Shoulder, Arm, and Breast

Clavicle - connections

Connects upper limb to truck through sternoclavicular and acromioclavicular joints

Clavicle - 2 confusions on radiological imaging

1. Late fusion of epiphyseal plate at sternal end with main shaft of clavicle

2. Failure of 2 ossification centers in shapt to fuse (typically bilateral)

Clavicle - ends

Sternal end - round

Acromial end - flat

Sternoclavicular joint - type of joint

saddle synovial joint w/ articular disc; functions as a ball and socket joint

Sternoclavicular - articular surfaces

Sternal end of clavicle and the clavicular notch on the manubrium of the sternum

Sternoclavicular - movements

flexion/extension, adduction/abduction, circumduction, some rotation (med/lat)

Sternoclavicular - strength

very strong due to ligaments, clavicle is more likely to fracture that be dislocated

Acromioclavicular joint - type

plane synovial joint w/ articular disc

Acromioclavicular joint - articular surfaces

Acromial end of clavicle and the acromion process of the scapula

Acromioclavicular joint - movements

slight gliding

Sternoclavicular joint - type

joint is synovial articulation between sternal end of clavicle, manubrium and 1st rib

Anterior and posterior SC ligaments

Reinforce joint capsule

Interclavicular ligament

Runs between 2 sternal ends of clavicles (superior)

Costoclavicular ligament

Anchors inferior sternal end to first rib

Superior acromioclavicular ligament

From acromion to acromiol end of clavicle (strengthened by coracoclavicular ligament)

Coracoclavicular ligaments

1. Conoid ligament - coracoid process of scapula to conoid tubercle

2. Trapezoid ligament - coracoid process to trapezoid line of clavicle

Glenohumeral (shoulder joint) - type

Ball and socket synovial joint

Shoulder joint - Articular surfaces

Glenoid cavity of scapula with head of humerus

Shoulder joint - movements

Flexion/extension, adduction/abduction, circumduction, rotation

Coracohumeral ligament (of glenohumeral joint)

Coracoid process of the scapula to the greater tubercle of the humerus (strengthens capsule superiorly)

Transverse humeral ligament (of glenohumeral joint)

Greater tubercle to lesser tubercle of humerus, on top of the tendon of the long head of the biceps brachii (forms canal for tendon of long head of biceps)

Coracoacromial ligament (of glenohumeral joint)

Coracoid process to acromion process of the scapula (prevents superior dislocation of humeral head; humorous or clavicle will fracture instead)

Glenohumeral joint - ligaments

Reinforce anterior part of joint capsule

Glenohumeral joint - ligament attachments

Edge of the glenoid cavity to the anatomical neck of the humerus

Dislocation of AC joint

Hard fall on shoulder or outstretched upper limb (shoulder separation: Both AC and coracoclavicular ligaments torn)

Dislocation of glenohumeral joint

Typically inferior dislocation, but clinically termed anterior (common), or posterior (rarer). Depends on position relative to long head of triceps. Joint capsule and labrum can be ripped. Axillary nerve may be damaged

Superior/descending Trapezius

Attaches from nuchal ligament to acromion of scapula and clavicle

Superior/descending Trapezius Action

Elevates scapula

Middle trapezious

Attaches from spinous process of thoracic vertebrae to spine of scapula

Middle trapezious action

retracts scapula

inferior/ascending trapezius

Lower than middle, but still spinous process of thoracic vertebrae to spine of scapula

inferior/ascending trapezius action

Depresses scapula

trapezius innervation

Spinal acessory nerve (and anterior rami of C3-C4)

Latissimus dorsi

Attaches from spinous process of thoracic and lumbar vertebrae, iliac crest and lower ribs to intertubercular sulcus (bicipital groove) of humerus

Latissimus dorsi action

adduct, extend, medially rotate arm

Latissimus dorsi innervation

Thoracodorsal nerve (C6-C8)

Rhomboid major and minor attachment

Attach from spinous process of C7/T1 (minor) and upper thoracic vertebrae (major) to medial border of scapula

Rhomboid major and minor action

retract scapula

rhomboid major and minor innervation

Dorsal scapular nerve

Levator scapulae attachments

Transverse process of cervical vertebrae to medial border of scapula

Levator scapulae action

elevates scapula

levator scapulae innervations

Dorsal scapular nerve and anterior rami of C3-C4

Deltoid attachments

All attach from deltoid tuberosity of humerus. Anterior from clavicle. Middle from acromion of scapula. Posterior from spine of scapula.

Deltoid action

All resist inferior displacement of humeral head. Anterior flexes and medially rotates arm. Middle abducts arm (after first 15 degrees). posterior extends and laterally rotates arm.

Deltoid innervation

Axillary nerve (C5-C6)

Supraspinatus attachment

Attaches from supraspinous fossa of scapula to greater tubercle of humerus

Supraspinatus action

Abducts arm (initiates abduction - first 15 degrees). Rotator cuff muscle - hold humeal head in glenoid cavity.

Supraspinatus innervation

Suprascapular nerve (C5-C6)

infraspinatus attachments

Attaches from infraspinous fossa of scapula to greater tubercle of humerus

infraspinatus action

Laterally rotates arm. Rotator cuff muscle - holds humeral head in glenoid cavity.

Infraspinatus innervation

Suprascapular nerve (C5-C6)

Teres minor attachements

Attaches from lateral border of scapula to greater tubercle of humerus

Teres minor action

Laterally rotates arm. Rotator cuff muscle - holds humeral head in glenoid cavity.

Teres minor innervation

Axillary nerve (C5-C6)

Teres major attachments

Attaches from inferior angle of scapula to intertubercular sulcus (bicipital groove) of humerus

Teres major action

Adducts and medially rotates arm

Teres major innervation

Lower subscapular nerve (C5-C6)

Rotator cuff injury

Typically due to repetitive use of upper limb above horizontal. Supraspinatus is most commonly injured. Cannot abduct arm first 15 degrees. If arm abducted passively middle deltoid can complete action

Adhesive capsulitis of glenohumeral joint

Also called “Frozen Shoulder". Adhesive fibrosis and scarring between the rotator cuff, bursa, and deltoid (inflammation, dislocation, bicipital tendinitis. Patient has difficulty abducting the arm, but can elevate and rotate the scapula to compensate.

Triceps brachii attachments

All heads attach to olecranon process of ulna. Long head attaches to infraglenoid tubercle of scapula. Medial and lateral heads attach to shaft of humerus.

Triceps brachii action

All extend forearm. Long head also resists inferior displacement of humeral head.

Triceps brachii innervation

Radial nerve (C6-C8)

Serratus anterior (ventralis) attachment

Attaches from lateral surface of ribs to medial border of scapula

Serratus anterior action

protracts scapula, stabilizes scapula against thoracic wall

Serratus anterior innervation

Long thoracic nerve (C5-C7)

Paralysis of serratus anterior (winged scapula)

If long thoracic nerve is injured medial border of scapula moves laterally and posteriorly away from thoracic wall. Arm cannot be abducted above horizontal position. Serratus anterior cannot rotate glenoid cavity to allow abduction.

• can be durring mastectomy

Subscapularis (anterior) Attachments

Attaches from subscapular fossa of scapula to lesser tubercle of humerus

Subscapularis actions

Medially rotates arm (rotator cuff muscle: holds humeral head in glenoid cavity)

Subscapularis innervations

upper and lower subscapular nerves (C5-C6)

Coracobrachialis Attachments

Attaches from coracoid process of scapula to shaft of humerus

Coracobrachialis action

Flexes and adducts arm, resists inferior displacement of humeral head

Coracobrachialis innervation

Musculocutaneous nerve (C5-C7)

Biceps brachii attachments (together and of both heads)

Both attach to tuberosity of radius and bicipital aponeurosis. Short head: coracoid process of scapula. Long head: supraglenoid tubercle of scapula.

Biceps brachii actions (together and of short head)

Supinates forearm, flexes forearm when supinated. Short head: resists inferior displacement of humeral head.

Biceps brachii innervation

Musculocutaneous nerve (C5-C7)

Brachialis Attachments

Attaches from shaft of humerus to coronoid process of ulna and tuberosity of ulna

Brachialis action

Flexes forearm

Brachialis innervation

Musculocutaneous nerve (C5-C7) and radial nerve (C5-C7)

Pectoralis major attachments

Attaches from clavicle (head) or sternum and costal cartilages (head) to intertubercular sulcus (bicipital groove) of humerus.

Pectoralis major actions (both, and heads)

Both: adduct and medially rotate arm. Clavicular head flexes arm. Sternocostal head extends arm from flexed position.

Pectoralis major innervations

Both heads: Lateral pectoral nerve (C5-C7). Medial pectoral nerve (C8-T1) also innervates sternocostal head.

pectoralis minor attachments

Attaches from upper ribs to coracoid process of scapula

pectoralis minor action

Elevates upper ribs, syabilizes scapula against thoracic wall

pectoralis minor innervation

Medial pectoral nerve (C8-T1)

Subclavius attachment

Attaches from clavicle to first rib

Subclavius action

Depress clavicle

subclavius innervation

Nerve to subclavius (C5-C6)

Breast - Mammary glands

• production of milk

• modified sweat glands

Breast - Lactiferous ducts and sinuses

ducts-channel milk to nipple

sinus-store milk

Breast - Suspensory ligaments

Attach skin to deep fascia over pectoralis major

blood supply and drainage of medial breast

Internal thoracic artery (subclavian) and medial mammary branches [vein=same]

blood supply and drainage of superior breast

Pectoral branch of thoracoacromial trunk (axillary) [vein=same]

blood supply and drainage of lateral breast

Lateral thoracic artery (axillary) [vein=same]

Lymphatic of breast laterally drains to…

• axillary and clavicular lymph nodes

• subclavian trunk

Lymphatic of breast medially drains to…

• parasternal lymph nodes

• bronchomediastinal trunk

lymphatic of brest inferiorly drains to…

• Abdominal (subdiaphragmatic) lymph nodes

• intestinal trunk

Breast changes/cancer

• Carcinoma most common in superolateral quadrant

• breasts change due to age, hormones, pregnancy/nursing

• cancer is usually adenocarcinoma (epithelium of lactiferous ducts)

• Tumor pressing on suspensory ligaments can cause dimpling

• Edema (excess fluid) can cause abnormal contours or orange peel appearance

Humorous - red and orange

red - greater tubercle

orange - bicipital groove

humerus - green and blue

green - radial fossa

blue - capitulum

humerus - yellow and purple

yellow - head of humerous

purple - anatomical neck