Anatomy 391 2nd Midterm Lectures 1,2,3

The correct answer describes the thorax as an irregular cylinder-shaped structure formed by both bony and muscular components, unlike the other incorrect options that provide inaccurate information.

In the thorax, the inlet is formed by the circumference of the superior aperture which is widely open, while the outlet is formed by the inferior aperture and sealed by the diaphragm. The incorrect answers provide inaccurate descriptions or combinations of the inlet and outlet of the thorax.

The correct answer explains that the thorax is subdivided into three components, the mediastinum, and the two pleural cavities.

Ribs are an essential part of the thoracic cage, providing protection for vital organs in the chest cavity such as the heart and lungs.

True ribs are called as such because they attach directly to the sternum, while false ribs do not have a direct connection to the sternum.

Ribs articulate with vertebrae one level higher than the ribs themselves and at the same level as the ribs. This alignment is important for the structural support and movement of the thoracic spine.

Ribs are attached to the sternum through costal cartilage at the anterior end of the shaft, not at the posterior end or directly at the head or angle of the rib.

Ribs are connected to the thoracic vertebrae at the head and tubercle through synovial joints, allowing for various movements. The incorrect answers provided do not accurately describe the specific joints formed between the ribs and thoracic vertebrae.

The sternum is a vital bone in the human body located on the chest region and serves as the anchor for many muscles and protects vital organs such as the heart.

The correct answer explains the articulation points of the manubrium within the body, highlighting its connections to the clavicle, ribs, and sternum.

The correct answer is ribs 2-9 because these ribs directly attach to the sternum through cartilaginous connections.

The xiphoid process is the smallest and most inferior part of the sternum, and it articulates with the shaft of the sternum at the xiphisternal joint, forming a cartilaginous joint.

The pectoral muscles consist of the pectoralis major and pectoralis minor, not the deltoid muscle, trapezius muscle, or biceps brachii muscle.

The correct answer provides the accurate information about the origins, insertions, innervations, and functions of the pectoralis major, while the incorrect answers contain inaccurate details pertaining to other muscles and their respective origins, insertions, innervations, and functions.

The pectoralis minor muscle originates from ribs 3-5 and inserts into the coracoid process of the scapula. It is innervated by the pectoral nerve from the brachial plexus and functions to pull the shoulder down and forward.

The intercostal muscles are specifically located between the ribs and play a crucial role in breathing.

The correct answer describes the specific origin and path of the intercostal nerves in relation to the muscles and skin between the ribs in the thoracic region.

The diaphragm is a muscle that plays a crucial role in breathing by contracting and relaxing to help expand and contract the thoracic cavity.

Contracting the diaphragm plays a crucial role in breathing and various functions such as urination, defecation, and childbirth. It does not cause chest pain, restrict blood flow to the brain, or reduce blood pressure throughout the body.

Breasts are actually modified sweat glands that produce and secrete milk independently.

Intercostal arteries provide the blood supply to the breast tissue, delivering nutrients and oxygen for proper function.

Breasts are sensitized by nerve endings in the skin and surrounding tissues, not by the lymphatic system, muscle contractions, or hormonal changes.

Breast tissue lymph drainage involves specific quadrants and lymph nodes in the armpit area. Other options provided incorrect information regarding lymph drainage processes.

The upper outer quadrant of the right side and the upper inner quadrant of the left side are more susceptible to cancer due to drainage to the axillary lymph nodes. Surgeons may need to remove tissue from armpits and sometimes the pec major.

The heart is the first organ to start working and the last to stop working due to its crucial role in pumping oxygenated blood throughout the body. It begins functioning as early as the embryonic stage, while other organs mentioned do not perform essential functions at such an early stage or continue working after brain function ceases.

Surface anatomy of the heart helps in locating specific areas for precise examination and diagnosis. It is important for medical professionals to be familiar with the accurate locations of the heart angles to perform effective evaluations.

The correct answer mentions the specific location of the heart in the mediastinum and the three layers that surround it, which are the epicardium, the serous pericardium, and the fibrous pericardium. The incorrect answers provide alternative locations and coverings that do not accurately describe the heart's position and protection.

The spaces between the layers of the pericardium are crucial for the heart's function and protection. Understanding these spaces helps in comprehending the anatomy and physiology of the heart.