Inferior parathyroid develops from which pharyngeal pouch?
Skeletal derivative of 2nd pharyngeal arch -
Which of the following is derived from endoderm?
Development of labia majora is from -
What type of joint is the 1st carpometacarpal joint?
The nutrient artery to the femur is?
The right coronary artery supplies blood to all of the following structures, except?
All of the following arteries are branches of the coeliac trunk, EXCEPT which one?
Which of these best describes the renal angle?
From which ribs does the spleen extend?
NEET-PG 2012 - Anatomy NEET-PG Practice Questions and MCQs
Question 61: Inferior parathyroid develops from which pharyngeal pouch?
- A. 1st
- B. 2nd
- C. 3rd (Correct Answer)
- D. 4th
Explanation: The inferior parathyroid glands develop from the dorsal wing of the third pharyngeal pouch. Due to their origin, they often migrate further caudally than the superior parathyroid glands, sometimes even locating within the thymus which also develops from the third pouch. *1st* - The first pharyngeal pouch contributes to the formation of the eustachian tube, tympanic cavity, and mastoid air cells. - It has no role in the development of the parathyroid glands. *2nd* - The second pharyngeal pouch mainly gives rise to the palatine tonsils and their crypts. - It is not involved in the development of parathyroid tissue. *4th* - The fourth pharyngeal pouch gives rise to the superior parathyroid glands and the parafollicular cells (C cells) of the thyroid, which produce calcitonin. - While it forms parathyroid tissue, it is for the superior glands, not the inferior ones.
Question 62: Skeletal derivative of 2nd pharyngeal arch -
- A. Malleus
- B. Incus
- C. Stapes (Correct Answer)
- D. Maxilla
Explanation: ***Stapes*** - The **2nd pharyngeal arch** (also known as the hyoid arch) gives rise to several structures, including Reichert's cartilage, which forms the **stapes** bone, the styloid process, the lesser horn of the hyoid, and the upper part of the hyoid body. - Its muscles include the **stapedius**, stylohyoid, posterior belly of the digastric, and muscles of facial expression. *Malleus* - The **malleus** is derived from the **1st pharyngeal arch** (Meckel's cartilage), along with the incus. - The 1st pharyngeal arch is also responsible for forming the malleus, incus, and mandible. *Incus* - Similar to the malleus, the **incus** also originates from the **1st pharyngeal arch** (Meckel's cartilage). - Both the malleus and incus are crucial components of the middle ear ossicles but are structurally distinct from the stapes. *Maxilla* - The **maxilla** development is primarily from the **maxillary prominence** of the first pharyngeal arch, which is a subdivision of the first arch but does not originate from the 2nd arch. - It forms a significant portion of the midface and upper jaw, contributing to the nasal cavity and orbital floor.
Question 63: Which of the following is derived from endoderm?
- A. Gall bladder (Correct Answer)
- B. Lens
- C. Spleen
- D. Lymph nodes
Explanation: ***Gall bladder*** - The **gallbladder**, along with other organs of the **gastrointestinal tract** such as the liver, pancreas, and epithelial lining of the digestive and respiratory systems, originates from the **endoderm** [1]. - The endoderm forms the primitive gut tube, from which these accessory digestive organs bud off. *Lens* - The **lens of the eye** is derived from the **surface ectoderm**, which invaginates to form the lens vesicle. - This contrasts with the neural ectoderm, which forms the neural tube and retina. *Spleen* - The **spleen** is derived from the **mesoderm**, specifically from mesenchymal cells in the dorsal mesentery of the stomach. - It is involved in blood filtration and immune responses, making it a lymphoid organ. *Lymph nodes* - **Lymph nodes** are primarily derived from the **mesoderm**, specifically from specialized mesenchymal cells that form their connective tissue capsule and stroma. - The immune cells within the lymph nodes, such as lymphocytes, originate from hematopoietic stem cells that migrate into these developing structures.
Question 64: Development of labia majora is from -
- A. Urogenital sinus
- B. Mullerian duct
- C. Genital ridge
- D. Genital swelling (Correct Answer)
Explanation: ***Genital swelling*** - The **labia majora** develop from the **genital (labioscrotal) swellings** in females, which are homologous to the scrotum in males [3]. - These swellings enlarge and fuse anteriorly to form the mons pubis and posteriorly to form the posterior commissures of the labia majora. *Urogenital sinus* - The **urogenital sinus** gives rise to structures like the **bladder**, **urethra**, and parts of the **vagina** in females [2]. - It does not contribute to the formation of the external labial structures. *Mullerian duct* - The **Mullerian (paramesonephric) ducts** develop into the **fallopian tubes**, **uterus**, and the **upper third of the vagina** [1], [2]. - These structures are internal reproductive organs and do not form external genitalia like the labia majora. *Genital ridge* - The **genital ridge** is the embryonic precursor to the **gonads** (ovaries or testes). - It differentiates into either ovaries or testes and does not directly form external genital structures.
Question 65: What type of joint is the 1st carpometacarpal joint?
- A. Pivot
- B. Hinge
- C. Ball and Socket
- D. Saddle (Correct Answer)
Explanation: ***Saddle*** - The **1st carpometacarpal joint** (thumb CMC joint) is a classic example of a **saddle joint** due to the reciprocal concave-convex opposing surfaces of the trapezium and the first metacarpal [1]. - This unique shape allows for a wide range of motion, including **flexion/extension**, **abduction/adduction**, and **opposition**, which is crucial for thumb function. *Pivot* - A **pivot joint** allows for rotational movement around a single axis, like the **atlantoaxial joint** (C1-C2) or the **proximal radioulnar joint**. - This type of motion is not characteristic of the 1st carpometacarpal joint. *Hinge* - A **hinge joint** permits movement in only one plane, like the **elbow** or **interphalangeal joints**, allowing for **flexion and extension**. - The 1st carpometacarpal joint has a greater degree of freedom than a hinge joint. *Ball and Socket* - A **ball and socket joint** offers the greatest range of motion, allowing for movement in all planes, including **circumduction and rotation**, such as the **shoulder** and **hip joints**. - While the 1st carpometacarpal joint is highly mobile, it does not achieve the full range of motion of a ball and socket joint.
Question 66: The nutrient artery to the femur is?
- A. Profunda femoris artery (Correct Answer)
- B. Femoral artery
- C. Popliteal artery
- D. Medial circumflex femoral artery
Explanation: ***Profunda femoris artery*** - The **profunda femoris artery** (deep femoral artery) is the main blood supply to the **femur's diaphysis** via its perforating branches. - Typically, the **second perforating branch** gives rise to the nutrient artery, which enters the bone through the **nutrient foramen** in the middle third of the femoral shaft. *Femoral artery* - The **femoral artery** is the main artery of the thigh and gives off several branches, including the profunda femoris artery. - While it is the source of blood for the entire lower limb, it does not directly give rise to the main **nutrient artery of the femur**. *Popliteal artery* - The **popliteal artery** is a continuation of the femoral artery in the popliteal fossa behind the knee. - It primarily supplies structures around the knee joint and the lower leg, not the direct **diaphyseal nutrient supply** to the femur. *Medial circumflex femoral artery* - The **medial circumflex femoral artery** primarily supplies the head and neck of the femur, crucial for its vascularity, especially in children. - It does not serve as the **main nutrient artery** for the femoral shaft (diaphysis).
Question 67: The right coronary artery supplies blood to all of the following structures, except?
- A. Posterior wall of left ventricle
- B. SA node
- C. Anterior 2/3 of ventricular septum (Correct Answer)
- D. AV node
Explanation: ***Anterior 2/3 of ventricular septum*** - The **anterior two-thirds of the interventricular septum** is primarily supplied by the **septal branches of the left anterior descending artery** (LAD) [1], a branch of the left coronary artery. - Therefore, the right coronary artery does not typically supply this region. *SA node* - The **SA node** (sinoatrial node) is the heart's natural pacemaker and receives its blood supply from the **right coronary artery** in about 60% of individuals. - Occlusion of the RCA can lead to symptomatic **bradycardia** or **SA node dysfunction**. *AV node* - The **AV node** (atrioventricular node), crucial for coordinating ventricular contraction, is supplied by the **right coronary artery** in approximately 90% of individuals [1]. - Infarcts in the RCA territory can manifest as various degrees of **heart block**. *Posterior wall of left ventricle* - The **posterior wall of the left ventricle** is predominantly supplied by the **posterior descending artery (PDA)**, which in about 80% of people, is a terminal branch of the **right coronary artery** [1]. - This supply is vital for the contractile function of the left ventricle's posterior aspect.
Question 68: All of the following arteries are branches of the coeliac trunk, EXCEPT which one?
- A. Splenic artery
- B. Left gastric artery
- C. Common hepatic artery
- D. Right gastric artery (Correct Answer)
Explanation: ***Right gastric artery*** - The **right gastric artery** typically originates from the **proper hepatic artery**, which is a branch of the common hepatic artery. - Therefore, it is not a direct branch of the coeliac trunk itself. *Left gastric artery* - The **left gastric artery** is one of the three main direct branches of the **coeliac trunk**. - It supplies the lesser curvature of the stomach and the abdominal esophagus. *Splenic artery* - The **splenic artery** is another major direct branch of the **coeliac trunk**. - It supplies the spleen, pancreas, and parts of the stomach via various branches. *Common hepatic artery* - The **common hepatic artery** is the third main direct branch of the **coeliac trunk**. - It gives rise to the proper hepatic artery and the gastroduodenal artery, supplying the liver, gallbladder, pylorus, and duodenum.
Question 69: Which of these best describes the renal angle?
- A. The angle between the latissimus dorsi and the 12th rib
- B. The angle between the erector spinae and the iliac crest
- C. The angle between the 12th rib and the erector spinae (Correct Answer)
- D. The angle between the 12th rib and the rectus abdominis
Explanation: ***The angle between the 12th rib and the erector spinae*** - The **renal angle** (also known as the costovertebral angle) is the space formed by the junction of the **12th rib** and the **erector spinae muscles** laterally. - This anatomical landmark is clinically significant for assessing **kidney pain** or inflammation (e.g., in pyelonephritis) through percussion. *The angle between the latissimus dorsi and the 12th rib* - While the **latissimus dorsi** is a significant back muscle, it is not the primary anatomical landmark that defines the renal angle. - The renal angle specifically refers to the relationship between the rib cage and the deeper spinal muscles. *The angle between the erector spinae and the iliac crest* - This description refers to a region lower down on the back, closer to the **pelvis**, and not directly related to the position of the kidneys. - The **iliac crest** defines the upper border of the pelvis, far from the kidney's typical location relative to the 12th rib. *The angle between the 12th rib and the rectus abdominis* - The **rectus abdominis** muscle is located on the anterior (front) aspect of the abdomen, involved in trunk flexion. - This muscle is anatomically distinct and separate from the posterior flank region where the kidneys are located and where the renal angle is assessed.
Question 70: From which ribs does the spleen extend?
- A. 5th to 9th rib
- B. 2nd to 5th rib
- C. 11th to 12th rib
- D. 9th to 11th rib (Correct Answer)
Explanation: ***9th to 11th rib*** - The **spleen** is located in the **left upper quadrant** of the abdomen, deep to the 9th, 10th, and 11th ribs. - Its protected position beneath these ribs makes it vulnerable to injury from trauma to the left lower chest or upper abdomen. *5th to 9th rib* - This range primarily covers the location of the **heart** and the upper part of the **lungs**. - While the spleen is superior to other abdominal organs, it does not extend as high as the 5th rib. *2nd to 5th rib* - This region is mainly associated with the **upper lobes of the lungs** and the **superior mediastinum**. - The spleen is an abdominal organ and is situated much lower in the thoracic cavity. *11th to 12th rib* - This range is too low and posterior for the typical position of the spleen, especially for its superior border. - The 12th rib primarily overlies the **kidneys** and the more inferior aspects of the diaphragm.