Anatomy embryology histology videos & books

2022-08-12 14:11:13 Open / Comment

2022-08-12 14:09:57 74) Figure is a high magnification photomicrograph of the gall bladder. The arrow points to the internal lining that is formed by which of the following? Open / Comment

2022-08-10 15:59:01 73) Explanation

The infraorbital nerve, a branch of the maxillary (V2) division of the trigeminal (fifth cranial) nerve, courses below the orbital floor to reach the area of skin below the eye. It provides superior alveolar branches to supply the upper gums and is vulnerable in fractures involving the floor of the orbit and face area. All the nerves mentioned in the other choices will be spared by this type of injury. The frontal nerve (choice A) and nasociliary nerve (choice C) are branches from the ophthalmic division (V1) of the trigeminal (fifth cranial) nerve and course within the orbit. The supraorbital (choice D) nerve is a continuation branch of the frontal nerve onto the forehead, providing sensory innervation for this area. The trochlear (fourth cranial) nerve is also located within the orbit. Open / Comment

2022-08-09 15:57:45 73) A 19-year-old man was in a barroom brawl and was punched squarely in the right eye. He comes to the emergency room the next day and complains of diplopia. An X-ray reveals fracture of the orbital floor. Neurological examination shows loss of sensation… Open / Comment

2022-08-09 15:56:33 73) A 19-year-old man was in a barroom brawl and was punched squarely in the right eye. He comes to the emergency room the next day and complains of diplopia. An X-ray reveals fracture of the orbital floor. Neurological examination shows loss of sensation of the skin of the right face below the right eye and the upper gums. Which of the following nerves may be injured? Open / Comment

2022-08-05 13:36:01 72)
The capitate bone lies directly distal to the lunate. The mechanism of perilunate fracture dislocation involves rupture of the radioscaphocapitate and scapholunate interosseous ligaments, dislocation of the capitolunate joint, rupture of the lunotriquetral interosseous ligament, and finally dislocation/rupture of the lunate. In the anatomical position, the hamate (choice B) is the most medial carpal bone, located just distal to the triquetrum. The scaphoid (choice C) lies lateral to the lunate and proximal to the trapezium (choice D), the carpal bone articulating with the thumb. The trapezoid (choice E) is medial to the trapezoid and distal to the scaphoid. The lunate bone (choice C) lies adjacent to the scaphoid in the proximal row of carpals and with the scaphoid articulates with the radius at the radiocarpal or wrist joint. It is not related to the anatomic snuffbox. The pisiform bone (choice D) is a sesamoid bone in the tendon of the flexor carpi ulnaris on the lateral wrist. It is not related to the anatomic snuffbox. Open / Comment

2022-08-04 13:35:26 72) A perilunate fracture dislocation is a devastating closed injury of the wrist. It usually results from a fall where the weight of the body is transferred onto the wrist. The hand is caught in the hyperextended and ulnar deviated position. The fracture… Open / Comment

2022-08-04 13:34:17 72) A perilunate fracture dislocation is a devastating closed injury of the wrist. It usually results from a fall where the weight of the body is transferred onto the wrist. The hand is caught in the hyperextended and ulnar deviated position. The fracture dislocation involves rupture of interosseous ligaments, joints, and ultimately dislocation/fracture of the lunate bone. In the anatomical position, which carpal bone lies directly distal to the lunate? Open / Comment

2022-08-02 09:53:01 71) Schwann cells produce myelin in the peripheral nervous system whereas oligodendrocytes produce myelin in the central nervous system. Oligodendrocytes manufacture the proteolipid protein, the functional equivalent to P0 in the central nervous system. Fibrous (choice A) and protoplasmic (choice D) astrocytes are supportive cells which play a role in the regulation of brain metabolism. Microglia (choice B) are mesodermal in origin and have phagocytotic activity in the central nervous system. Open / Comment

2022-06-21 09:25:06 Hemiballismus is a movement disorder characterized by involuntary large amplitude movements of one or both limbs on one side of the body. It results from infarct damage to the contralateral subthalamic nucleus of Luys, in this case the right one. The left subthalamic nucleus (choice D) controls the limbs on the right side of the body, which are not affected in this case. The anterior limbs of the internal capsule (choices A and B) contain mainly thalamocortical and corticothalamic fibers and lesions in these areas do not result in hemiballismus. Lesions in the cerebellum (choice C) also do not result in hemiballismus. Open / Comment