Download Region 13: Axilla and Contents, Subscapular Region Surface

Region 13: Axilla and Contents, Subscapular Region
Surface Anatomy
--Anterior Axilary Fold: pectoralis major
--Posterior Axillary Fold: teres major and tendon of latissimus dorsi
Axilla “fat filled pyramidal space inf. to GH joint at junction of arm and thorax”
--Boundaries:
*Base: concave skin, subcutaneous tissue, and axillary (deep) fascia
extending from the arm to the thoracic wall (forms axillary fossa//armpit)
*Apex: cervicoaxillary canal (bounded by 1st rib, clavicle, and superior edge
of scapula), arteries, veins, lymphatic’s, and nerves traverse this superior
opening
*Anterior Wall: pectoralis major and minor and pectoral and clavipectoral
fascia associated with them. Anterior axillary fold is inferiormost part of
anterior wall
*Medial Wall: thoracic wall (1st=4th ribs and intercostal muscles) and
serratus anterior
*Posterior Wall: scapula and subscapularis, teres major and latissimus dorsi
(inferiorly, lat. inserts higher than the teres major), posterior axillary fold
(most inferior)
*Lateral Wall: intertubercular groove of humerus
--Contents
*Nerves: brachial plexus
*Vessels: axillary artery and its branches, axillary vein and its tributaries
*Lymph Nodes (CLASP) embedded in fat
--Central nodes
--Lateral/humeral nodes
--Apical nodes
--Subscapular/posterior nodes
--Pectoral/anterior nodes
--These 5 empty through the cervicoaxillary canal to the
supraclavicular/infraclavicular nodes where they enter the
subclavian lymphatic trunk to right or left venous angle
*Subscapularis Muscle
Subscapularis Muscle
O Subscapular fossa, anterior surface of scapula
I Lesser tubercle of humerus
Inn. Upper and lower subscapular nerves
Medially rotates arm
Act. Adducts arm
SITS (last S)
BS Subscapular artery
Deep Fascia
--Axillary sheath: from prevertebral fascia  surrounds 3 cords of plexus, axillary a,
axillary v.
--suspensory ligament of the axilla (from: clavipectoral fascia)
--Axilla covered by pectoral, axillary and bracial fascias
Brachial Plexus Branches: Supraclavicular Branches
--Dorsal Scapular nerve (3)
*From: C5 anterior rami
*Supplies: Rhomboid Major, Rhomboid Minor, sometimes Levator Scapulae
--Long thoracic nerve (1)
*From: C5, C6, C7 anterior rami
*Supplies: Serratus Anterior
--Suprascapular nerve (2)
*From: superior trunk
*Supplies: Supraspinatus, Infraspinatus, shoulder joint
--Nerve to Subclavius (1)
*From: Superior trunk
*Supplies: Subclavius
*Branch: accessory root to phrenic nerve
Brachial Plexus Branches: Infraclavicular Branches
--Lateral pectoral nerve (1)
*From: Lateral cord
*Supplies: pectoralis major
--Musculocutaneous nerve (3)
*From: terminal branch of lateral cord
*Supplies: anterior compartment (coracobrachialis, biceps brachii,
brachialis), skin of lateral aspect of forearm
*Terminates as: lateral cutaneous nerve of the forearm (name change
occurs at inferior lateral border of biceps brachii)
*Pierces coracobracialis to inn. anterior compartment of arm
--Median nerve
*From: lateral root of median nerve (terminal branch of lateral cord) and
medial root of median nerve (terminal branch of medial cord)
*Supplies: anterior forearm compartment (except flexor carpi ulnaris and
ulnar half of flexor digitorum profundus), five intrinsic muscles in thenar
of palm, palmar skin
--Medial pectoral nerve (2)
*From: medial cord
*Supplies: pectoralis minor and pectoralis major
*Lies lateral to lateral pectoral n. in pectoral region
half
--Medial brachial cutaneous nerve
*From: medial cord
*Supplies: skin of medial side of arm
*communicates with intercostobrachial nerve (lateral cutaneous branch of
2nd intercostal nerve)
--Medial antebrachial cutaneous nerve
*From: medial cord
*Supplies: skin of medial side of forearm
*Terminates: anterior and posterior branches
--Ulnar nerve
*From: terminal branch of medial cord
*Supplies: flexor carpi ulnaris, ulnar half of flexor digitorum profundus,
intrinsic muscles of hand, skin of hand medial to axial line of digit 4
--Upper subscapular nerve (1)
*From: posterior cord
*Supplies: subscapularis
--Lower subscapular nerve (2)
*From: posterior cord
*Supplies: subscapularis and teres major
--Thoracodorsal nerve 91)
*From: posterior cord
*Supplies: latissimus dorsi
--Axillary nerve (2)
*From: terminal branch of posterior cord
*Supplies: teres minor, deltoid, skin of superolateral arm
*Branches: superior lateral brachial cutaneous
--Radial nerve
*From: larger terminal branch of posterior cord
*Supplies: posterior compartments of arm and forearm, skin of posterior and
inferolateral arm, posterior forearm, and dorsum of hand lateral to axial line
of
digit 4
*Branches: inferior lateral brachial cutaneous nerve (sometimes a branch off
of the posterior brachial cutaneous), posterior brachial cutaneous nerve,
posterior antebrachial cutaneous nerve
*Divides: into terminal superficial (cutaneous) and deep (motor) radial
nerves in the cubital fossa
*4 cutaneous branches: inferior lateral brachial cutaneous, posterior brachial
cutaneous, posterior antebrachial cutaneous, superficial radial nerve
Arterial Supply To Axilla
--Subclavian Artery (Right from brachiocephalic trunk, left from arch of aorta to
axillary artery at lower border of 1st rib, split into 3 parts based on ant. scalene)
*First part: 3 branches  vertebral artery, internal thoracic artery,
thyrocervical trunk
--internal thoracic artery: gives rise to perforating branches, anterior
intercostal, musculophrenic, superior epigastric arteries
--thyrocervical trunk: 4 branches  suprascapular, transverse
cervical, ascending cervical, inferior thyroid arteries
*Suprascapular a:
*Second part: 1 branch  costocervical trunk
--Costocervical trunk: superior intercostal and deep cervical branches
*Superior intercostal: supplies 1st 2 intercostal spaces
*Deep cervical branches: posterior deep cervical muscles
*Third part: 1 branch  dorsal scapular artery
--Dorsal scapular: supplies rhomboids and levator scapulae
--Axillary Artery (from subclavian at the lateral border of 1st rib, divided into three
parts based on the pectoralis minor (passes posterior to it), ends at the inferior
border of the teres major)
*First part: one branch superior thoracic a.
--superior thoracic: 1st and 2nd intercostal spaces
*Second part: 2 branches  thoracoacromial trunk, lateral thoracic a.
--Thoracoacromial trunk: pectoral, deltoid, acromial, clavicular
branches
--lateral thoracic: serratus anterior, runs with long thoracic n.
--surrounded by the 3 cords of the brachial plexus (med., lat., post.)
*Third part: 3 branches  subscapular a., ant. circumflex humeral a.,
post. circumflex humeral a.
--subscapular artery: terminal branches  cirmcumflex scapular (in
triangular space) and thoracodorsal arteries (runs with
thoracodorsal n.)
--ant. circumflex humeral a.
--posterior circumflex humeral a: runs with axillary n. in quadrangular
space
--lies between medial and radial nerves
--Axillary Vein: brachial vv. and basilic v. (superficial vein up medial side of forearm
and arm) join to form axillary vein which is also joined by the cephalic vein to form
the subclavian vein
--Brachial Artery (from axillary artery at the inferior border of teres major)
*Profunda brachii artery: runs with radial nerve in triangular interval and
radial groove then anastomose around elbow, supplies posterior
compartment of arm
--middle collateral artery
--radial collateral artery
*Superior ulnar collateral artery: runs with ulnar nerve to posterior aspect of
elbow: anastomoses with posterior ulnar recurrent artery
*Inferior ulnar collateral artery: anastomose with anterior ulnar collateral
artery
Damage to the Brachial Plexus
--Damage to superior part (C5/C6): Erb-Duchenne palsy aka “waiter’s tip position”
--Damage to inferior part (C8/T1): Klumpke paralysis aka “claw hand”
Region 14: Arm and Cubital Fossa
Superficial Landmarks
--Medial Biciptial groove: under biceps brachii where brachial artery pulsations can
be felt
Cutaneous Vessels
--Cephalic Vein
*From: dorsal venous netwok on dorsum of hand
*Communicates: with medial cubital vein, joints axillary vein
--Basilic Vein
*From: Medial end of dorsal venous network on medial side of forearm
*To: axillary vein
*Runs superior to brachial artery
--Median Cubital Vein
Cutaneous Peripheral Nerves
--Lateral antebrachial cutaneous nerve
*Terminal branch of musculocutaneous n.
--Superior lateral brachial cutaneous nerve
*From: terminal branch of axillary nerve (C5, C6)
--Inferior lateral brachial cutaneous nerve
*From: radial nerve (C5, C6) sometiems a branch of post. cutaneous of arm n.
--Medial brachial cutaneous nerve
*From: medial cord
--Posterior brachial cutaneous nerve
*From: radial nerve (C5-C8)
--Intercostobrachial nerve
*From: 2nd intercostal n.
Lymph Nodes
--Cubital nodes: medial side of the elbow
Dermatomes
--C3/C4: base of neck and laterally over shoulder
--C5: supplies lateral arm
--C6: lateral forarm and thumb
--C7: middle and ring fingers and middle of posterior surface of limb
--C8: little finger, medial side of hand and forearm
--T1: middle of forearm to axilla
--T2: small part of arm and skin of the axilla
Deep Fascia
--Medial intermuscular septum: thickening of deep fascia, b/w vessels and medial
head of triceps brachii
--Lateral intermusclar septum: thickening of deep fascia, b/w brachialis and lateral
head of triceps brachii
Muscles of anterior compartment of arm (flexors): biceps brachii, brachialis,
coracobrachialis
Biceps Brachii
O
I
Inn.
Act.
BS
Not
Short head: tip of coracoid process of scapula
Long head: supraglenoid tubercle of scapula
Tuberosity of radius and fascia of forearm via bicipital aponeurosis (anchors
biceps to deep fascia of anterior forearm)
Musculocutaneous nerve
Supinates forearm
Flexes forearm
Flexes arm at shoulder
Brachial artery
*Long head more Lateral
*Transverse humeral ligament holds long head in intertubercular groove,
runs between the greater and lesser tubercles
Brachialis
O
I
Inn.
Act.
BS
Distal half of anterior surface of humerus
Coronoid process and tuberosity of ulna
Musculocutaneous nerve
Flexes forearm (strongest flexor of the forearm)
Brachial artery
Coracobrachialis
O Tip of coracoid process of scapula
Middle third of medial surface of humerus (inserts opposite of deltoid at the
I
location of the nutrient foramen of the humerus)
Inn. Musculocutaneous nerve
Flex arm
Adducts arm
BS Brachial artery
Not Musculocutaneous nerve pierces through this muscle
Act.
Muscles of posterior compartment of arm (extensors): triceps brachii
Triceps Brachii
Long head: infraglenoid tubercle of scapula
O Lateral head: posterior surface of humerus, superior to radial groove
Medial head: posterior surface of humerus, inferior to radial groove
I Proximal end of olecranon of ULNA and fascia of forearm
Inn. Radial nerve
EXTENDS forearm
Act.
Long head: extends arm at shoulder
BS Deep brachial artery
Not Extension assisted by deltoid, teres major, and latissimus dorsi
Arterial Supply to Arm
--Brachial Artery (from axillary artery at the inferior border of teres major)
*Ends as: ulnar and radial nerves in cubital fossa
*Runs with: median n.
*Branches:
--Profunda brachii artery: runs with radial nerve in triangular interval
and radial groove then anastomose around elbow, supplies posterior
compartment of arm
--middle collateral artery
--radial collateral artery
*Superior ulnar collateral artery: runs with ulnar nerve to posterior aspect of
elbow: anastomoses with posterior ulnar recurrent artery
*Inferior ulnar collateral artery: anastomose with anterior ulnar collateral
artery
Injuries to the Arm
--Rupture of Long head of the Biceps: popeye deformity
Cubital Fossa
--Boundaries
*Superiorly: imaginary line connecting medial and lateral epicondyles
*Medially: pronator teres
*Laterally: brachioradialis
--Roof: continuity of brachial and antebrachial deep fascia, reinforced by bicipital
aponeurosis, subcutaneous tissue (with median cubital vein, medial antebrachial
cutaneous nerve/basilic vein, lateral antebrachial cutaneous nerve/cephalic vein),
and skin
--Floor: brachialis and supinator muscles
--Contents: (TAN lateral to medial)
*Biceps brachii tendon
*terminal part of brachial artery and commencement of its terminal
branches (radial and ulnar arteries) and accompanying veins
*Median nerve
*Radial nerve (divides into superficial and deep branches)
--Ulnar nerve
*Runs posterior to medial epicondyle of humerus, most medial, not in the
fossa
--Anastomoses of 4 Collateral arteries with 4 Recurrent arteries
*Superior ulnar collateral (from brachial artery) with
Posterior ulnar recurrent (from ulnary artery distal to ant. recurrent)
*Inferior ulnar collateral (from brachial artery) with
Anterior ulnar recurrent (from ulnar artery just distal to joint)
*Middle collateral (from profunda brachii artery) with
Interosseous recurrent (from posterior interosseous artery)
*Radial collateral (from profunda brachii artery) with
Radial recurrent (from radial artery, just distal to bifurcation)