8.2 Anterior Arm and Cubital Fossa (Some Anterior Chest from Lecture added)

Question 1

Identify the biceps brachii muscle (its 2 heads), its attachments, innervation, and function.

Answer 1

• Proximal attachment tip of coracoid process (short head) and supraglenoid tubercle (long head) of scapula, distal attachment to the radial tuberosity
• Innervated by the musculocutaneous nerve (anterior compartment) (C5-C7)
• Actions: Supinates forearm, and when fixed flexes forearm. At glenohumeral joint flexes arm and resists dislocation

Question 2

Identify the coracobrachialis muscle, its attachments, innervation, and function.

Answer 2

• Proximal attachment from the tip of coracoid process of scapula, distal attachment to middle third of medial surface of the humerus
• Innervated by the musculocutaneous nerve (anterior compartment) (C5-C7).
• Actions: flexion and adduction of arm, and resists dislocation at glenohumeral joint

Question 3

Identify the Brachialis m, its attachments, innervation, and function.

Answer 3

• Proximal attachment along the distal half of the anterior humerus, distal attachment to the coronoid process/tuberosity of ulna
• Innervated by the musculocutaneous nerve (anterior compartment) (C5-C7).
• Actions: forearm flexor

Question 4

Identify the Brachial artery. From what proximal artery does this branch?

Answer 4

It forms from the axillary artery after it crosses the tendon of the teres major in the arm.

Question 5

Identify the Profunda brachii (deep brachial a). Describe its general course.

Answer 5

the first branch of the brachial artery in the arm. It passes posteriorly through the triceps hiatus with the radial nerve to supply the posterior compartment of the arm.

Question 6

Identify the Superior and Inferior ulnar collateral arteries. From what proximal artery do these branch? Describe the general course of each.

Answer 6

They branch from the Brachial artery, superior to the elbow.
The superior ulnar collateral a. travels posterior to the medial epicondyle of the elbow.
The inferior ulnar collateral a. travels anterior to the medial epicondyle of the elbow.

Question 7

Identify the radial and ulnar aa. These stem from the terminal end of what artery?

Answer 7

The brachial artery typically terminates just prior to entering the cubital fossa by bifurcating into the radial and ulnar arteries.

Question 8

Identify the Musculocutaneous nerve, Median Nerve, and Ulnar nerve.
Describe what division of the brachial plexus these stem from, which cord(s) contribute to each, and what root spinal nerves they are constitute.

Answer 8

• Musculocutaneous: Anterior Division, Continuation of Lateral Cord, C5-C7 Roots.
• Median: Anterior Division, Contributions from Lateral and Medial Cords, C6-T1 Roots.
• Ulnar: Anterior Division, Continuation of Medial Cord, C8-T1.

Question 9

Identify the Median cubital vein. Describe both the distal source vein and proximal vein it drains into

Answer 9

Source: Cephalic Vein

Drains Into: Basillic Vein

Question 10

Describe the boundaries of the cubital fossa.

Answer 10

• lateral: the brachioradialis
• medial: the prontator teres
• superior: an imaginary line connecting the epicondyles of the humerus
• roof: the bicipital aponeurosis (a broad aponeurosis of the biceps brachii which is located in the cubital fossa of the elbow and separates superficial from deep structures in much of the fossa.)
• floor: the brachialis

Question 11

Describe the course of the biceps brachii tendons.

Answer 11

the tendon of the long head of the biceps brachii passes deep to enter the bicipital groove, courses over the top of the glenohumeral joint, and attaches to the supraglenoid tubercle of the scapula.

The short head of the biceps brachii passes medially to anchor to the coracoid process along with the coracobrachialis.

Question 12

Identify the pectoralis major muscle, its attachments, innervation, and function.

Answer 12

• Originating at the anterior medial shaft of the clavicle (clavicular head) and the anterior surface of the sternum (sternal head) inserting into intertubercular groove of the humerus
• Innervated by the lateral (C5-C7) AND medial (C8-T1) pectoral nerves. Named based on origin in the lateral or medial cords of the brachial plexus, the medial passes either through or inferior to the pec minor, lateral will pass superior
• Actions: adducts and medially rotates the humerus etc

Question 13

Identify the pectoralis minor muscle, its attachments, innervation, and function.

Answer 13

• Originating at the 3rd-5th ribs near costal attachments, inserting at the coracoid process (scapula)
• Innervated by the medial pectoral nerve (C8-T1)
• Actions: stabilizes the scapula.

Question 14

Identify the subclavius muscle, its attachments, innervation, and function.

Answer 14

• Originating from the junction of the first rib and the manubrium, inserting into the inferior center of the clavicular shaft
• Innervated by the subclavian nerve (C5-C6).
• Actions: anchors and depresses the clavicle

Question 15

Identify the serratus anterior muscle, its attachments, innervation, and function.

Answer 15

• Originating from lateral parts of ribs 1-8, inserting into the medial anterior border of the scapula
• Innervated by the long thoracic nerve (C5-C7).
• Actions: protracts and rotates scapula