Download KUMC 23 Wrist and Hand Student

WRIST COMPLEX
Bones and Joints of the
Wrist
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.
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
Distal Row of Carpal Bones:

Trapezium:
Most lateral
Trapezoid
 Capitate
 Hamate

Distal Row of Carpal Bones:
Entire complex enclosed in a common
synovial membrane.
 Articulations are plane joints that perform
gliding motions.

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
Radiocarpal Joint Ligaments

Lateral (radial) collateral ligament.
Medial (ulnar) collateral ligament.
Dorsal radiocarpal ligament.
Palmar radiocarpal ligament.

Strengthen capsule



Radiocarpal Joint Functions
Some flexion and extension
 Ulnar deviation

Radiocarpal Joint Arteries
Articular arteries
 Arise from dorsal and palmar carpal
arches.

Radiocarpal Joint Nerves
Anterior interosseous branch of median
nerve.
 Posterior interosseous branch of radial
nerve.
 Dorsal and deep branches of the ulnar
nerve.

Radiocarpal Joint Injuries
Colle’s fracture
 Scaphoid fracture

Usually at “waist”
Compromises radial artery in snuffbox
Midcarpal Joint

Made up of intercarpal joints:
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.
Midcarpal Joint

Ligaments:
Dorsal ligaments.
Palmar ligaments.
Interosseous ligaments.

Nerves and arteries:
Same as for radiocarpal.
Palmar Structure Sequence
(radial to ulnar)
Radius
 Radial artery
 Flexor carpi radialis tendon
 Median nerve:

Under palmaris longus tendon
Palmar Structure Sequence
(radial to ulnar)
Flexor digitorum superficialis tendons
 Ulnar artery
 Ulnar nerve
 Flexor carpi ulnaris tendon

HAND
Carpometacarpal Joints
Plane synovial joints:
 Motion:

None for digits 2-3
Limited for 4
More mobile for 5
Carpometacarpal Joints
Saddle (sellaris) joint between metacarpus
and trapezium:
 Movements:

Abduction/adduction
Flexion/extension
Circumduction
Opposition
Metacarpophalangeal Joints
Condyloid synovial joints
 Movements:

Flexion/extension
Abduction/adduction
Some opposition at MCP 5

Capsular ligaments:
Palmar ligaments (pads)
Collaterals
Interphalangeal Joints
Synovial hinge joints
 Only flexion/extension allowed
 Ligaments:

Strong collaterals
Proximal interphalangeal joints (PIPs)
 Distal interphalangeal joints (DIPs)

Dorsal Venous Drainage
Dorsal venous arch drains hand dorsum.
 Medially drains into basilic.
 Laterally drains into cephalic.

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:
Lateral axillary nodes.
Arterial Supply to Dorsum

Via dorsal arterial arch from:
Radial and ulnar arteries.
Dorsal metacarpals.
 Dorsal digitals.

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.
Long Extensors
Superficial Palm
Palmar aponeurosis
 Flexor retinaculum
 Palmaris brevis

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).

Flexor Retinaculum
= Transverse carpal ligament.
 Laterally attaches to tubercles of scaphoid
and trapezium.
 Medially attaches to hook of hamate and
pisiform.

Palmaris Brevis Muscle

O:
I:
 A:

Flexor retinaculum and palmar
aponeurosis.
Skin on medial side of palm.
Tenses skin on palm.
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.
Long Flexors
Intrinsic Muscles of the Thumb
Thenar eminence:
 Adductor pollicis:

Innervation:
Deep branch of ulnar nerve (C8, T1).
Thenar Eminence Muscles
Abductor pollicis brevis
 Flexor pollicis brevis
 Opponens pollicis


Innervation:
Recurrent branch of median nerve (C8, T1).
Thenar Muscles
Hypothenar Eminence

Intrinsic muscles for digit V.
Abductor digiti minimi
 Flexor digiti minimi brevis
 Opponens digiti minimi


Innervation:
Ulnar nerve
Hypothenar Muscles
Long Digital Flexors
Flexor digitorum superficialis
 Flexor digitorum profundus

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.

Flexor Digitorum Profundus
Flexes DIP (and PIP and MCP).
 More active than superficialis.
 Each tendon inserts on distal phalanx.

Vinculae
Small vascular bundles connecting palmar
surface of phalanges with long flexor
tendons.
 Long and short

Long Flexors
Dorsal Interossei
Four bipennate muscles.
 Each arises via two heads from adjacent
sides of two metacapals.

Dorsal Interossei

Insertion:
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.
Interossei Muscles
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
Interossei Muscles
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.
Arterial Supply to Hand

Superficial palmar arch:
Continuation of ulnar artery.

Deep palmar arch:
Continuation of radial artery.
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.

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.

Deep Palmar Arch
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.
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.
Ulnar Nerve in the Hand

Deep branch:
Supplies hypothenar muscles, all interossei,
two ulnar side lumbricals, and adductor
pollicis.
Nerve Supply to Hand
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.
Spaces in the Hand

Thenar 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.
Clinical Notes

Mallet finger:
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.

Clinical Notes

Median 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.
EXTENSOR MECHANISM
Components
Hood
 Lateral bands:

To bases of distal phalanges.

Central band:
To base of middle phalanx.

Function:
Flexion at MCP joint.
Extension at PIP, DIP joints.
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

Clinical Notes

If lateral bands detach:
Lateral bands will flex the PIP and
hyperextend the DIP.