The intermammary cleft, intermammary sulcus, or sulcus intermammarius is a surface feature of males and females that marks the division of the two breasts with the sternum (breastbone) in the middle.Dr. Ted Eisenberg and Joyce K. Eisenberg, The Scoop on Breasts: A Plastic Surgeon Busts the Myths, Incompra Press, 2012, Heide Schatten and Gheorghe M. Constantinescu, Comparative Reproductive Biology, page 17, John Wiley & Sons, 2008, Genaro Andres Contreras, The Use of Tylosin to Treat Intramammary Infections , page 22, ProQuest, 2008, Olufunmilayo I. Olopade and Carla I. Falkson, Breast Cancer in Women of African Descent, page 125, Springer Science & Business Media, 2010, The International Federation of Associations of Anatomists (IFAA) uses the terms "sulcus intermammarius" or "intermammary cleft" when referring to the area between the breasts.Keith L. Moore, Anne M.R. Agur and Arthur F. Daley, Essential Clinical Anatomy (4th edition), page 49, Lippincott Williams and Wilkins, 2010, Muhammad Adil Abbas Khan, Ammar Asrar Javed and Nigel Mercer, Cleavage classification: categorizing a vital feminine aesthetic landmark, Plastic and Aesthetic Research (PAR), 016-01-15
Etymology "Intermammary" ("inter", between + "mamma", breasts + "ry", placeinter-, Merriam-Webstermamma, Charlton T. Lewis and Charles Short (1879), A Latin Dictionary, Oxford: Clarendon Press-ery, Dictionary.com) means something that is located or performed between the breasts (example: intermammary intercourse).intermammary, Merriam-Webster "Sulcus" is a Latin word that means a furrow or groove, commonly used to mean a fold, fissure or furrow of the brain (example: lateral sulcus).sulcus, Charlton T. Lewis and Charles Short (1879), A Latin Dictionary, Oxford: Clarendon Presssulcus, Merriam-Webstersulcus, Cambridge Dictionarysulcus, Collins Dictionary In popular usage the area is commonly referred to as a cleavage of breasts. In surgical parlance, the cleavage or intermammary cleft is also known as the "medial definition" or "medial fold" of breasts.John Bostwick, Plastic and Reconstructive Breast Surgery (volume 1), page 21, Quality Medical Pub, 2000, Sylvia H. Heywang-Koebrunner, Ingrid Schreer and Susan Barter, Diagnostic Breast Imaging, page 62, Thieme, 2019, An imaginary line between the nipples that crosses the intermammary cleft, serving as a landmark for some CPR procedures, is known as the "intermammary line".
Anatomy
Skin At the midline of the breast—the intermammary cleft—a deep layer of superficial fascia (lowermost layer of the skin) is firmly attached to the pectoral fascia (outer side of chest muscles) and the periosteum (bone membrane) of the sternum. It forms a shelving edge that supports the breasts.John Blair Deaver, The Breast: its anomalies, its diseases, and their treatment, page 30, P. Blakiston's Son & Company, 1917,
Muscles The sternalis muscle is an anatomical variation that lies in front of the sternal end of the pectoralis major runs along the anterior aspect of the body of the sternum. The sternalis muscle often originates from the upper part of the sternum and can display varying insertions such as the pectoral fascia, lower ribs, costal cartilages, rectus sheath, aponeurosis of the abdominal external oblique muscle. There is still a great deal of disagreement about its innervation and its embryonic origin. The sternal side (towards the breastbone) of the pectoralis major is distinct from the clavicular side (towards the collarbone), and the two are separated by a fascial interval.William C. Wood, Charles Staley and John E. Skandalakis, Anatomic Basis of Tumor Surgery, page 140, Springer Science & Business Media, 2010, The sternal side is usually more robust and has a fiber orientation that best emulates the downward pull of the subscapularis muscle (armpit muscle).Neal S. Elattrache, Surgical Techniques in Sports Medicine, page 139, Lippincott Williams & Wilkins, 2007,
Ligaments A dense structure of Cooper's ligaments is medially inserted into the skin overlying the sternum, determining the shape of the breasts and intermammary sulcus.Elizabeth Hall-Findlay and Gregory Evans, Aesthetic and Reconstructive Surgery of the Breast, Elsevier Health Sciences, 2010, These ligaments helpful in supporting the breasts in a youthful disposition; loss of elasticity or attenuation of these ligaments results in ptosis (sagging) of breasts.Maurice Y Nahabedian and Peter C. Neligan, Plastic Surgery (Volume 5), page 89, Elsevier Health Sciences, 2017, Jeffrey Weinzweig, Plastic Surgery Secrets, page 453, Elsevier Health Sciences, 2010,
Arteries
Major blood supply in the area happens through the intermammary artery (also known as the internal thoracic artery) in the thoracic cavity.Ruth A. Lawrence MD and Robert M. Lawrence, MD, Breastfeeding: A Guide for the Medical Profession page 47, Elsevier Health Sciences, 2015, Among women, this artery is larger.Rebecca F. Black, The Science of Breastfeeding (Volume 3), page 13, Jones & Bartlett Learning, 1998, From which anterior perforating branches carry blood into the circummammary arterial plexus, a vascular network formed by branches between minute arteries around the breasts, with lateral mammary branches curving around the lateral border of the pectoralis major.Theresa Hornstein and Jeri Lynn Schwerin, Biology of Women, page 146, Cengage Learning, 2012,
Lymphs Lymph vessels originating at the base of the nipples can ventrally extend as far as the intermammary cleftCharles Wesley Turner, The mammary gland (vol. 1), page 80, Lucas Bros., 1952 and to the opposite breast. The intermammary lymphatics begin as a bunch of small channels consisting of a single layer of epithelium that is supported by stroma tissues. Each mesh of this network surrounds one or more of the ultimate lobules of the glands and receives its lymph from the interacinous spaces between the acini of glands.Albert Henry Buck and Thomas Lathrop Stedman, A Reference Handbook of the Medical Sciences (volume 2), W. Wood, 1901
Nerves The first intercostal nerve, a tiny branch (ramus) of the anterior division of the first thoracic nerve, runs along the first intercostal space (the lower margin of the first rib), travels towards the sternum to innervate the skin near the midline, and, as the first anterior cutaneous (skin) branch of the thorax, ends on the front of the chest.Gray's Anatomy of the Human Body, 20th edition (1918), Henry Albert Reeves, Human Morphology: A Treatise on Practical and Applied Anatomy (Volume 1), page 91, Smith, Elder, & Company, 1882Marios G Lykissas, Ioannis P Kostas-Agnantis, Ananstasios V Korompilias, Marios D Vekris, and Alexandros E Beris, "Use of intercostal nerves for different target neurotization in brachial plexus reconstruction", World Journal of Orthopedics, 2013 Jul 18; 4(3): 107–111 The nerve supply to sternalis muscles comes from the right third intercostal nerve through its anterior cutaneous branch.Ramachandran Kalpana and Kothandaraman Usha, "Three unilateral recti sternalis muscles – an unusual variation and its clinical significance", European Journal of Anatomy, 14 (2): 99–103 (2010)
Clinical conditions
Poikiloderma of Civatte Poikiloderma of Civatte, a condition of dilated blood vessels and red to red-brown spots, is common to upper part of the cleavage, especially for those who wear sports bras or push-up bras for prolonged periods, and commonly affects fair skinned middle-aged to elderly women.Daphne Merkin, "The Great Divide", New York Times, August 28, 2005 It is characterized by hypopigmentation, hyperpigmentation, telangiectasias and superficial skin atrophy (occasional itching is reported), is another condition caused by long exposure to sunlight.American Osteopathic College of Dermatology "Dermatologic Disease Database", aocd.org, referenced July 22, 2011. Poikiloderma and dermatoheliosis are treated by desquamation (skin peeling).
Hidradenitis suppurativa Hidradenitis suppurativa (HS) is a non-contagious chronic skin disease affects intertriginous skin of apocrine sweat gland bearing areas like inframammary fold, and intermammary sulcus. It is characterized by clusters of abscesses, epidermoid cysts, sebaceous cysts, pilonidal cysts.Faye Lyons, Dermatology for the Advanced Practice Nurse, pages 118–121, Springer Publishing Company, 2014, There is no single effective treatment for HS. The recommended treatments include antibiotics, antiandrogens, corticosteroids, ciclosporins, and TNF inhibitors.
Tinea versicolor Tinea versicolor is a condition characterized by pinhead to coin sized eruptions on the body trunk and proximal extremities, often affecting the breast cleavage as a narrow band of lesions.James Nevins Hyde, A Practical treatise on diseases of the skin, pages 625-626, Lea Bros. & Company, 1888 The majority of tinea versicolor is caused by the fungus Malassezia globosa, although Malassezia furfur is responsible for a small number of cases. Topical antifungal medications containing selenium sulfide are often recommended to treat tinea versicolor.
Psoriasis Intermammary cleft can get attacked by plaque type psoriasis, which can in turn can cause erythematosus.Alan Menter and Benjamin Stoff, Psoriasis, page 25, CRC Press, 2010, Prurigo pigmentosa is a rare skin condition of unknown cause that affects depressed places on chest and back like the intermammary area. It is characterized by the sudden onset of erythematous papules that leave a reticulated hyperpigmentation when they heal.James, William; Berger, Timothy; Elston, Dirk (2005). Andrews' Diseases of the Skin: Clinical Dermatology. (10th ed.). page 57, Saunders. .Q Ashton Acton, Issues in Dermatology and Cosmetic Medicine (2013 Edition), page 432, Scholarly Editions, 2013, Confluent and reticulated papillomatosis, characterized by asymptomatic, small, red to brown, slightly verrucous papules occurs on upper torso, the cleavage area and back.David Weedon, Weedon's Skin Pathology, page 505, Elsevier Health Sciences, 2009, Granular parakeratosis, though mostly an ailment of the armpit area, is also found on the cleavage.J Lazar and Phillip H. McKee, Pathology of the Skin, page 96, Elsevier Health Sciences, 2011,
Hirsutism Most women have an increase of hair as they grow older, but some gets more hair on their cleavage, face and elsewhere because of hirsutism, often as a result of polycystic ovary syndrome. The hair on the cleavage is upsetting for many women. There are two ways to remove the hair — temporary (i.e. shaving, waxing, plucking, hair removal creams or bleaching) and permanent (electrolysis or laser hair removal). Contraceptive pills also help.Condition: Hirsutism, NHSRachel Lapidos, What's the Best Way to Get Rid of Cleavage Hair?, Well+Good, 2019-10-17
Symmastia Symmastia is a condition defined as a confluence of the breast tissue of both breasts across the intermammary cleft that normally divides them. It can be surgically corrected by a plastic surgeon through symmastia revision. Symmastia can either be a congenital anomaly or iatrogenic. Congenital symmastia is a rare condition with few published cases. Iatrogenic symmastia may occur following breast augmentation, forming what is also colloquially referred to as a "uniboob" or "breadloafing" as a result of the release of skin and muscle tissue around the sternum due to over-dissection.
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