Upper Limb Muscles of the Shoulder Region Flashcards
What are the superficial muscles of the extrinsic shoulder?
Trapezius and latissimus dorsi.
What are the deep muscles of the extrinsic shoulder?
Levator scapulae and rhomboid minor and major.
What are the proximal attachments of the trapezius?
Medial third of superior nuchal line, external occipital proturberance, nuchal ligament, spinous processes of C7-T12 vertebrae.
What are the distal attachments of the trapezius?
Lateral third of clavicle, acromion and spine of scapula.
What is the trapezius innervated by?
Spinal accesssory nerve and C3, C4 spinal nerves.
What is the arterial supply of the trapezius?
Transverse cervical artery.
What is the action of the trapezius?
Descending part elevates, ascending part depresses and the middle part retracts scapula. Descending and ascending parts act together to rotate the glenoid cavity superiorly.
What are the proximal attachments of the latissimus dorsi?
Spinous processes of inferior 6 thoracic vertebrae, thoracolumbar fascia, iliac crest, and inferior 3/4 ribs.
What is the distal attachment of the latissimus dorsi?
Floor of the intertubercular sulcus of humerus.
What is the latissimus dorsi innervated by?
Thoracodorsal nerve (C6, C7, C8).
What is the arterial supply of the latissimus dorsi?
Thoracodorsal artery.
What is the action of the latissimus dorsi?
Extends, adducts, and medially rotates humerus, raises body towards arms during climbing.
What are the proximal attachments of the levator scapulae?
Posterior tubercles of transverse processes of C1-C4 vertebrae.
What is the distal attachment of the levator scapulae?
Medial border of scapula superior to root of scapula spine.
What is the levator scapulae innervated by?
Dorsal scapula (C4, C5) and cervical (C3, C4) nerves.
What is the arterial supply of the levator scapulae?
Transverse cervical artery and ascending cervical artery.
What is the action of the levator scapulae?
Elevates scapula and rotates its glenoid cavity inferiorly by rotating scapula.
What is the proximal attachment of the rhomboid major?
Spinous processes of T2-T5 vertebrae.
What is the distal attachment of the rhomboid major?
Medial border of the scapula from level of spine to inferior angle.
What is the rhomboid major innervated by?
Dorsal scapula nerve (C4, C5).
What is the arterial supply of the rhomboid major?
Dorsal scapular artery.
What is the action of the rhomboid major?
Retract the scapula and rotate its glenoid cavity inferiorly, fix scapula to thoracic wall.
What are the proximal attachments of the rhomboid minor?
Nuchal ligament and spinous processes of C7 and T1 vertebrae.
What is the distal attachment of the rhomboid minor?
Smooth triangular area at medial end of scapula spine.
What is the rhomboid minor innervated by?
Dorsal scapular nerve (C4, C5).
What is the arterial supply of the rhomboid minor?
Dorsal scapular artery.
What is the action of the rhomboid minor?
Retract the scapula and rotate its glenoid cavity inferiorly, fix scapula to thoracic wall.
How can the accessory nerve be tested?
By assessing the trapezius function, ask the patient to shrug their shoulders.
What are the intrinsic shoulder muscles?
Scapulohumeral muscles: deltoid, supraspinatous, infraspinatous, teres minor, teres major, subscapularis.
What are the proximal attachments of the deltoid?
Lateral third of clavicle, acromion and spine of scapula.
What is the distal attachment of the deltoid?
Deltoid tuberosity of the humerus.
What is the deltoid innervated by?
Axillary nerves (C5, C6).
What is the arterial supply of the deltoid?
Posterior circumflex humeral artery.
What is the action of the deltoid?
Clavicular part flexes and medially rotates arm. Acromial part abducts arm. Spinal part extends and laterally rotates arm.
What is the proximal attachment of the supraspinatous?
Supraspinous fossa of scapula.
What is the distal attachment of the supraspinatous?
Superior facet of greater tubercle of humerus.
What is the supraspinatous innervated by?
Suprascapular nerve (C4, C5, C6).
What is the arterial supply of the supraspinatous?
Suprascapular artery.
What is the action of the supraspinatous?
Initiates and assists deltoid in abduction of arm and acts with rotator cuff muscles.
What is the proximal attachment of the infraspinatous?
Infraspinous fossa of scapula.
What is the distal attchament of the infraspinatous?
Middle facet of greater tubercle of humerus.
What is the infraspinatous innervated by?
Suprascapular nerve (C5, C6).
What is the arterial supply of the infraspinatous?
Circumflex scapular artery and suprascapular artery.
What is the action of the infraspinatous?
Laterally rotates arm and acts with rotator cuff muscles.
What is the proximal attachment of the teres minor?
Middle part of lateral border of scapula.
What is the distal attachment of the teres minor?
Inferior facet of greater tubercle of humerus.
What is the teres minor innervated by?
Axillary nerve (C5, C6).
What is the arterial supply of the teres minor?
Circumflex scapular artery and posterior circumflex humeral artery.
What is the action of the teres minor?
Laterally rotates arm and acts with rotator cuff muscles.
What is the proximal attachment of the teres major?
Posterior surface of inferior angle of the scapula.
What is the distal attachment of the teres major?
Medial lip of intertubercular sulcus of humerus.
What is the teres major innervated by?
Lower subscapular nerve (C5, C6).
What is the arterial supply of the teres major?
Circumflex scapular artery, subscapular artery.
What is the action of the teres major?
Adducts and medially rotates arm.
What is the proximal attachment of the subscapularis?
Subscapular fossa.
What is the distal attachment of the subscapularis?
Lesser tubercle of humerus.
What is the subscapularis innervated by?
Upper and lower subscapular nerves (C5, C6, C7).
What is the arterial supply for the subscapularis?
Subscapular artery.
What is the action of the subscapularis?
Medially rotates arm, as part of the rotator cuff, helps hold head of humerus in glenoid cavity.
What are the four rotator cuff muscles?
Supraspinatus, infraspinatus, supscapularis and teres minor.
What is the function of the rotator cuff muscles?
To pull the humeral head into the glenoid fossa to give the glenohumeral joint more stability.
What is rotator cuff tendonitis?
Inflammation of the tendons of the rotator cuff muscles.
What causes rotator cuff tendonitis?
Repetitive use of the shoulder joint.
Which of the rotator cuff muscles is most commonly affected by rotator cuff tendonitis?
Supraspinatus. In abduction, it rubs against the coracoacromial arch and this causes inflammation and degeneration in the tendon eventually.
How is rotator cuff tendonitis treatment?
Rest, analgesia, and physiotherapy. Steroid injections and surgery can be used in severe cases.
