W1: Upper limb general

Question 1

Photo from E-learning

Question 2

Where does the clavicle articulate? What types of joints are. these?

Answer 2

The clavicle articulates with the manubrium of the sternum at the sternoclavicular joint (saddle synovial) and with the acromion of the scapula at the acromio-clavicular joint (plane synovial).

Question 3

Discuss clavicle ligaments

Answer 3

The clavicle is attached to the coracoid process (scapula) by the conoid ligament medially and the trapezoid ligament laterally (known collectively as the coraco-clavicular ligament).

Question 4

What are the two points of the scapula?

Question 5

Functions of scapula

Answer 5

1. Connecting the axial skeleton (core) to the appendicular skeleton (extremities).
2. Assisting optimal movement of the glenohumeral joint as a result of interactions between the scapula and

humerus (scapulohumeral rhythm).

3. Act as the site of attachment for 17 muscles which function across multiple joints.

Question 6

What does the coracoacromial ligament do?

Answer 6

between the coracoid and acromion helps prevent the upward dislocation of the humerus

Question 7

Discuss clavicle fractures

Answer 7

The weakest and thinnest point of the clavicle is the border between the middle and distal thirds of the bone. This is therefore the most common site of fracture. 80-85% of fractures occur within the middle third of the clavicle. Following fractures, the medial portion is pulled superiorly by sternocleidomastoid whilst the lateral portion is pulled inferiorly by the weight of the upper limb.

Question 8

What does the coraco-clavicular ligament do?

Answer 8

attaches the coracoid process to the clavicle and thus to the axial skeleton

Question 9

What forms the glenohumeral joint?

Answer 9

The glenohumeral joint is formed by the rounded humeral head articulating against the shallow glenoid cavity on the lateral aspect of the scapula. Only about 25-30% of the humeral head articulates with the socket at any one time, a key contributor to joint mobility.

Inside the joint capsule, the socket is deepened and therefore stabilised by, the glenoid labrum, a fibrocartilagi- nous structure similar to the acetabular labrum in the hip joint.We know that this is an important structure for joint stability as if it is lost or damaged (e.g. Bankart lesion), the joint frequently dislocates.

The joint capsule’s fibrous layer attaches to the circumference of the glenoid cavity and inserts into anatomical neck of the humerus. Inferiorly, near the armpit region, the capsule is lax, minimising impingement to motion. The synovial membrane lining the fibrous capsule wraps around the tendon of the long head of biceps brachii, which passes within the intertubercular sulcus, reducing the friction between bone, tendon and capsule.

Question 10

What are the rotator cuff muscles?

Answer 10

The rotator cuff muscles can be remembered by using the mnemonic “SITS”:
S = supraspinatus I = infraspinatus T = teres minor S = subscapularis

Question 11

Supraspinatus muscle

Answer 11

Origin: supraspinatous fossa of scapula
Insertion: greater tubercle of humerus
Function: initiation of abduction of arm to 15° at glenohumeral joint; stabilization of humeral head in glenoid cavity.

It is supplied by the suprascapular nerve from C4, 5 and 6. Damage to this nerve results in difficulty in initiating abduction of the arm. Patients can learn to swing the arm away from the trunk allowing the deltoid muscle to complete full abduction of the arm.

Question 12

Infraspinatus muscle

Answer 12

Origin: infraspinatous fossa of scapula
Insertion: greater tubercle of humerus
Function: external rotation of arm at glenohumeral joint; stabilization of the humeral head in glenoid cavity.

It is supplied by the suprascapular nerve (C4, 5 and 6).

Question 13

Subscapularis

Answer 13

The subscapularis arises from the subscapular fossa and inserts into the lesser tuberosity of the humerus and capsule of the shoulder joint. It rotates the humerus medially, draws it forwards and pulls it down when the arm is raised. It is supplied by the upper and lower subscapular nerves (C5, 6 and 7).

Question 14

Teres minor

Answer 14

The teres minor muscle arises from the dorsal surface of the axillary border of the scapula for the upper two-thirds of its extent, and from two aponeurotic laminae, one of which separates it from the infraspinatus muscle, the other from the teres major muscle. Its fibres run obliquely upwards and laterally; the upper ones end in a tendon which is inserted into the lowest of the three impressions on the greater tubercle of the humerus; the lowest fibres are inserted directly into the humerus immediately below this impression.

Supports the deltoid

Question 15

Deltoid

Answer 15

The deltoid muscle has a horse-shoe shaped origin from the spine of the scapula, the acromion and the lateral third of the clavicle. It inserts into the deltoid tuberosity about halfway down the lateral aspect of the humerus. When the whole muscle contracts it abducts the arm at the shoulder. When the anterior fibres contract they flex and medially rotate the arm. The lateral fibres alone act to extend and laterally rotate the arm. The deltoid is supplied by the axillary nerve (c 5, 6) which winds around the (surgical) neck of the humerus. Damage to this nerve results in atrophy of the muscle with flattening of the shoulder and a reduction in the ability to abduct the arm and can occur after dislocation of the shoulder (A) or fracture of the neck of the humerus (B).

Question 16

Discuss shoulder dislocations

Answer 16

Anterior dislocations are far more common than posterior dislocations (which are typically caused by electric shocks, seizures and physical restraint). Anterior dislocations are commonly seen following blows to the shoulder, particularly in contact sports. Patients classically hold out their arm slightly abducted and laterally rotated once dislocated.Anterior dislocations may cause damage to the nearby axillary nerve, causing paralysis of deltoid and impaired sensation in the badge patch area.

Question 17

A patient presents with a shoulder that is clearly dislocated in the usual antero-inferior direction. How would you test whether there has been damage to the axillary nerve?

Answer 17

Testing axillary supply to deltoid by abduction would NOT be done because it would risk creating more damage. Conveniently the axillary nerve supplies a patch of skin over the insertion of deltoid “regimental badge area” so this area is tested for loss of sensation.

Question 18

In a patient with a fractured neck of the humerus (subcapital fracture) such as illustrated above, which nerve is likely to have been damaged?

Answer 18

The axillary nerve, which supplies deltoid (and teres minor) and some skin.

Question 19

What are the muscles attaching the scapula to the trunk?

Answer 19

Rhomboid, lev scapulae, trapezius, pectoralis minor muscle, serratus anterior, subclavius (6)

Question 20

Rhomboid muscle

Answer 20

The rhomboid muscles (minor and major) arise from cervical/thoracic vertebrae and insert into the vertebral border of the scapula. They retract the scapula and rhomboid major can rotate the bone to depress the glenoid cavity. The rhomboids are supplied by the dorsal scapular nerve containing fibres from the 5th cervical nerve.

Question 21

Levator scapulae

Answer 21

he levator scapulae arises from the first 4 cervical vertebrae and inserts into the vertebral border of the scapula above the scapular spine. It acts to rotate and elevate the scapula.

Question 22

Trapezius muscle

Answer 22

The trapezius muscle lies above the rhomboids and levator scapulae. It originates from the base of the skull and the nuchal ligament attached to the spines of the cervical vertebrae and directly from the spines of the thoracic vertebrae. It inserts into the lateral third of the clavicle, the acromion and the spine of the scapula. The action of the muscle in general is to retract the scapula and brace back the shoulders. The upper fibres also aid in elevating the point of the shoulder and it also acts to rotate the scapula. This muscle is supplied by the spinal accessory nerve which also supplies the sternocleidomastoid. The accessory nerve can be damaged, for example in surgical interventions in the posterior triangle to remove diseased lymph nodes. This can lead to a weakness in head rotation and shoulder elevation. Lack of rotation of the scapula will cause patients to complain that they cannot reach up to a high shelf or to brush their hair. cant do abduction

or

Function: Upper fibres: elevation & rotation of the scapula during abduction

Middle fibres: retraction the scapula against the chest wall

Innervated by the accessory nerve (XI).

Question 23

Pectoralis minor muscle

Answer 23

From the anterior wall of the thorax the pectoralis minor muscle runs from the 3rd, 4th and 5th ribs to insert into the coracoid process. It acts to depress the glenoid fossa and protract the scapula. It is supplied by the medial pectoral nerve containing fibres from the 8th cervical and 1st thoracic nerves

Question 24

serratus anterior muscle

Answer 24

The serratus anterior muscle rises by interdigitations from the upper 8 ribs as a broad flat muscle that passes posteriorly between the rib cage and subscapular surface of the scapula to insert along the length of its vertebral border. With pectoralis minor, it protracts the scapula and is involved in reaching and pushing movements. It is supplied by the long thoracic nerve from the roots of C5, 6 and 7. Damage to this nerve results in a winged scapula. Pushing against a wall further accentuates the winging.

 Functions to retract the scapula against the chest wall.

 Innervated by the long thoracic nerve.

Question 25

The subclavius muscle

Answer 25

The subclavius muscle originates from the upper border of the 1st rib and inserts into the inferior surface of the clavicle. It draws the clavicle downwards, forwards and medially, helping to hold it against the manubrium.

Question 26

What are the muscles acting from the vertebral column or rib cage on humerus?

Question 27

Pectoralis major

Answer 27

The pectoralis major arises from the medial half of the clavicle (the clavicular head) and the margin of the sternum (sternal head) and adjacent rib cartilages. The fibres of this muscle converge to insert into the bicipital groove of the humerus. Its action is to adduct the humerus and rotate it medially. When the raised arm is fixed, the muscle acts to assist in climbing. It can also act as an accessory muscle for inspiration. The clavicular head is supplied from C5 and 6 and the sternal head from C7, 8 and T1.

Question 28

Latissmus dorsi

Answer 28

The latissimus dorsi muscle arises from the spines of the lower 6 thoracic vertebrae, the lumbo-dorsal fascia and the crest of the ilium, to insert into the floor of the bicipital groove. It acts to adduct and medially rotate the humerus and extend it. It is supplied by nerve fibres from C6, 7 and 8.

Question 29

Difference between anatomical neck and surgical neck

Question 30

What are edges of humerus called?

Answer 30

tubercle

Question 31

Discuss which parts of humerus articular with ulna and radius

Answer 31

The trochlea of the humerus articulates with the ulna medially, and the capitulum of the humerus with the radius laterally.

Question 32

What is contained in the axilla?

Answer 32

Axillary artery

Axillary vein

Brachial plexus

Axillary lymph nodes

Question 33

Discuss ligaments in the elbow joint

Answer 33

Joint stability is maintained by a capsule which is thickened laterally and medially by ligaments. The medial collateral ligament extends from the medial epicondyle to the ulna (coronoid process), but the lateral collateral ligament cannot be attached to the head of the radius, which rotates in pronation/supination. It is therefore attached to the anular ligament that holds the head of the radius to the ulna.

Question 34

Which muscles act on the elbow joint?

Answer 34

Brachialis (ant)

Biceps brachii (ant)

Coracobrachialis (ant)

Triceps (post)

Brachioradialis (post)

Question 35

The brachialis muscle

Answer 35

he brachialis muscle is supplied by the musculocutaneous nerve (C5 and 6). It arises from the lower two thirds of the anterior surface of the humerus to be inserted into the coronoid process and tuberosity of the ulna. It acts to flex the forearm on the arm.

Question 36

The biceps muscle

Answer 36

The biceps muscle, which attaches proximally to the coracoid process of the scapula (short head) and to the supraglenoid tuberosity of the scapula (the long head), runs through the anterior compartment of the arm to be attached distally to the radial tuberosity on the medial aspect of the radius. This attachment therefore allows biceps to act both as a flexor of the forearm on the arm and as a powerful supinator, pulling the radius over the ulna, turning the hand to face upwards. Biceps is supplied by the musculo-cutaneous nerve (C5, 6).

The attachment of the tendon of the long head of biceps to the supra-glenoid tubercle also assists in stabilising the shoulder joint.

Question 37

The coraco brachialis

Answer 37

There is one further muscle in the anterior compartment of the arm also supplied by the musculocutaneous nerve (C5, 6). This is the coraco brachialis muscle, which runs from the middle of the medial border of the humerus to the tip of the coracoid process of the scapula. It flexes and adducts the arm at the shoulder joint. You will have noticed that all of the muscles in this compartment are supplied by the musculocutaneous nerve. Damage to the nerve itself is rare but would result in a weakening of flexion of the forearm on the arm and of supination. As the muscles of the anterior compartment of the arm are largely supplied from C5 and 6, paralysis of all three muscles will occur if the roots of these nerves are torn (see brachial plexus module).

Question 38

The triceps muscle

Answer 38

The posterior compartment of the arm is occupied by the triceps muscle. This arises via three heads, the long head from infraglenoid tubercle of the scapula, the lateral head from the posterior and lateral aspects of the humerus and the medial head from the lower posterior surface of the olecranon process of the ulna. The main function of this muscle is to extend the forearm on the arm. It can also, via the long head, extend the arm at the shoulder. The nerve supply comes from the radial nerve (C6, 7 and 8). Damage to the nerve below the level at which branches to triceps are given off will not compromise these movements, but damage to the cervical roots will result (besides other motor deficits) in an inability to extend the forearm (see brachial plexus in the nerves of the upper limb module.)

Question 39

The brachioradialis

Answer 39

There is one further muscle acting on the elbow joint and that is the brachioradialis, which arises from the upper two thirds of the supracondylar ridge of the humerus and inserts into the base of the styloid process of the radius. It is supplied by the radial nerve and aids in flexion of the forearm at the elbow joint. In life, it contracts during both rapid flexion and extension to prevent the radial head being pulled away from the humerus by the centrifugal force generated by the movement.

Question 40

What forms the borders of the cubital fossa?

Answer 40

Its upper margin is theoretical - the line between the medial and lateral epicondyles.

Its medial boundary is the pronator teres muscle as it passes laterally to its insertion on the humerus

Its lateral boundary is the brachioradialis muscle.

Question 41

The tendons of which two muscles run down from the arm and into the forearm through the cubital fossaa?

Answer 41

The tendons of biceps and of brachialis. Note, the aponeurosis of the biceps (bicipital aponeurosis) passes medially over pronator teres and the muscles coming from the common flexor origin (medial epicondyle) to attach into the subcutaneous posterior border of the ulna. Through this attachment biceps exerts flexor pull on both forearm bones.

Question 42

Palpate your own cubital fossa or that of a colleague; can you feel an arterial pulsation. Adjacent to it is a large nerve. Which artery, which nerve?

Answer 42

The brachial artery runs into the cubital fossa where it divides into radial and ulnar branches. The nerve which accompanies it is the median nerve, which supplies most of the muscles of the forearm and those of the thenar eminence in the hand. Both the artery and nerve can be damaged by a fracture which passes above the articular surface and epicondyles (supracondylar fracture of humerus)

Question 43

Discuss joints of pronation and supination

Answer 43

These movements occur at two pivot joints, the proximal and distal radioulnar joints. Besides the flexion and extension between the humerus and radius and ulna, the round head of the radius allows rotation of this bone upon the ulna at the proximal radio-ulnar joint which is surrounded by an annular ligament.

The round head of the radius allows rotation of this bone upon the ulna at the proximal radio-ulnar joint. At the distal radio-ulnar joint the rotation of the radius around the ulna allows pronation and supination of the forearm.

Question 44

What muscles are involved in pronation and supination? Describe them.

Answer 44

Pronator teres - Pronator teres arises from the medial epicondyle of the humerus with an ulnar head from the medial side of the coronoid process of the ulna. It inserts into the middle and lateral surface of the radius and pulls the radius across the ulna, turning the palm of the hand backwards. It is supplied by the median nerve with fibres from roots C6 and 7.

Pronator quadratus - Pronator quadratus extends across the front of the bottom third of the radius and ulna and again rotates the radius across the ulna moving the palm of the hand to the rear (pronation). It is supplied by a branch from the median nerve containing fibres from C8 and T1.

Supinator - The supinator muscle arises from the lateral epicondyle of the humerus and from the lateral part of the upper part of the ulna and adjacent ligaments. It wraps around the lateral and anterior borders of the upper third of the radius and pulls the radius over the ulna to turn the hand forward. It is supplied by the radial nerve (C5 and 6).

Question 45

Type of joint - shoulder

Answer 45

Ball and socket synovial

Question 46

Where does longhead of biceps pass?

Question 47

Discuss shoulder dislocation

Answer 47

⚫ Anterior – most frequent direction of displacement

⚫ Complications: axillary nerve and axillary artery.

Question 48

Borders of axilla?

What does it contain?

Answer 48

• Anterior: pectoralis major and minor,
• Posterior: subscapularis, teres major and latissimus dorsi,
• Medial: thoracic wall
• Lateral: intertubercular sulcus of the humerus.
• Axillary artery
• Axillary vein
• Brachial plexus
• Axillary lymph nodes

Question 49

What type of joint is elbow? What is it made up of?

 radiohumeral: capitellum of humerus with radial head

 ulnohumeral: trochlea of humerus with trochlear notch of the ulna(with separate olecranon and coronoid process articular facets).

Question 51

Discuss cubital fossa

Answer 51

Limits:

• Proximal: line joining medial and lateral epicondyle
• Lateral: Brachioradialis muscle
• Medial: Pronator teres muscle

Superficial structures: Median cubital vein

Deep structures:

• Radial nerve
• Biceps tendon
• Median nerve
• Brachial artery

Question 52

What can be damaged following supraondylar humerus fracture?

Answer 52

Median nerve and branchial artery

Question 53

Draw hand bones

Answer 53

Question 54

What are the hand bones?

Answer 54

Scaphoid

Lunate

Triquetrum

Pisiform

Trapezium

Trapezoid

Capitate.

Hamate

Question 55

What type of joint is radiocarpal? Discuss

Answer 55

Synovial condyloid

^{distal radius and prox prox row expect pisiform}

Question 56

How many metacarpals and phalanges do we have?

Question 57

Carpo-metacarpal type of joint

Answer 57

Carpo-metacarpal joints

 Thumb: synovial saddle joint
permits opposition of the thumb
 2nd-5th digits: ellipsoid synovial joints (only 4th and 5th move to enhance grip).

Question 58

Metacarpo-phalangeal joint type

Answer 58

condylar synovial

Question 59

Interphalangeal joint type

Answer 59

Hinge synovial

Question 60

What forms the roof of the carpal tunnel? What about floor?

Answer 60

Flexor retinaculum (connective tissue)

Floor = arch of carpal bones

Question 61

What is contained in the carpal tunnel? Discuss carpal tunnel syndrome

Answer 61

4 x tendons of flexor digitorum profundus

4 x tendons of flexor digitorum superficialis

1 x tendon of flexor pollicis longus

Median nerve

If there is inflammation of tendons - median nerve damaged - carpal tunnel syndrome

Symptoms:

• numbness of the radial 3 1⁄2 digits,
• atrophy of the thenar eminence of the hand.

(palmar sensation is spared due to a branch of the median nerve passing superficial to the flexor retinaculum).

Treatment: surgical incision to the flexor retinaculum to relieve compression.

Question 62

Discuss anatomical snuffbox

Answer 62

Triangular fossa on the lateral aspect of the dorsum of the hand (with full extension of the thumb).

Limits:

• Medially: extensor pollicis longus tendon, Laterally: extensor pollicis brevis and abductor pollicis longus tendon
• Proximally: styloid process of the radius.

Important anatomical landmark:

• radial artery crosses its floor obliquely
• contains a branch of radial nerve and cephalic vein.

Fractures of the scaphoid typically cause tenderness on palpation of the anatomical snuffbox.

Question 63

What is palmar aponeurosis?

Answer 63

•  the central part of the deep fascia of the palm which is a highlyspecialized thickened structure
• little mobility
• covers the underlying neurovascular and tendon structures.

Question 64

Where do muscles involved in flexors of wrist originate from? What about extensors of the wrist?

Answer 64

Flexion of the wrist - common flexor tendon, medial epicondyle of the humerus

Extensors - lateral epicondyle as common extensor

Question 65

Discuss muscles of hand

Answer 65

Thenar - base of thumb, fine thumb movements

Hypothenar - fine movements of little finger

Lumbrical - flexion of MCP joints and ex of the interphalangeal joints

Dorsal interossei muscles - between metacarpals

Question 66

Discuss innervation of hand muscles

Answer 66

All apart from radial lumbricals (L), oppenens pollicis (O), abducture pollicus brevis (A), flexor pollicus brevis (F) = ulnar nerve

LOAF = median nerve