The Hand Flashcards
ID of carpal bones
So Long to Pinky (scaphoid, lunate, triquetral, pisiform)
Here Comes the Thumb (hamate, capitate, trapezoid, trapezium)
Movement of the digits
Abduction, adduction, extension, flexion
Thumb is also known as
First digit
What is the deep fascia of the hand?
Palmar aponeurosis
Thenar muscle group
Flexor pollicis brevis, abductor pollicis brevis, opponens pollicis
Hypothenar group muscles
Flexor digiti minimi, abductor digiti minimi, opponens digiti minimi
Adductor pollicis function
Innervated by ulnar nerve, NOT A THENAR MUSCLE
Lumbricals
Originate from tendons of FDP, insert into dorsal expansion
Innervation of 1&2 - median nerve
Innervation of 3&4 - ulnar nerve
1&2 median nerve lumbrical innervation also known as…
Anterior interosseous nerve
Dorsal interossei (DABS)
Abduct fingers at the MP joint “DAB” away from the 3rd digit
Innervated by ulnar nerve
Palmar interossei (PADS)
Function: adduct the fingers at MP joints “PAD” towards the 3rd digit
Innervated: ulnar nerve
Superficial arteries of the hand
Ulnar artery contributor, joins superficial palmar branch of radial artery, common palmar digital arteries, proper palmar digital arteries
What is the superficial arteries of the hand referred to?
Superficial palmar arch
Deep palmar arch is mainly from…
Radial artery
Deep branch of the ulnar nerve supplies most muscles in the hand…
Hypothenar muscles, medial two lumbricals, adductor pollicis, all interossei muscles
Superficial branch of ulnar nerve is…
Mainly sensory to the medial hand
Guyon’s tunnel injury
- Spares the palmar cutaneous branch (supplies skin over the hypothenar eminence) and the dorsal cutaneous br (supplies skin over the dorsum of 5th digit)
- Lesions to the nerve more proximally in the tunnel will involve all branches, sparing only FDP, FCU and the dorsal cutaneous branch
- Lesions more distally in the tunnel may spare the superficial sensory branch and innervation to hypothenar muscles
Deficits to ulnar nerve at WRIST
- Wrist flexion is not affected (FCU intact)
- Wasting of hypothenar eminence and interosseous spaces
- severe clawing of digits 4 & 5 because of unbalanced action of FDP
- Froment’s sign
- Sensory loss on palmar aspect of 4th and 5th digits (spares the dorsal cutaneous br)
Clawing of digits mechanism
The interosseii and lumbricals function together to flex the MP joints, extend the IP joints AND counterbalance the strong flexors/extensors of the digits (FDS, FDP & ED). The palmar and dorsal interoseii also work together in adduction/abduction of digits.
When the interosseii and lumbrical acting on a digit are paralyzed, the digit “claws” from unopposed and unbalanced action of forearm muscles (namely extensor digitorum and flexor digitorum superficialis/profundus).
The “clawing” position is opposite the action of the interosseii/lumbricals: therefore, a clawed digit is hyperextended at the MP joint and flexed at the PIP and DIP joints
If ulnar nerve injury occurs, the… lumbricals will be clawed
Medial
Avascular necrosis of scaphoid bone
non-union of proximal and distal fragments after transverse fracture along
the middle 1/3 (“waist” of the scaphoid); the distal portion includes the nutrient artery entrance site – “waist”
fracture can damage this artery and leave the proximal fragment without a blood supply = avascular necrosis
Allen test
tests the integrity of communication between the ulnar and radial arteries in the hand; pt will make a tight fist and the radial and ulnar arteries are compressed at the wrist with your fingers, the pt opens the hand (it should appear pale); the ulnar compression is removed → if the circulation is intact, normal color will return in a few seconds, if the hand remains pale it indicates that ulnar circulation to the hand is insufficient
Mononeuropathy
refers to nerve signs/symptoms restricted to the cutaneous and muscular
distribution of a single nerve (e.g. median mononeuropathy) compare to radiculopathy
Polyneuropathy
refers to nerve signs/symptoms within multiple nerve territories
• diabetes often causes a symmetric, distal polyneuropathy characterized by “stocking and glove” sensory loss
