Hand Flashcards

1
Q

[10-minute video]: an easy way to remember hand and arm muscles [Part 1]
[8-minute video]: an easy way to remember hand and arm muscles [Part 2]

A

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2
Q

[6-minute video]: cadaveric dissection of the Thenar muscles

A

🔪

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3
Q

State the dermatome of the:
(a) Thumb
(b) Small finger
(c) Middle finger

A

(a) Thumb: C6
(b) Small finger: C8
(c) Middle finger: C7
[Diagram]

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4
Q

State the characteristic features of the skin of the palm.

A
  1. It is thick to withstand wear and tear during work.
  2. It is richly supplied by the sweat glands but contains no hair or sebaceous glands.
  3. It is immobile as it is firmly attached to the underlying palmar aponeurosis.
  4. It presents several longitudinal and transverse creases where the skin is firmly bound to the deep fascia.
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5
Q

What are the two important features of the superficial fascia of the palm?

A
  1. Palmaris brevis, a subcutaneous muscle [innervated by the superficial branch of the ulnar nerve]
  2. Thickens to form a superficial transverse metacarpal ligament, which stretches across the roots of fingers over the digital nerve and vessels
  3. Note: the palmar aponeurosis is considered a part of the deep fascia of the palm.
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6
Q

The palmar fascia is specialized to form three structures, namely:

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7
Q

State the functions of palmar aponeurosis.

A
  1. Helps to improve the grip of hand by fixing the skin.
  2. Protects the underlying tendons, nerves, and vessels.
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8
Q

What is the function of the fibrous flexor sheaths?

A

They hold the tendons in position during flexion of digits.

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9
Q

List the groups of the intrinsic muscles of the hand.

A
  1. Thenar muscles
  2. Hypothenar muscles
  3. Lumbricals
  4. Interossei
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10
Q

The thenar muscles are arranged around the polex (thumb). List the thenar muscles.

A

Abductor pollicis brevis (lies laterally)
Flexor pollicis brevis (lies medially)
Opponens pollicis (deep to abductor pollicis brevis)

[Diagram]

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11
Q

(a) State the function of each of the thenar muscles.
(b) What is the nerve supply of the thenar muscles?

A

(a) Functions:
~ Flexor pollicis brevis: flex the metacarpophalangeal and carpometacarpal joints
~ Abductor pollicis brevis: abduct the thumb
~ Opponens pollicis: produce opposition of thumb
~ [Diagram]

(b) All are supplied by the recurrent branch of the median nerve.

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12
Q

Name the three hypothenar muscles.

A
  1. Abductor digiti minimi [lies medially]
  2. Flexor digiti minimi [lies laterally]
  3. Opponens digiti minimi [lies deep to abductor digiti minimi and flexor digiti minimi]
  4. [Diagram]
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13
Q

(a) State the action of each of the hypothenar muscles.
(b) What is the nerve supply of the hypothenar muscles?

A

(a) Functions:
~ abductor digiti minimi: abduction and flexion of the 5th finger at the metacarpophalangeal joint
~ flexor digiti minimi: flexion of the 5th finger at the metacarpophalangeal joint
~ opponens digiti minimi: flexion, lateral rotation and opposition of 5th finger

(b) All of them are supplied by the deep branch of ulnar nerve (C8, T1).

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14
Q

The flexor pollicis brevis has dual nerve supply: superficial head by the median nerve and deep head by the deep branch of the ulnar nerve. TRUE or FALSE?

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15
Q

Discuss the following under the adductor pollicis muscle:
origin, insertion, nerve supply, action

A

Origin:
1. Oblique head arises from anterior aspects of capitate bone and bases of second and third metacarpal bones—forming a crescentic shape.
2. Transverse head arises from ridge on distal two-third of the anterior surface of the shaft of the third metacarpal.
[Diagram: Two heads of adductor pollicis]
Insertion: Medial side of the base of proximal phalanx of the thumb (tendon has a sesamoid bone)
Nerve supply: Deep branch of the ulnar nerve
Actions: Adduction of the thumb to provide power to the grip

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16
Q

Discuss lumbrical muscles [nerve supply and are actions of greater significance].

A

Origin:
Lumbricals 1 and 2, from lateral side of lateral two tendons of the flexor digitorum profundus
Lumbricals 3 and 4, from adjacent sides of medial three tendons of the flexor digitorum profundus
[Diagram]

Insertion: lateral side of dorsal digital expansion of the corresponding digit from second to fifth

Nerve supply:
1. first and second lumbricals - median nerve
2. third and fourth lumbricals - deep branch of ulnar nerve [Diagram]

Actions:
✓ flex the metacarpophalangeal joints
✓ extend the interphalangeal joints

17
Q

The interossei are divided into two, namely: ______________.

A

palmar and dorsal interossei

18
Q

Nerve supply and actions of the interossei?

A

Nerve supply: deep branch of the ulnar nerve
Actions: palmar interossei adduct the digits whereas dorsal interossei abduct the digits. PAD DAB i.e. Palmar ADduct, Dorsal ABduct

19
Q

The anatomical snuff-box is an elongated triangular depression seen on the lateral side of the dorsum of hand when the thumb is hyperextended. State its boundaries. [Hint: anterolateral, posterolateral, floor and roof]

A

Anterolaterally:
(1) Tendon of abductor pollicis longus
(2) Tendon of extensor pollicis brevis
Posteromedially:
Tendon of extensor pollicis longus
Floor: It is formed by
(1) scaphoid and 2. trapezium [Diagram: bones of the hand]
Roof: It is formed by
(1) skin and
(2) superficial fascia

[Diagram: the anatomical snuffbox]
[3-minute video]: cadaveric study of the Anatomical Snuff Box

20
Q

Give the contents and structures crossing the roof of the anatomical snuff box deep to skin.

A

Contents: Radial artery.
Structures crossing the roof deep to skin:
(a) Cephalic vein, from medial to lateral side.
(b) Terminal branches of the superficial radial nerve, from
lateral to medial side.
[Diagram 1] [Diagram 2]

21
Q

State the clinical significance of anatomical snuff-box.

A

☯︎ The pulsations of radial artery can be felt in the anatomical box.
☯︎ The tenderness in the anatomical box indicates fracture of scaphoid bone.
☯︎ The cephalic vein at this site is often used for giving intravenous fluids.
☯︎ The superficial branches of the radial nerve can be rolled over the tendon of extensor pollicis longus. [May not necessarily be a clinical relevance.]

22
Q

What is the space of Parona? What is its clinical significance?

A

The space of Parona is a potential space in the distal forearm/volar wrist, deep to the flexor tendons. The space lies between the fascia of the pronator quadratus muscle and the flexor digitorum profundus tendon sheath. [Diagram]

Clinical relevance:
The clinical significance of the space of Parona is that it can act as a conduit for the spread of a hand infections into the forearm. An infection can travel up a flexor tendon to either the radial or ulnar bursa, from there may pass into the space of Parona proximal to the transverse carpal ligament and into the forearm. The space of Parona can also be involved in cases of thenar or midpalmar abscesses.

23
Q

Describe the formation of the superficial and deep palmar arterial arches of the hand.

A
  1. Superficial palmar arterial arch is formed by anastomosis between the direct continuation of the ulnar artery with the small superficial palmar branch of the radial artery.
  2. The deep palmar arterial arch is formed by anastomosis between the direct continuation of the radial artery with the small deep palmar branch of the ulnar artery.
24
Q

Name the boundaries and contents of the midpalmar space.

A

Boundaries
1. Ventral: flexor tendons within the common flexor sheath
2. Dorsal: 3rd to 5th metacarpal bones
3. Medial: septum to 5th metacarpal (medial palmar septum)
4. Lateral: septum to 3rd metacarpal (intermediate palmar septum)

Contents
1. 2nd, 3rd and 4th lumbricals

[Diagram]

Further notes:
The midpalmar space contains the 2nd, 3rd, and 4th lumbrical muscles and lies posterior to the long flexor tendons to the middle, ring and little fingers. It lies in front of the interossei and the 3rd, 4th and 5th metacarpal bone.

25
Q

Proximally, the midpalmar space is continuous with ____(a)____, whereas distally it is continuous with the medial three ____(b)____.

A

(a) the space of Parona
(b) web spaces

26
Q

State the boundaries [anterior, posterior] and contents of the carpal tunnel.

A

Boundaries
- Anteriorly: flexor retinaculum
- Posteriorly: carpals

Contents
- tendons of flexor digitorum superficialis
- tendons of flexor digitorum profundus
- tendon of flexor pollicis longus
- median nerve

[Diagram]

Notes:
✔ The flexor tendons of fingers (i.e., tendons of FDS and FDP) are enclosed in a synovial sheath called ulnar bursa.
✔ The tendon of flexor pollicis longus is on the radial side and enclosed in a separate synovial sheath called radial bursa.
✔ The tendon of flexor carpi radialis pass through a separate canal in the lateral part of the flexor retinaculum.

27
Q

Name 6 structures passing superficial to the flexor retinaculum from medial to lateral.

A
  1. ulnar nerve
  2. ulnar artery
  3. palmar cutaneous branch of ulnar nerve
  4. tendon of palmaris longus
  5. palmar cutaneous branch of median nerve
  6. superficial palmar branch of radial artery
  7. [Diagram 1] [Diagram 2]
28
Q

Sketch a simple diagram showing the cutaneous innervation of the palmar aspect of the hand.

A
29
Q

Sketch a simple diagram showing the cutaneous innervation of the dorsal aspect of the hand.

A
30
Q

Name the boundaries of the thenar space.

A

Ventral: palmar aponeurosis
Dorsal: fascia covering the transverse head of adductor pollicis
Medial: septum to 3rd metacarpal (intermediate palmar septum)
Lateral: septum to 1st metacarpal (lateral palmar septum)
[Diagram]

31
Q

The pulp spaces of the digits are subcutaneous spaces on the palmar side of tips of the fingers and thumb. The pulp space is filled with subcutaneous fatty tissue. State the boundaries of that space.

A

Superficially: Skin and superficial fascia
Deeply: Distal two-third of distal phalanx
[Diagram]

32
Q

The space of Parona (forearm space) is merely a fascial interval underneath the flexor tendons on the front of distal part of the forearm. Proximally, it is continuous with the inter-muscular spaces of the forearm. State its boundaries.

A

Ventral:
(a) Tendon of flexor digitorum profundus and flexor digitorum superficialis surrounded by a synovial sheath (ulnar bursa).
(b) Tendon of flexor pollicis longus surrounded by a synovial bursa (radial bursa).
Dorsal: pronator quadratus
Lateral: outer border of the forearm
Medial: inner border of the forearm
[Diagram 1] [Diagram 2]

Further notes:
The ulnar bursa is the synovial tendon sheath enclosing the tendons of the medial 4 fingers’ flexors as they pass through the carpal tunnel.
The raidal bursa encases the flexor pollicis longus tendon.

33
Q

a) What are web spaces?
b) Name the contents of the first web space of the hand.

A

(a) The web space is a subcutaneous space in each interdigital cleft and is filled with loose areolar tissue. It contains lumbrical tendon, interosseous tendon, digital nerve, and vessels.
The web space extends from the free margin of the web, as far proximally as the level of transverse metacarpal ligaments.

(b) contents:
Transverse head of adductor pollicis
First dorsal interossei
✔ Radialis indicis artery
✔ Princeps pollicis artery
✔ [Diagram: radialis indicis and princeps pollicis arteries]

34
Q

Draw a simple diagram indicating the arrangement of carpal bones.