UL Boundaries Flashcards
(7 cards)
Anatomical snuff box
When the thumb is extended (like thumbs up), a triangular hollow appears at the base of your thumb
Boundaries-
-Medial side (top)- EPL- extensor pollicis longus
-Lateral side- EPB and APL (extensor pollicis brevis and abductor pollicis longus)
-roof: skin, fascia, cephalic vein and superficial branch of radial nerve
-Floor from proximal to distal:
Styloid process of radius, scaphoid bone, trapezium bone, base of first metacarpal
Content- radial a.
Clinical Importance-
- when fracture scaphoid, doesn’t show up right away on X-rays (lots of fractures don’t apparently)
- so if fall on outstretched hand, push deep into snuffbox on fractured/bruised/injured scaphoid process, patient will scream in pain
- extensor retinaculum in vicinity
Cubital fossa
Triangular hollow space at the junction of arm and forearm
Boundaries-
- Superiorly: an imaginary line connecting the medial and lateral epicondyles.
- Medially: pronator teres (humerus (superior) and ulnar head (inf))
- Laterally: brachioradialis (sf) (elbow flexor lying in extensor compartment;
- originates at lateral epicondyle
- inserted at distal end of radius)
- Floor: brachialis medially (superficial-sf) and supinator laterally (deep) muscles
-Roof: Skin and superficial fascia
(• Bicipital aponeurosis
• Median cubital vein
• Medial cutaneous nerve of forearm
• Lateral cutaneous nerve of forearm)
[most imp structure in roof is median cubital vein (vein used to draw blood (vein = no smooth muscle > collapse), ideal vein for venipuncture, intravenous injections and cardiac catheterizations; comm. btwn basilic (medial) and cephalic v. (lateral); runs upwards and medially from the cephalic to the basilic vein
-separated from the brachial a. and median n. by the bicipital aponeurosis]
-medial cutaneous and lateral cutaneous nerves (lat cutaneous n. from MUSCULOCUTANEOUS nerve) of the forearm
-median cubital v. continues w cephalic v. as median antebrachial v.
Content- medial to lateral: Madeline Brown’s Big Red Purse
- Median Nerve (leaves the cubital fossa by passing between two heads of the pronator teres to enter the forearm)
- Brachial Artery (continuation of axillary artery beyond the lower margin of teres major muscle; continues down ventral surface of the arm until [cubital fossa]/neck of radius, where it divides into the radial and ulnar a.)
- Biceps tendon (inserts on radial tuberosity)
- Radial Nerve (req deep dissection to see) (terminates in the lateral part of the cubital fossa by dividing into superficial and deep (posterior interosseous) branches)
- Posterior interosseous nerve (req deep dissection to see) (deep branch of the radial nerve, after crossing/piercing supinator m.)
- -
- Radial artery gives rise to radial recurrent branch
- Ulnar artery gives rise to the 1) anterior and 2) posterior ulnar recurrent branches and 3) common interosseous artery (which divides into anterior and posterior interosseous branches)
Carpal Tunnel
Structures-
Tendons of the FDS (4, lie superficially) and FDP (4) pass through a common ulnar sheath/ulnar bursa (8 tendons total), while the tendon of FPL (flexor pollicis longus) passes through a separate radial sheath (1 tendon lateral). > 9 tendons TOTAL
Median n. passes through the tunnel between tendons of FDS and FDP
Functional loss-
- Compression of the median nerve can occur here (carpal tunnel syndrome) leading to clinical symptoms associated with median nerve lesion.
- Since carpal tunnel is so narrow, tight, will get carpal tunnel syndrome from pressure on nerve if overuse wrist (eg typing, hairstyling)-common US occupational hazard
Carpus, the bones of the wrist, form an arch which is convex on the dorsal side of the hand and concave on the palmar side.
Groove on the palmar side, the sulcus carpi, is covered by the flexor retinaculum (bridges across carpal bones and converts the space into carpal tunnel)
Flexor retinaculum of wrist is attached
-laterally to scaphoid and trapezium bones
-medially to pisiform and hook of hamate bones
Superficial to the carpal tunnel and the flexor retinaculum, the ulnar artery and ulnar nerve pass through the ulnar tunnel
Narrowest section of the tunnel is located a centimeter beyond the mid-line of the distal row of carpal bones
Axilla
- It is a pyramidal space which lies between the upper parts of the medial side of the arm and the side of the chest wall.
- It has an apex, base, anterior, posterior, medial and lateral walls
Boundaries-
Shape- Pyramid/triangular shape
Apex: cervico-axillary canal (triangular opening for the passage of structures between neck and upper limb) Cervico=neck; axillary=axilla;
-Boundaries- middle 3rd of clavicle, 1st rib, superior border of scapula
Base
skin, superficial and deep fascia (axillary fascia)
Anterior wall (4)- (forms anterior axillary fold) pectoralis major, pectoralis minor, subclavius m., clavipectoral fascia- from pec minor to subclavius
Posterior wall (forms post. axillary fold)
• Subscapularis
• Teres major
• Latissimus dorsi
Subscapularis-insert into lesser tubercle-most powerful medial rotator of shoulder joint, rarely injured in rotator cuff injuries
Teres major-inserted into lower lip of bicipital groove (deep groove on upper humerus that separates the greater tubercle from the lesser tubercle)
Lats-inserted into bicipital groove
Medial wall
Ribs 1-4
Upper 3-4 intercostal spaces, contains intercostal muscles
Serratus anterior (Upper 4 or 5 digitations)
Long thoracic nerve
Lateral wall
-Intertubercular groove (sulcus) with its attachments (Teres major and pec major come together, inserted into intertubercular sulcus; lats)
x Contents • Vessels - Axillary • Nerves – Brachial plexus • Lymph nodes – Axillary • A pad of Fat • Tail of the breast!
[axillary a. (in axilla, subclavian a. > axillary a. > (pass lower margin of teres major) brachial a.), axillary v., brachial plexus, axillary sheath, axillary lymph nodes (Each gp has own area of drainage
eg enlarged axillary lymph nodes sometimes indicate breast cancer but also drains other structures besides breasts)]
x Clinical Importance-
If axillary v. lacerated in axilla, risk of producing air embolus (travelling air bubble that can block artery/lung, can cause death)
Vessel actually punctured in typical “subclavian” vein puncture (for catheter insertion aka subclavian catheter) > actually accessory vein
Lies anterior, medial to axillary artery (superficial)
Formed by union of brachial and basilic veins
May receive blood from inguinal (groin) region of body
Quadrangular Space
Boundaries- • Above: subscapularis, teres minor • Below: teres major • Lateral: surgical neck of humerus • Medial: long head of triceps
Content- axillary n., posterior circumflex humeral a., v.
Upper Triangular Space
Lies medial to long head of triceps
Boundaries-
• Above: teres minor (inserts into greater tubercle)
• Below: teres major
• Lateral: long head of triceps
Content- circumflex scapular vessels (a., v.)
Lower Triangular Space
Boundaries-
• Above: teres major
• Medial: long head of triceps
• Lateral: shaft of the humerus
Content- radial n., profunda brachii vessels
