Learning goals axilla and arm, Boundaries and contents of the Axilla LG 3

Question 1

Axilla Boundaries and Contents

Answer 1

Apex: 1st rib, clavicle
Base: Skin of armpit
Anterior: Pectoralis muscles
Posterior: Scapula, Subscapularis muscle
Medial: Thoracic wall, serratus anterior muscle
Lateral humerus
Axilla contents: Axillary artery, axillary vein, axillary lymph nodes, 3 cords of brachial plexus

Question 2

Spinal Nerve naming Convention and Number

Answer 2

For the most part, the spinal nerves exit the vertebral canal through the intervertebral foramen below their corresponding vertebra. Therefore, there are 12 pairs of thoracic spinal nerves, 5 pairs of lumbar spinal nerves, 5 pairs of sacral spinal nerves, and a coccygeal nerve.

The cervical spinal nerves differ from this pattern. C1-C7 spinal nerves emerge from the vertebral canal above the corresponding vertebra, with an eighth pair of cervical spinal nerves emerging below the C7 vertebra

Question 3

Describe the fascial compartments of the anterior and posterior arm and list their contents, general actions, innervation and blood supply

Answer 3

Compartments spilt by lateral and medial intermuscular fascia (connect at humerus)

Anterior Compartment: Function is shoulder and elbow flexion. Innervation is Musculocutaneous nerve. Arterial supply is brachial artery. Muscles are the biceps brachii, coracobrachialis, and brachialis muscles

Posterior Compartment: Function is shoulder and elbow extension. Innervation is the radial nerve. Arterial blood supply is the profunda (deep) brachial artery. Muscles are the triceps brachii and the anconeus.

Question 4

Predict what neurovascular structures would be injured based on bone fracture located at the surgical
neck of the humerus, radial groove of the humerus?

Answer 4

Fracture at surgical neck of humerus would damage the axillary nerve and the posterior circumflex artery

Fracture at the radial groove of the humerus would damage the radial nerve and the profounda brachii artery