Comparative Osteology & Arthrology

• Myology of the Sublumbar Region:
• Sublumbar Muscles: The ventral sublumbar muscles comprise Psoas major, Psoas minor, Iliacus, and Quadratus lumborum.
• Gracilis Exclusion: The Gracilis is a broad, thin muscle of the medial thigh region, acting as an adductor of the hindlimb, completely separate from the sublumbar group.

Correct option: (4) Gracilis

• Biventer Masticatory Muscle: The Digastricus (musculus digastricus) is the mandibular muscle composed of two fleshy bellies (rostral/anterior and caudal/posterior bellies) united by a central intermediate tendon, acting to depress the lower jaw and open the mouth.

Correct option: (4) Digastricus

• Inverted Lymph Node Architecture in Swine: In the Pig (swine), the histological architecture of lymph nodes is uniquely reversed/inverted compared to all other domestic mammals.
• Morphological Reversal: Cortical lymphoid follicles and germinal centers reside in the central interior core, while medullary cords and loose sinuses occupy the outer periphery. Afferent lymphatics penetrate at the hilus and efferent lymph leaves from the outer capsular periphery.

Correct option: (4) pig

• Boundaries and Contents of the Femoral Canal:
• Femoral Canal Contents: Encloses the Femoral artery, Femoral vein, deep inguinal lymphatic vessels, and the Saphenous nerve (Internal saphenous nerve).
• Femoral Nerve Exclusion: The Femoral nerve does NOT enter the femoral canal; it travels deeply between the psoas major and iliacus muscles, emerging high in the thigh to innervate the quadriceps femoris.

Correct option: (3) femoral nerve