Inversion and eversion of foot occurs at which joint
Which of the following statements about the femoral triangle is NOT true?
Which structure is contained within the femoral canal?
The structure which lies outside the femoral sheath is:
Which structure forms the lateral border of the ischiorectal fossa?
Which nerve roots are primarily involved in Erb's palsy?
Which of the following muscles is not supplied by the femoral nerve?
Superior gluteal nerve does not supply?
A nerve injured during axillary lymph node dissection leads to loss of sensation in the medial side of the arm. Which nerve is injured?
Azygos vein drains into:
NEET-PG 2015 - Anatomy NEET-PG Practice Questions and MCQs
Question 71: Inversion and eversion of foot occurs at which joint
- A. Ankle
- B. Subtalar (Correct Answer)
- C. Tarso-metatarsal
- D. None of the options
Explanation: ***Subtalar*** - The **subtalar joint** (talocalcaneal joint) is primarily responsible for **inversion** and **eversion** movements of the foot. - **Inversion** involves tilting the sole of the foot medially (turning inward), while **eversion** involves tilting the sole laterally (turning outward). - This joint allows the foot to **adapt to uneven surfaces** and plays a crucial role in the biomechanics of walking and running. - The subtalar joint is essential for shock absorption and balance during gait. *Ankle* - The **ankle joint** (talocrural joint) is a hinge joint primarily responsible for **dorsiflexion** and **plantarflexion** of the foot. - It allows moving the foot up and down but has minimal contribution to inversion and eversion. *Tarso-metatarsal* - The **tarso-metatarsal joints** (Lisfranc joints) connect the tarsal bones to the metatarsal bones. - These joints contribute primarily to the **stability and arch integrity** of the foot, with minimal movement capacity. - They allow slight gliding movements but not significant inversion or eversion. *None of the options* - This option is incorrect because the **subtalar joint** is indeed the primary joint responsible for inversion and eversion of the foot. - Understanding foot joint biomechanics is essential for diagnosing gait abnormalities, ankle sprains, and foot pathologies.
Question 72: Which of the following statements about the femoral triangle is NOT true?
- A. Contains the femoral vessels
- B. Floor is formed by adductor longus (Correct Answer)
- C. Lateral margin is formed by sartorius
- D. Medial margin is formed by adductor longus
Explanation: ***Floor is formed by adductor longus*** - The floor of the femoral triangle is actually formed by the **iliopsoas** laterally and the **pectineus** medially. - The **adductor longus** forms part of the medial boundary of the femoral triangle, not its floor. - This is the INCORRECT statement (correct answer for a "NOT true" question). *Contains the femoral vessels* - The femoral triangle is a crucial anatomical space containing the **femoral artery**, **femoral vein**, and **femoral nerve**. - These structures are organized from lateral to medial as nerve, artery, vein (NAVY). *Lateral margin is formed by sartorius* - The **sartorius muscle** forms the lateral boundary of the femoral triangle. - Its medial border defines one of the triangle's sides. *Medial margin is formed by adductor longus* - The **adductor longus** does form the medial boundary of the femoral triangle. - This is anatomically correct along with the inguinal ligament (superior boundary) and sartorius (lateral boundary).
Question 73: Which structure is contained within the femoral canal?
- A. Deep inguinal lymph node (Correct Answer)
- B. Loose areolar tissue and fat
- C. Lymphatic vessels
- D. Femoral vein
Explanation: ***Deep inguinal lymph node*** - The **femoral canal** contains several structures: a **lymph node (of Cloquet or Rosenmüller)**, **lymphatic vessels**, and **loose areolar tissue**. [1] - Among these contents, the **deep inguinal lymph node** (also called the lymph node of Cloquet or Rosenmüller) is the **most clinically significant and specifically named structure**. - This lymph node is an important anatomical landmark, serving as a sentinel node that drains lymph from the lower limb, external genitalia, and perineum. - **Clinically**, it is the structure most commonly referenced when discussing femoral canal contents, particularly in the context of femoral hernias and lymphatic drainage patterns. [1] *Loose areolar tissue and fat* - While **loose areolar tissue and fat** are indeed present within the femoral canal, they are **supporting contents** rather than specifically named anatomical structures. [1] - These tissues fill the space and allow for expansion of adjacent vessels (femoral artery and vein), but they are not the primary structure of anatomical or clinical significance. - When asked about "the structure" in the femoral canal, the named lymph node is the more specific answer. *Lymphatic vessels* - **Lymphatic vessels** do traverse the femoral canal, but they are **conduits** rather than a discrete, named structure. [1] - These vessels drain lymph towards the deep inguinal lymph node (of Cloquet) located within the same canal. - The specifically named lymph node is the more definitive anatomical answer than the unnamed vessels passing through. *Femoral vein* - The **femoral vein** is located in the **intermediate compartment of the femoral sheath**, NOT within the femoral canal. - The femoral sheath has three compartments: lateral (femoral artery), intermediate (femoral vein), and medial (femoral canal). - The femoral vein lies lateral to the femoral canal, making this option clearly incorrect.
Question 74: The structure which lies outside the femoral sheath is:
- A. Genitofemoral nerve
- B. Femoral vein
- C. Femoral artery
- D. Femoral nerve (Correct Answer)
Explanation: ***Femoral nerve*** - The **femoral nerve** lies lateral to the femoral artery and is therefore situated outside the **femoral sheath**, which encloses the femoral artery, femoral vein, and lymphatic vessels [2]. - It originates from the lumbar plexus (L2-L4) and provides motor innervation to the quadriceps femoris and sensory innervation to the anterior thigh and medial leg. *Femoral artery* - The **femoral artery** is a primary content of the **femoral sheath**, occupying the most lateral compartment. - It is a continuation of the external iliac artery and is a major blood supply to the lower limb. *Femoral vein* - The **femoral vein** lies within the **femoral sheath**, positioned medial to the femoral artery. - It is the primary vein responsible for draining blood from the lower limb and eventually becomes the external iliac vein. *Genitofemoral nerve* - The **genitofemoral nerve** typically emerges on the anterior surface of the psoas major muscle and then usually divides into genital and femoral branches [1]. - While its femoral branch supplies sensory innervation to the skin over the femoral triangle, it does not course within the femoral sheath itself but rather anterior to it or outside its immediate vicinity [1].
Question 75: Which structure forms the lateral border of the ischiorectal fossa?
- A. Perineal membrane
- B. Obturator internus muscle (Correct Answer)
- C. Gluteus maximus
- D. Sacrotuberous ligament
Explanation: ***Obturator internus muscle*** - The **ischiorectal fossa** (also known as the **ischioanal fossa**) is a wedge-shaped space in the perineum, and its lateral wall is formed by the **obturator internus muscle** and its covering fascia [1]. - This muscle originates from the inner surface of the **obturator membrane** and the surrounding bone, descending through the lesser sciatic foramen to insert on the greater trochanter of the femur. *Perineal membrane* - The **perineal membrane** is a dense fibrous sheet that forms the inferior boundary of the **deep perineal pouch**. - It does not form a lateral border of the ischiorectal fossa but rather contributes to the floor of the **urogenital triangle**, anterior to the fossa. *Gluteus maximus* - The **gluteus maximus** is a large muscle of the buttock, primarily involved in extension and lateral rotation of the hip. - It lies superficial to the structures of the perineum and therefore does not form a boundary of the **ischiorectal fossa**. *Sacrotuberous ligament* - The **sacrotuberous ligament** is a strong fibrous band connecting the sacrum to the ischial tuberosity. - While it helps to define the boundaries of the **perineum** posteriorly and contributes to the stability of the **sacroiliac joint**, it does not form the lateral wall of the **ischiorectal fossa**.
Question 76: Which nerve roots are primarily involved in Erb's palsy?
- A. C5, C6 (Correct Answer)
- B. C4, C5
- C. C5, C7
- D. C6, C8
Explanation: C5, C6 - **Erb's palsy** primarily involves injury to the **upper trunk of the brachial plexus**, which is formed by the ventral rami of **C5 and C6** spinal nerves. - This lesion results in a characteristic "waiter's tip" posture due to paralysis of muscles supplied by these nerve roots, including the **deltoid**, **biceps**, and **brachialis**. *C4, C5* - While C5 is involved, **C4** is typically associated with the **phrenic nerve** and diaphragm function, and its primary involvement is not characteristic of Erb's palsy. - Injury to C4 and C5 alone would not produce the comprehensive motor deficits seen in Erb's palsy involving shoulder and elbow flexion. *C5, C7* - This option includes C5 but also **C7**, which is more commonly associated with the **middle trunk** of the brachial plexus. - While C7 can be involved in extended brachial plexus injuries, its primary involvement alone is not the classic presentation of Erb's palsy. *C6, C8* - This combination includes C6 but introduces **C8**, which is part of the **lower trunk** of the brachial plexus. - Injuries involving C8 and T1 are characteristic of **Klumpke's palsy**, affecting intrinsic hand muscles and causing a "claw hand" deformity, which is distinct from Erb's palsy.
Question 77: Which of the following muscles is not supplied by the femoral nerve?
- A. Pectineus
- B. Sartorius
- C. Vastus medialis
- D. Obturator externus (Correct Answer)
Explanation: ***Obturator externus*** - The **obturator externus** muscle is primarily supplied by the **obturator nerve** (L3-L4), which arises from the lumbar plexus, not the femoral nerve. - Its main function is the **lateral rotation of the thigh** at the hip joint. *Pectineus* - The **pectineus** muscle receives dual innervation, typically from both the **femoral nerve** (L2-L4) and the obturator nerve. - It aids in **adduction**, **flexion**, and **medial rotation** of the thigh. *Sartorius* - The **sartorius** muscle is entirely supplied by the **femoral nerve** (L2-L3). - It is responsible for **flexing, abducting, and laterally rotating the thigh** at the hip, and flexing the leg at the knee. *Vastus medialis* - The **vastus medialis** is one of the four muscles forming the quadriceps femoris group, all of which are exclusively supplied by the **femoral nerve** (L2-L4). - This muscle is crucial for **extending the leg** at the knee joint.
Question 78: Superior gluteal nerve does not supply?
- A. Tensor fasciae latae
- B. Gluteus medius
- C. Gluteus minimus
- D. Gluteus maximus (Correct Answer)
Explanation: ***Gluteus maximus*** - The **gluteus maximus** muscle is primarily innervated by the **inferior gluteal nerve** (L5, S1, S2), not the superior gluteal nerve. - Its main actions include **extension** and **external rotation** of the hip. *Tensor fasciae latae* - The **tensor fasciae latae** is innervated by the **superior gluteal nerve** (L4, L5, S1). - This muscle helps in **flexion**, **abduction**, and **internal rotation** of the hip. *Gluteus medius* - The **gluteus medius** muscle receives its innervation from the **superior gluteal nerve** (L4, L5, S1). - It is a primary **abductor** and **internal rotator** of the hip, crucial for pelvic stability. *Gluteus minimus* - The **gluteus minimus** is also innervated by the **superior gluteal nerve** (L4, L5, S1). - Its functions are similar to the gluteus medius, including **abduction** and **internal rotation** of the hip.
Question 79: A nerve injured during axillary lymph node dissection leads to loss of sensation in the medial side of the arm. Which nerve is injured?
- A. Long thoracic nerve
- B. Intercostobrachial nerve (Correct Answer)
- C. Medial pectoral nerve
- D. Accessory nerve
Explanation: ***Intercostobrachial nerve*** - The **intercostobrachial nerve** (T2) is the nerve most commonly injured during **axillary lymph node dissection** - It provides **sensory innervation to the medial side of the upper arm**, specifically the skin over the medial and posterior aspects of the arm [1] - This nerve arises from the **lateral cutaneous branch of the second intercostal nerve** and crosses the axilla to reach the arm [1] - Injury during axillary surgery results in **numbness or paresthesia** in the medial upper arm region, which is a well-recognized complication of breast cancer surgery with axillary node dissection [1] - Studies show **30-80% of patients** undergoing axillary dissection experience intercostobrachial nerve injury *Long thoracic nerve* - The **long thoracic nerve** (C5-C7) innervates the **serratus anterior muscle**, which is crucial for scapular protraction and rotation - Damage to this nerve causes **"winged scapula"**, where the scapula protrudes posteriorly - This is a **motor nerve**, not sensory, so injury does not result in sensory deficits in the arm *Medial pectoral nerve* - The **medial pectoral nerve** (C8-T1) primarily innervates the **pectoralis major** and **pectoralis minor** muscles [1] - This is a **motor nerve** playing a role in muscle function rather than sensation [1] - Injury would result in weakness of these muscles, not sensory loss *Accessory nerve* - The **accessory nerve** (cranial nerve XI) innervates the **sternocleidomastoid** and **trapezius muscles** - This nerve is located in the **posterior triangle of the neck**, not in the axilla - Injury would lead to weakness in shrugging the shoulders or turning the head, not sensory loss in the arm during axillary dissection
Question 80: Azygos vein drains into:
- A. Right subcostal vein
- B. Right ascending lumbar vein
- C. Superior vena cava (Correct Answer)
- D. Brachiocephalic
Explanation: ***Superior vena cava*** - The **azygos vein** is a major venous channel that drains the walls of the thorax and abdomen, emptying directly into the **superior vena cava (SVC)**. [1] - This connection is crucial for venous return from the posterior thoracic wall, pericardium, and bronchi, especially bypassing the inferior vena cava if it's obstructed. [1] *Right subcostal vein* - The right subcostal vein is a tributary that helps form the **azygos vein**; it does not receive drainage from the azygos vein. - It contributes to the initial formation of the azygos system, not its termination. *Brachiocephalic* - The **brachiocephalic veins** are formed by the union of the internal jugular and subclavian veins, and they merge to form the **superior vena cava**. - The azygos vein drains into the superior vena cava, not directly into the brachiocephalic veins. *Right ascending lumbar vein* - The **right ascending lumbar vein** is a major tributary that contributes to the formation of the **azygos vein** in the lumbar region. - It drains into the azygos system, illustrating its origin rather than its termination.