T2 L6: Anatomy of the hand Flashcards
What are the 3 types of bone in the hand?
The carpals, metacarpals, and phalanges bones
What are the 8 carpel bones?
Scaphoid Lunate Triquetral Pisiform Trapezium Trapezoid Capitate Hamate
What are some complications of a scaphoid fracture?
There is poor radial blood supply to the proximal part of the bone so there will be avascular necrosis id the injury is not fixed
What are the 6 joints in the hand?
- Saddle joint at the thumb
- Radiocarpal joint at the wrist
- Midcarpal/ intercarpal
- Carpometacarpal
- Metacarpophalangeal
- Interphalangeal
Which ligaments reinforce the radiocarpal joint?
Ulnar and radial collateral ligaments limit abduction/adduction
Ligaments on the palmar/dorsal surface limit extension/flexion
What types of joints are carpometacarpal joints?
plane joints apart from the saddle joint between trapezius and metacarpal d1
What types of joints are metacarpophalangeal joints?
Condyloid joints
What is the deep transverse metacarpal ligaments?
They unify the metacarpals but not between d1 and d2
What types of joints are interphalangeal joints?
Hinge joints
What is the clinical significance of the palmar aponeurosis?
It’s composed from longitudinal and transverse fibres and is continuous with palmaris longus
It’s where Dupuytren’s contracture occurs
In which digits is flexor digitorum and profundus found?
D2-D5 (all except thumb)
How do flexor digitorum profundus and superficialis interact?
They pass through eachother at the proximal interphalangeal joint
What are vinculae?
Bands of connective tissue that attach tendons to phalangeal bones
What are fibrous annular and cruciate ligaments?
They attach the finger tendons to the phalangeal bones
Annular are simple rounded, cruciate cross over the phalangeal joints
What are the names of the long extensor tendons to the digits?
D1
- Extensor pollicis longus
- Extensor pollicis brevis
- Abductor pollicis longus
D2-D5
- Extensor digitorum
- Extensor indicis
- Extensor digit minimi
They extend from muscles in the posterior forearm
What muscles attach to the extensor hood of fingers?
Intrinsic muscles of the hand (the lumbricals and the interossei)
What is the clinical significance of the anatomical snuff box?
To palpate the scaphoid bone and the radial pulse
What are the boundaries of the anatomical snuff box?
Extensor pollicis brevis and extensor pollicis longus
What is the function of the lumbricals?
They extend the interphalangeal joints and flex metacarpophalangeal joints
They’re for precision grip Eg. pinching
Which digits have bifennate lumbricals?
d3,d4, and d5 (ring and pinky finger)
What is the function of palmar interossi?
They adduct metacarpalphalangeal joints (bring finger together)
There are none on d1 and d3 because they don’t adduct (all fingers move away from d3)
How many palmar interossei muscles are there?
3
How many lumbricals are there?
4 (2 are bifennate)
What is the function of dorsal interossei?
They abduct at the metacarpalphalangeal joint (bring fingers apart)
How many dorsal interossei muscles are there?
4 (d2, d3 x2, and d4)
Why are there no interossei muscles on d1 and d5?
Abduction is performed by thenar and hypothenar muscles instead
What is the origin of thenar and hypothenar bones?
Flexor retinaculum and adjacent carpal bones
Which muscles make up the thenar group?
Opponens pollicis (deepest)
Abductor pollicis brevis
Flexor pollicis brevis
Which muscles make up the hypothenar group?
Opponens digiti minimi (deepest)
Abductor digiti minimi
Flexor digiti minimi
What are the intrinsic muscles of the hand?
Thenar Hypothenar Lumbricles Interossei Adductor pollicis
Which muscles performs adduction of the thumb?
Adductor pollicis
It has an oblique head based on 2nd and 3rd metacarpal and carpal bones and it has a transverse head attaches to the 3rd metacarpal
It attaches to the proximal phalanx
Which artery supplies d1 and 1/2 d2?
Radial artery
Which artery forms the deep palmar arch?
Radial artery
Which artery forms the superficial palmar arch?
Ulnar artery
Which artery supplies 1/2 d4 - d5?
Ulnar artery
Which nerve passes through the carpal tunnel?
The median nerve
What causes a clawed hand?
Damage to the ulnar nerve at the wrist
