Humerus

Question 1

Anatomical location

Answer 1

Forms upper arm

Joins it to shoulder and forearm

Question 2

Proximal region

Answer 2

Articulates with scapula to form glenohumeral joint (at glenoid fossa)

Question 3

Important anatomical features of proximal humerus

Answer 3

Head - articulates with glenoid fossa of scapula
Anatomical neck - connects head to tubercles
Greater tubercle - lateral on humerus, anterior and posterior face, point of attachment for supraspinatus, infraspinatus and teres minor
Lesser tubercle - more medial, only anterior, place of attachment of subscapularis
Intertubercular sulcus - separates two tubercles, tendon of long head of biceps brachii runs through this groove
Surgical neck - runs from tubercles to shaft of humerus

Question 4

Surgical neck fracture

Answer 4

Occurs by direct blow to area or fall on outstretched hand
Axillary nerve and posterior circumflex artery at risk
Axillary nerve damage - paralyses deltoid and teres minor, patient can’t abduct arm
Also innervates skin over lower deltoid, some sensory loss may be present here (regimental badge area)

Question 5

Shaft of humerus

Answer 5

Deltoid tuberosity - lateral side of humerus, roughened surface, attachment point of deltoid
Radial groove - shallow depression, runs diagonally do posterior surface, radial nerve and profunda brachii artery lie in groove

Question 6

Muscles that attach to humerus

Answer 6

Anteriorly - Coracobrachialis, deltoid, brachialis, brachioradialis

Posteriorly - Medial and lateral heads of triceps

Question 7

Mid-shaft fracture

Answer 7

Can damage radial nerve or profunda brachii artery as they are in the radial groove
Radial nerve innervates extensors of the wrist and so damage to this causes unopposed flexion (wrist drop)
Some sensory loss could also occur over dorsal surface of the hand and the proximal ends of the lateral 3 and 1/2 digits dorsally

Question 8

Distal region

Answer 8

Articulates with ulna and radius at elbow
Medial and lateral epicondyles can be palpated at elbow (medial bigger)
Ulnar nerve - posterior side of medial epicondyle (funny bone)
Trochlea - articulates with the ulnar
Capitulum - articulates with radius
Radial, coronoid and olecranon fossae - accomodate forearm bones during movement of elbow

Question 9

Distal humeral fracture - supracondylar

Answer 9

Supraepicondylar fractures occur with a fall on a flexed elbow (fracture spans the two epicondyles)

Question 10

Distal humeral fracture - medial epicondylar

Answer 10

Could damage ulnar nerve causing ulnar claw

Loss of sensation over medial 1 and 1/2 fingers on both dorsal and palmar surfaces

Question 11

Volkmann’s ischaemic contracture

Answer 11

Uncontrolled flexion of the hand

Direct damage or swelling can cause interference to blood supply from brachial artery