Anterior forearm and palm of the hand

Question 1

What are the major features of the radius?

Answer 1

Long bone in the forearm
Lies laterally parallel to the ulnar
Radius pivots around the ulnar
Made up of the head of the radius, neck of the radius, radial tuberosity (attachment of biceps brachii), shaft.
At the distal end there is the styloid process (lateral) and the ulnar notch (medial).
Articulates with scaphoid and lunate carpal bones.

Question 2

What are the major features of the ulnar?

Answer 2

Long bone in the forearm
Lies medially parallel to the radius
Acts as the stabilising bone
Made up of the olecranon (attachment of triceps brachii), coronoid process, trochlear notch (articulates with the trochlea of the humerus), radial notch (articulates with the head of the radius), the ulna tuberosity (attachment of brachialis) and the styloid process (distal projection).

Question 3

What are the bones of the hand?

Answer 3

Carpals: eight irregularly shaped bones located in the wrist area
Scaphoid, Lunate, Triquetrum, Pisiform, Trapezium, Trapezoid, Capitate, Hamate
(left to right starting at the thumb)
Metacarpals: five, each one related to a digit
Phalanges: each has 3 apart from the thumb which has 2

Question 4

What are the major features of the pronator teres?

Answer 4

Forms the medial border of the cubital fossa.
Originates from the medial epicondyle of the humerus and the coronoid process of the ulna.
Attaches onto the radial shaft.
Action: pronates the forearm
Innervated by the median nerve

Question 5

What are the major features of the flexor carpi radialis?

Answer 5

Originates from the medial epicondyle.
Attaches onto the base of metacarpals II and III.
Action: flexion and abduction of the wrist.
Innervated by the median nerve.

Question 6

What are the major features of the palmaris longus?

Answer 6

Absence in about 15% of the population.
Originates from the medial epicondyle.
Attaches to flexor retinaculum of the wrist.
Action: flexion of the wrist.
Innervated by the median nerve.

Question 7

What are the major features of the flexor carpi ulnaris?

Answer 7

Originates from the medial epicondyle.
Attaches to the pisiform carpal bone.
Action: Flexion and adduction at the wrist
Innervated by the ulnar nerve

Question 8

What are the major features of the flexor digitorum superficialis?

Answer 8

Lies between the deep and superficial layers of muscles (intermediate)
The median nerve and ulnar artery pass between its two heads.
Two heads: one originates from the medial epicondyle of the humerus and the other from the radius. Its four tendons travel through the carpal tunnel.
Attaches onto the middle phalanges of the four fingers.
Action: Flexes the metacarpophalangeal joints and proximal interphalangeal joints at the four fingers and flexes at the wrist.
Innervated by the median nerve.

Question 9

What are the major features of the flexor digitorum profundus?

Answer 9

Originates from the ulna and associated interosseous membrane.
Its four tendons travel through the carpal tunnel.
Attach to the distal phalanges of the four fingers.
Action: Flex the distal interphalangeal joints of the fingers, metacarpophalangeal joints and the wrist.
Innervated medial half by the ulnar nerve, lateral half by the median nerve.

Question 10

What are the major features of the Flexor pollicis longus?

Answer 10

Originates from the radius and associated interosseous membrane.
Attaches to the distal phalanx of the thumb.
Flexes the interphalangeal joint and metacarpophalangeal joint of the thumb.
Innervated by the median nerve.

Question 11

What are the major features of the Pronator Quadratus?

Answer 11

A square shaped muscle, deep to the tendons of the other deep muscles.
Originates from the anterior surface of the ulna.
Attaches to the anterior surface of the radius.
Action: pronates the forearm
Innervated by the median nerve.

Question 12

What is the carpal tunnel syndrome?

Answer 12

Carpal tunnel is formed by the flexor retinaculum and the carpal bones of the wrist. The tunnel transmits eight flexor tendons of the fingers and median nerve. Swelling of the tendons or arthritis affecting the joints of the carpal bones can increase pressure in the tunnel. This will compress the median nerve. Manifests as pain and diminished sensation on the skin along the distribution of the median nerve. May also be weakness of the hand muscles supplied by the median nerve (LLOAF). Ulnar nerve is not affected.

Question 13

What is a colles fracture?

Answer 13

Falls in the elderly are common. In females a reduction in oestrogen after the menopause leads to weaker bone - osteoporosis. If people put out their hand to ‘break the fall’, it can lead to a fracture of the distal end of the radius. May cause carpal tunnel syndrome.

Question 14

What is De Quervain’s synovitis (repetitive strain injury)?

Answer 14

Common in people who carry out the same movements again and again. The synovial sheath of the tendons of the wrist becomes inflamed and painful. Only occurs in the presence of a synovial sheath.

Question 15

What is a ganglion cyst?

Answer 15

Normally the amount of synovium surrounding a joint or tendon is just enough to provide friction free movement. Sometimes the synovium undergoes hypertrophy and the excess synovium and any containing fluid presents as a soft squidgy bulge. Often near the dorsal aspect of the wrist.

Question 16

What are the thenar muscles?

Answer 16

3 muscles of the thumb that produce a bulge known as the thenar eminence. They are responsible for the fine movements of the thumb.
Opponens pollicis
Abducens pollicis
Flexor pollicis brevis

Question 17

What are the major features of the opponens pollicis?

Answer 17

Present most laterally (O = outside)
Originates from the trapezium and the associated flexor retinaculum.
Inserts into the metacarpal of the thumb.
Action: opposes the thumb
Innervated by the median nerve

Question 18

What are the major features of the abducens pollicis?

Answer 18

Found between the opponens pollicis and flexor pollicis brevis.
Originates from the scaphoid and trapezium and associated flexor retinaculum.
Inserts into the proximal phalanx of the thumb.
Action: Abducts the thumb
Innervated by the median nerve

Question 19

What are the major features of the flexor pollicis brevis?

Answer 19

Present most medially
Originates from the trapezium and associated flexor retinaculum.
Attaches to the proximal phalanx of the thumb.
Action: Flexes the metacarpophalangeal joint of the thumb.
Innervated by the median nerve.

Question 20

What are the hypothenar muscles?

Answer 20

Produce the hypothenar eminence, a muscular protrusion on the medial side of the palm.

Question 21

What are the major features of the Opponens Digiti Minimi?

Answer 21

Deep to the ADM and the FDMB
Originates from the hamate and associated flexor retinaculum
Inserts onto metacarpal V
Action: Rotates the little finger towards the palm, causing opposition
Innervated by the ulnar nerve

Question 22

What are the major features of the Abductor Digiti Minimi?

Answer 22

Most superficial of the hypothenar muscles
Originates from the pisiform
Attaches to the proximal phalanx of the little finger
Action: abduct the little finger
Innervated by the ulnar nerve

Question 23

What are the major features of Flexor Digiti Minimi Brevis?

Answer 23

Originates from the hamate and flexor retinaculum
Inserts onto the proximal phalanx of the little finger
Action: Flexes the metacarpophalangeal joint at the little finger
Innervated by the ulnar nerve

Question 24

What are the lumbricals?

Answer 24

Four lumbricals in the hand, each associated with a finger.
Link extensor tendons to the flexor tendons.
Denervation of these muscles is the basis for the ulnar claw and hand of benediction.
Originate from the tendons of the flexor digitorum profundus
Insert into the extensor hood
Action: flex at the metacarpophalangeal joint and extend at the interphalangeal joints of each finger
Innervated by the median nerve (2 most lateral) and the ulnar nerve (2 most medial)

Question 25

What are the interossei?

Answer 25

Located between the metacarpals

Important for abduction (dorsal) and adduction (palmar), and assisting the action of the lumbricals.

Question 26

What are the major features of the dorsal interossei?

Answer 26

Four
Originates from the lateral and medial surfaces of the metacarpals
Attach onto the extensor hood and proximal phalanx of each finger.
Action: Abduct the fingers at the metacarpophalangeal joint
Innervated by the ulnar nerve

Question 27

What are the major features of the palmar interossei?

Answer 27

Three
Each interossei originates from a medial or lateral surface of a metacarpal
Attach onto the extensor hood and proximal phalanx of each finger (excluding the middle finger)
Action: Adducts the finger at the metacarpophalangeal joint
Innervated by the ulnar nerve

Question 28

What are the major features of the palmaris brevis?

Answer 28

Small, thin muscle found superficially in the hypothenar eminence.
Originates from the palmar aponeurosis and flexor retinaculum.
Inserts onto the dermis of the skin.
Action: Wrinkles the skin of the hypothenar eminence and deepens the curvature of the hand, improving grip.
Innervated by the ulnar nerve.

Question 29

What are the major features of the adductor pollicis?

Answer 29

Triangular muscle with two heads, the radial artery passes through the space between the two heads, forming the deep palmar arch.
One head originates from metacarpal III, the other head originates from the capitate.
Attach to the proximal phalanx of the thumb.
Action: Adduct the thumb
Innervated by the ulnar nerve

Question 30

What does the radial artery supply?

Answer 30

Radial artery: supplies the posterolateral aspect of the forearm. It contributes to anastomotic networks surrounding the elbow joint and carpal bones.

Question 31

What does the ulnar artery supply?

Answer 31

Supplies the anteromedial aspect of the forearm. It contributes to an anastomotic network surrounding the elbow joint. Also gives rise to the anterior and posterior interosseous arteries, which supply deeper structures in the forearm.

Question 32

Where can you feel the radial and ulnar pulses?

Answer 32

At the wrist, the radial artery lies lateral to the flexor carpi radialis against the radius where its pulsation can be easily felt.
The ulnar lies just lateral to the pisiform, its pulse can be felt but it is more challenging.

Question 33

Why is the anastomosis so important in the hand?

Answer 33

These two arteries anastomose in the hand by forming two arches – the superficial palmar arch, and the deep palmar arch.
The hand has a rich arterial supply with many anastomoses between vessels. This allows the hand to be perfused even when under high resistance to flow (such as when grasping or applying pressure).

Question 34

What does the ulnar artery contribute to in the hand?

Answer 34

The ulnar artery enters the hand anteriorly to the flexor retinaculum and laterally to the ulnar nerve. It gives rise to the deep palmar branch and continues laterally across the palm as the superficial palmar arch.

Question 35

What does the radial artery contribute to in the hand?

Answer 35

The radial artery enters the hand dorsally, crossing the floor of the anatomical snuffbox. It then turns medially and travels between the heads of the adductor pollicis muscle. The radial artery supplies a branch to the thumb, index finger and to the superficial palmar arch – it then continues as the deep palmar arch.

Question 36

What is the superficial palmar arch?

Answer 36

Located anteriorly to the flexor tendons in the hand and deep to the palmar aponeurosis. It gives rise to the digital arteries, which supply the four fingers.

Question 37

What is the deep palmar arch?

Answer 37

Located deep to the flexor tendons of the hand. It contributes to the blood supply to the digits and to the wrist joint.

Question 38

What are the superficial veins of the arm and forearm?

Answer 38

The major superficial veins of the upper limb are the cephalic and basilic veins. They are located within the subcutaneous tissue of the upper limb.

Question 39

What’s the pathway of the basilic vein?

Answer 39

The basilic vein originates from the dorsal venous network of the hand and ascends the medial aspect of the upper limb.
At the border of the teres major, the vein moves deep into the arm. Here, it combines with the brachial veins from the deep venous system to form the axillary vein.

Question 40

What is the pathway of the cephalic vein?

Answer 40

The cephalic vein also arises from the dorsal venous network of the hand. It ascends the antero-lateral aspect of the upper limb, passing anteriorly at the elbow.
At the shoulder, the cephalic vein travels between the deltoid and pectoralis major muscles (known as the deltopectoral groove), and enters the axilla region via the clavipectoral triangle. Within the axilla, the cephalic vein empties into axillary vein.

Question 41

What connects the basilic and cephalic veins?

Answer 41

The cephalic and basilic veins are connected at the elbow by the median cubital vein.

Question 42

What are the deep veins of the arm or forearm?

Answer 42

The deep venous system of the upper limb is situated underneath the deep fascia. It is formed by paired veins, which accompany and lie either side of an artery. In the upper extremity, the deep veins share the name of the artery they accompany.
The brachial veins are the largest in size, and are situated either side of the brachial artery. The pulsations of the brachial artery assist the venous return. Veins that are structured in this way are known as vena comitantes.
Perforating veins run between the deep and superficial veins of the upper limb, connecting the two systems.

Question 43

What is Dupuytren’s contracture?

Answer 43

The palmar fascia lies immediately deep to the skin of the palm and extends from the flexor retinaculum of the wrist and attaches to the flexor sheath of each finger. In manual workers the fascia can progressively scar. This leads to shortening of the fascia which pulls the affected fingers into flexion. In its severest form the fingers are held tightly flexed against the palm of the hand (rendering the hand as useless).

Question 44

What is Trigger finger?

Answer 44

The tendons to the fingers run in tight tendon sheath which holds the tendon against the bones during a tight grip. If the tendon becomes damaged and swollen or if the sheath becomes narrowed, then the tendon will not slide freely. The tendon catches the muscle slowly increases the force until the tendon suddenly pulls through.

Question 45

What is Gamekeeper’s (skier’s) thumb?

Answer 45

The thumb has two ligaments which attach the metacarpal to the proximal phalanx, one on the medial side and one on the lateral side of the joint. If the thumb is forced rapidly away from the hand the medial ligament may rupture. This causes instability of the joint and any grip using the thumb is weaker.

Question 46

What is Avascular necrosis of the scaphoid?

Answer 46

After a fall on the outstretched hand, tenderness in the anatomical snuff box is suggestive of fracture of the scaphoid bone. The scaphoid forms in two parts each with its own artery. During growth the two parts fuse together and the artery to the proximal part disappears. The whole bone is then supplied by a single artery which enters the bone from the distal end. If the scaphoid fractures the proximal end of the bone may be disconnected from the blood supply and will undergo ‘avascular necrosis’, - death of tissue due to no blood vessel.