and Edgar D. Guzman-Arrieta3
(1)
Department of Surgery Advocate Illinois Masonic Medical Center, University of Illinois Metropolitan Group Hospitals Residency in General Surgery, Chicago, IL, USA
(2)
University of Illinois at Chicago, Chicago, IL, USA
(3)
Vascular Specialists – Hattiesburg Clinic, Hattiesburg, MS, USA
Keywords
BreastAxillaNerves of the axillaSentinel nodeMastectomyAxillary dissection1.
Select the incorrect statement regarding the embryogenesis of the breast:
(a)
The glandular tissue of the breast is a modified sebaceous gland; it is of ectodermal origin.
(b)
The stromal tissue of the breast is derived from the mesoderm.
(c)
The nipple is a proliferation of the stratum spinosum.
(d)
The milk lines extend along the thorax and abdomen along the midclavicular line.
(e)
Amastia is often accompanied by absence of the underlying pectoralis major muscle.
Comments
During the second month of gestation, two bands of thickened ectoderm develop in the ventral body wall, extending from the axillae to the groins. These are the milk lines and give origin to the breast and nipple. In humans, the pectoral portion gives rise to two mature breasts. However, it is possible for other portions of the milk line to give rise to accessory breast tissue (polymastia), accessory nipples (polythelia), or both. Accessory breast tissue is most common in the axilla. In animals, the milk lines give rise to multiple breasts that are proportional to the size of the litters (Fig. 3.1).
Fig. 3.1
Milk line. Accessory breast tissue in the axilla is the most common ectopic location. Changes with menstruation and pregnancy are diagnostic. Accessory breasts rarely have benign or malignant diseases of the breast. The milk line is an embryologic remnant of the animal kingdom, and extends from the axilla to the groin. It may demonstrate polythelia or polymastia
Poland’s syndrome consists of absence or hypoplasia of the breast with concurrent underdevelopment or absence of the associated subcutaneous tissue and pectoralis major muscle. The pectoralis minor and ribs 2 through 5 may also be involved. The extensive nature of this defect often requires complex, staged reconstruction [1]. Poland’s syndrome is three times more common in boys than girls and affects the right side of the body twice as often as the left. The reasons for these differences are unknown, as is the cause [2].
Answer
d
2.
Select the incorrect statement regarding the anatomy of the chest wall and axilla.
(a)
The superficial fascia of the breast is continuous with Camper’s fascia and the superficial cervical fascia.
(b)
The deep pectoral fascia envelops the pectoralis major.
(c)
The clavipectoral fascia envelops the latissimus dorsi and inserts in the clavicle.
(d)
The clavipectoral fascia is pierced by the cephalic vein.
(e)
The axillary sheath, enveloping the axillary vessels, is an extension of the prevertebral fascia.
Comments
The clavipectoral fascia is attached superiorly to the inferior border of the clavicle, surrounding the subclavius muscle. Inferior to the subclavius muscle, the anterior and posterior layers fuse and form the costocoracoid membrane as they travel towards the pectoralis minor muscle. Upon reaching it, the layers once again divide to envelop this muscle. The clavipectoral fascia forms part the anterior wall of the axilla and fuses with the axillary fascia. It must be incised to gain access to the axillary space. This is done along the lateral border of the pectoralis minor, extending into the roof of the axilla along the axillary vein for an excellent exposure to the axilla.
Answer
c
3.
All of the following are correct except:
(a)
The posterior boundary of an axillary dissection is the latissimus dorsi muscle, which forms the posterior axillary fold.
(b)
The pectoralis minor muscle lies anterior to the axillary vessels and attaches to the coracoid process of the scapula.
(c)
The nerves to the latissimus dorsi and serratus anterior should be preserved in an axillary node dissection, unless involved by tumor.
(d)
The medial and lateral pectoral nerves should be preserved, as they supply the pectoralis major and minor.
(e)
The intercostobrachial nerve is a purely motor nerve.
Comments
The axilla is described as pyramidal space with an apex, four walls, and a base. Its contents are lymph nodes and the axillary sheath containing the blood vessels and nerves to the arm. The pectoralis minor muscle is a fan-shaped muscle, which crosses the axillary vessels and divides the axillary lymph nodes into three levels. Level 1 is lateral to the pectoralis minor, level 2 underlies the pectoralis minor, and level 3 is medial to it (Fig. 3.2).
Fig. 3.2
The breast with key surgical anatomy. The applied surgical anatomy of the breast is illustrated demonstrating the muscles, nerves, and blood vessels of the chest wall. The subscapular vessels that accompany the thoracodorsal nerve and the nerves to the pectoralis muscles are not shown
Five nerves are encountered in the course of an axillary node dissection. Some branches of the medial and lateral pectoral nerves run along the lateral edge of the pectoralis minor, innervating it. From there, they travel medially to innervate the pectoralis major. Injury to these nerves may cause muscular atrophy of these muscles.
The long thoracic nerve runs along the midaxillary line and supplies the serratus anterior muscle. Section of this nerve produces winged scapula. The thoracodorsal nerve travels on the anterior edge of the latissimus dorsi muscle, along with the lateral thoracic vessels. Injury to this nerve produces atrophy of said muscle. These four nerves must be preserved, unless directly invaded by cancer. Finally, the intercostobrachial nerve travels parallel to the axillary vessels to reach the skin of the inner arm. It is a purely sensory nerve that may be sacrificed [3–5] (Fig. 3.3).
Fig. 3.3
Critical anatomy of the nerves of the axilla. The extent of the axillary lymph node dissection varies depending on the type of cancer and whether it is for diagnostic sampling or therapeutic excision. In either case, extensive knowledge of the exact anatomical location and relative relationships, as described above, is critical. When muscles are being spared or used for flap reconstructions, their nerve supply must be preserved. The nerve supply to the pectoral muscles are specifically at risk
Answer
e
4.
Mark the false statement.
(a)
Fat necrosis of the breast may manifest itself as skin dimpling.
(b)
Skin dimpling may be caused by invasion of Cooper’s ligaments.
(c)
Breast cancer may directly invade the skin of the breast causing skin dimpling.
(d)
Peau d’orange signifies invasion of the subcutaneous lymphatics.
(e)
Optimal breast examination is performed with the patient in supine position only.
Comments
Cooper’s ligaments extend from the posterior layer of the superficial pectoral fascia towards the dermis, forming a suspensory network of septations. Breast tumors invading Cooper’s ligaments cause them to shorten. This in turn induces retraction of the mammary skin, which may itself be free of tumor. Optimal breast examination is performed in at least two positions so as to examine all the breast tissue. This may also help emphasize the dimpling of the skin as the breast moves in relation to deeper structures [6].
Fat necrosis of the breast is often caused by trauma and may mimic breast malignancy, including skin retraction [7]. Peau d’orange is edema of the dermis, with prominent hair follicles, which appear as pits, giving an orange-peel appearance. This sign is often seen in inflammatory carcinoma of the breast, where the skin must be biopsied in addition to the underlying breast tissue to confirm this diagnosis [8].
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
