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Questions and Answers
A surgeon encounters pus collection behind the pectoralis minor muscle. Which of the following pathways is LEAST likely to be the source of this collection?
A surgeon encounters pus collection behind the pectoralis minor muscle. Which of the following pathways is LEAST likely to be the source of this collection?
- Local spread from an infection within the axilla itself.
- Infection spreading from the neck through the cervico-axillary canal.
- Direct hematogenous spread from a distant infection site. (correct)
- Atypical migration of pus from the neck region.
During a surgical procedure involving the pectoralis major, a surgeon must carefully dissect the muscle's insertion. Damage to which anatomical structure would MOST directly affect the function of the clavicular head fibers?
During a surgical procedure involving the pectoralis major, a surgeon must carefully dissect the muscle's insertion. Damage to which anatomical structure would MOST directly affect the function of the clavicular head fibers?
- The lower part of the lateral lip of the bicipital groove. (correct)
- The lateral pectoral nerve.
- The upper part of the lateral lip of the bicipital groove.
- The medial pectoral nerve.
A patient presents with a painful mass in the axilla. Imaging reveals a structure extending superolaterally from the breast, piercing the deep fascia. Which anatomical feature is MOST likely involved in this patient's condition?
A patient presents with a painful mass in the axilla. Imaging reveals a structure extending superolaterally from the breast, piercing the deep fascia. Which anatomical feature is MOST likely involved in this patient's condition?
- Foramen of Langer
- Tubercle of Montgomery.
- Axillary tail of Spence. (correct)
- Lactiferous sinus
During a breast examination, a physician notes an enlarged areolar area with prominent tubercles. The patient is in her third trimester of pregnancy. What is the MOST likely explanation for these findings?
During a breast examination, a physician notes an enlarged areolar area with prominent tubercles. The patient is in her third trimester of pregnancy. What is the MOST likely explanation for these findings?
A bodybuilder is performing exercises targeting the pectoralis major. They notice that during the upward phase of a dumbbell press, they are unable to fully adduct and medially rotate their arm. Which nerve is MOST likely affected, leading to this specific functional deficit?
A bodybuilder is performing exercises targeting the pectoralis major. They notice that during the upward phase of a dumbbell press, they are unable to fully adduct and medially rotate their arm. Which nerve is MOST likely affected, leading to this specific functional deficit?
A surgeon is performing a procedure in the pectoral region and needs to carefully dissect the layers. Which statement accurately describes the relationship between the superficial fascia and the mammary gland?
A surgeon is performing a procedure in the pectoral region and needs to carefully dissect the layers. Which statement accurately describes the relationship between the superficial fascia and the mammary gland?
During a clinical examination, a physician notes a prominent hollow in the axilla when a patient abducts their arm. Which anatomical structure is most directly responsible for the change in the axillary region during abduction?
During a clinical examination, a physician notes a prominent hollow in the axilla when a patient abducts their arm. Which anatomical structure is most directly responsible for the change in the axillary region during abduction?
A patient presents with damage to the anterior cutaneous nerve after a surgical error, leading to numbness and tingling in the skin near the sternum. From which artery do the anterior cutaneous nerves typically receive their blood supply?
A patient presents with damage to the anterior cutaneous nerve after a surgical error, leading to numbness and tingling in the skin near the sternum. From which artery do the anterior cutaneous nerves typically receive their blood supply?
A bodybuilder is performing a bench press, which heavily utilizes the pectoralis major. If the sternocostal head of the pectoralis major is torn from its origin, which specific anatomical location would be affected?
A bodybuilder is performing a bench press, which heavily utilizes the pectoralis major. If the sternocostal head of the pectoralis major is torn from its origin, which specific anatomical location would be affected?
A surgeon is planning to make an incision in the pectoral region parallel to the deltoid groove. What is the primary anatomical significance of the deltoid groove in this region?
A surgeon is planning to make an incision in the pectoral region parallel to the deltoid groove. What is the primary anatomical significance of the deltoid groove in this region?
Flashcards
Pectoral Region
Pectoral Region
The area in front of the chest beside the sternum, contains breast, fascia, muscles, vessels, nerves, and rib cage.
Superficial Fascia
Superficial Fascia
Layer of connective tissue lying under the skin and enveloping the mammary gland; absent under the areola.
Pectoral Fascia
Pectoral Fascia
Deep fascia that covers the pectoralis major muscle, extends to clavicle and sternum.
Pectoralis Major
Pectoralis Major
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Suspensory Ligament of Axilla
Suspensory Ligament of Axilla
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Pectoralis Major Insertion
Pectoralis Major Insertion
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Axillary Tail of Spence
Axillary Tail of Spence
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Breast Structure
Breast Structure
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Lobes of the Breast
Lobes of the Breast
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Study Notes
Ana222 Pectoral Region
- The pectoral region is a region in front of the chest on either side of the sternum.
- It includes the breast, superficial fascia, deep fascia, muscles, vessels, nerves, and rib cage.
- Superficial fascia lies under the skin, absent under the areola, and splits to enclose the mammary gland.
- The mammary gland rests on the superficial fascia.
- Cutaneous nerves pierce the pectoral major lateral to the sternum and supply adjacent skin, accompanied by anterior cutaneous arteries from the internal mammary artery.
- Lateral cutaneous nerves are branches of intercostal nerves.
- Pectoral fascia is the name for the deep fascia covering the pectoralis major muscle.
- It attaches superiorly to the clavicle and extends medially to the sternum.
Pectoralis Major
- The pectoralis major is the largest muscle of the pectoral region, triangular or fan-shaped.
- It has two heads: clavicular and sternocostal.
- The clavicular head originates from the anterior surface of the medial 1/2 to 2/3 of the clavicle, and the fibres run downward and lateral.
- The sternocostal fibres originate from the front of the manubrium and body of the sternum, reaching the 6th costal cartilage, and occasionally from the 1st to 6th cartilages.
- A small portion originates from the external oblique aponeurosis.
- The two heads are separated by the deltoid groove for the cephalic vein.
- It inserts via a bilaminar tendon with fibres from the clavicular head running laterally downward superficial to the 2nd head attaching to the lower part of the lateral lip of the bicipital groove.
- Fibres from the sternocostal head ascend upward and laterally, deep to the tendon of the clavicular head, attaching to the upper part of the lateral lip of the bicipital groove.
Pectoralis Minor
- The pectoralis minor is a small triangular muscle deep to the pectoralis major.
- It originates from the 2nd-4th or 3rd-5th ribs, as well as the external intercostal membrane.
- It inserts at the upper medial surface of the coracoid bone.
- It runs upward and laterally.
- Innervated by the medial pectoral nerve.
Breast
- The breast is a modified sweat gland present in both sexes.
- It develops in females after puberty and secretes milk.
- It’s an accessory organ of the female reproductive system.
- It is situated on the superficial fascia of the pectoral region, with a small portion extending into the axilla.
- In young adults, the breast is spherical; later it becomes pendulous.
- Vertically, it extends from the 2nd to 6th rib.
- Horizontally, it extends from the lateral sternal border to the midaxillary line.
- It extends superiorly and laterally; the superior portion pierces the deep fascia. Known as the foramen of Langer lies on the 3rd rib and that part is known as the axillary tail of Spence.
Breast Structure
- Skin: Encloses the breast, and forms the nipple—a conical projection below the breast centre at the 4th space—pierced by 15–20 lactiferous ducts.
- Areola: Pigmented area at the nipple base, rich in modified sebaceous glands (tubercles of Montgomery), which secrete oil lubricating the nipple and areola. The areola is fat-free.
Breast Parenchyma
- Composed of 15–20 lobes.
- Each lobe is a cluster of alveoli, drained by lactiferous ducts.
- The ducts converge at the nipple, resembling spokes.
- The stroma forms a supporting framework of fibrous tissue dividing the breast into compartments via suspensory ligaments of Cooper, anchoring the skin and gland tissue to the pectoral fascia.
- Infiltration of these ligaments by cancer can cause breast fixation.
- Fatty stroma forms the majority of the breast, except around the nipple and areola.
- Blood supply to the breast involves the internal thoracic arteries, lateral thoracic artery, superior thoracic artery, and acromiothoracic branches.
Clinical Anatomy
- Breast is a common site for tumours, with lymphatic channels as the pathway for carcinoma.
- Benign tumours, such as papilloma, are treated with surgical excision.
- Malignant tumours (breast cancer) are treated with surgical procedures like radical mastectomy, usually targeting the affected side, or bilateral surgical procedures.
- Polymastia is an extra breast, often along the milk line, sometimes in unusual ectopic sites like the back or buttocks.
Lymphatic Drainage
- Drainage of the breast is crucial in disease spread.
- Superficial nodes drain the breast skin (excluding areola and nipple) and deep nodes drain the parenchyma, nipple, and areola.
- Drainage pathways include the axillary, infraclavicular, parasternal, posterior intercostal, and sub diaphragmatic nodes, as well as a smaller percentage to the mammary region.
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