cervical and brachial phlexus Flashcards
(44 cards)
Main roots(ventral rami) of cervical plexus:
C1 to C4, C5 not a major root
The plexus is formed in front of the Levator scapula and Scalenus medius, and covered by the Sterno-cleido-mastoid.
Each nerve, except the first, divides into an
upper and a lower branch, and the branches
unite to form three loops.
Cervical plexus is sandwiched between the
scalene muscles posteriorly and SCM anteriorly.
middle post. border of SCM, a point where nerves wrap around the border of SCM.
Punctum nervousum-Is formed by the anterior divisions of the upper four cervical nerves. (4 branches go to the punctum nervousum)
cervical plexus- branches are divided into
two (superficial & deep) groups
which supplies the skin of the upper and back part of the auricle.
lesser occipital(C2) (superficial sensory)
is distributed to the skin of the face over the parotid gland, and the skin over the mastoid process and on the back of the auricle.
Great auricular(C2,3)(superficial sensory)
distributed to the antero-lateral parts of the neck.
Transverse cervical(C2,3) (superficial sensory) which formed by the midline,scm and the lower border of mandible
branches that are divided into three major groups (anterior, middle, and posterior) supplying the skin from the middle line to the skin over the Pectoralis major and Deltoid and also the skin of the upper and posterior parts of the shoulder.
Supraclavicular(C3,4) (superficial sensory)-above the clavicle
(deep branches of cervical)
Deep Internal communicating With:
Hypoglossal (C1) cranial nerve 12 communicate with c1
vagus (C1,2), cranial nerve 10 communicates with c1 ,c2
sympathetic (C1-4).
deep branches of cervical
Muscular branches to:
Rectus capitis lateralis (C1),
Rectus capitis anterior (C1,2),
Longus capitis (C1-3).
deep branches of cervical
Deep External communicating with:
Accessory (C2-4).
deep branches of cervical
Muscular branches to:
Sternocleidomastoid (C2),
Trapezius (C3,4),
Levator scapula (C3,4),
Scalenus medius (C3,4).
contains motor and sensory fibers in the proportion of about two to one. It arises chiefly from the fourth cervical nerve, but receives a branch from the third and another from the fifth.
It’s motor fibers supply the diaphragm, and the sensory fibers will supply parts of pleura and peritoneum lining the diaphragm.
Phrenic Nerve roots C 3, 4, 5
NOTE: If asked in exam phrenic nerve is a pure motor!
sandwiched between ant scalene and middle scalene
Brachial Plexus
SCM not touching the brachial plexus
Is formed by the anterior ram (roots of plexus)i of spinal nerves C5-T1.
C5 and C6 will join to form the upper trunk
C7 will make the middle trunk by itself
C8 and T1 also unite to form the lower trunk.
Each trunk will divide into anterior and posterior divisions.
_____ of the upper and middle trunk will unite to form the lateral cord.
Anterior divisions
The medial cord is just made by the anterior division of the lower trunk.
The posterior cord is formed by the union of all posterior divisions.
The branches derived from the roots or trunks of the plexus are called supraclavicular branches
those derived from the cords are called infraclavicular branches.
(brachial)The main branches derived from the cords include:
Lat. Cord:
Lat. Pectoral [C5 – C7] (motor) -pec major and pec minor*more important for pec major
Musculocutaneous [C5 – C7] (Mixed)
Lat. Root of median nerve [C5– C7]
(brachial)The main branches derived from the cords include: Med. Cord:
Med. Pectoral [C8 – T1] (motor) pec major and pec minor *pec minor
Med. Cutaneous n. of arm [T1] (sensory)
Med. Cutaneous n. Of forearm [C8 – T1] (sensory)
Ulnar [C7 – T1]mixed nerve
Med. Root of median nerve [C8 – T1] - combine with lateral root of median nerve to become median nerve
(brachial)The main branches derived from the cords include: Post. Cord:
Upper subscapular [C5 – C6]-pure motor,supplies half of subscapularis
Thoracodorsal [C6 – C8], lats
Lower subscapular [C5 – C6],-pure motor nerve that reaches the lower part of subscapularis,supplies also teres major
Axillary [C5 – C6]-mixed nerve with motor and sensory
Radial [C5 – T1] -largest and more important branch
The major nerves in supra-clavicular group include:
Nerve to scaleni and longus coli root[C5 – C8]
Long thoracic root[C5 – C7] to serratus anterior
Dorsal scapular [rootC5] to rhomboidei and levator scapula
Suprascapular [C5 – C6] to supraspinatus and infraspinatus
upper trunk
Nerve to subclavius upper trunk [C5 – C6]
This nerve is one of the branches of the lateral cord.
It enters the arm by piercing the coracobrachialis muscle and then lies between biceps and brachialis. Here it supplies all the muscles in the anterior compartment.
Musculo-cutaneous
After leaving the arm the remaining part of the musculo-cutaneous is called “lateral cutaneous nerve of forearm”, which supplies the skin of the lateral aspect of the forearm.
sympathetic/visceral motor branch
This nerve is formed by the union of medial and lateral roots derived from medial and lateral cords respectively.
After entering the arm, this nerve descends on the medial bicipital groove and leaves the arm with only giving off one sympathetic (vasomotor) branch to the artery (brachial branch).
The median nerve enters the forearm region deep to the pronator teres and flexor digitorum superficialis. Here it gives branches to most of the muscles of the anterior compartment (except FCU and medial half of FDP). The deep muscles of this area are supplied by the anterior interosseous branch of median nerve.
Just above the wrist the palmar cutaneous branch is derived from the median nerve. This branch innervates the skin of the lateral 2/3 of the palmar surface of the hand.
After passing through the carpal tunnel, the nerve enters the hand and just inferior to flexor retinaculum it gives off the recurrent branch that supplies the thenar muscles (except half of the FPB).
Finally after supplying the lumbricals (1-2), the terminal branches of the nerve (common palmar digital nerves) will supply the lateral 3 ½ fingers.
median nerve
