Shoulder muscles Flashcards
Name the muscles on the anterior axio-appendicular compartment
Pectoralis major, pectoralis minor, subsclavius, and serratus anterior
What is the proximal attachment of the pectoralis major?
Clavicular head: anterior surface of the medial half of the clavicle
Sternocostal head: anterior surface of the sternum, superior 6 costal cartilages, and aponeuroses of the external oblique
What is the distal attachment of the pectoralis major?
Lateral lip of the intertubercular sulcus of the humerus
What is the innervation of the pectoralis major?
Lateral and medial pectoral nerves
What are the main actions of the pectoralis major?
Synergestically
- Adducts and medially rotates the shoulder joint
- Draws scapula inferiorly and anteriorly
Acting alone
- Clavicular head flexes the shoulder joint and sternocostal head
- Extends shoulder joint from flexed position
What is the proximal attachment of the pectoralis minor?
3rd - 5th rib near their costal cartilages
What is the distal attachment of the pectoralis minor?
Medial border and anterior surface of the coracoid process of scapula
What is the innervation of the pectoralis minor?
Lateral and medial pectoral nerves
What is the main action of the pectoralis minor?
Stabilizes the scapula by drawing it anteriorly and inferiorly against the thoracic wall
What is the proximal attachment of the subclavius?
At the junction of the 1st rib with its costal cartilage
What is the distal attachment of the subclavius?
Inferior surface at the middle third of the clavicle
What is the innervation of the subclavius?
Subclavian nerve
What are the main actions of the subclavius?
Anchors and depresses the clavicle
What is the proximal attachment of the serratus anterior?
External surface at the lateral part of 1st - 8th rib
What is the distal attachment of the serratus anterior?
Anterior surface of the medial border of the scapula
What is the innervation of the serratus anterior
Thoracolumbar nerve
What are the main actions of the serratus anterior?
Protract and rotate the scapula; as well as holding this against the thoracic wall
What are the main actions of the serratus anterior?
Protract and rotate the scapula; as well as holding this against the thoracic wall
Name the muscles on the posterior axio-appendicular compartment
Superficial layer: trapezius and latissimus dorsi
Deep layer: levator scapulae and rhomboids
What is the medial attachment of the trapezius?
- Medial third of superior nuchal line
- External occipital protuberance
- Spinous processes of C7 - T12
- Nuchal ligament
What is the lateral attachment of the trapezius?
- Lateral third of the clavicle
- Spine of scapula
- Acromion
What is the innervation of the trapezius?
Motor: spinal accessory
Pain and proprioception: C3, C4
What are the functions of the trapezius?
Ascending part: depress scapula
Descending part: elevate scapula
Middle part (or all parts together): retract the scapula
Ascending+descending: rotate glenoid cavity superiorly
What is the medial attachment of the latissimus dorsi?
- Thoracolumbar fascia
- Iliac crest
- Spinous processes of inferior 6 thoracic vertebrae
- Inferior 3 or 4 ribs
What is the lateral attachment of the latissimus dorsi?
Floor of the intertubercular sulcus of the humerus
What is the innervation of the latissimus dorsi?
Thoracodorsal nerve
What are the main function sof the latissimus dorsi?
Extend, adduct, and medially rotate the shoulder joint
What is the medial attachment of the levator scapulae?
Posterior tubercle on transverse processes from C1 - C4
What is the lateral attachment of the levator scapulae?
Medial border of the scapula, superior to the root of spine
What is the innervation of the levator scapula?
Dorsal scapular and cervical spinal nerves
What is the main function of the levator scapula?
Elevate scapula and rotate glenoid cavity inferiorly
What is the medial attachment of the rhomboids minor and major?
Minor: nuchal ligament and spinous processes of C7 and T1
Major: spinous processes from T2-T5
What is the lateral attachment of the rhomboids minor and major?
Minor: medial border of the scapula at the medial end of the scapular spine
Major: medial border of scapula from the level of the spine to the inferior angle of this
What is the innervation of the rhomboids?
Dorsal scapular nerve
What are the main functions of the rhomboids?
Retracts scapula and rotate glenoid cavity inferiorly; as well as fixing the scapula against the thoracic wall
Name the scapulohumeral muscles
Deltoid, supraspinatus, infraspinatus, teres minor, teres major, and subscapularis
What is the proximal attachment of the deltoid?
- Lateral third of the clavicle
- Acromion
- Spine of scapula
What is the distal attachment of the deltoid?
Deltoid tuberosity of humerus
What is the innervation of the deltoid?
Axillary nerve
What are the main functions of the deltoid?
Clavicular head: flex and medially rotate shoulder joint
Acromial head: abduct shoulder joint
Spinal head: extend and laterally rotate shoulder joint
What is the proximal attachment of the supraspinatus?
Supraspinous fossa of the scapula
What is the proximal attachment of the infraspinatus?
Infraspinous fossa of the scapula
What is the proximal attachment of the teres minor?
Middle part of the lateral border of the scapula
What is the distal attachment of the supraspinatus, infraspinatus, and teres minor?
Greater tubercle of the humerus
What is the innervation of the supraspinatus and infraspinatus?
Suprascapular nerve
What are the main functions of the supraspinatus?
Initiates and assists the deltoid in abducting the shoulder joint; also acts with other rotator cuff muscles
What are the main functions of the infraspinatus and teres minor?
Laterally rotate the shoulder joint; help hold humeral head in glenoid cavity
What are the innervation of the teres minor?
Axillary neve
What is the proximal attachment of teres major?
Inferior part of the lateral border of the scapula and the posterior surface of the inferior angle of the scapula
What is the distal attachment of teres major?
Medial lip of the intertubercular sulcus of the humerus
What is the innervation of the teres major?
Lower subscapular nerve
What is the proximal attachment of the subscapular muscle?
Subscapular fossa of scapula
What is the distal attachment of the subscapular muscle?
Lesser tubercle of the humerus
What is the innevation of the subscapular?
Upper and lower subscapular nerves
What are the main functions of the subscapular muscle?
Medially rotates and adducts shoulder joint; helps hold humeral head in glenoid cavity
What is the main function of the teres major?
Adducts and medially rotates the shoulder joint
