Ps2017 - Cga - Lab 3 (The Axilla And Brachial Plexus) Flash Cards

Front 1

Axillary Artery (source, course, branches)

Back 1

Source: A continuation of the subclavian artery; begins at the lateral border of the first rib.

Course: Runs through the axilla giving off several branches that supply the shoulder, scapular region, and proximal arm. At the inferior border of the teres major muscle, becomes the brachial artery.

Branches (typically proximal to distal): Superior thoracic artery, Thoracoacromial artery, Lateral thoracic artery, Subscapular artery, Anterior circumflex humeral artery, Posterior circumflex humeral artery (useful mnemonic: Screw The Lawyer, Save A Patient)

Front 2

Thoracoacromial Artery (source, branches)

Back 2

Source: A branch of the axillary artery, distal to the superior thoracic artery and proximal to the lateral thoracic artery.

Branches: Four branches are clavicular, acromial, deltoid, and pectoral (useful mnemonic: Cadavers Are Dead People).

Front 3

Superior Thoracic Artery (source, course)

Back 3

Source: A branch of the axillary artery proximal to the origin of the thoracoacromial artery

Course: Runs inferiorly to the first and second intercostal spaces

Front 4

Subscapular Artery (source, course)

Back 4

Source: Usually a branch of the axillary artery

Course: Runs inferiorly on the subscapularis muscle briefly (~1/4 inch) before bifurcating into the circumflex scapular and thoracodorsal arteries.

Front 5

Circumflex Scapular Artery (source, course)

Back 5

Source: Usually a branch of the subscapular artery, may directly branch from the axillary artery

Course: Goes through the triangular space to reach the posterior surface of the infraspinous fossa of the scapula, anastomoses with the dorsal scapular and suprascapular arteries.

Front 6

Thoracodorsal Artery (source, course)

Back 6

Source: Usually a branch of the subscapular artery, may directly branch from the axillary artery

Course: Travels with the thoracodorsal nerve to the latissimus dorsi muscle; also has a branch to the thoracic wall

Front 7

Anterior Circumflex Humeral Artery (source, course)

Back 7

Source: Usually a branch of the axillary artery

Course: Usually runs laterally deep to the coracobrachialis and biceps, encircling the head and neck of the humerus. Anastomoses with the posterior circumflex humeral artery.

Front 8

Posterior Circumflex Humeral Artery (source, course)

Back 8

Source: Usually a branch of the axillary artery; can be a branch of the deep brachial artery

Course: Goes through the quadrangular space with the axillary nerve to reach the deltoid muscle (if it is a branch of the deep brachial artery, will not go through the quadrangular space but can still be identified on the basis it accompanies branches of the axillary nerve to supply the deltoid muscle); anastomoses with the anterior circumflex humeral artery.

Front 9

Latissimus dorsi (attachments, innervation, action)

Back 9

Proximal Attachments: Inferior half of the vertebral column (spinous processes), sacrum, and ribs; inferior angel of the scapula; iliac crest of the pelvis; thoracolumbar fascia

Distal Attachments: Bicipital groove of the humerus (intertubercular sulcus)

Innervation: Thoracodorsal nerve

Action: Extension, adduction, and medial rotation of the glenohumeral joint; downward rotation and retraction of the scapula

Front 10

Teres major muscle (attachments, innervation, action)

Back 10

Proximal Attachment: Posterior surface of the scapula near the inferior angle

Distal Attachment: Medial edge of the bicipital groove (intertubercular sulcus; medial to latissimus dorsi attachment)

Innervation: Lower subscapular nerve

Action: Adduction and medial rotation of the arm at the glenohumeral joint

Front 11

Serratus anterior muscle (attachments, innervation, action)

Back 11

Proximal Attachment: Ribs 1-8

Distal Attachment: Anterior surface of the scapula adjacent the medial border

Innervation: Long thoracic nerve

Action: Upward rotation, depression, and protraction of the scapula

Front 12

Subscapularis muscle (attachments, innervation, action)

Back 12

Proximal attachment: Subscapular fossa of the scapula (most of the anterior surface of the scapula)

Distal Attachment: Lesser tubercle of the humerus

Innervation: Upper and lower subscapular nerves

Actions: Adduction and medial rotation of the glenohumeral joint, part of the rotator cuff therefore helps hold the humeral head in the glenoid fossa of the scapula.

Front 13

Lateral cord of the brachial plexus (origin, path, branches)

Back 13

Origin: Formed by the anterior divisions of the superior and middle trunks of the brachial plexus; contains axons from C5, C6, and C7.

Path: The lateral cord travels to the axilla giving off its branch and terminates by bifurcating into the musculocutaneous nerve and the lateral head of the median nerve.

Branches: Lateral pectoral nerve.

Front 14

Long thoracic nerve (origin, muscles innervated, skin innervated, path)

Back 14

Origin: A nerve formed by branches off the ventral rami (roots of the brachial plexus) of C5, C6, and C7.

Muscles Innervated: Serratus anterior

Skin Innervated: None

Path: Passes from the neck to the axilla through the cervico-axillary canal; runs inferiorly on the lateral surface of the serratus anterior, it is accompanied by the lateral thoracic artery.

Front 15

Lower subscapular nerve (origin, muscles innervated, skin innervated, path)

Back 15

Origin: Third branch of the posterior cord of the brachial plexus; contains axons from C6

Muscles Innervated: Subscapularis & teres major

Skin Innervated: None

Path: Branches off the posterior cord in the axilla; travels on the anterior surface of the subscapularis muscle bifurcating into branches supplying the subscapularis and the teres major.

Front 16

Medial cord of the brachial plexus (origin, path, branches)

Back 16

Origin: Formed by the anterior division of the inferior trunk of the brachial plexus, contains axons from C8 and T1.

Path: The medial cord travels through the axilla giving off its branches and terminates by bifurcating into the medial head of the median nerve and the ulnar nerve.

Branches: Medial pectoral nerve; medial cutaneous nerve of the arm, medial cutaneous nerve of the forearm.

Front 17

Medial cutaneous nerve of the arm (origin, muscles innervated, skin innervated, path)

Back 17

Origin: A branch of the medial cord of the brachial plexus (contains axons from C8 and T1)

Muscles Innervated: None

Skin Innervated: Medial side of the arm

Path: Passes through the axilla to reach the superficial fascia of the arm.

Front 18

Medial cutaneous nerve of the forearm (origin, muscles innervated, skin innervated, path)

Back 18

Origin: A branch of the medial cord of the brachial plexus (contains axons from C8 and T1)

Muscles Innervated: None

Skin Innervated: Medial side of the forearm

Path: Passes through the axilla traveling with the ulnar nerve in the arm; it then goes into the superficial fascia of the forearm.

Front 19

Median nerve (origin - path and innervation will be covered in later labs)

Back 19

Origin: A terminal branch of both the medial and lateral cords (contains axons from C6, C7, C8, and T1).

Front 20

Musculocutaneous nerve (origin, muscles innervated, skin innervated, path)

Back 20

Origin: One of the terminal branches of the lateral cord of the brachial plexus (the other being the lateral head of the median nerve; contains axons from C5, C6, and C7)

Muscles Innervated: Coracobrachialis, biceps brachialis, and brachialis.

Skin Innervated: Lateral forearm (once it becomes the lateral cutaneous nerve of the forearm).

Path: Passes through the coracobrachialis muscle and then travels in the anterior compartment of the arm between the biceps brachii and the brachialis muscle; after giving off its last muscular branch it becomes the lateral cutaneous nerve of the forearm.

Front 21

Posterior cord of the brachial plexus (origin, path, branches)

Back 21

Origin: Formed by the posterior divisions of the superior, middle, and inferior trunks of the brachial plexus; contains axons from all levels (C5, C6, C7, C8, and T1)

Path: The posterior cord is located in the anterior surface of the subscapularis muscle in the axilla where it gives off its branches; the posterior cord terminates by bifurcating into the axillary nerve and the radial nerve.

Branches: Upper subscapular nerve, thoracodorsal nerve; Lower subscapular nerve

Front 22

Radial nerve (origin, muscles innervated, skin innervated, path)

Back 22

Origin: One of the two terminal branches of the posterior cord of the brachial plexus (the other being the axillary nerve; contains axons from all levels: C5, C6, C7, C8, and T1)

Muscles Innervated: Muscles of the forearm (will be explicitly covered in later labs)

Skin Innervated: Lateral arm, forearm, and hand

Path: Passes through the triangular interval and runs through the radial (spiral) groove of the humerus into the cubital fossa where it terminates by bifurcating into the deep radial and superficial radial nerves.

Front 23

Thoracodorsal nerve (origin, muscles innervated, skin innervated, path)

Back 23

Origin: The second branch of the posterior cord of the brachial plexus (contains axons from C6, C7, and C8)

Muscles Innervated: Latissimus dorsi

Skin Innervated: None

Path: Branches off the posterior cord within the axilla, travels inferiorly along the anterior surface of the subscapularis muscle to reach the latissimus dorsi.

Front 24

Ulnar nerve (origin only; innervation and path covered in later labs)

Back 24

Origin: One of two terminal branches of the medial cord of the brachial plexus (the other being the medial head of the median nerve; contains axons from C8 & T1)

Front 25

Upper subscapular nerve (origin, muscles innervated, skin innervated, path)

Back 25

Origin: The first branch of the posterior cord of the brachial plexus; contains axons from C5.

Muscles Innervated: Subscapularis

Skin Innervated: None

Path: Branches of the posterior cord near the apex of the axilla; directly enters the anterior surface of the subscapularis muscle

Front 26

Axillary nerve (origin, muscles innervated, skin innervated, path)

Back 26

Origin: One of two terminal branches of the posterior cord (the other being the radial nerve; contains axons from C5 & C6)

Muscles Innervated: Deltoid & teres minor

Skin Innervated: Superior lateral arm

Path: Passes through the quadrangular space to reach the deltoid and teres minor; accompanied by the posterior circumflex humeral artery