Hand Flashcards
What clinical feature will show up with a nerve palsy to the ulnar nerve (at the wrist)?
CLAW HAND. Inability to extend fingers at the interphalengeal joints. This results in permanant flexion
What are the functions of ulnar nerve in the hand?
Abduction and Adduction.
Note that adductor pollicis is innervated by the ulnar nerve as well. Therefore all of adduction will be gone if the ulnar nerve becomes damaged. Conversely, you will still get abduction in the thumb as well as well as opposition and flexion in the thumb becuase the median nerve innervates those structures.
What clinical feature will show up with a nerve palsy to the median nerve (at the wrist)?
- APE HAND
2. HAND OF BENEDICTION (Will see the deformity when trying to make a fist)
What clinical feature will show up with a nerve palsy to the radial nerve (at the wrist)?
Loss of sensation. However, proximal to the elbow will be Wrist Drop
What would happen if the radial nerve was damaged at the WRIST?
Loss of sensation (Dorsal side, Lateral 3 1/2 fingers) but not motor function because the radial nerve does not provide motor functon at the wrist
What muscles do the ulnar nerve supply in the hand?
The ulnar nerve supplies most of the hand except for the lateral 1/2 LOAF which is supplied by the median nerve.
What is the normal function of the lumbricals? Where do they originate?
- Flex the metacarpalphalengeal joints
- Extend the proximal and distal interphalengeal joints
They originate from the flexor digitorum profundus
This allows us to SALUTE. It allows us to PINCH THE PULP OF THE FINGERS NOT THE TIPS ( The interphalangeal joint must remain extended)
What muscle does the median nerve innervate in the hand.
1/2 LOAF. Lateral 1/2 Lumbricals Opponens Pollicis Abductor Pollicis brevis Flexor Pollicis brevis
Extensor Expansion Hood
Common hood which aids in extension of fingers because it receives the extensor digitorum, interossei and the lumbrical tendons.
Dorsal Interossei
DABS. Four 2-headed muscles starting at the thumb. They abduct the fingers.
Palmer Interossei
PADS. Three single-headed muscles starting at the pinky which adduct the fingers. There is no muscle for the middle because we don’t need it. The middle finger is our reference point.
What are the bones of the hand?
List starting from attachment to the radius and swinging back around to the radius.
Scaphoid ( We have a tubercle of scaphoid) Lunate Triquetrum Pisiform Hamate ( We have a hook of hamate) Capitate Trapazoid Trapezium
What are the bones of the hand?
List starting from attachment to the radius and swinging back around to the radius. Considered Proximal Row and then Distal Row.
Scaphoid ( We have a tubercle of scaphoid) Lunate Triquetrum Pisiform Hamate ( We have a hook of hamate) Capitate Trapazoid Trapezium
How does the ulnar nerve and ulnar artery enter the hand?
Through the Canal of Guyon
The Carpal Tunnel houses one nerve. Which is it?
Median Nerve
Carpal Tunnel contents and boundaries
9 tendons and 1 nerve
- Tendons of the Flexor Digitorum Superficialis (4 tendons)
- Tendons of the Flexor Digitorum Profundus (4 tendons)
- Flexor Pollicis Longus (1 tendon)
Carpal Tunnel contents and boundaries
9 tendons and 1 nerve (Median Nerve)
- Tendons of the Flexor Digitorum Superficialis (4 tendons)
- Tendons of the Flexor Digitorum Profundus (4 tendons)
- Flexor Pollicis Longus (1 tendon)
Posterior boundry: Carpal bones
Anterior boundry: Flexor retinaculum
Palmar Aponeurosis
Thin over the thenar and hypothenar eminences, but thick in the palm.
Blood supply to the hand?
Radial Artery
Continues around the lateral carpi bones (Radial pulse). It then moves dorsally where it can be seen across the floor of the snuff box. It then dives DEEP piercing the FIRST DORSAL INTEROSSEOUS where it continues through the palm to form the DEEP PALMER ARCH.
Note: There is a superficial palmer branch of the radial artery that branches off to anastomose with superficial palmer arch of the ulnar artery.
Other branches are the principes pollicis and the radialis indicis
Ulnar Artery
Enter the hand with the ulnar nerve via the canal of Guyon. The superficial branch becomes the SUPERFICIAL PALMER ARCH. It flows across the palm to the fingers giving off the COMMON PALMER DIGITAL ARTERY which becomes the PROPER PALMER DIGITAL ARTERY
Note: there is a deep branch of the ulnar artery that passes between the ABductor digiti minimi and the flexor digiti minimi to anastomose with the deep palmer arch of the radial artery.
Median Artery
There is no Median artery
USRD (Arteris)
Ulnar superficial: Radial Deep
Nerve supply
Radial Cutaneous only (called Superficial Branch)
Passes over the anatomical snuff box. Innervates dorsal lateral 2 1/2 digits proximal to the DIP joint (distal interphalangeal joints)
Median Nerve
Enters the hand under the flexor retinaculum throught the carpal tunnel. Innervates:
1/2 LOAF
Recurrent Thenar Branch
Becomes common palmer digital and then proper palmer digital.
Provides cutaneous sensation to the palmer lateral 3 1/2 fingers and the dorsal nail beds of the same fingers (considered distalP
Ulnar Nerve
Pierces every muscle in the hand except the few exceptions 2 1/2 on dorsal side (named dorsal cutaneous branch) and 1 1/2 on palmer side (named palmer cutaneous branch)
Claw Hand
Effects your ulnar nerve. We know that the ulnar nerve innervates almost every muscle of the hand but the lumbricals are the most important in this situation.
We know that only the 3 and 4 lumbricals are innervated by the the ulnar nerve so we expect to the the deformity in the pinky and ring finger.
Instead of normal action of the lumbricals we get hyperextension of the 4th and 5th metacarpalphalnegeal joints and flexion of the PIP’s and DIP’s.
Also important in the chracteristic claw hand is due to the unopposed action activity of the extensor digitorum muscle.
USUALLY AT THE WRIST IF AT THE ELBOW WILL SEE TO A LESSER DEGREE
Ape Hand
Median Nerve.
Wasting of Thenar muscle. Inability to oppose thumbs. Thumb is pulled posteriorly and lines up with the other digits.
This can happen if the median nerve is injured at the wrist or the elbow
Hand of Benediction
Median nerve deformity while trying to make a first. It almost looks like the claw hand but for different reasons. In this case the pinky and ring finger (partially) are completely fine they can flex down but the lateral 3 1/2 fingers cannot.
Wrist Drop
Radial nerve usually damaged proximal to the elbow causing a loss of motor innervation to the wrist extensers in the forearm.
There is no opposition to the flexors so the wrist hangs down.
