Brachial Plexus
Division of brachial plexus
3 anterior, 3 posterior divisons
Branches of brachial plexus that emerge from trunks
Both from superior trunk Suprascapular n. (C5, C6) Nerve to subclavius muscle
Muscles for lateral rotation of shoulder
C5 Infraspinatus Teres minor Posterior deltoid
Muscles for shoulder abduction
C5 Lateral deltoid Supraspinatus
Muscles for flexion of shoulder
C5 anterior deltoid coracobrachialis pect. major (clavicular head) biceps brachii
Muscles for adduction of shoulder
C6-C8 Pect. major Latissimus dorsi Teres major
Muscles for extension of shoulder
C6-C8 Posterior deltoid Latissimus dorsi Teres major Triceps, long head Pect. major (sternocostal portion)
Muscles for medial rotation of shoulder
C6-C8 Subscapularis Pect. major Teres major Latissimus dorsi Anterior deltoid
Branches of brachial plexus that emerge from roots
Dorsal scapular n. (C5) Long thoracic n. (C5, C6, C7)
Upper brachial plexus injuries often result in
Erb-Duchenne palsy. "waiter's tip". Occurs when shoulder and neck are violently separated, causing paralysis of muscles in shoulder and arm supplied by C5 and C6)
Lower brachial plexus injuries (C8 and T1) results in
Klumpe paralysis. "claw hand". Occurs when upper limb is suddenly pulled superiorly, injuring inferior trunk of brachial plexus.
Branches of brachial plexus that emerge from lateral cord
Lateral pectoral nerve (C5, C6, C7) Musculocutaneous nerve (C5-C7) Lateral head of median nerve (C6, C7)
Which artery supplies muscles of chest wall?
Lateral thoracic a.
Klumpe paralysis is caused by
Lower brachial plexus injuries. Occurs when upper limb is suddenly pulled superiorly, injuring inferior trunk of brachial plexus.
Branches of brachial plexus that emerge form medial cord
Medial pectoral nerve (C8, T1) Medial cutaneous nerve of arm (C8, T1) Medial cutaneous nerve of forearm (C8, T1) Medial head of medial nerve (C8, T1) Ulnar nerve (C8, T1)
Branches of brachial plexus that emerge from divisions
NONE
Which artery supplies deltoid muscle and glenohumeral joint?
Posterior circumflex humeral arteries
Brachial plexus is divided into which 5 parts
Root Trunk Division Cords Branches
Rotator cuff muscles
SITS: Supraspinatus Infraspitantus Teres minor Subscapularis
Which branch of axillary a. is located below the pect. minor?
Subscapular a. (scapular circumflex, thoracodorsal) Anterior/posterior circumflex humeral a.
Which rotator cuff muscle attaches to lesser tubercle of humerus?
Subscapularis
Which branch of axillary a. is located above the pect. minor?
Superior thoracic a.
6 branches of axillary artery
Superior thoracic a. (above pect. minor) Thoracoacromial a. (behind pect minor) Lateral thoracic a. (behind pect. minor) Subscapular a. (below pect.minor) Anterior and posterior circumflex humeral a. (below pect. minor, divides into scapular circumflex a. & thoracodorsal a.)
Trunks of brachial plexus
Superior= C5+C6 roots Middle= C7 root Inferior trunk= C8+T1
Cutaneous innervation of shoulder region
Supraclavicular c. (C3-4) Superior lateral cutaneous of arm- branch from axillary n. Intercostobrachial n. (T2)
Which rotator cuff muscle attach to greater tubercle of humerus?
Supraspinatus Infraspinatus Teres minor
Which branches of axillary a. is located behind the pect. minor?
Thoracoacromial a. Lateral thoracic a.
Which artery supplies muscles of anterior shoulder?
Thoracoacromial artery
Which artery supplies muscles of posterior axillary wall?
Thoracodorsal branch of subscapular artery
Branches of brachial plexus that emerge from posterior cord
ULTRA: Upper subscapular nerve (C5) Lower subscapular nerve (C6) Thoracodorsal nerve (C6, C7, C8) Radial nerve (C5-T1) Axillary (C5, C6)
Brachial plexus derives from ___ of spinal nerve.
anterior primary rami
Roots of brachial plexus derive from ___.
anterior primary rami of cervical spinal nerve C5, C6, C7, C8, T1
Posterior circumflex humeral artery passes
around the posterior aspect of the surgical neck
Which artery passes behind pect. minor?
axillary artery
Anterior deltoid is innervated by
axillary n.
Teres minor is innervated by
axillary n.
Lateral thoracic artery supplies
chest wall, and gives rise to lateral mammary branches
Rotator cuff injury may occur from
chronic wear and tear or an acute fall on an outstretched arm, producing instability of glenohumeral joint. Often the tendon of the supraspinatus is ruptured due to inflammation and calcification of the tendon, producing pain during abduction of arm.
Thoracic outlet syndrome is caused by
compression of neurovascular structures passing through the cervico-axillary canal (thoracic outlet), often involving inferior trunk. The compression occurs as a result of cervical ribs or abnormal insertions or size of the anterior and middle scalene muscles. Compression of subclavian artery can result in ischemic muscle pain.
Which ligament form an arch above the shoulder joint?
coracoacromial lig.
Branches from the infraclavicular part of the plexus arise from
cord of the plexus
Axillary nerve innervates
deltoid teres minor skin of shoulder
Posterior circumflex humeral artery supplies
deltoid muscle and glenohumeral joint
Median nerve innervates
forearm flexor muscles
Injury to Axillary nerve can be caused by
fracture of surgical neck of humerus or inferior dislocation of the humerus
which two ligaments strengthen the glenohumeral joint?
gelnohumeral lig. coracohumeral lig.
Glenohumeral joint involves articulation of which structures?
humerus and glenoid cavity of scapula
Subscapular artery supplies
lateral border of scapula (scapular circumflex a.) muscles of posterior axillary wall (thoracodorsal a.-latissimus dorsi)
Anterior circumflex humeral artery passes
laterally around the front of the surgical neck of humerus
Erb duchenne has what characteristic posture?
limb hanging by the side of the body (adduction) in medial rotation.
What marks the transition from subclavian to axillary artery?
lower border of first rib
What marks the transition from axillary to brachial artery?
lower border of teres major
Teres major is innervated by
lower subscapular n.
Ulnar nerve innervates
majority of hand muscles
Pect. major is innervated by
medial and lateral pectoral n.
Musculocutaneous nerve innervates
muscles of anterior compartment of arm, skin of lateral forearm
Thoracoacromial artery supplies
muscles of anterior shoulder
Biceps brachii is innervated by
musculocutaneous n.
Coracobrachialis is innervated by
musculocutaneous n.
Cords of brachial plexus
named after their relationship to axillary artery. Lateral- formed from anterior division of superior and middle trunk. Medial- formed from anterior division of inferior trunk Posterior- formed from posterior divisions of all three trunks
Symptoms of thoracic outlet syndrome
pain, numbness, tingling, or weakness and fatigue in upper limb.
Axillary artery passes behind what muscle?
pectoralis minor. Axillary artery is divided into the part above the muscle, behind the muscle, below the muscle.
Radial nerve innervates
posterior compartment muscles and skin of arm and forearm
Rotator cuff muscle function
provide major support for shoulder joint and form a musculotendinous cuff around the joint
Triceps long head is innervated by
radial nerve
Nerve branches from the supraclavicular part of the plexus are derived from
roots (2 branches) superior trunk (2 branches)
Axillary artery is a direct continuation of
subclavion artery
Lower subscapular nerve innervates
subscapularis teres major
Upper subscapular nerve innervates
subscapularis muscle
Infraspinatus is innervated by
suprascapular n.
Supraspinatus is innervated by
suprascapular n.
Suprascapular nerve innervates
supraspinatus and infraspinatus
Rotator cuff injury often produce rupture of ___ tendon.
supraspinatus due to inflammation of the tendon. Produces pain during abduction of arm.
Subscapularis is innervated by
upper and lower subscapular n.
Erb-Duchenne palsy results from
upper brachial plexus injuries. Occurs when shoulder and neck are violently separated, causing paralysis of muscles in shoulder and arm supplied by C5 and C6)
Erb duchenne is due to
upper brachial plexus injury that damages C5 muscles responsible for abduction and lateral rotation. So muscles responsible for adduction and medial rotation act unopposed.
Injury to axillary nerve can result in
weakness of lateral rotation and abduction of the arm at the glenohumeral point