Brachial Plexus

BRAQUIAL PLEX

Brachial Plexus SchemeThe upper limb is innervated by the brachial plexus in the neck and armpit, formed by anterior branches of the four lower cervical spinal nerves (C5, C6, C7, C8) and the first thoracic (T1). The brachial plexus is located lateral to the cervical spine and is located between the anterior and middle scalene muscles, posteriorly and laterally to the sternocleidomastoid muscle.

The plexus passes posteriorly to the clavicle and follows the
axillary artery under the pectoralis major muscle.

The ventral branches of the fifth and sixth cervical nerves (C5-C6) form the upper trunk; the anterior branch of the seventh cervical nerve (C7) forms the middle trunk; and the anterior branches of the eighth cervical nerve and first thoracic nerve (C8-T1) form the lower trunk.

 Brachial Plexus - Trunks

The three trunks, located in the supraclavicular fossa, are divided into two branches, one anterior and one posterior, which form the fascicles, located around the axillary artery. The anterior branches of the upper and middle trunks form the lateral fascicle; the anterior branch of the lower trunk forms the medial fascicle; and the posterior branches of the three trunks form the posterior fascicle. In the inferior and lateral border of the pectoralis minor muscle, the fascicles are subdivided in the terminal branches of the brachial plexus.

 Brachial Plexus - Anterior and Posterior Branches

BRAQUIAL PLEX
  Brachial Plexus
Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.

The branches of the brachial plexus can be described as supraclavicular and infra-clavicular.

Supravavicular Branches:

 Nerves for Scalene and Long Neck Muscles & #8211; they originate from the ventral branches of the lower cervical nerves (C5, C6, C7 and C8), near their exit from the intervertebral foramina.

 Phrenic Nerve & #8211; anteriorly to the anterior scalene muscle, the phrenic nerve is associated with a branch from the fifth cervical nerve (C5). More details of the phrenic nerve in Cervical Plexus.

 Dorsal Scapula Nerve & #8211; from the ventral branch of C5, it innervates the scapula lifter and the rhomboid muscle.

 Long Thoracic Nerve & #8211; It is formed by the branches of C5, C6 and C7 and innervates the anterior serratus muscle.

 Subclavian Muscle Nerve & #8211; it originates near the junction of the ventral branches of the fifth and sixth cervical nerves (C5 and C6) and usually communicates with the phrenic nerve and innervates the subclavian muscle.

 Suprascapular Nerve & #8211; originated from the upper trunk (C5 and C6), innervates the supraspinatus and infraspinatus muscles.

SUPRA-SCAPULAR, AXILARY, TORACODORSAL AND SUBSCAPULAR NERVES
SUPRA-SCAPULAR, AXILARY, TORACODORSAL AND SUBSCAPULAR NERVES

 

Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.

Infra-clavicular branches:

These branch off from the fascicles, but their fibers can be traced back to the spinal nerves.

From the lateral fascicle the following nerves come out:

 Lateral Pectoral & #8211; from the branches of the fifth to seventh cervical nerves (C5, C6 and C7). It innervates the deep face of the pectoralis major muscle;

 Musculocutaneous Nerve & #8211; derived from the ventral branches of the fifth to seventh cervical nerves (C5, C6 and C7). Innervates the anterior brachial, biceps brachii, and coracobrachial muscles;

MUSCULOCUTANIAN NERVE
MUSCULOCUTANIAN NERVE

 

Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.

 Lateral Root of the Median Nerve & #8211; derived from the ventral branches of the fifth to seventh cervical nerves (C5, C6 and C7). It innervates the muscles of the forearm and short thumb, as well as the skin on the side of the hand.

MEDIUM NERVE
MEDIUM NERVE

 

Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.

From the medial fascicle the following nerves come out:

 Medial Breastplate & #8211; derived from the ventral branches of the eighth cervical nerve and first thoracic nerve (C8 and T1). It innervates the major and minor pectoral muscles;

 Medial Forearm Nerve & #8211; derived from the ventral branches of the eighth cervical nerve and first thoracic nerve (C8 and T1). It innervates the skin over the biceps to near the elbow and heads toward the ulnar side of the forearm to the wrist;

 Medial Cutaneous Nerve Arm & #8211; which originates from the ventral branches of the eighth cervical nerve and first thoracic nerve (C8, T1). Innervates the medial part of the arm;

 Ulnar Nerve & #8211; originated from the ventral branches of the eighth cervical nerve and first thoracic nerve (C8 and T1). It innervates the flexor ulnar carpus muscles, the ulnar half of the deep flexor of the fingers, the adductor pollicis and the deep part of the short flexor of the thumb. It also innervates the muscles of the hypotenar, third and fourth lumbrial and all interosseous regions;

ULNAR NERVE
ULNAR NERVE

 

Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.

 Medial Root of Median Nerve & #8211; originated from the ventral branches of the eighth cervical nerve and first thoracic nerve (C8 and T1). It innervates the muscles of the forearm and short thumb, as well as the skin on the side of the hand.

From the posterior fascicle the following nerves come out:

 Superior subscapular & #8211; originated from the branches of the fifth and sixth cervical nerves (C5 and C6). Innervates the subscapular muscle;

 Thoracodorsal Nerve & #8211; originated from the branches of the sixth to eighth cervical nerves (C6, C7 and C8). It innervates the latissimus dorsi muscle;

 Lower Subscapular Nerve & #8211; originated from the branches of the fifth and sixth cervical nerves (C5 and C6). It innervates the subscapular and larger round muscles;

 Axillary Nerve & #8211; originated from the branches of the fifth and sixth cervical nerves (C5 and C6). Innervates the deltoid and minor round muscles;

AXILAR NERVE
 
AXILAR NERVE
Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.

 Radial nerve & #8211; originated from the branches of the fifth to eighth cervical nerves and first thoracic nerve (C5, C6, C7, C8 and T1). It innervates the triceps brachii, brachioradialis, long and short radial carpal extensor, supinator muscles and all muscles of the posterior forearm.

RADIAL ARM NERVE
RADIAL ARM NERVE

 

Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.
RADIAL NERVE & #8211; FOREARM
 
RADIAL NERVE - FORECAST
Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.
PLEX BRACHIAL SUMMARY
 PLEX BRACHIAL SUMMARY
Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.

PLEX BRACHIAL SUMMARY