferior surface of middle 1/3 of clavicle
what are the actions of subclavius?
anchors and depresses clavicle
what are the motor & sensory innervation of subclavius?
“nerve to subclavius”
what group of muscles attach the scapula to the humerus & move the humerus at the shoulder joint and contribute to the stabilization of this joint?
scapulohumeral (intrinsic) musculature
what innervates all of the scapulohumeral musculature?
brachial plexus
what muscles are included in the scapulohumeral musculature?
-deltoid
-teres major
-subscapularis
-supraspinatus
-infraspinatus
-teres minor
what are the rotator cuff muscles?
-subscapularis
-supraspinatus
-infraspinatus
-teres minor
ID muscle
deltoid
what is the proximal attachment of deltoid?
-lateral 1/3 of clavicle
-acromion
-spine of scapula
what is the distal attachment of deltoid?
deltoid tuberosity of humerus
what are the actions of deltoid?
-flexes, medially rotates, abducts, extends, and laterally rotates humerus
what is the innervation of the deltoid?
axillary nerve
ID muscle
teres major
what is the proximal attachment of teres major?
posterior surface of inferior angle of scapula
what is the distal attachment of teres major?
medial lip of intertubercular groove of humerus
what are the actions of teres major?
abducts and medially rotates humerus
what is the motor & sensory innervation of teres major?
lower subscapular nerve
which two muscles both attach to medial lip of intertubercular sulcus of humerus?
latissimus dorsi and teres major
ID muscle
supraspinatus
what is the proximal attachment of supraspinatus?
supraspinous fossa of scapula
what is the distal attachment of supraspinatus?
superior facet of greater tubercle of humerus
what are the actions of supraspinatus?
works with deltoid in abduction of humerus & acts with other rotator cuff muscles in stabilizing shoulder joint
what are the motor & sensory innervation of supraspinatus?
suprascapular nerve
ID muscle
infraspinatus
what is the proximal attachment of infraspinatus?
infraspinous fossa of scapula
what is the distal attachment of infraspinatus?
middle facet of greater tubercle of humerus
what are the actions of infraspinatus?
laterally rotates humerus & helps hold humeral head in place
what are the motor & sensory innervation of infraspinatus?
suprascapular nerve
ID muscle
teres minor
what is the proximal attachment of teres minor?
middle part of lateral border of scapula
what is the distal attachment of teres minor?
inferior facet of greater tubercle of humerus
what are the actions of teres minor?
laterally rotates humerus & helps hold humeral head in place
what is the motor & sensory innervation of teres minor?
axillary nerve
what two muscles are innervated by axillary nerve?
-deltoid
-teres minor
ID muscle
subscapularis
what is the proximal attachment of subscapularis?
subscapular fossa (anterior surface of scapula)
what is the distal attachment of subscapularis?
lesser tubercle of humerus
what are the actions of subscapularis?
medially rotates and adducts humerus helps hold humeral head in place
what are the motor & sensory innervation of subscapularis?
upper & lower subscapular nerves
