scapular region, scapulohumeral muscles, arm

anconeus

Assists triceps in extending forearm, stabilizes elbow joint, abducts ulna during pronation; Innervated by radial nerve

teres major

Attachments: posterior surface of inferior angle of scapula, medial lip of intertubercular groove of humerus Adducts and medially rotates arm Innervated by lower subscapular nerve (branch of the posterior cord)

brachialis

Flexes forearm in all positions Innervated by musculocutaneous nerve

deltoid

Has proximal attachments to the clavicle, acromion, and spine of the scapula. Distal attachment is to the deltoid tuberosity of the humerus. Actions: Clavicular head—flexes and medial rotates arm Acromial head—abducts arm Spinal head—extends and laterally rotates arm When all three parts contract simultaneously the arm is abducted. Innervated by the axillary nerve (a terminal branch of the posterior cord of the brachial plexus)

coracobrachialis

Helps flex and adduct arm Innervated by musculocutaneous nerve

supraspinatus

Initiates and assists deltoid in abduction of arm Innervated by suprascapular nerve (from superior trunk of BP)

teres minor

Laterally rotates arm, holds head of humerus in glenoid cavity Innervated by axillary nerve (from posterior cord of BP)

infraspinatus

Laterally rotates arm, holds head of humerus in glenoid cavity Innervated by suprascapular nerve (see supraspinatus)

subscapularis

Medially rotates and adducts arm Innervated by upper and lower subscapular nerves (from posterior cord of BP)

biceps brachii

Supinates forearm, flexes forearm when it is supinated, flexes arm Innervated by musculocutaneous nerve

arterial anastomosis around the scapula

The blood supply to the shoulder and scapula is derived from the dorsal scapular and suprascapular arteries (direct or indirect branches of the subclavian artery) and the circumflex scapular branch of the subscapular artery (a branch of the 3rd part of the axillary artery). These arteries contribute to clinically important alternate (anastomotic) routes of blood flow around the should joint.

rotator cuff muscles (lateral oblique view)

The rotator cuff muscles form a musculotendinous sleeve around the glenohumeral joint. Their health is critical for stability of the shoulder joint. Three of the muscles (subscapularis, infraspinatus, and teres minor) are rotators of the humerus. The supraspinatus initiates (first 15° of movement) and assists the deltoid in abduction of the upper limb.

anterior compartment of the arm

biceps brachii, coracobrachialis, brachialis

_______ circulation around the scapula/shoulder is supplied by branches of the _______ and _______ arteries.

collateral; axillary; subclavian

The four scapulohumeral muscles that form the rotator cuff are commonly damaged (e.g., _______ tendinitis or a rupture or tear of the _______ tendon), causing instability in the glenohumeral joint.

degenerative; supraspinatus

triceps brachii

extends forearm, long head extends arm; innervated by radial nerve

Muscles in the anterior and posterior compartments of the arm act on the shoulder and/or elbow joint(s). Anterior compartment muscles are _______ (the biceps brachii also supinates the forearm), are innervated by the ______________ nerve, and receive their blood supply from branches of the _______ artery. The posterior compartment muscles are _______ (the triceps brachii and anconeus), are innervated by the radial nerve, and supplied by the deep brachial (profunda brachii) artery.

flexors; musculocutaneous; brachial; extensors

Six scapulohumeral muscles connect the scapula to the humerus and act on the _______ joint. These muscles receive their innervation and blood supply from branches of the brachial plexus and _______ and _______ arteries.

glenohumeral; axillary; subclavian

scapulohumeral muscles

join the scapula and humerus and act on the glenohumeral joint. six muscles - deltoid, teres major, subscapularis, supraspinatus, infraspinatus, teres minor

humerus fractures

portions of the radial nerve and deep (profunda) brachial artery in the radial groove are in danger of damage when the midshaft of the humerus is fractured

Due to their location, the _______ nerve and _______ brachial artery may be damaged when the _______ of the humerus is fractured.

radial; deep; midshaft

pectoral girdle

scapulae and clavicles form the pectoral girdle, which is completed anteriorly by the manubrium of the sternum but is incomplete posteriorly. the clavicles connect the upper limbs to the axial skeleton. they articulate with the manubrium of the sternum (sternoclavicular joints) medially, and the acromia of the scapulae (acromioclavicular joints) laterally

The pectoral girdle includes the _______ and _______. The sternoclavicular joint is the sole connection between the upper limb and _______ skeleton.

scapulae; clavicles; axial

rotator cuff muscles

subscapularis, supraspinatus, infraspinatus, teres minor

posterior compartment of the arm

triceps brachii, anconeus