1. Bones and Joints of the Wrist
WRIST COMPLEX
Bones and Joints of the Wrist

2. Proximal Row of Carpal Bones
Review- testable
Scaphoid:
Most lateral.
Forms floor of anatomical snuff box.
Most commonly fractured wrist bone.
Fractures may compromise radial artery in snuff box.
Articulates with radius.

3. Proximal Row of Carpal Bones
Lunate:
Articulates with radius
Triquetral:
Articulates with ulna (via articular (ulnar) disc) during extreme ulnar deviation.
Pisiform:
Sesamoid bone
Forms in tendon of the flexor carpi ulnaris

4. Distal Row of Carpal Bones:
Trapezium:
Most lateral
Trapezoid
Capitate
Hamate

5. Distal Row of Carpal Bones:
Entire complex enclosed in a common synovial membrane.
Articulations are plane joints that perform gliding motions.

6. Radiocarpal Joint Condyloid (ellipsoidal) synovial joint.
Two degrees of freedom.
Articular surfaces:
Scaphoid (convex)
Lunate (convex)
Distal radius:
Two concave fossae (lateral and medial)
Triquetral (convex)
Only during extreme ulnar deviation

7. Radiocarpal Joint Ligaments
Lateral (radial) collateral ligament.
Medial (ulnar) collateral ligament.
Dorsal radiocarpal ligament.
Palmar radiocarpal ligament.
Strengthen capsule

8. Radiocarpal Joint Functions
Some flexion and extension
Ulnar deviation

9. Radiocarpal Joint Arteries
Articular arteries
Arise from dorsal and palmar carpal arches.

10. Radiocarpal Joint Nerves
Anterior interosseous branch of median nerve.
Posterior interosseous branch of radial nerve.
Dorsal and deep branches of the ulnar nerve.

11. Radiocarpal Joint Injuries
Colle’s fracture
Scaphoid fracture
Usually at “waist”
Compromises radial artery in snuffbox

12. Midcarpal Joint Made up of intercarpal joints: Movements:
Between proximal and distal rows of carpals and between carpals.
Movements:
Some flexion and extension.
Radial deviation (abduction).
Especially due to movement of head of capitate in its socket.
Enclosed within synovial capsule.

13. Midcarpal Joint Ligaments: Nerves and arteries: Dorsal ligaments.
Palmar ligaments.
Interosseous ligaments.
Nerves and arteries:
Same as for radiocarpal.

14. Palmar Structure Sequence (radial to ulnar)
Radius
Radial artery
Flexor carpi radialis tendon
Median nerve:
Under palmaris longus tendon

15. Palmar Structure Sequence (radial to ulnar)
Flexor digitorum superficialis tendons
Ulnar artery
Ulnar nerve
Flexor carpi ulnaris tendon

16. HAND

17. Carpometacarpal Joints
Plane synovial joints:
Motion:
None for digits 2-3
Limited for 4
More mobile for 5

18. Carpometacarpal Joints
Saddle (sellaris) joint between metacarpus and trapezium:
Movements:
Abduction/adduction
Flexion/extension
Circumduction
Opposition

19. Metacarpophalangeal Joints
Condyloid synovial joints
Movements:
Flexion/extension
Abduction/adduction
Some opposition at MCP 5
Capsular ligaments:
Palmar ligaments (pads)
Collaterals

20. Interphalangeal Joints
Synovial hinge joints
Only flexion/extension allowed
Ligaments:
Strong collaterals
Proximal interphalangeal joints (PIPs)
Distal interphalangeal joints (DIPs)

21. Dorsal Venous Drainage
Dorsal venous arch drains hand dorsum.
Medially drains into basilic.
Laterally drains into cephalic.

22. Lymphatic Drainage
Medial via lymph vessels accompanying basilic vein to:
Supratrochlear nodes to:
Lateral axillary nodes.
Lateral via lymph vessels accompanying cephalic vein to:
Infraclavicular nodes to:

23. Arterial Supply to Dorsum
Via dorsal arterial arch from:
Radial and ulnar arteries.
Dorsal metacarpals.
Dorsal digitals.

24. Muscles of Dorsum of Hand
Long extensor tendons.
Dorsal interosseous muscles (4):
Attachments:
DAB:
Abductors
Middle finger is reference
Middle finger has two
First and fifth digits have none.

25. Long Extensors

26. Superficial Palm
Palmar aponeurosis
Flexor retinaculum
Palmaris brevis

27. Palmar Aponeurosis
Triangular layer of deep fascia located between two eminences.
Provides protection for superficial vessels, nerves, and tendons.
Anchored to skin and flexor retinaculum.
Splits into four slips that blend with fibrous flexor sheaths of four medial digits (II – V).

28. Flexor Retinaculum = Transverse carpal ligament.
Laterally attaches to tubercles of scaphoid and trapezium.
Medially attaches to hook of hamate and pisiform.

29. Palmaris Brevis Muscle
O: Flexor retinaculum and palmar aponeurosis.
I: Skin on medial side of palm.
A: Tenses skin on palm.

30. Carpal Tunnel Contents
Long flexor tendons of:
Flexor digitorum superficialis
Flexor digitorum profundus
Flexor pollicis longus
Median nerve
Note: ulnar nerve and artery pass through Guyon’s canal.

31. Long Flexors

32. Intrinsic Muscles of the Thumb
Thenar eminence:
Adductor pollicis:
Innervation:
Deep branch of ulnar nerve (C8, T1).

33. Thenar Eminence Muscles
Abductor pollicis brevis
Flexor pollicis brevis
Opponens pollicis
Innervation:
Recurrent branch of median nerve (C8, T1).

34. Thenar Muscles

35. Hypothenar Eminence Intrinsic muscles for digit V.
Abductor digiti minimi
Flexor digiti minimi brevis
Opponens digiti minimi
Innervation:
Ulnar nerve

36. Hypothenar Muscles

37. Long Digital Flexors Flexor digitorum superficialis
Flexor digitorum profundus

38. Flexor Digitorum Superficialis
Flexes PIP (and MCP and wrist).
Each tendon passes through fibrous flexor sheath.
Each tendon bifurcates opposite proximal phalanx.
Each tendon inserts on middle phalanx.

39. Flexor Digitorum Profundus
Flexes DIP (and PIP and MCP).
More active than superficialis.
Each tendon inserts on distal phalanx.

40. Vinculae
Small vascular bundles connecting palmar surface of phalanges with long flexor tendons.
Long and short

41. Long Flexors

42. Dorsal Interossei Four bipennate muscles.
Each arises via two heads from adjacent sides of two metacapals.

43. Dorsal Interossei Insertion: Abducts MP joints of digits 2-4:
Onto extensor expansions and:
Radial sides of proximal phalanges 2 and 3;
Ulnar sides of proximal phalanges 3 and 4.
Note: digit has two dorsal interossei.
Abducts MP joints of digits 2-4:
Reference is line through middle finger.

44. Interossei Muscles

45. Palmar Interossei Four unipennate muscles:
First is sometimes considered part of flexor pollicis brevis.
Supply each digit except third:
Reference is middle finger.
Innervation for all interossei (incl. dorsal):
Ulnar nerve

46. Interossei Muscles

47. Lumbricals Four small, narrow, elongated muscles.
Each arises from the radial side of a flexor digitorum profundus tendon.
Innervation:
Two on radial side:
Median nerve
Two on ulnar side:
Ulnar nerve
Flex MCP joints and extend IP joints.

48. Arterial Supply to Hand
Superficial palmar arch:
Continuation of ulnar artery.
Deep palmar arch:
Continuation of radial artery.

49. Route of Radial Artery Smallest terminal branch of brachial artery.
Passes proximally deep to brachioradialis muscle.
Distally the artery lies against the radius lateral to the tendon of the flexor carpi radialis, where it can be felt (radial pulse).
Passes across scaphoid in anatomical snuff box.

50. Route of Radial Artery Wraps around the dorsum of first metacarpus:
Gives off arteries to the thumb and index finger.
Pierces the first dorsal interosseous muscle and reappears in the palm of the hand.
Gives rise to the deep palmar arch.

51. Deep Palmar Arch

52. Boundaries of the Anatomical Snuff Box
Lateral (anterior):
Tendons of the:
Abductor pollicis longus.
Extensor pollicis brevis.
Medial (posterior):
Tendon of the:
Extensor pollicis longus.

53. Ulnar Nerve in the Hand Enters hand superficial to flexor retinaculum.
Superficial branch:
Muscular branch to palmaris brevis
Cutaneous to palmar aspect of ulnar side of little finger and adjacent sides of little and ring fingers, including tips and dorsum.

54. Ulnar Nerve in the Hand Deep branch:
Supplies hypothenar muscles, all interossei, two ulnar side lumbricals, and adductor pollicis.

55. Nerve Supply to Hand

56. Median Nerve in the Hand
Enters palm deep to flexor retinaculum.
Divides into lateral and medial branches:
Lateral branch:
To thenar muscles and first lumbrical.
Cutaneous to anterior surface of thumb and radial side of index finger.
Medial branch:
To second lumbrical.
Cutaneous to adjacent sides of digits 2-4, including nail-bed and finger tips.

57. Spaces in the Hand Thenar space: Midpalmar space:
Located between the palmar side of the adductor pollicis muscle and the long flexor tendons to the index finger and the thumb.
Midpalmar space:
Located between metacarpals 4-5 and the long flexor tendons to digits 4-5.

58. Clinical Notes Mallet finger: Dupuytren’s contracture:
Avulsion by long flexor tendon.
Results in hyperflexion of DIP.
Dupuytren’s contracture:
Progressive fibrosis of palmar aponeurosis.
Results in marked flexion of fingers at MP joints.
Colle’s fracture.
Fracture of scaphoid.

59. Clinical Notes Median nerve injury: Ulnar nerve injury:
Loss of thumb opposition.
Atrophy of thenar muscles.
Ape hand.
Ulnar nerve injury:
Paralysis and atrophy of interossei.
Guttering
Loss of thumb adduction.
Clawhand.

60. EXTENSOR MECHANISM

61. Components Hood Lateral bands: Central band: Function:
To bases of distal phalanges.
Central band:
To base of middle phalanx.
Function:
Flexion at MCP joint.
Extension at PIP, DIP joints.

62. Functional Notes
Extension of the PIP is always accompanied by the simultaneous extension of the DIP.
When the PIP is flexed, the DIP may be extended or flexed

63. Clinical Notes If lateral bands detach:
Lateral bands will flex the PIP and hyperextend the DIP.