Axilla Flashcards
Axilla
. Pyramidal space inferior to glenohumoral joint and sup. To axillary fascia at junction of arm and thorax
. Base, 4 walls, and apex boundaries
. Contents: brachial plexus, axillary blood vessels, lymph vessels, and axillary lymph nodes
Function of axilla
. Passageway for vessels and nerves to reach upperlimb
Axilla base boundary
. Formed by skin, subQ, and axillary deep fascia of concave armpit
Axillary fascia
. Continuous w/ pectoral fascia covering pec major m.
Ant. Wall boundary in axilla
. Formed by pec major and minor mm and pec and clavipectoral fascia assoc. w/ them
Pectoral fascia
Invests pec major and is continuous inf. W/ fascia of ant. Abdominal wall
Clavipectoral fascia
. Fascial layer extends from axillary fascia
. Encloses pec major and subclavius m. Then attaches to clavicle
. Lat. border of pec major form ant. Axillary fold
Medial wall border of axilla
. Thoracic wall (1st-4th ribs and intercostal muscles) and overlying serratus ant. M.
Axilla posterior wall boundary
. Subscapularis m. Superiorly and teres major and latissimus dorsi inf.
. Post. Axillary fold formed by lat. borders of teres major and latissimus dorsi
Axilla lateral wall boundary
Narrow only wall formed by intertubercular sulcus (groove) of humerus
Axilla apex boundary
. Entrance from neck to axilla
. Between 1st rib medially, clavicle ant., sup. Border fo scapula post.
. Nerve and vessels of upper limb pass through
. Axillary sheath forms neuromuscular bundle
Axillary sheath is extension of ____
Cervical fascia
Contents of axilla
. Infraclavicular part of brachial plexus and its branches
. Axillary vessels and branches
. Axillary lymph nodes
. Muscles: Tendon of long head of biceps, Short head of biceps, Coracobrachialis
. Fat and loose areolar tissue
Axillary artery pathway
. Direct continuation of subclavian
a.
. Begins at the lat. border of 1st rib
. Ends at inf. border of teres major
WHen does axillary a. Become brachial a.
When it passes distal to
the inferior border of teres major
What separates axillary a. Into parts and where does it separate them?
. Pec minor
. Part one: prox. To muscle
. Part 2: post. To muscle.
. Part 3: distal to muscle
Part 1 of axilla artery
. 1 branch
. Btw lat. border of 1st riba nd med. border pec minor
. Enclosed in axilla sheath
. Sup. Thoracic a
Sup. Thoracic artery supplies __
. Sup. Part of thoracic wall including pecs
Second part axilla artery
. 2 branches
. Thoracoacromial a.
. Lat. thoracic artery
Thoracoacromial a.
. Passes med. to pec minor
. Divides into 4 branches
. Supply pecs and ant. Part fo deltoid
Lat. thoracic artery
. Passes lat. to pec minor
. Supplies pecs, serratus anterior
. Gives off lat. mammary arteries of breast in females
Third part fo axilla artery
. 3 branches
. Subscapular a.
. Ant. Circumflex humeral a.
. Post. Circumflex humeral a.
Subscapular a.
. Largest branch
. Gives off circumflex scapular a.
. Becomes thoracodorsal a. Past branching point of circumflex scapular a.
Circumflex scapular a.
. Curves around lat. border fo scapula and anastomoses w/ arteries in dorsal scapular region
Ant. Circumflex humeral a.
. Small branch
. Runs ant. Around surgical neck of humerus and anastomoses w/ post. Humeral circumflex a.
Post. Circumflex humeral a.
. Runs post. Around humerus and supplies shoulder joint and adjacent muscles
What to do if profuse bleeding of upper limb occurs?
. Compress 3rd branch of axilla artery to stop bleeding
Axillary vein
. Med. to axillary a.
. Union of brachial veins and basilic vein at inf. Border of teres major
. Cephalic vein enters close to transition of subclavian v.
. Ends at lat. border 1st rib where it becomes subclavian
Exceptions of axillary vein following axillary artery branches
. Veins corresponding to thoracoacromial a. Don’t merge to common tributary, some enter independently and others enter into cephalic vein
. Axillary vein receives thoracoepigastric vein
Where does cephalic v. Course into?
Deltopectoral triangle
Thoracoepigastric v.
. Formed by anastomoses of superficial veins from inguinal region w/ lat. thoracic v. (Axillary tributary)
. Gives collateral route for venous return in presence of obstruction of inf. Vena cava
Principal groups of axillary lymph nodes
. Apical . Pectoral . Subscapular . Humeral . Central
Apical auxiliary lymph nodes
. At apex of axilla
. Receives lymph from all other axillary lymph nodes and cephalic vein lymph
. Efferent vessels from group unite to form subclavian lymphatic trunk
What trunks forms right lymphatic duct?
. Subclavian lymphatic trunk join jugular and bronchomediastinal trunks on right side
Pectoral group of axillary lymph nodes
. Anterior
. 3-5 nodes along med. wall of axilla
. Receives lymph from ant. Thoracic wall including breast
. Efferent lymph vessels pass to central and apical groups of nodes
Subscapular group of axillary lymph nodes
. 6-7 lymph nodes
. Lie along post. Axillary fold and subscapular blood vessels
. Receives lymph from post. Aspect thoracic wall and scapular region
. Efferent lymph vessels pass to central and apical node groups
Humeral axillary lymph group
. 4-6 nodes on lat. wall of axilla, med. and post. To axillary vein
. Receives nearly all lymph from upper limb except that carried by lymph accompanying cephalic vein
Central axillary lymph node group
.3-4 nodes deep to pec minor near base of axilla
. Associates w/ second part fo axilla a.
. Receives lymph from pectoral, subscapular, and humeral groups
. Efferent vessels pass to apical group of nodes
. Lymph vessels accompanying cephalic v. Drain here
. Lymphangitis
. Warm, red streaks in skin
. Lymph nodes enlarge and become tender
The brachial plexus is the union of ____
. Union of ventral rami of C5-8 and greater part of ventral ramus of T1
. Small contributions from C4 and T2 spinal nerves
Rami/roots of brachial plexus
. 5 segmental ventral rami (C5-T1)
Trunks of brachial plexus
. 5 roots form 3 trunks
. Sup. (Upper) trunk: formed by uniting C5-C6 ventral rami
. Middle trunk: formed by C7 ventral rami
. Inf (lower) trunk: C8 and T1 ventral rami
Anterior and posterior divisions of brachial plexus
. Each trunk splits into anterior and posterior divisions forming 3 ant. And post. Divisions
Cords of brachial plexus
. 6 ant. And post. Divisions unite to form 3 cords
. Lateral cord: ant. Divisions of upper and middle trunks unite (C5-7)
. Med. cord: ant. Division of lower trunk continues alone as medial cord (T8, T1)
. Post. Cord: post. Division of all 3 trunks unite to form post. Cord (C5-T1)
Branches of brachial plexus
. 3 cords form 5 terminal branches
. Lat. cord splits into musculocutaneous nerve and lat. root of median nerve and ulnar nerve
. Post. Cord divides into small axillary nerve and axial nerve
Location of roots and trunks of brachial plexus
. Sup. To clavicle in post. Triangle of neck
. Roots emerge between scalenus anterior and scalenus medius mm.
Location of divisions in brachial plexus
. Post. To clavicle in apex of axilla
Location of cords in brachial plexus
. Inf. To clavicle in axilla where they’re found post. To pec minor
. Surround second part of axillary artery on 3 sides
Terminal branches location of brachial plexus
. Inf. Part of axilla is when cords split into these
Groups of branches of brachial plexus
. Supraclavicular and infraclavicular
How are supraclavicular branches grouped?
. Those arising from roots of brachial plexus and those arising from upper trunk of brachial plexus
Suprascapular branches arising from roots of brachial plexus
. Muscular branches
. Branch that joins phrenic nerve
. Dorsal scapular nerve
. Long scapular nerve
Muscular branches from brachial plexus spinal cord levels and distribution
. C5-8
. Scaleni and longus colli muscles
Branch from brachial plexus that joins phrenic nerve spinal cord level and distribution
. C5
. Thoracoabdominal diaphragm
Dorsal scapular nerve spinal cord level and distribution
. C4-5
. Rhomboideus major and minor
. Levator scapulae
Long thoracic nerve spinal cord level and distribution
. C5-7
. Serratus anterior
Suprascapular Branches from brachial plexus upper trunk
. Nerve to subclavius
. Suprascapular nerve
Nerve to subclavius from brachial plexus spinal cord level and distribution
. C4-6
. Subclavius and sternoclavicular joint
Suprascapular nerve spinal cord level and distribution
. C4-6
. Supraspinatus, infraspinatus, and glenohumoral joint
Infraclavicular branches and how they are traced
. Derived from 3 cords of plexus
. Fibers traced through plexus to spinal cord nerve they originated form
Lateral cord infrascapular branches
. Lat pectoral n.
. Musculocutaneous n.
. Lat. root of median n.
Lateral pectoral nerve spinal cord level and distribution
. C5-7
. Pec major
Musculocutaneous n. Spinal cord level and distribution
. C5-7
. Coracobrachialis, biceps brachii, brachialis
. Continues as lat. antebracxhial cutaneous nerve
Lateral and medial roots of median nerve spinal cord level and distribution
. lat: C5-7
. Med: C8-T1
. Flexor muscles in forearm (except flexor carpi ulnaris, ulnar half of flexor digitorum profundus) and 5 hand muscles
Medial cord infrascaplar branches from brachial plexus
. Med. root of median nerve . Med. brachial cutaneous n. . Med. antebrachial cutaneous n. . Ulnar n. . Med. pectoral n.
Medial brachial cutaneous nerve spinal cord level and distribution
C8, T1
. Skin of med. side of arm
Medial antebrachial cutaneous n. Spinal cord level and distribution
. C8, T1
. Skin over med. side of forearm
Ulnar nerve spinal cord level and distribution
. C7-8, T1
. 1.5 flexor muscles in forearm, most small muscles in hand and skin of hand med. to line bisecting 4th digit
Medial pectoral nerve spinal cord level and distribution
. C8, T1
. Pec major and minor
Posterior cord infrascapular branches from brachial plexus
. Upper subscapular n. . Thoracodorsal n. . Lower subscapular n. . Axillary n. . Radial n.
Upper subscapular nerve spinal cord level and distribution
. C5-6
. Sup. Portion of subscapularis
. Thoracodorsal n. Spinal level and distribution
. C6-8
. Latissimus dorsi
Lower subscapular nerve spinal cord level and distribution
. C5-6
. Inf. Portion of subscapularis and teres major
Axillary nerve spinal cord level and distribution
. C5-6
. Teres minor and deltoid, shoulder joint, and skin over inf. Part of deltoid
Radial nerve spinal cord level and distribution
. C5-8, T1
. Triceps brachii, anconeus, brachioradialis, and extensor muscles of forearm
. Skin on post. Aspect of arm and forearm via post. Cutaneous nerves of arm and forearm
Upper plexus injuries (Erb’s palsy or Erb-DUchenne palsy)
. C5-6 rami or sup. Trunk torn/severed
. Paralysis of proximal limbs (C5-6 myotomes) and loss of sensation in C5-6 dermatomes
. Examples: thrown from horse, stretching infant neck during delivery
What nerve branches are affected by paper plexus injuries?
. Axillary (C5,6), musculotaneous (C5-7), and suprascapular nerves
Signs and symptoms of upper plexus injuries and what muscles correspond
. Loss of flexion and weakness of supination (biceps, brachialis, and brachioradialis)
. Loss of flexion, adduction, and loss of lat. rotation of shoulder joint/arm (biceps, deltoid, supraspinatus, infraspinatus, teresminor)
. Contracture deformities
. Adducted upper limb, medially rotated arm, extended and prostrated forearm (waiter’s tip position)
. Loss sensation on lat. side of upper limb
Lower plexus injuries (Klumpke’s palsey)
. C8, T1 ventral rami or inf. Trunk are torn/severed
. Less common
. Causes: grasping something to break fall, rotate shoulder during birth
Nerve branches affected in lower plexus injuries
. Skin/ muscle or arm and forearm from medial cutaneous arm and forearm, ulnar nerve, part of median nerve (C8-T1)
Signs and symptoms of lower plexus injuries and muscles associated
. Loss of movement in intrinsic hand (palm hollowed ou)
. All digits (esp 9 and 10) extended at metacarpophalangeal joints by unopposed extensors
. Flexed at inter phalange always joint by long digital flexors
. Clawing contracture from loss of medial 2 lumbricals and all interossei m.
. Weakness of grip of digits 9-10 from FDP and hypothenar m.
. Loess of sensation in C8,T1 dermatomes
Posterior cord injury
. Affects radial nerve
. Most frequently encountered
. Causes: incorrect use of crutches
.
Movements affected by posterior cord injury
. Loss of extension of elbows and triceps reflex causing elbow flexion
. Loss of wrist extension and weakness of ulnar/radial deviation causing wrist flexion
. Loss fo extension of MCP joints causing MCP flexion
. Loss of extension and abduction of thumb causing flexion and adduction
Position of limb in radial nerve injury
. Hand is flexed at wrist, lies flaccid (wrist drop)
. Forearm pronated
. Thumb adducted, flexed, and opposed
. Fingers flexed
