Quiz 5: Axilla, Pectoral, Shoulder region

Pectoralis major Origin

clavicular head: anterior surface of medial half of clavicle

sternocostal head: anterior surface of sternum, upper 7 costal cartilages, sternal end of 6th rib, aponeurosis of external oblique muscle

Pectoralis major insertion

lateral lip of intertubercular groove of humerus

Pectoralis major innervation

lateral and medial pectoral nerves

clavicular head: C5-C6

sternocostal head: C6-T1

Pectoralis major action

adduction and medial rotation of arm at glenohumeral joint

clavicular head: flexes an extended arm

sternocostal head: extends a flexed arm

Pectoralis minor origin

ribs 3-5 and deep fascia related to intercostal muscles

Pectoralis minor insertion

Coracoid process

Pectoralis minor innervation

medial pectoral nerve (C5-T1)

Pectoralis minor action

depress scapula

tilts scapula anteriorly

secondary protractor of scapula, elevates ribs (accessory muscle of inspiration)

Subclavius origin

1st rib

Subclavius insertion

groove on inferior surface of middle third of clavicle

Subclavius innervation

nerve to subclavius (C5, C6)

Subclavius action

depress scapula

pulls clavicle medially to stabilize sternoclavicular joint

tilt scapula anteriorly

Serratus anterior origin

lateral surfaces of ribs 1-8 and deep fascia of related intercostal muscles

Serratus anterior insertion

costal surface of medial border of scapula

Serratus anterior innervation

Long thoracic nerve (C5,C6,C7)

Serratus anterior action

Protracts scapula

rotates scapula upward (glenoid-up); keeps medial border & inferior angle of scapula opposed to thoracic wall

Interclavicular Ligament attachment 1

Medial right clavicle

Interclavicular ligament attachment 2

Medial left clavicle

Interclavicular ligament taut in

Depression of clavicles

Anterior sternoclavicular ligament attachments 1 & 2

Anterior thickening of sternoclavicular joint capsule

Anterior sternoclavicular ligament taut in

Retraction of clavicle

Posterior sternoclavicular ligament attachments 1 & 2

Posterior thickening of sternoclavicular joint capsule

Posterior sternoclavicular ligament taut in

Protraction of clavicle

Costoclavicular (anterior & posterior bundles) attachment 1

Cartilage of 1st rib

Costoclavicular (anterior & posterior bundles) attachment 2

Costal tuberosity on inferior clavicle

Costoclavicular (anterior & posterior bundles) taut in

All options EXCEPT depression

Coracoclavicular ligament attachments

- conoid

- trapezoid

• medial side of coracoid process

• Conoid tubercle; trapezoid line

Coracoclavicular ligament function

- conoid

- trapezoid

Functions to stabilize acromioclavicular

joint & suspend scapula

Coracoclavicular ligament taut in

- conoid

- trapezoid

Upward rotation of scapula

Inferior/medial force to acromion process

Superior & Inferior acromioclavicular ligament attachments

Superior and inferior thickenings of the acromioclavicular joint capsule (between the Lateral end of the clavicle and the Acromion process)

Superior & Inferior acromioclavicular ligament taut in

Inferior/medial force to acromion process

Coracoacromial ligament attachments

• Lateral coracoid

• acromion process

Coracoacromial ligament taut in

Upward translation of the humerus

Coracohumeral ligament attachments

• Coracoid process: lateral side of

  base

• Anterior side of greater tubercle

  of humerus

Coracohumeral ligament taut in

Adduction of humerus; inferior translation

of humeral head; external rotation of

humerus

Superior Glenohumeral Ligament attachments

• Supraglenoid tubercle

• Anatomic neck above lesser

  tubercle

Superior Glenohumeral Ligament taut in

Adduction of humerus; inferior and ant-

post translations of humeral head

Middle Glenohumeral Ligament attachments

• Superior/middle anterior rim of glenoid fossa

• Ant aspect of neck- blends with subscapularis tendon

Middle Glenohumeral Ligament taut in

Anterior translation of humeral head

especially in 45-60 deg abduction; external

rotation

Inferior Glenohumeral Ligament (anterior band; posterior band; maxillary pouch) attachments

• Anteroinferior rim of glenoid fossa

• Broad sheet to Anteroinferior and posteroinferior margins of anatomical neck

Inferior Glenohumeral Ligament (anterior band; posterior band; maxillary pouch) taut in

Anterior band: 90 deg abduction and full

external rotation; anterior translation

Posterior band: 90 deg abduction and full

internal rotation

Axillary pouch: 90deg abduction with ant-

posterior & inferior translations

Transverse Humeral Ligament attachments

• Greater tubercle

• Lesser tubercle

Transverse Humeral Ligament taut in

Maintains tendon of long head of biceps

brachii in bicipital groove