1.1.1 Pre-Midterm Anatomy - Upper Limb

Front 1

List the sites commonly used for veniputure in the upper limb:

Back 1

1. Basilic Vein
2. Median Cubital Vein
3. Cephalic vein

Front 2

Describe the basic medchanism of radial head subluxation (“nursemaid's elbow”)

Back 2

The pathologic lesion is generally a tear in the attachment of the annular ligament to the periosteum of the radial neck, with the detached portion becoming trapped between the head of the radius and the capitellum. The older child will usually point to the dorsal aspect of the distal forearm when asked where it hurts. This may mislead one to suspect a buckle fracture of the distal radius.If the forearm of a young child is pulled, it is possible for this traction to pull the radius into the annular ligament with enough force to cause it to be jammed therein. This causes significant pain, partial limitation of flexion/extension of the elbow and total loss of pronation/supination in the affected arm. The situation cannot arise in adults, or in older children, because the changing shape of the radius associated with growth prevents it.

Front 3

What is the anatomical snuffbox?

Back 3

The anatomical snuffbox, or radial fossa, (in Latin Foveola radialis), is a triangular deepening on the radial, dorsal aspect of the hand—at the level of the carpal bones, specifically, the scaphoid and trapezium bones forming the floor. The name originates from the use of this surface for placing and then sniffing powdered tobacco, or “snuff.”

Front 4

Describe the landmarks used when taking the radial pulse

Back 4

Pulsation of the radial arteries can be felt on the inside of the wrist. A good way to find this is to use the index and middle finger of the opposite hand. Follow the line of the thumb down until the wrist is reached. People will note bones at the wrist right below the thumb. Once these bones are passed, a small area of soft tissue is reached, and the radial pulse should be noticed. This is about an inch to half an inch (2.54 cm- 1.27cm) below where the hand meets the wrist on the thumb side, not directly in the center of the wrist.

Front 5

Describe the signs and symptoms of Carpal tunnel syndrome:

Back 5

Carpal tunnel syndrome typically starts gradually with a vague aching in your wrist that can extend to your hand or forearm. Other common carpal tunnel syndrome symptoms include: Tingling or numbness in your fingers or hand, especially your thumb and index, middle or ring fingers, but not your little finger. This sensation often occurs while holding a steering wheel, phone or newspaper or upon awakening. Many people “shake out” their hands to try to relieve their symptoms. As the disorder progresses, the numb feeling may become constant. Pain radiating or extending from your wrist up your arm to your shoulder or down into your palm or fingers, especially after forceful or repetitive use. This usually occurs on the palm side of your forearm. A sense of weakness in your hands and a tendency to drop objects.

Front 6

Explain the important of an Allen Test:

Back 6

Allen's test, also Allen test, is used to test blood supply to the hand. It is performed prior to radial arterial blood sampling or cannulation Testing for collateral circulation to the hand by evaluating the patency of the radial and ulnar arteries. The hand is normally supplied by blood from the ulnar and radial arteries. The arteries undergo anastomosis in the hand. Thus, if the blood supply from one of the arteries is cut off, the other artery can supply adequate blood to the hand. A minority of people lack this dual blood supply.

Front 7

Describe the cause of ulnar “claw-hand” deformity:

Back 7

Pathogenesis, aka the “cause”:
An ulnar claw may follow an ulnar nerve lesion[5] which results in the partial or complete denervation of the medial two lumbricals of the hand. Since the lumbricals normally flex the MCP joints (aka the proximal knuckles), their denervation causes these joints to become extended by the newly unopposed action of the extensor muscles of the forearm (namely the extensor digitorum and the extensor digiti minimi).
However, if the lesion of the ulnar nerve occurs at the level of the wrist, the innervation of the medial half of the flexor digitorum profundus muscle (FDP), which is responsible for flexing the IP joints (the two distal joints of the fingers), is unaffected. It is the extension of the MCP joints coupled with the slight flexion of the IP joints that gives the hand the claw-like appearance.
Ulnar nerve: Deficit is primarily in 4th and 5th fingers. Deficit is most prominent at rest and when the patient is asked to extend his fingers. Often accompanied by inability to abduct or adduct the 2nd, 3rd, 4th, and 5th finger. Often accompanied by apparent atrophy of the first dorsal interosseous muscle of the hand

Front 8

List the commonly fractured bones in the carpus:

Back 8

Carpal bone fractures account for 18% of hand fractures. Of the carpal elements, bones in the proximal row are the most frequently fractured. The scaphoid is by far the most common carpal bone fractured, representing 70% of fractures in the carpal group and 10% of all hand fractures.3,4 Triquetral fractures are the second most common, accounting for 14% of wrist injuries. The incidence of isolated fractures of any of the remaining carpal bones is comparatively low, in the range of 0.2-5%.

Front 9

List the steps in performing an Allen's Test:

Back 9

1) The hand is elevated and the patient is asked to make a fist for about 30 seconds.
2) Pressure is applied over the ulnar and the radial arteries so as to occlude both of them.
3) Still elevated, the hand is then opened. It should appear blanched (pallor can be observed at the finger nails).
4) Ulnar pressure is released and the color should return in 7 seconds. Inference: Ulnar artery supply to the hand is sufficient and it is safe to cannulate/prick the radial If color does not return or returns after 7-10 seconds, then the ulnar artery supply to the hand is not sufficient and the radial artery therefore cannot be safely pricked/cannulated.