Upper Extremity - Anatomy Practical 1

NAU OTD

Subscapularis

Origin: Subscapular fossa of scapula.

Insertion: Lesser tubercle of humerus.

Action: Medially rotates and stabilizes arm at glenohumeral (shoulder) joint.

Innervation: Upper and lower subscapular nerves (C5-C7).

Serratus Anterior

Origin: External surfaces of first to ninth ribs

Insertion: Medial border of scapula.

Action: Protracts and upwardly rotates pectoral (shoulder) girdle at acromioclavicular and sternoclavicular joints.

Innervation: Long thoracic nerve (C5-C7).

Pectoralis Major

Origin: Clavicular head: anterior aspects of medial half of clavicle

Sternocostal head: manubrium, sternal body, the true ribs and their costal cartilages

Abdominal part: external abdominal oblique aponeurosis.

Insertion: Crest of greater tubercle of humerus.

Action: Adducts, medially rotates, and transversely adducts arm at glenohumeral (shoulder) joint; depresses pectoral (shoulder) girdle at acromioclavicular and sternoclavicular joints.

Innervation: Medial and lateral pectoral nerves (C5-T1)

Pectoralis Minor

Deep to pectoralis major

Origin: Anterior ends of third to fifth ribs.

Insertion: Coracoid process of scapula.

Action: Protracts and downwardly rotates pectoral (shoulder) girdle at acromioclavicular and sternoclavicular joints.

Innervation: Medial and lateral pectoral nerves (C5-T1).

Supraspinatus

Origin: Supraspinous fossa of scapula.

Insertion: Greater tubercle of humerus.

Action: Abducts and stabilizes arm at glenohumeral (shoulder) joint.

Innervation: Suprascapular nerve (C5-C6)

Infraspinatus

Origin: Infraspinous fossa of scapula.

Insertion: Greater tubercle of humerus.

Action: Laterally rotates, transversely abducts, and stabilizes arm at glenohumeral (shoulder) joint.

Innervation: Suprascapular nerve (C5-C6)

Teres Minor

Origin: Posterior aspect of superior half of lateral border of scapula.

Insertion: Greater tubercle of humerus.

Action: Laterally rotates, transversely abducts, and stabilizes arm at glenohumeral (shoulder) joint.

Innervation: Axillary nerve (C5-C6)

Teres Major

Origin: Posterior aspect of inferior angle of scapula.

Insertion: Crest of lesser tubercle of humerus.

Action: Adducts and medially rotates arm at glenohumeral (shoulder) joint.

Innervation: Lower subscapular nerve (C5-C7)

Scapula

It articulates with:

humerus at the glenohumeral (shoulder) joint

clavicle at the acromioclavicular joint.

Sternoclavicular Joint

Only true bony articulation between axial and appendicular skeleton

Acromioclavicular Joint

Formed between the acromion of the scapula and he acromial end of the clavicle

pink structure

Coracoid Process

thick, curved, anterior projection that extends from the head and neck of the scapula

pink structure

Lesser tubercle of the humerus

Insertion site for subscapularis

pink structure

Greater tubercle of the humerus

Insertion site for supraspinatus, infraspinatus, and teres minor

green structure

Bicipital Groove

Long head of biceps brachii

Origin: Supraglenoid tubercle of scapula.

Insertion: Radial tuberosity and antebrachial fascia (the screenshot clips the end of this line, so “antebrachial” is cut off at the edge).

Action: Supinates forearm; flexes forearm at elbow joint, most effectively when the forearm is supinated. (The word “at” is partly clipped at the right edge.)

Innervation: Musculocutaneous nerve (C5-C6)

Posterior Deltoid

Origin: Spine of scapula.

Insertion: Deltoid tuberosity of humerus.

Action: Extends, laterally rotates, and transversely abducts arm at glenohumeral (shoulder) joint.

Innervation: Axillary nerve (C5-C6).

Middle Deltoid

Origin: Acromion of scapula.

Insertion: Deltoid tuberosity of humerus.

Action: Abducts arm at glenohumeral (shoulder) joint.

Innervation: Axillary nerve (C5-C6)

Anterior Deltoid

Origin: Lateral one third of clavicle.

Insertion: Deltoid tuberosity of humerus.

Action: Flexes and medially rotates arm at glenohumeral (shoulder) joint.

Innervation: Axillary nerve (C5-C6).

Coracobrachialis

Origin: Coracoid process of scapula.

Insertion: Middle third of medial aspect of humerus.

Action: Adducts and flexes arm at glenohumeral (shoulder) joint.

Innervation: Musculocutaneous nerve (C5-C7)

Tricep Brachii

Origin: Posterior surface of humerus and infraglenoid tubercle of scapula.

Insertion: Olecranon process of ulna and adjacent antebrachial fascia.

Action: Extends forearm at elbow joint.

Innervation: Radial nerve (C6-C8)

Clavicle

Acromial end, body, sternal end

Humerus

Head, anatomical neck, greater and lesser tubercles, body, and condyle of humerus.

Articulates With: Scapula, radius, and ulna.