Superficial Back and Axilla Anatomy

These flashcards cover the surface anatomy, boundaries, musculature, and neurovasculature of the axilla and superficial back, including the structures of the vertebral column and brachial plexus as detailed in the Human Anatomy I lecture.

Axilla Boundary Muscles

The muscular borders includes the Pectoralis major, Pectoralis minor, Biceps brachii, Coracobrachialis, Serratus anterior, Subscapularis, Latissimus dorsi, and Teres major.

Axilla Contents (NAVL)

The main contents are terminal branches of the Brachial Plexus, the Axillary artery, the Axillary vein, and lymph nodes.

Axillary Artery Boundaries

This vessel begins as a continuation of the subclavian artery at the $1\text{st}$ rib and terminates at the lower border of the Teres major muscle where it becomes the Brachial artery.

Sections of the Axillary Artery

Divided into three parts containing the Superior thoracic artery ($1\text{st}$ part), Thoracoacromial and Lateral thoracic arteries ($2\text{nd}$ part), and the Subscapular, Anterior circumflex humeral, and Posterior circumflex humeral arteries ($3\text{rd}$ part).

Axillary Vein Boundaries

This vessel begins as a continuation of the brachial vein at the Teres major muscle and terminates at the $1\text{st}$ rib where it becomes the Subclavian vein.

Brachial Plexus Organization

Composed of $5$ roots ($C5$-$T1$ anterior rami), $3$ trunks (Superior, Middle, Inferior), $6$ divisions ($3$ anterior, $3$ posterior), and $3$ cords (Lateral, Posterior, Medial).

Spinal Accessory Nerve ($CN XVIII$)

The nerve responsible for the motor innervation of the Trapezius muscle.

Dorsal Scapular Nerve

The nerve providing innervation to the Rhomboid major, Rhomboid minor, and Levator scapulae muscles.

Thoracodorsal Nerve

The nerve that innervates the Latissimus dorsi muscle.

Vertebral Column Composition

Consists of $33$ total vertebrae: $7$ cervical ($C1$-$C7$), $12$ thoracic ($T1$-$T12$), $5$ lumbar ($L1$-$L5$), $5$ fused sacral, and $4$ fused coccygeal.

Atlas ($C1$)

The first cervical vertebra featuring an anterior arch, posterior arch, and lateral masses, but lacking a vertebral body and spinous process.

Axis ($C2$)

The second cervical vertebra distinguished by the dens (odontoid process) which serves as a pivot for rotation of the head.

Zygapophysial Joints

Also known as facet joints, these are the synovial articulations between superior and inferior articular processes of adjacent vertebrae.

Nuchal Ligament

A fibroelastic membrane extending from the external occipital protuberance to the spinous process of $C7$, providing attachment for back muscles.

Posterior Axio-appendicular Muscles (Superficial)

A muscle layer consisting of the Trapezius and Latissimus dorsi that originate on the vertebrae and insert on the scapula or humerus.

Posterior Axio-appendicular Muscles (Deep)

A muscle layer consisting of the Levator scapulae, Rhomboid major, and Rhomboid minor.

Major Vertebral Ligaments

Includes the Anterior longitudinal ligament, Posterior longitudinal ligament, Ligamentum flavum, Interspinous ligament, and Supraspinous ligament.