Thorax and Breast Anatomy for Radiation Therapy

Flashcards covering the anatomical landmarks, bony structures, and musculature of the thorax and breast as they relate to radiation therapy.

Thorax

The structure that encloses and protects organs in the thoracic cavity and upper abdomen while providing support for the pectoral girdle and upper extremities.

Manubrium

The superior portion of the sternum that articulates with the first $2$ ribs and the medial ends of the clavicles.

Suprasternal notch (SSN)

A depression on the manubrium occurring at the level of $T2$, used as a palpable landmark for setting up a Supra Clavicular Field ($SCF$).

Sternal angle (Angle of Louis)

The junction of the manubrium and the body of the sternum, located at the level of $T4$.

Body of the sternum

The middle and largest portion of the sternum, which articulates with the $2^{nd}$ through $10^{th}$ ribs.

Xiphoid process

The inferior projection of the sternum that serves as an attachment point for ligaments and muscles.

Vertebrosternal ribs (True ribs)

The superior seven pairs of ribs that connect directly to the sternum.

Vertebrochondral ribs

Ribs $8, 9, \text{ and } 10$ which join with the vertebrae posteriorly and the cartilage of the superior rib anteriorly.

Floating ribs

Ribs ($10 \text{ and } 11$ according to the text) that articulate only with the vertebrae and do not connect with the sternum.

Supraclavicular lymph nodes

Lymph nodes located superior to the clavicles, often treated prophylactically in head, neck, and lung cancers.

Brachial plexus

A network of nerves at the medial section of the clavicle frequently involved in superior sulcus (Pancoast) tumors.

Pectoralis major

Anterior chest muscle attached medially to the clavicle and superior six costal cartilages, inserting laterally on the humerus.

Tail of Spence

The upper outer portion of the teardrop-shaped breast tissue that extends into the axilla.

Internal mammary nodes

Medially located lymph nodes that may be involved if a breast tumor is located in the inner quadrant.

Inframammary sulcus

The inferior point of breast attachment, also known as the under-breast fold.

Trapezius

A flat triangular muscle with a superior angle at the EOP and an inferior angle at the level of $T12$.

Teres major

A band of muscle between the inferior angle of the scapula and the humerus that forms the posterior wall of the axilla.

Latissimus dorsi

A broad muscle of the back spanning from the iliac crest to the posterior axilla.

Spine of the scapula

A posterior bony landmark located at the level of $T3$.

Inferior angle of the scapula

A posterior bony landmark located at the level of $T7$.

Crest of the ilium

A bony landmark located at the level of $L4$, used to locate the subarachnoid space for lumbar punctures.

Posterosuperior iliac spine (PSIS)

A palpable landmark approximately $5,cm$ from the midline, located at the level of $S2$.