Lecture 12 Flashcards
What is the precision grip?
When the intermediate and distal phalanges and thumbs press against each other.
Prehensile.
How many carpal bones and how many rows of carpals are there?
Eight bones in two rows.
What carpal bones are in the bottom row?
Scaphoid, lunate, triquetrum, pisiform
What carpal bones are in the second row?
Trapezium, trapezoid, capitate, Hamate.
Which carpal bones make contact with the radius?
Lunate
Scaphoid
Which side of the scaphoid has its blood supply compromised when the scaphoid is fractured?
Proximal
At which point does the scaphoid fracture?
Between the proximal and distal ends = point of weakness.
What does a fracture of the hook of Hamate cause?
Ulnar canal syndrome
Handlebar neuropathy
Compression of the ulnar artery
What are the fascial components?
Palmar aponeurosis Hyperthenar fascia Thenar fascia Adductor pollicis Interosseous
Which metacarpals are most likely to fracture?
The first and fifth.
What movements occur at the first metacarpal?
Flexion Extension Opposition Circumduction Adduction Abduction
What is the power grip?
When the fingers (sometimes palm) clamp down on an object with the thumb.
Prehensile.
What occurs with contracture of palmar aponeurosis?
Thickening and shrinking of palmar fascia.
Typically affecting ring and little finger.
Thought to be inherited.
What is the contents of the carpal tunnel?
Flexor tendons
Median nerve
Synovial sheath
What forms the roof and floor of the carpal tunnel?
Roof: flexor retinaculum
Floor: carpal bones
What structures pass superficial to the flexor retinaculum?
Over roof of carpal tunnel
Palmaris longus tendon. Ulnar artery and ulnar nerve. Superficial branch of radial artery. Palmar cutaneous branch of median nerve. Flexor carpi ulnaris.
What structures pass deep to the flexor retinaculum?
AKA the carpal tunnel
Flexor digitorium superficialis (4 tendons) Flexor digitorium profundus (4 tendons) Flexor pollicis longus Median nerve Flexor carpi radialis Synovial sheaths
What are the attachments of the extensor retinaculum?
Laterally: radius
Medially: triquetrum, pisiform, flexor carpi ulnaris
What are the contents of the extensor retinaculum?
Nine tendons Six tunnels 1. APL + EPB 2. ECRL + ECRB 3. EPL 4. ED + EI 5. EDM 6. ECU
Synovial sheaths
What are the boundaries and contents of the anatomical snuff box?
Contents: radial artery.
Roof: skin, subcutaneous tissue, cephalic vein, radial nerve(superficial branch).
Floor: scaphoid, trapezium.
Boundaries: anteriorly tendons of APL and EPB, posteriorly tendons of EPL.
Which muscles form layer 1 of the intrinsic muscles of the hand?
What is their origin and insertion?
Thenar:
> Abductor pollicis brevis
> Flexor pollicis brevis
Hypothenar:
> Abductor digiti minimi
> Flexor digiti minimi
Origin: edges of flexor retinaculum
Insertion: base of proximal phalanx
Which muscles form layer 2 of the intrinsic muscles of the hand?
What is their origin and insertion?
Lumbricals (x4)
Origin: arise from FDP tendons, pass to lateral side of digits
Insertion: dorsally onto extensor expansion (digits 2-4)
Which muscles form layer 3 of the intrinsic muscles of the hand?
What is their origin and insertion?
Thenar:
> Opponens pollicis
> Adductor pollicis
Hypothenar:
> Opponens digiti minimi
Origin: edges of flexor retinaculum
Insertion: borders of metacarpals
Which muscles form layer 4 of the intrinsic muscles of the hand?
What is their origin and insertion?
Interossei
X3 palmar
X4 dorsal
Origin: metacarpals
Insertion: extensor expansion (digits 1-4)
What is the median nerve supply of intrinsic hand muscles?
Recurrent branch:
Abductor pollicis brevis
Flexor pollicis brevis
Opponens pollicis
Lateral branch:
First and second lumbricals
What is the ulnar nerve supply of intrinsic muscles of the hand?
Deep branch: Adductor digit minimi Flexor digitorium minimi Opponens digiti minimi Adductor pollicis Third and fourth lumbricals Interossei
