ANAT: Axilla Flashcards
Axillary fascia
continuous with the pectoral fascia covering pectoralis major m.
Axillary base
formed by the skin, subcutaneous tissue, and axillary (deep) fascia of the concave armpit
Anterior axillary wall
formed by pectoralis major and minor mm. and the pectoral and clavipectoral fascia associated with them
Medial axillary wall
formed by the thoracic wall (ribs 1-4 and intercostal muscles) as well as serratus anterior muscle
Posterior axillary wall
formed by subscapularis m. superiorly, and the teres major and latissimus dorsi mm. inferiorly
Posterior axillary fold
formed by lateral borders of the teres major m. and latissimus dorsi m.
Lateral axillary wall
narrow, bony wall formed by intertubercular sulcus (groove) of the humerus.
Axillary apex
Entrance from the neck to the axilla, lies between the 1st rib medially, the clavicle anteriorly, and the superior border of scapula posteriorly
*Nerves and BVs of the upper limb pass thru the axillary apex
First part of axillary artery
1 branch = Superior thoracic artery
Second part of the axillary a.
2 branches =
- Thoracoacromial a.
- Lateral thoracic a.
Third part of the axillary a.
3 branches =
- Subscapular a. (branches into circumflex scapular a.)
- Anterior circumflex humeral a.
- Posterior circumflex humeral a.
Brachial Plexus
5 Rami/roots 3 Trunks 6 Divisions 3 Cords 5 Branches
Rami of Brachial Plexus
(5)
C5-T1
Trunks of Brachial Plexus
(3)
Superior
Middle
Inferior
Divisions of brachial plexus
(6)
3 anterior
3 posterior
Cords of brachial plexus
(3)
Lateral - anterior divisions of upper and middle trunks
Medial - anterior division of lower trunk
Posterior - all 3 posterior division = posterior cord
Branches of brachial plexus
(5) Lateral cord = Musculocutaneous nerve Lateral root of median nerve Medial cord = medial root of median nerve Ulnar nerve Posterior cord = axillary nerve radial nerve
Root branches
muscular branches: C5, 6, 7, 8
Branch to phrenic nerve C5
Dorsal scapular nerve C(4), 5
Long thoracic nerve C5, 6, 7
Branches from Trunk
Nerve to subclavius - C(4), 5, 6
Suprascapular n. - C(4), 5, 6
Branches off Lateral cord
Lateral pectoral n. - C5, 6, 7
Musculocutaneous n. - C5, 6, 7
Lateral root of median n. - C(5), 6, 7
Branches from medial Cord
Medial root of median n. C8, T1 Medial brachial cutaneous n. - C8, T1 Medial antebrachial cutaneous n. - C8 T1 Ulnar n. - C(7), C8, T1 Medial pectoral n. - C8 T1
Branches from posterior cord
Upper scapular n. - C5 C6 Thoracodorsal n. - C6, 7, 8 Lower subscapular n. - C5, 6 Axillary n. - C5, 6 Radial n. - C5-8, T1
Muscular branches
- originate from the roots C5-8
- Innervates: Scaleni and longus colli mm.
Branch to phrenic n.
- Originates from C5 root
- Innervates: Thoracoabdominal diaphragm
Dorsal scapular n.
- Originates from C(4) contribution and C5 root
- Innervates Rhomboideus major and minor mm., levator scapulae
Long thoracic n.
- Originates from C5, 6, 7 roots
- Innervates: serratus anterior m.
Nerve to Subclavius
- Originates C(4) contribution, and C5-6
Innervates: Subclavius m. and sternoclavicular joint
Suprascapular n.
- Originates C4 contribution, C5-6
- Innervates: Supraspinatus, infraspinatus, and glenohumeral joint
Lateral pectoral n.
- Originates from C5-7
- Innervates Pectoralis major m.
Musculocutaneous n.
- Originates C5-7
- innervates: Coracobrachialis, biceps brachii, brachialis, and continues as lateral antebrachial cutaneous n.
Lateral root of median n.
Originates some (C5), C6-7 - Innervates: Flexor carpi muscles in forearm (except FCU and ulnar 1/2 FDP) and 5 hand muscles
Medial root of the median n.
Originates C8 and T1
-Innervates: flexor carpi mm. (except FCU and ulnar 1/2 of FDP) + 5 hand muscles
Medial brachial cutaneous n.
- Originates C8 and T1
- Innervates: Skin on the medial side of the arm
Medial antebrachial cutaneous n.
- Originates from C8 and T1
- Innervates: Skin over medial side of the forearm
Ulnar n.
- Originates C(7), C8 and T1
- Innervates: 1 1/2 flexor muscles in the fore arm, most small mm. in hand, and skin of hand medial to line bisecting 4th digit
Medial pectoral n.
- Originates C8 and T1
Innervates: Pectoralis major and minor mm.
Upper subscapular n.
Origin: C5 and C6
Innervates: Superior portion of subscapularis
Thoracodorsal n.
- Originates from C6-8
- innervates: Latissimus dorsi
Lower subscapular n.
Origin: C5 and 6
Innervates: Inferior portion of subscapularis and teres major m.
Axillary n.
Originates at C5 C6
Teres minor and deltoid, shoulder joint, and skin over inferior deltoid
Radial n.
- Originates C5-8 and T1
- Innervates: Triceps brachii, anconeus, brachioradialis, and extensor mm. of forearm, skin on posterior arm and forearm via posterior cutaneous n. of arm and forearm
Erb’s Palsy (Erb-Duchenne palsy)
C5 and C6 ventral rami torn or superior trunk
nerves affected: axillary, musculocutaneous, suprascapular
Signs: Loss of flexion (biceps brachii, deltoid), abduction (deltoid suprspinatus), and lateral rotation of shoulder/arm (deltoid, infraspinatus, teres minor). Loss of flexion of forearm (biceps brachii, brachioradialis, brachialis) weakness of supination (biceps brachii, brachioradialis)
Position: waiter’s tip
Klumpke’s palsy
C8 and T1 ventral rami or inferior trunk or torn or severed
Effects: medial cutaneous nn. of arm and forearm, ulnar n., and part of median n.
Motor: lost of wrist flexion, and intrinsic muscles of the hand, total claw hand– due to loss of function of lumbricals and interossei, atrophy of intrinsic muscles of hand (Simian hand), weakness of grip at digits IV and V
Horner’s syndrome
Seen in patients with Klumpke’s palsy
-miosis (paralysis of dilator pupillae m.) ptosis (drooping eye lid, paralysis of superior tarsal m.), hemianhydrosis (loss of sweating on one side, injury to cervical sympathetic ganglia)
Posterior cord injury (“Saturday night palsy”)
Injury to posterior cord of brachial plexus
Affects: radial n.
Motor: loss of extension of elbow and triceps reflex (triceps brachii and anconeus) = flexion of elbow
Weakness of forearm flexion (brachioradialis)
Loss of wrist extension and weakness of ulnar and radial deviation (extensor carpi ulnaris, extensor carpi radialis longus and brevis mm.) = wrist flexion
Loss of extension of MCP joints of fingers (extensor digitorum, extensor indicis, extensor digit minimi) = flexion of MCP joints
Loss of extension and abduction of the thumb (extensor pollicis longus and brevis, abductor pollicis longus) = flexion/adduction of the thumb
Sign: Hand is flexed and wrist flaccid “wrist drop”, forearm pronated, thumb adducted, flexed and opposed, fingers flexed.
Chicken wing
