Anatomy: The Brachial Plexus

Musculocutaneous nerve innervates what?

Innervates biceps brachii

What forms the medial cord?

It is a continuation of the anterior division of the inferior trunk.

Median nerve (location and innervations)

Anterior of brachium, to elbow, then goes through carpal tunnel and then branches into hand. Innervates all other flexors.

Posterior cord branches.

Axillary Nerve and Radial nerve

Branches that are needed to know.

Axillary nerve, radial nerve, musculocutaneous nerve, ulnar nerve, and median nerve.

What roots combine to form the inferior trunk?

C8 and T1

What roots combine to form the superior trunk?

C5 and C6

What ventral rami make of the 5 roots of the brachial plexus

C5-T1

What root forms the middle trunk?

C7

What does each trunk split into?

Each trunk splits into an anterior division and posterior division.

What forms the lateral cord?

Formed by fusion of the anterior divisions of superior and middle trunk.

what forms the posterior cord?

Formed by the fusion of the posterior divisions of the superior, middle and inferior trunks.

KNOW WHAT NERVES INNERVATE WHERE IN THE HAND

KNOW WHAT NERVES INNERVATE WHERE IN THE HAND

What are the 3 cords?

Lateral, medial and posterior cords.

Branches of Lateral cord

Musculocutaneous nerve, also a split that goes to the median nerve

Ulnar nerve (location and innervations)

Posterior side of elbow and medial side of forearm. Innervates flexor carpi ulnaris, muscles to pinky, skin of that side.

From proximal to distal, the parts of the brachial plexus

Roots, Trunks, Divisions, cords, branches (peripheral nerves)

Axillary nerve (location, innervations)

Runs lateral to innervate the deltoid and skin of the shoulder

Radial nerve (location, innervations)

Runs posterior to humerus, crosses at elbow, then branches down the lateral side of the antebrachium and hand. Innervates triceps brachii, brachioradialis, and branches innervates extensors mostly.

What are the 3 trunks of the brachial plexus?

Superior, middle and inferior trunks.

The 5 roots of the brachial plexus ARE NOT THE SAME THING as ventral and dorsal roots.

The 5 roots of the brachial plexus ARE NOT THE SAME THING as ventral and dorsal roots.

Anterior divisions are anterior to axillary artery

Vice versa with posterior division

Branches of Medial Cord

Ulnar nerve and a split that goes to the median nerve.