Posterior Triangle Of The Neck

Explanation
The correct answer is d. The patient's symptoms, including pain, weakness, and vascular insufficiency in the right upper limb, suggest that there is an occlusion of a large vessel in the upper extremity. The description of the vessel passing between the anterior and middle scalene muscles indicates that it is the subclavian artery that is being occluded. This is likely due to hypertrophy of the muscles caused by the patient's regular weightlifting exercise. Therefore, the artery involved in this case is the subclavian artery.

Explanation
The correct answer is the recurrent laryngeal nerve. The question states that the nerve passes around to the posterior surface of the artery, indicating that it is a nerve that is closely associated with the subclavian artery. The phrenic nerve is not specifically mentioned in the question and does not have a close association with the subclavian artery. The vagus nerve does not encircle the subclavian artery on either side. The sympathetic trunk and ansa cervicalis are not specifically mentioned in the question and do not have a close association with the subclavian artery. Therefore, the most appropriate answer is the recurrent laryngeal nerve.

Explanation
A stab wound just above the left clavicle, lateral to the sternocleidomastoid muscle, may be life-threatening because of the possibility of injury to the subclavian artery. The subclavian artery is a major blood vessel that supplies blood to the upper limbs, head, and neck. Injury to this artery can cause severe bleeding and potentially lead to life-threatening hemorrhage.

Explanation
During surgery to transect the anterior scalene muscle, the surgeon must be careful to spare the phrenic nerve, which is in contact with the anterior surface of the muscle. The phrenic nerve innervates the diaphragm, and damaging it could lead to respiratory complications.

Explanation
The correct answer is e) Vertebral. Subclavian steal syndrome occurs when there is a blockage or narrowing in the subclavian artery, leading to a reversal of blood flow in the vertebral artery. In this case, the atherosclerotic plaque in the subclavian artery is causing blood to be "stolen" from the vertebral artery, resulting in cerebral insufficiency and the symptoms of light-headedness and dizziness.

Explanation
The phrenic nerve is the nervous structure lying immediately deep to the subclavian vein as it crosses the anterior scalene muscle. Injury to the phrenic nerve can result in difficulty breathing, which is consistent with the patient's symptoms.

Explanation
The internal jugular vein is accompanied by the deep cervical chain of lymph nodes.

Explanation
The structure that lies immediately anterior to the right anterior scalene muscle at its costal attachment is the subclavian vein.

Explanation
The correct answer is the Accessory (XI) nerve. The Accessory nerve innervates the trapezius and sternocleidomastoid muscles, which are responsible for shoulder movement and head rotation. Damage to this nerve can result in weakness or paralysis of these muscles, leading to shoulder drooping and difficulty raising the arm above the head.

Explanation
During a deep cervical lymph node dissection, the surgeon may encounter the phrenic nerve, subclavian vein, and transverse cervical artery upon the anterior surface of the anterior scalene muscle. However, the middle trunk of the brachial plexus is not typically found in this location.

Explanation
The middle cervical sympathetic ganglion, recurrent laryngeal nerve, and parathyroid glands are all closely related to the inferior thyroid artery.

Explanation
When the carotid sheath is retracted during surgical procedures of the neck, the structures within it are pulled aside as a unit. The cervical sympathetic trunk, which is a part of the sympathetic nervous system, would remain in place when the carotid sheath is retracted. The other structures within the carotid sheath, such as the common carotid artery, internal jugular vein, internal carotid artery, and vagus nerve, would be pulled aside along with the carotid sheath.

Explanation
The greater occipital nerve is derived from the dorsal primary rami of spinal nerves.

Explanation
The omohyoid muscle is an important landmark in both the anterior and posterior triangles of the neck. It is a long, thin muscle that runs from the superior border of the scapula to the hyoid bone. Its superior belly forms the posterior border of the anterior triangle, while its inferior belly forms the anterior border of the posterior triangle. This muscle helps to divide the neck into these two triangles and is used as a reference point for anatomical landmarks in the neck.

Explanation
The superior belly of omohyoid is not seen in the posterior triangle of the neck. The posterior triangle of the neck is an anatomical region bounded by the sternocleidomastoid muscle, trapezius muscle, and clavicle. It contains several structures, including the spinal accessory nerve, transverse cervical artery, and middle trunk of the brachial plexus. However, the superior belly of the omohyoid muscle is not located in this region.

Explanation
The correct answer is e) only a and c. The lesser occipital nerve and spinal accessory nerve are both found in the posterior triangle of the neck. The recurrent laryngeal nerve, on the other hand, is not found in the posterior triangle of the neck.

Explanation
The correct answer is d. All of the above. The respiratory diaphragm, levator scapulae, and omohyoid muscles all receive motor fibers derived from the cervical plexus.

Explanation
The phrenic nerve is part of the cervical plexus, is derived from spinal segments C3, C4, and C5, and lies on the anterior scalene muscle. Therefore, the correct answer is e, which includes all of these statements.

Explanation
The periosteum is a dense fibrous membrane that covers the outer surface of bones. In the case of the skull, the periosteum is called pericranium. Therefore, the correct answer is d.

Explanation
The correct answer is b. The vertebral artery is found deep in the occipital triangle. This means that it is located in the region formed by the posterior belly of the digastric muscle, the superior belly of the omohyoid muscle, and the sternocleidomastoid muscle. It is important to note that the vertebral artery does not pass through the foramen transversium of the 1st cervical vertebrae, which is mentioned in option a. Option c is incorrect because the vertebral artery is not a branch of the maxillary artery. Option d is also incorrect because the vertebral artery enters the vertebral foramen at the C6 level. Option e is incorrect because the vertebral artery does have branches.

Explanation
The correct answer is d because all of the structures listed (anterior scalene, phrenic nerve, and vagus nerve) pass between the subclavian artery and the subclavian vein (or brachiocephalic vein).

Explanation
The costocervical trunk usually arises from the second part of the subclavian artery.

Explanation
The correct answer is e. The thoracic duct turns laterally to pass between the common carotid artery and vertebral artery on the left side of the root of the neck. This is an important anatomical landmark to be aware of when considering the lymphatic drainage in this region. The thoracic duct is the main channel for lymphatic drainage from the lower half of the body and the left side of the upper half of the body, so its course and relationship with other structures are significant.

Explanation
The subclavian artery and subclavian vein in the root of the neck are separated by the anterior scalene muscle.

Explanation
The correct answer is c. The spinal accessory nerve passes between the investing fascia and the prevertebral fascia. This means that it is located between the layers of fascia that surround the neck muscles. This positioning allows the nerve to travel through the posterior cervical triangle, which is a region of the neck.

Explanation
The correct answer is c. Teres minor. This muscle is not found in the floor of the posterior triangle of the neck. The muscles that can be found in the floor of the posterior triangle of the neck are scalenus medius, scalenus anterior, and levator scapulae. Teres minor is actually a muscle of the shoulder.

Explanation
The correct statement is c. The spinal accessory nerve enters the cranial cavity through the foramen magnum. This is the correct answer because the spinal accessory nerve, also known as cranial nerve XI, is a motor nerve that originates from the spinal cord and enters the cranial cavity through the foramen magnum. It then exits the skull through the jugular foramen and innervates the trapezius and sternocleidomastoid muscles.