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Anatomy - Limbs > The Hand > Flashcards

The Hand Flashcards

1
Q

What are the bones in the hand and wrist?

A

The Radius and the Ulna ( The distal ends of these bones have styloid processes and an articular surface to articulate with the proximal row of the carpal bones. The pisiform does NOT form an articulation (it is a sesamoid bone – a bone that is formed within a tendon))

The Carpus (carpal bones):

  • Proximal row – scaphoid, lunate, triquetrum, pisiform
  • Distal row – trapezium, trapezoid, capitate, hamate

The metacarpal bones – link the carpals to the phalanges

The phalanges – bones of the digits

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2
Q

What are the features of palmar fascia?

A

the skin on the palms and soles of the feet is very tough (due to grasping and gripping)

On the palms and soles of feet (plantar-palmar skin), the cornified layer is much thicker

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3
Q

What is the palmar aponeurosis?

A

fan-like structure lying underneath fascia

  • Overlies the long flexor tendons of the hand
  • Proximally continuous with the flexor retinaculum (at the wrist)
  • Distally continuous with the fibrous digital sheaths (contain the flexor tendons and their synovial sheaths)

The aponeurosis originates at the wrist region, and is a continuation of palmaris longus tendon (a small muscle coming from the common flexor attachment, but has a VERY LONG tendon). Not everyone has this tendon (10-15% without it). When present, PL spans over the flexor retinaculum and fans out. If it is absent, the aponeurosis is still there.

The aponeurosis lays over the deeper structures in the palm. We can see the flexor retinaculum (transverse carpal ligament).

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4
Q

What are the compartments of the hand?

A

The two main spaces are the THENAR SPACE and the MIDPALMAR SPACE
- Septa extend from the palmar aponeurosis to:
> Medially: the little finger metacarpal
> Laterally: the middle finger metacarpal

Muscular compartments

  • Hypothenar compartment (elongated prominence associated with the little finger)
  • Central compartment (contains lots of tendons)
  • Thenar compartment (muscle compartment at the base of the thumb)
  • Adductor compartment (small compartment – essentially just a single muscle)
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5
Q

What are the sepatae in the hand?

A

Septa: essentially a wall between two structures. The two major types in the hand:

SEPTUM BETWEEN THE MIDPALMAR AND THENAR SPACES This is a long septum

SEPTA FORMING CANALS Smaller septae between the tendons

Septae come off the palmar aponeurosis

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6
Q

What are the intrinsic muscles of the hand?

Whats their function?

A
  • mainly for precision movement

Thenar muscles:

  • Abductor pollicis brevis (abducts thumb)
  • Flexor pollicis brevis (flexes thumb)
  • Opponens pollicis (allows opposition, medially roates)

Adductor muscle:
- Adductor pollicis (abducts thumb)

Hypothenar muscles:

  • Abductor digiti minimi (abducts little finger)
  • Flexor digiti minimi (flexes little finger)
  • Opponens digiti minimi (laterally rotates)

Interossei and lumbricals:

  • Lumbricals – flex the MCP’s, extend the IPJs
  • Palmar interossei – adduct the digits (“PAD”)
  • Dorsal interossei – abduct the digits (“DAB”)

palmaris brevis - improves grip

  • Interossei are muscles that have attachments between bones
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7
Q

What are the attachments of the thenar muscles?

What innervates them?

A

Abductor pollicis brevis:
- flexor retinaculum and tubercles of scaphoid + trapezium bone to outer side of base of proximal phalynx of thumb

Flexor pollicis brevis:
- f.lexor retinaculum and tubercle of trapezium to proximal phalanx of thumb

Opponens pollicis:
- flexor retinaculum and tubercle of trapezium to lateral margin and adjacent palmar surface of metacarpal one

all innervated by RECURRENT BRANCH OF MEDIAN NERVE (C8,T1)

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8
Q

What are the attachments of the hypothenar muscles?

What innervates them?

A

Abductor digiti minimi:
- pisiform, pisohamate ligament and tendon of FCU to proximal phalanx of little finger

Flexor digiti minimi:
- hook of hamate and flexor retinaculum to proximal phalanx of little finger

Opponens digiti minimi:
- hook of hamate and flexor retinaculum to medial aspect of metacarpal 5

all innervated by DEEP BRANCH OF ULNAR NERVE (C8,T1)

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9
Q

What are the attachments of the interossei and lumbricals?

What innervates them?

A

dorsal interossei (4 muscles):

  • adjacent sides of metacarples to extensor hood and base of proximal phalanges of index, middle, and ring fingers
  • DEEP BRANCH OF ULNAR NERVE (C8.T1)

palmar interossei (3/4 muscles):

  • sides of metacarpals to extensor hoods of thumbs, index, ring and little fingers and proximal phalanges of thumb
  • DEEP BRANCH OF ULNAR NERVE (C8.T1)

lumbricals (4 muscles):

  • tendons of flexor digitorum profundus to extensor hoods of index, midle and little fingers
  • medial two by DEEP BRANCH OF ULNAR NERVE (C8.T1), lateral two by DIGITAL BRANCHES OF MEDIAN NERVES
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10
Q

What are the attachments of abductor pollicis and palmaris brevis?

What innervates them

A

abductor pollis:

  • metacarpal 3 (transverse head), capitate and bases of metacarpals 2 and 3 (oblique head) to base of proximal phalanx and extensor hood of thumb
  • DEEP BRANCH OF ULNAR NERVE (C8.T1)

Palmaris brevis:

  • palmar aponeurosis and flexor retinaculum to dermis of skin on the medial margin oft he hand
  • SUPERFICIAL BRANCH OF ULNAR NERVE (C8.T1)
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11
Q

Which muscles move the thumb?

A
  • Abduction: APL, APB
  • Adduction: Adductor pollicis, first dorsal interosseous
  • Extension: EPL, EPB, APL
  • Flexion: FPL, FPB
  • Opposition: Opponens pollicis
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12
Q

Describe the anterior tendinous anatomy of the hand

A

Fibrous digital sheath

Osseo-fibrous tunnels
- In the tunnels run the long flexor tendons and their synovial sheaths

Annular and cruciform pulleys

FDP and FDS tendons pass in the carpal tunnel beneath the flexor retinaculum -> enter a common synovial sheath
-> enter a digital synovial sheath, within its own fibrous digital sheath

Little finger and thumb sheaths continuous

FDS splits around FDP

FDS to middle phalanx, FDP to distal phalanx

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13
Q

What covers tendons as the go through the carpal tunnel?

A

As groups of tendon pass under the flexor retinaculum into the carpal tunnel, they are covered with a synovial sheath. In some areas at the elbow joint, there are structures called bursae (little, closed bags of synovium that act as ball-bearing, cushioning structures at joints). The sheaths surrounding the tendons have a similar effect.

Synovial sheaths wrap around the tendons. They continue right up into the little finger and thumb. The sheath stops for the middle three fingers (they have a separate sheath surrounding them).

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14
Q

What are the parts of the fibrous digital sheaths?

A

A = annular parts (ring) C = cruciate parts (crossing)

In some digits anteriorly, there are thickened plates at the anterior surface of joints. These are important structures to protect the joint region.

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15
Q

Describe the posterior tendinous anatomy of the hand

A
  • Extensor retinaculum (at the wrist)
  • Synovial tendon sheaths
  • Inter-tendinous bands (between the tendons, linking them)
  • Extensor expansions
  • Lumbricals and interossei attach to the expansions
  • Extensor digitorum, EI, EDM

The extensor retinaculum is NOT as thick and chunk as the flexor retinaculum, but it is able to hold the tendons down.
The tendons have sheaths (this is because there is a lot of movement in these regions – sheaths act as a lubricant).
The tendons, as they head towards individual digits, can be linked by the inter-tendinous bands.

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16
Q

Describe the anterior tendinous anatomy of the digits

A

Flexor digitorum superficialis attaches into the middle phalanx. The flexor digitorum profundus goes to the distal phalanx. In order to do that, it has to pierce the FDS – this allows the FDP to go through.

The long muscles FDS and FDP therefore act at two different regions in the digit. This is important for the efficiency of the movements of the fingers.

There is a lumbrical coming along the digit, as well as interossei binding in these regions. The lumbrical tendons come up and merge with the extensor expansion (where the long tendon has fascia, that fans out as a little hood over the proximal pharangeal joint). So the lumbrical muscle (anterior) is actually acting posteriorly in some respect. It comes round onto the posterior (at the extensor expansion).

It pulls on the extensor expansion to straighten the finger. Because it goes from anterior to posterior, it can flex the metacarpal-phalangeal joint (knuckle)

17
Q

What are the joints in the hand?

A
  • Distal radio-ulnar joint
  • Wrist joint
  • Intercarpal joints
  • Carpo-metacarpal and inter-metacarpal joints
  • Metacarpo-phalangeal joints
  • Interphalangeal joints
18
Q

Which bones articulate in the wrist joint?

A

The radius articulates with part of the carpal bones (the scaphoid).

The ulna is not part of the wrist joint – it articulates with the radius, just proximal to the wrist joint, at the distal radioulnar joint. It is prevented from articulating with the carpal bones by a fibrocartilaginous ligament, called the articular disc, which lies over the superior surface of the ulna

19
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:
- APL, FCR, ECRL, ECRB

Ulnar deviation:
- ECU, FCU

20
Q

What are the movements of the carpometacarpal and inter metacarpal joint?

A

flexion and extension
radial deviation and ulnar deviation
circumduction

21
Q

What are the movements of the metacapophalangeal joints (knuckles)?

A

Flexion and extension
Abduction and adduction
Ulnar collateral ligament of the thumb help to prevent over-extension

22
Q

What are the movements of the interphalangeal (IP) joints?

A 
Flexion and extension only
Proximal Interphalangeal PIP
Distal Interphalangeal DIP
IP (thumb)
Volar plate
23
Q

What is the function of collateral ligaments?

A

help prevent over extension/flexion (particularly in interphalangeal joints

  • volar plates also important in preventing over flexion of joints
24
Q

What are extensor expansions?

A

dorsal (posterior) surface of hand - extensor tendons fan into a hood to become extensor expansion

The lumbricals and the interossei attach in these regions

The lumbricals will pull on the extensor expansion, helping to straighten the fingers

The interossei can make a contribution to this movement

25
Q

What are the arteries of the hand?

A

Ulnar Artery (on the medial side)

  • Beside FCU at the wrist
  • Interosseous arteries in the forearm
  • Superficial palmar arch – palmar digital arteries
  • Deep palmar branch

Radial Artery (on the lateral side)

  • Under brachioradialis and beside FCR at the wrist
  • At the floor of the anatomical snuff box
  • Deep palmar arch
  • Palmar metacarpal arteries
  • The radial and ulnar arteries supply the hand. Each of these provides contribution to arterial arches in the hand. Most commonly, the ulnar provides LARGER supply to the SUPERFICIAL PALMAR ARCH – the radial supply is generally less in the palmar arch, but a larger supply to the DEEP PALMAR ARCH.
26
Q

What are the veins of the hand?

A

Posteriorly is the dorsal venous arch. This arch gives rise to the two major superficial veins of the forearm and arm (the cephalic vein and the basilic vein)

27
Q

What are the main nerves of the forearm?

A
  • DIGITAL NERVES: Purely sensory and are often damaged. This can be fairly debilitating.

Median nerve – ANTERIOR FOREARM

  • Main nerve of the anterior compartment of forearm
  • Some supply to hand intrinsic muscles

Ulnar nerve – HAND

  • Main nerve of the hand
  • Some of anterior compartment (FCU, half of FDP)

Radial nerve – POSTERIOR FOREARM

  • Posterior compartment of the forearm
  • Some sensory component to the hand
  • No supply to intrinsic muscles of the hand
28
Q

What does the median nerve supply?

A

The median nerve does not supply anything in the arm. It supplies many muscles in the forearm, and it crosses the wrist in the carpal tunnel to supply the thenar muscles (muscles of the thenar eminence)

At the wrist it lies between FDS and FDP, deep to PL

It enters the carpal tunnel with FDP, FDS and FPL

Motor:

  • THENAR MUSCLES (APB, FPB, OP)
  • Lumbricals I and II

Sensory:
- Palmar surface of thumb, IF, MF and half of RF

o Some of the dorsal surface of those digits

29
Q

What does the ulnar nerve supply?

A

The ulnar nerve only supplies one and a half muscles (FCU) and the ulnar half of flexor digitorum profundus. Then it supplies all of the other intrinsic muscles of the hand

At the wrist, it lies by FCU and runs lateral to the pisiform

It runs over the flexor retinaculum (NOT OVER IT)

SUPERFICIAL BRANCH (SENSORY):
- Palmar surfaces of LF and half of RF

DEEP BRANCH (MOTOR):

  • Hypothenar muscles
  • Adductor pollicis
  • Lumbricals III and IV (medial two)
  • All the interossei (palmar and dorsal)
30
Q

What does the radial nerve supply?

A

The radial nerve supplies all the posterior muscles of the arm and forearm. It has no motor supply in the hand, but it does have some sensory supply

Divides just above the level of the elbow into:

  • Deep branch – the posterior interosseous nerve (motor)
  • Superficial branch – the superficial radial nerve (sensory)

No motor supply in the hand

Sensory supply to the dorsum of the hand

31
Q

Describe the pattern of innervation in the hand

A

The median nerve passes under the flexor retinaculum and goes into the palmar region -> gives off branches that supply the thenar muscles and the lateral two lumbricals

  • It also has sensory branches, going to the thumb, index finger, middle finger and half of the ring finger

The ulnar nerve doesn’t pass through the carpal tunnel - goes through a small medial space

Ulnar supplies all of the other intrinsic hand muscles (hypothenar, lumbricals, interossei)

Ulnar nerve gives off digital sensory branches to the little finger and half of the ring finger

Superficial branch of radial nerve divides into dorsal digital branches and supplies sensory innervation to thumb, index, middle and half of the ring finger

32
Q

Describe the cutaneous innervation of the hand

A

The ulnar nerve is supplying the medial part of the palm and the medial one and a half digits

The median nerve is supplying the rest of the palm, and the rest of the digits. There is a small contribution on the palmar surface from radial at the wrist

Posteriorly, ulnar nerve supplies the medial part of the dorsal of the hand and the digits there. The radial nerve supplies the bulk of the dorsal, and dorsal of the thumb

33
Q

What is contained in the carpal tunnel?

A

bony attachments:

  • Scaphoid
  • trapezoid
  • pisiform
  • hamate (form a gutter)

The roof is the flexor retinaculum (transcarpal ligament)

Contains:

  • Median nerve
  • FPL tendon
  • 4 tendons of FDP
  • 4 tendons of FDS
34
Q

What are the different types of grip?

Which muscles are involved?

A

Power Grip – when you grasp something very firmly

  • Long flexors of the fingers and thumb
  • Intrinsic muscles of the palm
  • Extensors of the wrist joint – if the wrist is flexed, you can’t get a good grip

Precision Grip – grasping something with a more graded grip

  • The wrist and fingers are held rigidly by the long flexors and extensors
  • The intrinsic muscles of the hand carry out the fine movements needed

Hook Grip – for carrying something
- Consumes little energy, mainly involves long flexors of digits; e.g. carrying shopping or briefcase

Anatomy - Limbs (9 decks)

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