Is convex anteriorly at the sternal end (medial ⅔ rds) and concave anteriorly at the acromial end (lateral ⅓ rd)

Provides for the attachment of four muscles:

• Pectoralis major

• Deltoid

• Trapezius

• Sternocleidomastoid

Transmits force from the upper limb to the axial skeleton

Is paired

Is frequently fractured

Is flat and triangular in shape

Is paired

Has numerous parts:

• Costal surface—provides attachment for subscapularis

• Spine—provides attachment for trapezius and deltoid

• Acromion—provides attachment for trapezius and deltoid and articulates with clavicle

• Glenoid cavity—articulates with the head of the humerus

• Supraglenoid tubercle—provides attachment for the long head of the biceps brachii

• Infraglenoid tubercle—provides attachment for the long head of the triceps brachii

• Scapular notch—is crossed superiorly by the transverse scapular ligament; suprascapular n. passes inferior to ligament while suprascapular vv. pass superior to ligament

• Coracoid process—provides attachment for pectoralis minor, short head of biceps brachii, and coracobrachialis

Articulates with the scapula, ulna, and radius

Also known as the arm

Longest bone of the upper limb

Has eight centers of ossification

Has 16 major parts:

• Head’smooth surface that articulates with the glenoid cavity of the scapula

• Anatomical neck—oblique passing groove that provides attachment for the articular capsule

• Greater tubercle—provides attachment for 3 rotator cuff muscles: supraspinatus, infraspinatus, and teres minor

• Lesser tubercle—provides attachment for 1 rotator cuff muscle: subscapularis

• Intertubercular groove—between greater and lesser tubercles; long head of the biceps brachii located in groove

• Surgical neck—axillary nerve and posterior humeral circumflex vv. lie in contact with medial portion of surgical neck

• Radial groove—posterior surface of humerus where radial n. and profunda brachii vv. are located

• Deltoid tuberosity—provides attachment of deltoid

• Capitulum—rounded distal end of the lateral humerus that provides articulation with the radius (head)

• Trochlea—pulley-shaped distal end of the medial humerus that provides articulation with the ulna (trochlear notch)

• Olecranon fossa—depression on posterior humerus superior to trochlea; provides area for olecranon process of ulna to occupy during extension of antebrachium

• Coronoid fossa—depression on anterior humerus superior to trochlea that provides area for coronoid process to occupy during flexion of antebrachium

• Radial fossa—depression on anterior humerus superior to capitulum that provides area for radius (head) during flexion of antebrachium

• Supracondylar ridges’sharp elevations of bone on lateral portion of distal humerus that provides attachment of brachial fascia

• Medial epicondyle—elevation at distal part of medial supracondylar ridge; ulnar n. and superior ulnar collateral vv. are located posterior

• Lateral epicondyle—elevation at distal part of lateral supracondylar ridge

Articulates with capitulum of humerus superiorly

Articulates with scaphoid and lunate inferiorly

Is shorter than ulna

Is frequently fractured at distal end (Colles fracture)

Has 3 major anatomical structures:

• Head—proximal end of radius; provides articulation with capitulum of humerus

• Radial tuberosity—provides attachment for biceps brachii

• Styloid process—provides attachment for brachioradialis

Articulates with trochlea of humerus

Has 6 major anatomical structures:

• Olecranon—proximal portion of ulna; provides attachment for triceps brachii

• Coronoid process—provides attachment for brachialis

• Troclear notch—depression for articulation with trochlea of humerus

• Radial notch—depressed area for radius (head)

• Head—distal portion of ulna

• Styloid process—projects posterior and medial

Is described in 2 rows:

Proximal row (lateral to medial)

• Scaphoid—frequently fractured

• Lunate

• Triquetrum

• Pisiform

Distal row (lateral to medial)

• Trapezium

• Trapezoid

• Capitate

• Hamate

Atrioventricular—close during systole to prevent the backflow of blood into the atrium

• Tricuspid—between right atrium and right ventricle

• Bicuspid (mitral)—between left atrium and left ventricle

Semilunar—close during diastole to prevent the backflow of blood into the ventricles

• Pulmonary—between pulmonary artery and right ventricle

• Aortic—between aorta and left ventricle