Muscles of the Shoulder Flashcards
These muscles cross the shoulder joint to insert in the arm and therefore actually move the arm.
Muscles of the shoulder
The 6 intrinsic shoulder muscles
Deltoid, Infraspinatus, subscapularis, supraspinatus,teres major, teres minor
Large fan shaped muscle that covers superior part of thorax
Pectoralis Major
Muscle of the shoulder that has two heads, on clavicular and one sternum forming the anterior wall of the axilla (anterior axillary wall)
Pectoralis Major
This muscle is a powerful adductor of the arm and medial rotator of the humerus, and its two parts can activate separately
Pectoralis Major
Originates at clavicle, sternum, and ribs 1-6 cartilage
Inserts into intertubercular sulcus of the humerus
Pectoralis Major
Innervated by the lateral and medial pectoral nerves, which arise from the brachioplexus
Pectoralis Major
Flexus, adducts, and rotates the humerus medially
Pectoralis Major
Widest muscle on the posterior side of the thorax, covers half of back (trunk) and inserts into the humerus
Latissimus Dorsi
Forms the posterior axillary fold
Latissimus Dorsi
Extends, Retracts, and rotates the humerus medially
Ex: touching scapula on the opposite side
Latissimus Dorsi
Powerful adductor of the humerus when working with the pectoralis major.
Ex: Important in restoring the upper limb to the shoulder from an abducted position like in climbing
Latissimus Dorsi
Raises the trunk to the arm like pullups
Latissimus Dorsi
Originates at thoracolumbar, or lumbardorsal fascia
Latissimus Dorsi
A wide band of fascia, like an aponeurosis that originates of spinous processes of T7-T12, the lumbar vertabrae, iliac crest, and sometimes the inferior angle of the scapula
Lumbodorsal Fascia
Inserts into intertubercular groove of the humerus
Latissimus Dorsi
Innervated by the thoracodorsal nerve
Latissimus Dorsi
Extends retracts and rotates the humerus medially and is a powerful adductor and depresses the shoulder
Latissimus Dorsi
Good area to hear the lungs because its not covered by muscle, good for identifying muscles
Triangle of Ausculation
Rounded part of the shoulder, shaped like triangle, divided into three parts
Deltoid
Anterior fibers in deltoid aid the pectoralis major in
flexing the arm and medial rotation
Posterior fibers of deltoid aid the latissimus dorsi with
extending the arm and lateral rotation
Posterior and anterior fibers do what to the arm while walking?
Swings the arm
Stabilizes the shoulder joint by holding the head of the humerus in the glenoid cavity during shoulder movement
Deltoid
Involved in abductory movement esp avove 15 degrees
Deltoid
Axillary nerve runs deep to it from behind
Deltoid
Originates from the lateral one third of clavicle, acromion process, and the lateral aspect of the spine of the scapula
Inserts into deltoid tuberosity on humerus
Deltoid
Muscle that is trianglular and fills in the subscapular fossa and inserts into the lesser tubercle
Subscapularis
This rotator cuff muscle is the primary medial rotator of the arm
Subscapularis
Rotator cuff muscles do what to the humerus in the glenoid cavity?
Hold the head inside of it
Helps to form part of posterior axillary fold along with latissimus dorsi
Subscapularis
Origin is from the deep side of the scapula - the subscapular fossa (costal surface of the scapula) and inserts and at the lesser tubercle
Subscapularis
Inervated by the subscapular nerve
Subscapularis
Occupies the supraspinous fossa and inserts into the greater tubercle of the humerus
Supraspinatous
To view this muscle, the trapezius and the deltoid must be reflected
Supraspinatus
Muscle that initiates abduction until 15 degrees away from body.
Supraspinatus
Origin is supraspinous fossa and insertion is in the greater tubercle of the humerus.
Supraspinatus
Innervated by the suprascapular nerve
Supraspinatus
Also helps to stabilize the shoulder during rotation
And prevents downward dislocation of the humerus when carrying a suitcase
Supraspinatus
Muscle that occupies the infraspinous fossa and inserts into the greater tubercle of the humerus.
Infraspinatus
Also must reflect the deltoid and the trapezius for this muscle
Infraspinatus
A powerful lateral rotator of the humerus
Originates from infraspinus fossa of the scapula and inserts in the greater tubercle just posterior to the supraspinatus
Infraspinatus
Innervated by the suprascapular nerve
Infraspinatus
Narrow muscle that is not distinct from infraspinatus having the same action as the infraspinatus
Teres Minor
Origin is on the lateral border of the posterior surface of the scapula and insertion is on the greater tubercle, posterior to the infraspinatus
Teres minor
Innervated by the axillary nerve and has same action as infraspinatus (rotates laterally and stabilizes)
Teres minor
Rotator cuff muscles can also be called
Scapulohumeral muscles
Have a steadying effect on the head of the humerus and rotate in the glenohumeral joint
Rotator Cuff
All muscles of rotator cuff help rotate the humerus except the…
supraspinatus
All 4 rotator cuff muscles do this to hold the humeral head
Tonic contraction
The most commonly injured injury occurs with the…
Supraspinatus
Tearing of this muscle may follow dislocation of the humerus and
degenerative tendonitis is common in older people
ex of injury: Violently pushing into abduction like checking a shoulder into a board or throwing the ball hard or swimming.
rotator cuff muscle
To diagnose, person is asked to lower their arm from a 90 degree angle. If injured, limb will quickly drop to the side.
Rotator cuff muscle
Thick cylinder shaped muscle, forms rounded area on the inferior lateral third of scapula when arm is abducted against resistance and helps form posterior axillary fold with the latissimus dorsi
Teres Major
Adducts and medially rotates the arm and is important stabilizer of humeral head by holding it in place against the pull of the deltoid
Teres Major
Originates off the posterior surface of the scapula along the inferior angle and nserts into the intertubercular sulcus of the humerus and the tendon fuses with the latissimus dorsi
Teres Major
Innervated by the subscapular nerve
Teres Major
Adducts extends and medially rotates the arm, like the lattisimus dorsi
Teres major
Name the three muscles that insert in the intertubercular sulcus. There is a major on both sides.
Pectoralis Major (laterally) Latissimus Dorsi (intermediate) Teres Major (medial)
Extends from the corocoid process to the brachium
Coracobrachialis
The musculocutaneous nerve runs right through it
Coracobrachialis
Originates from the corocoid process and inserts on medial surface of the humerus.
Coracobrachialis
Flexes and adducts the arm
Coracobrachialis
