Lecture-7 Axilla & Arm Flashcards
Pectoralis Major
2 heads: -Clavicular head
-Sternocostal Head
Inserts: crest if greater tubercle of humerus/lateral lip of intertubercular sulcus
Innervation: lateral/medial pectoral nerves
Action: -adducts, medial rotation, flex humerus, scapula protraction
-enclosed in pwctoral fascia
Pectoralis Minor
Origin: ribs 3-5
Inserts: -coracoid process
Innervation: - medial pectoral nerve
Action: -Stabilizes scapula against thorax wall by drawing it anteriorly and inferiorly
Subclavius
-Attaches clavicle to 1st rib
-Innervation: subclavian nerve
Action: depresses scapula
Serratus Anterior
Inserts: attaches to medial scapular border
Innervation: long thoracic nerve
Action: -protraction, upward rotation of scapula
Axila
- pyramidal shaped region at junction of upper extremity/thorax
- transmits nerves/vessels between neck/thorax proximally and the upper extremity distally
Axillary contents
- axillary artery + branches
- axillary vein +tributaries
- axillary lymph nodes +lymph vessels
- Parts of brachial plexus
- axillary sheath of fascia
Borders of Axilla
Apex: formed by convergence of clavicle, scapula, and 1st rib
Base: formed by axillary fascia
Anterior wall: pec major and minor + fascia
Posterior wall: anterior part of scapula and scapular muscles
Lateral wall: intertubercular groove of humerus, tendon of long head of biceps braccii traverses the intertubercular groove
Axillary Artery
-begins at lateral border of 1st rib, ends at inferior border of teres major
-divided into 3 parts by pec minor
First part: -medial to pec minor -one branch: superior thoracic artery
Second part: -posterior to pec minor - 2 branches: -Thoracoacromial artery
(4 branches: pectoral, clavicular, deltoid, acromial)
-Lateral thoracic artery
Third part: -lateral to pec minor -3 branches: -subscapular -anterior circumflex -posterior circumflex
Axillary Vein
- A continuation of basilic vein
- at inferior border of teres minor
- turns to subclavian at lateral broder of 1st rib
- cephalic vein pierces costocoracoid membrane to enter medial part of axillary vein
Brachial plexus
-goes inferior and deep to clavicle
-has region superior to claavicle and distal to clavicle
C5-T1
Primarily responsible for motor and sensory
-thoracoappendicular and appendicular muscles
Musculocutaneous
- Terminal Branch
- C5,6,7
- provides innervation to anterior arm
- becomes lateral cutaneous nerve of forearm
Median
- Terminal Branch
- C6-T1
- Innervates anterior compoartment of forearm -except flexor carpi ulnaris and part of flexor digitorum profundus
- innervates thenar muscls and lateral 2 lumbricals in hand
Ulnar
-Terminal Branch
-C8-T1
Innervates 2 and a half muscles
Radial
- Terminal Branch
- From posterior cord
- C5-T1
- innervates posterior aspect of upper extremity
Axillary
-Terminal Branch
From posterior cord
-C5,6
-innervates deltoid, teres minor, long head of triceps
Dorsal Scapular
- From root level
- C5
Suprascapular
-From trunk
level
-C5,6
-to supraspinatus and infraspinatus
Nerve to subclavius
- From trunk level
- C5
Lateral/medial pectoral
- From cord level
- C5,6,7 / C8,T1
- To pec majorm medial nerve also supplies pec minor
Upper subscapular
- From cord level
- C5,6
- to subscapularis
middle subscapular/thoraco dorsal
- From cord level
- C6,7,8
- To lat. dorsi
lower subscapular
- From cord level
- C6,7,8
- to subscapularis and teres major
Long thoracic
- From root level
- C5,6,7
Lesion types
Avulsion: nerve torn from spine, can’t heal
Rupture: nerve is torn but not at spinal attachment
Neuroma: nerve torn and healed, but scar tissue puts pressure on injured nerve and prevents it from conducting signals to muscles
Neuropraxia: - damaged but not torn
Biceps Brachii
Distal Attachment: Radial tuberosity and fascia of forearm
Proximal Attachment: short head: tip of coracoid long head: supraglenoid tubercle of scapula
Innervation: Musculocutaneous nerve (C5,6)
Action: Supinates forearm, flexes forearm
Brachialis
Distal Attachment: Coronoid process and ulnnar tuberosity
Proximal Attachment: Distal half of anterior surface of humerus
Innervation: Musculocutaneous nerve (C5,6)
Action:Flexes forearm in all positions
Coracobrachialis
Distal Attachment: Middle third of medial surface of humerus
Proximal Attachment: Tip of coracoid process
Innervation: Musculocutaneous nerve (C5,6,7)
Action: flex and adduct arm
Musculocutaneous nerve
innervates: -coracobrachialis -biceps brachii -brachialis
- gives rise to lateral cutaneous nerve of forearm
Median nerve
-travels distally behind biceps entering forearm in cubital fossa -no innervation of arm
Ulnar nerve
- most medial, passes to forearm posterior to medial epicondyle
- no innervation of arm
Radial nerve
- innervates triceps brachii
- descends posterior to humerus along radial groove
- ccourses anteriorly at distal humerus and crosses anterior to lateral condyle
Brachial Artery
- Deep artery of arm (profunda brachii)
- muscular branches
- middle collateral
- radial collateral
- humeral nutrient branch
- superior ulnar collateral
- inferior ulnar collateral
- muscular branches
Triangular space
Made by: -long head of triceps brachii
-teres minor -teres major
passage to posterior arm for:
-circumflex scapular artery
Quadrangular space
Made by: -long head of triceps brachii -teres major -teres minor -neck of humerus
passage to posterior arm for: -posterior circumflex humeral artery -axillary nerve
Triangle interval
Made by: - teres major -long head of triceps brachii -shaft of humerus
passage to posterior arm for: -radial nerve
-deep artery of the arm
