MSK L4.1 Upper Limb Flashcards
(28 cards)
What are the four major segments of the upper limb?
What are the 3 areas of transition in the upper limb?
- Shoulder
- Arm
- Forearm
- Hand
Axilla
Cubital fossa
Carpal tunnel
Upper limb movements:
Shoulder and arm
Upper limb movements – elbow and forearm
Movements of the upper limb – wrist and hand
Compartments of upper limb
Anterior compartment & Posterior compartment
Golden rule
- Deep fascia wraps mucles, forms compartmets via intermuscular septa
- Anterior compartment: mostly flexors
- Posterior compartment: mostly extensors
Clinical considerations of fascia:
1) 2 properties of deep fascia
2) What does it do?
3) How is it linked to surgery?
4) What happens in severe swelling of fascia?
- Deep fascia is thick, non-expandable
- Creates tight compartments → limits swelling
- Fascial planes = potential spaces for surgical access
- In severe swelling (e.g., burns) → fasciotomy/escharotomy needed to relieve pressure
1) Causes of compartment syndrome
2) Symptoms of COMPARTMENT SYNDROME
3) What can compartment syndrome be confused with?
4) Treatment for compartmeny syndrome?
1) High pressure in closed compartment. Due to bleeding, fracture, swelling (burn, fracture, exercise)
This leads to reduced blood supply, ischemia, nerve and muscle damage (could be temporary or permanent
2) Symptoms (Think: “Pain + Nerve”):
Pain+++ (out of proportion) Paresthesia (tingling/numbness) Pulses usually still present un til late (important clue!)
3) It can be confused with acute arterial injury, which is a blocked artery, with this, pulses are abscent or very weak early on. Remember 5 Ps of arterial injury: Pain, pale skin (pallor), pulselesness, paresthesia, paralysis (late sign)
4) Fasciotomy
Bony structure of upper limb
- Shoulder girdle: Clavicle + scapula
- Arm: humerus
- Forearm: Radius (lateral, thumb side) Ulna (medial, little finger side)
- Hand = carpals, then metacarpals, then phalanges
Pathway into and out of upper limb
- Major structures (artery, vein, nerves) pass from thorax intoo arm:
1. Over first rib
2. Under clavicle
3. Through axillry inlet (entry point to armpit)
🧠 Memory Tip: “OVER, UNDER, THROUGH” = 1st rib, clavicle, axilla
Motor Nerve Supply of Upper Limb
1) What innervates the upper limb?
2) Where does the plexus originate?
3) Formation of plexus
- Innervated by brachical plexus
- Cervical and thoracic spninal cord levels: C5, C6, C7, C8, T1
3) Formation of brachial plexus begins in neck, and
continues into axilla arm forearm hand
Dermatomes
Cutaneous Nerve Area
Peripheral nerve
- Dermatomes: skin area supplied by a single spinal nerve root e.g. C6 dermatome = thumb
- Cutaneous Nerve Area - Skin area supplied by a named periheral nerve. Radial nerve = back of hand
- Peripheral nerve - Mixed nerve, motor + sensory, formed from multiple roots, part of brachial plexus.
Main nerves of the upper limbs
Arteries of the upper limb
Deep veins vs Superficial Veins
Superficial veins - clinical importance
Deep Veins: Travel with arteries, named after the artery they follow
Superficial: Do not run with arteries, found in subcutaneous tissue, under skin. Main veins cepalic ]
USED FOR VENEPUNCTURE, transfusion, cardiac catheterisation
Lymphatic system - general
📍 Lymph Nodes
Bean-shaped immune filters Found along lymphatic vessels Filter lymph before it returns to the venous system
Lymphoid tissue = immune aggregates (e.g. tonsils)
Describe the lymphatic drainage system of the upper limb
- Superficial lymphatic vessels: Run with superficial veins (cephalic, basilic), drain into axillary lymph nodes
- Deep lymphatic vessels: Run with deep veins (brachical veins), also drain into axillary nodes
🧠 Key Area: Axilla has many lymph nodes
Cause, effects and signs of Lymphoedema
Cause: blocked/damged lymphatic drainage (e.g. after lymph node removal_
Effect: Accumulation of intersitital fluid
Signs: Swelling, usually non-pitting
🧠 Memory Tip:
"No nodes = No drain = Swell remains"
What is the function of the pectoral region?
Where is it located?
What does it consist of?
- Anchors upper limb to trunk
- External to anterior thoracic wall
- Sternoclavicular joint, muscles, ligaments.
Superficial compartment: Skin, superficial fascia, brest tissue
Deep compartment: muscles
X - pectoral region, over pectoralis major
Scapula and humerus anatomy
- Acromion
-Coracoid process
-Greater tubercle
-Lesser tubercle
Greater + lesser tuburcle = attatchment point for rotator cuff muscles.
Clavicle anatomy
Acromioclavicular joint vs Sternoclavicular joint
Which one is dislocation more common in
Which ligament supports the sternoclavicular joint?
Which ligament supports the acromioclavicular joint?
Type of joints
What is the function of the coracoacromial ligament?
Connects coracoid to acromion.
Forms arch over shoulder joint
- Supports shoulder joint supeiorly
- Prevents dislocation
- CAN IMPINGE ON SUPRASPINATUS/SUBACROMIAL BURSA
AC joint dislocation
Clinical signs
Common causes
- Ligaments holding joint torn (coracoclavicaulr ligaments)
- C lacicle pops up, visible bump on shoulder
Clinical signs
-Obvious shoulder deformity
-Pain, tenderness
Sports injuries, falls.
🧠 Memory Tip:
"AC joint dislocation = collarbone sticks up because the straps (ligaments) are torn."
Fractures of clavicle
1) ✅ Where do fractures usually happen?
2) ⚠️ How do they happen?
3) 💥 What happens when it breaks?
4) Which vessels may be damaged?
5) What can it be confused with?
1) Middle 1/3 most common. Weakest point.
2) Fall onto outstretched hand.
Fall directly onto lateral shoulder
3) Two ends of bone move in opposite directions, due to muscle contractions and gravity
4) Subclavian artery/vein
5) AC joint dislocation. In AC dislocation, ends of clavicle is sticking up alone, in clavicular fractures, both parts of bone still visible.
