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Anatomy - Limbs > Elbow, Forearm and Wrist > Flashcards

Elbow, Forearm and Wrist Flashcards

1
Q

What are the articular surfaces of the radius and ulna?

A

radius -> capitulum (lateral)

ulna -> throchlea (medial)

*The capitulum is a ball-like, rounded surface and the trochlea is a pulley-like surface

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2
Q

What is a styloid process?

A

usually acts at points of attachment of muscles

slender, pointed protrusions of bone - e.g in distal ends of radius and ulna

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3
Q

What is the interosseous membrane?

A

fibrous membrane that connects radius and ulna along the shafts - separates anterior and posterior compartments

  • important for mechanical (forces transmitted between bones) and structural reasons (membrane acts as partial/ complete attachment site for muscles)
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4
Q

Where do the radius and ulna articulate?

A

distal ends of radius and ulna articulate with proximal row of bones in the wrist (except the pisiform)

  • scaphoid
  • lunate
  • triquetrum
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5
Q

What is the pisiform?

A

sesamoid bone in the wrist - forms within a tendon (another example is the patella)

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6
Q

What are the muscles of the anterior compartment of the forearm?

A

SUPERFICIAL Anterior Compartment:

  • Pronator teres (PT)
  • Flexor carpi radialis (FCR)
  • Palmaris longus (PL)
  • Flexor digitorum superficialis (FDS)
  • Flexor carpi ulnaris (FCU)

DEEP Anterior Compartment of the Forearm:

  • Flexor digitorum profundus (FDP)
  • Flexor pollicis longus (FPL)
  • Pronator quadratus (PQ)
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7
Q

What are the attachments of the pronator teres?

What does it do?

A

proximal:
- common flexor tendon at medial epicondyle

distal:
- lateral side of radius

when contracted - pulls arm to pronate it

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8
Q

What are the attachments of the flexor carpi muscles?

What do they do?

A

proximal:
- coomon flexor tendon at medial epiconyle

distal :

  • base of second and third metacarpal (radialis)
  • pisiform and hook of hamate (ulnaris)

flexor of wrist on radial/ ulnar side

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9
Q

What are the attachments of the flexor digitorum superficialis?

What does it do?

A

proximal:

  • medial epicondyle
  • coronoid process of ulna
  • anterior portion of radius

distal:
- middle phalanges of middle 4 digits

flexion of the middle phalanges of the fingers at the proximal interphalangeal joints

  • under continued action it also flexes the metacarpophalangeal joints and wrist joint
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10
Q

What are the attachments of the flexor digitorum profundus?

What does it do?

A

proximal:
- upper anterior and medial surfaces of ulna

distal:
- palmar base of distal phalanx (2nd-5th digits)

flexes hands and both interphalangeal joints

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11
Q

What are the attachments of the flexor pollicis longus?

What does it do?

A

proximal:
- anterior surface of radius

distal:
- palmar side of distal phalynx of thumb

fascilitates thumb flexion

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12
Q

What are the attachments of the pronator quadratus?

What does it do?

A

anterior surfaces of distal part of shafts of ulna to radius

pronates hand

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13
Q

What is the significance of the palmaris longus tendon?

A
  • most popular for use in tendon grafts for the wrist due to the length and diameter of the palmaris longus tendon, and the fact that it can be used without producing any functional deformities

fans into aponeurosis in hand - tendon not needed to have aponeurosis

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14
Q

What are the posterior muscles that move the wrist joint?

What are their attachments?

A

Extensor carpi radialis longus (ECRL) - lateral supracondylar ridge (humerus) to third metacarpal

Extensor carpi radialis brevis (ECRB) - lateral supracondylar ridge to third metacarpyl

Extensor carpi ulnaris (ECU) - lateral epicondyle of humerus to posterior border of ulna

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15
Q

What are the posterior muscles that move the digits?

What are their attachments?

A

Extensor digitorum (ED) - lateral epicondyle to middle and distal phalynges of 2nd - 5th fingers

Extensor indicis (EI) - posterior surface of ulna and interosseous membran to index finger

Extensor digit minimi (EDM) - lateral epicondyle to extensor hood of little finger

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16
Q

What are the posterior muscles that move the thumb?

What are their attachments?

A

Abductor pollicis longus (APL) - dorsal surface of radius and ulna and interosseus membrane to first metacarpal bone

Extensor pollicis brevis (EPB) - posterior side of radius and interosseous membrane to base of proximal phalynx of thumb

Extensor pollicis longus (EPL) - posterior lateral surface of the ulna and interosseous membrane to base of distal phalynx of thumb (dorsal surface)

17
Q

What are the attachments of the brachoradialis and the supinator?

A

brachoradialis - lateral ridge of distal humerus to lateral surface of distal radius near the styloid process

flexion of elbow, supination of forearm, pronation of forearm

supinator - lateral epicondyle and supinator crest of ulna to lateral surface and posterior border of radius

supinates forearm

18
Q

What is the clinical significance of the anatomical snuff box?

A

You have the tendons of extensor pollicis longus and extensor pollicis brevis.

It is also possible to palpate the scaphoid bone (most lateral of the proximal carpal row).

Scaphoid is commonly fractured. If you fall, you commonly put your hands out to break your fall -> scaphoid fracture. Its blood supply comes from arteries that have entered the wrist, gone past scaphoid and then given branches back. So a scaphoid fracture can result in an interruption of blood supply to a more proximal part (e.g. part involved in the wrist joint) -> avascular necrosis of the bone (can be very debilitating).

If pain is elicited during palpation of the anatomical snuffbox, this can indicate injury.

19
Q

What is the elbow joint?

A

The elbow joint is the joint between the capitulum and trochlea of the distal humerus, and the head of radius and proximal part of ulna

The radius articulates with the capitulum (lateral) and the ulna with the trochlea. It is a synovial joint

  • Movements: flexion and extension
20
Q

What ligaments are associated with the elbow joint?

A

collateral ligaments (both ulnar and radial) – they prevent deviation (adduction and abduction)

radial annular ligament that wraps around the neck of radius, allowing for rotation

  • arranged to stabilise the joint, but allow pronation/supination movements
21
Q

What are sex differences in the carrying angle at the elbow?

A

greater in women than men - may be due to differences in width of hips (pelvis) - arms of women needs to deviate more

22
Q

What is the proximal radio-ulnar joint?

A

the head of radius is held close to the proximal part of ulna

It has an articular surface that articulates with the capitulum as part of the elbow joint (head of radius)

The JOINT also has a trochlear articulating surface (proximal part of ulna)

On the joint is a rim, allowing the head of radius to also articulate with the radial notch of ulna

When radius is pronated (by pronator teres and pronator quadratus), it is held in place at the proximal RUJ and crosses over ulna to bring about pronation

23
Q

What is the distal radio-ulnar joint?

A

We see the ulna and radius articulating with the 3 bones of the proximal row of carpals (not pisiform)

On an x-ray, there is a bigger gap between the ulna and the bones because there is an intervening articular disc

The ulna actually articulates with this disc, that in turn articulates with the proximal carpal bones

  • the articular disc, during pronation and supination, changes position slightly. It moves over a bit, but still is acting as the surface for the articulation with the carpal bones. The bones cross over, and the orientation of the hand is essentially changed by 180 degrees going from pronation to supination
24
Q

Which muscles are involved in the movement of the elbow joint?

A

FLEXION:

  • brachialis
  • biceps
  • brachioradialis
  • pronator teres

EXTENSION:

  • triceps (mainly)
  • anconeus
25
Q

What muscles are involved in the movement of the radio-ulnar joints?

A

SUPINATION:

  • supinator
  • biceps
  • EPL
  • ECRL

PRONATION:

  • pronator quadratus
  • pronator teres
  • FCR
  • PL
  • brachioradialis
  • In the supine position, the pronator teres is stretched around the bone. It is attached to the lateral side of the shaft of the humerus.
    Pronator quadratus is stretched into its approximately quadrate shape.
    Supinator has contracted here, and has pulled the radius round so that the bones are parallel again. In the prone position, the pronator teres has contracted and has rotated the radius round, as has pronator quadratus.
26
Q

Which muscles are involved in the movement of the wrist joint?

A

Flexion:

  • FCR and FCU – important
  • Long flexors of thumb and fingers, (PL, APL)

Extension:

  • ECRL, ECRB, ECU – important
  • Long extensors of the thumb and fingers

Radial deviation (abduction):

  • APL
  • FCR
  • ECRL
  • ECRB

Ulnar deviation (adduction):

  • ECU
  • FCU
  • If the flexor muscles work together, you’ll get straightforward flexion.

** If just one of them works, you’ll get slight deviation one way or the other. It is the combinations of activities that determine the movement.

*** In order to get abduction or adduction, there is a flexor and an extensor working. Flexors work together to carry out flexion; extensors work together to carry ou

27
Q

What are the arteries of the region?

A

At the elbow, the brachial artery divides into the ulnar and radial arteries

The ulnar artery branches almost immediately to give a common interosseous branch - common interosseous branch immediately branches to give anterior & posterior interosseous arteries

The radial artery continues down the forearm to the wrist.

The posterior interosseous artery pierces the upper part of the interosseous membrane to supply the posterior compartment. The anterior artery supplies deep structures.

arteries go down to palmer arches (deep and superficial)

28
Q

What are veins of the region?

A

Superficial and deep systems

  • Cephalic vein (superficial) runs up lateral border of arm
  • Basilic vein (superficial) runs up the medial border of arm

Basilic veins joins venae comitantes to form the axillary vein in the arm

Cephalic vein joins axillary vein in the axilla

Axillary vein becomes the subclavian vein at the level of the first rib

Cephalic and Basilic veins arise from the dorsal venous arch of the hand

Commonly connected at the cubital fossa by the median cubital vein (not always present or prominent)

  • Median cubital vein is commonly used in phlebotomy
  • When median cubital vein is absent, cephalic or basilic in the region are used to take blood

** There is the dorsal venous arch, giving the cephalic vein laterally and the basilic vein medially. The median cubital vein joins them. It is not always present, or when it’s present it may be a very small, weedy vein. When present, it is the vein of choice for routinely taking blood

*** Deep drainage follows the arteries. Particularly in the more distal parts of the limb, veins accompanying the artery are often not a single vein (that’s why they’re called the venous comitantes). This is seen both anteriorly and posteriorly

29
Q

Describe the lymphatic drainage of the region?

A

Superficial and deep systems, running with veins

Cubital lymph nodes drain the forearm (usually 3 or 4 lymph nodes, often on the medial side)

Cubital lymph nodes are very important – if they are enlarged, this may indicate HIV status, they may also get inflamed is due to syphilis

Axillary nodes are also draining nodes for the distal parts of the upper limb

30
Q

What does the musculocutaneous nerve supply?

A

C5, 6, 7

Supplies all the anterior compartment of the upper arm

Sensory to the lateral forearm (as the lateral cutaneous nerve of the forearm – terminal branch

31
Q

What does the median nerve supply?

A

C6, 7, 8, T1

Courses through the anterior compartment of the arm (no significant branches)

Lies anterior to the elbow, with the brachial artery (easily damaged) – found in cubital fossa

  • Main nerve to the muscles of the forearm

The median nerve supplies LOADS of the flexors, but only HALF of the flexor digitorum profundus

32
Q

What does the ulnar nerve supply?

A

C8, T1

Courses via the posterior compartment of the upper arm

No significant branches in the upper arm

Lies behind the medial epicondyle at the elbow (easily damaged)

The main nerve of the hand

33
Q

What does the radial nerve supply?

A

C5, 6, 7, 8, T1

Supplies all the muscles of the posterior compartments of the upper arm and forearm

Passes around the body of the humerus at its mid-shaft in the radial groove (easily damaged)

Supplies triceps in the arm

Courses via the anterior compartment of the upper arm more distally

Divides just above the level of the elbow into:

  • Deep branch – the posterior interosseous nerve (motor – mainly extensor muscles)
  • Superficial branch – the superficial radial nerve (sensory)
34
Q

What is the retinaculum?

A

As we get towards the hand, we see a retinaculum. It is the flexor retinaculum of the wrist (also the transverse carpal ligament)

It is a structure that forms the roof of the carpal tunnel. The carpal tunnel allows lots of tendons and the median nerve to pass through to the hand

This arrangement can be problematic

Anatomy - Limbs (9 decks)

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