Anatomy of the hand Flashcards
Starting most laterally, state the names of the proximal carpal bones
Scaphoid
Lunate
Triquetral
Pisiform
Starting most laterally, state the names of the distal carpal bones
Trapezium
Trapezoid
Capitate
Hamate
Which bone in the proximal carpal bone is prone to francture?
Scaphoid
- slow recovery due to poor blood supply to proximal part –> avascular necrosis
State the joints of hands
Wrist (radiocarpal)
Midcarpal/intercarpal
Carpometacarpal (saddle joint)
Metacarpophalangeal
Interphalangeal
Describe the wrist joint
Between radius/disc and first carpal row
Reinforced by ligaments
- Ulnar and radial collateral ligaments
- Ligaments on the palmar/dorsal surfaces
Facilitates flexion/extension, abduction/adduction and circumduction
State the functions of the ligaments which stabilise the wrist
Ulnar and radial collateral ligaments
- limits abduction/adduction
Ligaments on the palmar/dorsal surfaces
- limits extension/flexion
Radial styloid process
- limits range of abduction
Describe the carpometacarpal joinits
- Plane joints which limit movement
EXCEPT for the saddle joint (between trapezium and d1) which enables opposition
State the movements of the thumb
Extension, flexion, abduction, adduction, opposition, reposition
Describe the metacarpophalangeal joints
Condylar joints
Facilitate flexion/extension, abduction/adduction
The deep transverse metacarpal ligaments unifies metacarpals but not between d1 and d2
Describe the interphalangeal joints
Hinge joints
Facilitate flexion/extension
Proximal interphalangeal joints (PIPs) AND Distal interphalangeal joints (DIPs)
Describe the palmar aponseurosis and its clinical relevance
Thickened deep fascia in a triangular shape which is continuous with palmaris longus. Contains longitudinal and transverse fibres
Dupuytren’s contracture is fibrosis of it
Describe the long flexor tendons to digits
From muscles in anterior forearm and pass through carpal tunnel
Paired tendons enter fibrous digital sheaths –> synovial sheath
Alternating fibrous annular (a1-5 pulleys) and cruciate ligaments
The vinculae attaches tendons to phalanges
Which muscles from the posterior forearm serve d2-5?
Extensor digitorum
Extensor indicis
Extensor digit minimi
Which muscles from the posterior forearm serve d1?
Extensor pollicis longus
Extensor pollicis brevis
Abductor pollicis longus
How can you detect fracture in scaphoid bone?
Scaphoid fracture = pain in anatomical snuff box
State the borders of the anatomical snuff box and give their insetions
Abductor pollicis longus
-To base of 1st metacarpal
Extensor pollicis brevis
- To base of proximal phalanx
Extensor pollicis longus
- To base of distal phalanx
State the insertion of the medial and lateral bands of the extensor digitorum
Medial band
- into middle phalanx
Lateral band
- into distal phalanx
Which muscles insert into the extensor hoods
lumbricals and interossei
What is the function of the lumbricals?
- Link flexor to extensor tendons
- Extend interphalangeal joints and flex MCP joints
- Precision grip
State the location and innervation of the lumbricals
Lateral to d2-5 (intrinsic muscles)
Median nerve supple lateral 2
Ulnar nerve supplies medial two
Describe the palmar interossei muscles
- Three of them which sit between the metacarpals
- Insert into extensor hoods (d2,4,5)
- They ADDUCT MCP joints (relative to middle finger)
Which muscle causes adduction of D1?
Which muscle causes abduction of D1 and 5
adductor pollicis muscle
thenar and hypothenar muscles
Describe the dorsal interossei muscles
- Four of them which originate at metacarpals and insert into extensor hoods of d2, d3 (x2) and d4
- They ABducT MCP joints
State the function and origin of the thenar and hypothenar muscles
Thenar muscles - fine movement of d1
Hypothenar muscles- fine movement sof d5
Originate at flexor retinaculum and adjacent carpal bones
Describe the thenar muscles
Composed of three muscles
- Opponens pollicis (deepest) inserts into first metacarpal
- Abductor pollicis brevis
- Flexor pollicis brevis
(both insert into proximal phalanx)
Describe the hypothenar muscles
Composed of three muscles
- Opponens digiti minimi (deepest) inserts into fifth metacarpal
- Abductor digiti minimi
- Flexor digiti minimi
(both insert into proximal phalanx)
Describe the muscle responsible for adduction of the thumb
Adductor pollicis (deep to thenar muscles)
Oblique head
- base 2nd and 3rd metarcarpal and carpal bones
Transverse head
- ased 3rd metacarpal
Insert onto proximal phalanx\
How is the hand anastomosis made? Why is it important?
Radial artery (towards dorsal surface) and ulnar artery
So that blood can reach all parts in all hand positions
D1 and 1/2 D2 mainly radial artery
Describe the deep palmar arch
- BELOW long flexor tendons
- ## forms floor of anatomical snuff box
State the arterial supply to d1 and d2
D1 and 1/2 D2 mainly radial artery
The branches are:
- princeps pollicis artery
- radialis indicis artery
Describe the superficial palmar arch
- ABOVE long flexor tendons
- three common palmar digital arteries and proper palmer digital arteries
1/2 d2 -d5 = ulnar artery
Describe the median nerve in the hand
- Passes through carpal tunnel and gives off recurrent branch (to thenar muscles)
- Digital nerve supplies lateral 2 lumbricals and sensory d1 to 1/2 d4
- Clinically responsible for carpal tunnel syndrome
Describe the ulnar nerve in the hand
Superficial branch
- sensory to 1/2 d4 and d5
Deep branch
- to hypothenar muscles, interossei, medial two lumbricals and adductor pollicis
- Clinically responsible for ‘clawed hand’
