Identifying Nerves and Blood Vessels - Anatomy

The maxillary artery supplies blood to the mouth and nose. The axillary artery is located near the armpit and does not supply the head with blood. The carotid supplies most of the tissues of the head, but divides into branches, and most of its blood is taken to the brain. The superficial temporal artery supplies the top and sides of the head.

Cranial nerve (CN) II is also known as the optic nerve, which carries visual stimuli to the brain. CN I is the olfactory nerve and it allows for the detection of odors. CN III is the oculomotor nerve, which allows the eyeball to move. CN IV is the trochlear nerve, which helps rotate the eye inferiorly and laterally.

C7 gives rise to the middle trunk of the brachial plexus because it is the middle root. C5 and C6 are superior while C8 and T1 are inferior.

There are 6 division in the brachial plexus: 3 anterior of the superior, middle, and inferior trunks as well as 3 posterior of the superior, middle, and inferior trunks.

The arm has a few major veins that drain it. The brachial vein drains the deep portions of the arm, the basilic vein drains the medial superficial portion of the arm, and the cephalic vein drains the lateral superficial portion of the arm. The brachial and basilic veins join in the armpit (axilla) to form the axillary vein.

There are 31 pairs of spinal nerves: 8 cervical nerves, 12 thoracic nerves, 5 lumbar nerves, 5 sacral nerves and 1 coccygeal nerve.

Each nerve separates from the spinal cord and exits the spine through the intervertebral foramen found between adjacent vertebrae. The nerves innervate regions of the peripheral nervous system and relay information to and from the central nervous system.

A dermatome is an area of skin innervated by the cutaneous branches of a single spinal nerve. When spinal nerves diverge from the spinal cord, they innervate regions of the periphery and serve to relay information between the periphery and central nervous system. T10 innervates tissue around the level of the umbilicus, or navel. The C4 spinal nerve innervates the top of the shoulder, T4 innervates the level of the chest, T7 innervates slightly lower at the level of the xiphoid process, and L1 innervates the inguinal region around the groin.

When at rest, the neuron initially has a negative membrane potential. At the beginning of an action potential, voltage-gated sodium channels open, allowing sodium ions to enter the cell. This causes the cell to become positively charged compared to the outside of the cell. This process is called depolarization.

After depolarization occurs, the sodium channels close, initiating the absolute refractory period. Voltage-gated potassium channels then open and potassium ions exit the cell. This results in hyperpolarization and the relative refractory period. The potassium channels then close and the sodium-potassium pump returns the cell to its resting potential by removing sodium and collecting potassium.

The aorta has three crucial segments. The aortic arch is the beginning of the aorta, where it exits the left ventricle. Three blood vessels branch from the aortic arch: the brachiocephalic artery, the left subclavian artery, and the left common carotid artery. Around the T4 vertebra the aortic arch transitions into the thoracic aorta. The thoracic aorta has four major branches: the intercostal, bronchial, esophageal, and phrenic arteries. After the thoracic aorta, the vessel transitions into the abdominal aorta.

The vertebral arteries come off of the subclavian arteries, which branch off of the aortic arch (left) and brachiocephalic artery (right).

The recurrent branch of the median nerve innervates the lateral two lumbricals and the thenar muscles. Damage along any part of the median nerve will result in the "papal sign" when the patient is asked to make a fist.

The ulnar nerve divides into the deep and superficial branches when it terminates in the hand. The deep branch innervates the third and fourth lumbricals, while the superficial branch innervates the palmaris brevis. The radial nerve innervates several structures, including the biceps brachii and triceps brachii.

The two medial lumbricals are innervated by the deep branch of the ulnar nerve. The lateral two lumbricals are innervated by the digital branches of the median nerve.

The other answer choices show correct muscle-nerve pairings.

The palmar digital branches of the median nerve are responsible for cutaneous innervation of the palmar side of the thumb, index finger, middle finger and half of the ring finger.

The superficial branch of the ulnar nerve innervates the palmaris brevis, while the deep branch of the ulnar nerve innervates the third and fourth lumbricals. The radial nerve innervates several structures including the biceps and triceps brachii.

Compression of the radial nerve in the axilla due to poorly fitted crutches is also known as crutch palsy and causes the pins and needles described in the question.

The median and unlar nerves primarily serve to innervate the hand and wrist, while the musculocutaneous nerve is more involved with forearm movements at the elbow.

The skier likely compressed her superficial peroneal nerve which innervates the dorsum of the foot.

The superficial peroneal nerve wraps around the neck of the fibula and is a common site of compression when people cross their legs or wear high boots.

The plantar surface of the foot is innervated by the tibial nerve, which courses through the posterior leg. The lateral aspect of the foot is innervated by the sural nerve, which arises from the tibial nerve. The first dorsal web space of the foot is innervated by the deep peroneal nerve, which arises from the common peroneal nerve and runs in the anterior leg. The medial aspect of the leg is supplied by the saphenous nerve, which arises from the femoral nerve.

The lateral femoral cutaneous nerve supplies the lateral thigh and is highly visible during the anterior approach to the hip as it lies between the sartorius and the tensor fasciae latae. The lateral femoral cutaneous nerve is part of the lumbar plexus and arises from spinal root L2.

The medial leg is supplied by the saphenous nerve, which arises from the femoral nerve. The groin area is supplied by the ilioinguinal nerve, arising from L1. The anterior leg is innervated by the common peroneal and superficial peroneal nerves, arising from the sciatic nerve. The plantar surface of the foot is innervated by the tibial nerve, which courses through the posterior leg and also arises from the sciatic nerve.

Maxillary is a branch of the trigeminal nerve (V), and not of the facial nerve (VII).

The branches of the facial nerve, from superior to inferior, are: temporal, zygomatic, buccal, mandibular, and cervical.

The latissimus dorsi muscle is innervated by the thoracodorsal nerve and functions to extend, adduct, and medially rotate the humerus. Damage to the thoracodorsal nerve would result in diminished capacity to pull the body up, such as during climbing or doing pull-ups.

The dorsal scapular nerve innervates the rhomboid and levator scapulae muscles. The accessory nerve innervates the sternocleidomastoid and trapezius. The intercostal nerves innervate the thoracic cavity and some upper extremity regions.

The pectoralis major is innervated by both the medial and lateral pectoral nerves. In contrast, the pectoralis minor is only innervated by the medial pectoral nerve.

The long thoracic nerve innervates the serratus anterior muscle. The superior and inferior pectoral nerves are false answer choices and do not refer to anatomical structures.

The long thoracic nerve innervates the serratus anterior muscle, which keeps the medial border and inferior angle of the scapula pressed against the thoracic wall. The long thoracic nerve is located very superficially and is often damaged during surgery. Damage to the long thoracic nerve causes the medial border and inferior angle of the scapula to elevate away from the thoracic wall, resulting in "winging" of the scapula. When this occurs, normal elevation of the arm is not possible.

The thoracodorsal nerve innervates the latissimus dorsi. Damage to the thoracodorsal nerve results in diminished capacity to use the arms to pull the body forward or upward, such as the motion of doing pull-ups. The superior and inferior subscapular nerves innervate the subscapularis muscle, a rotator cuff muscle used to stabilize the glenohumeral joint (shoulder). The median nerve innervates the flexors of the forearm and some parts of the hand. The axillary nerve innervates the deltoid, teres minor, and triceps brachii. Damage to the axillary nerve results in inability to abduct the arm greater than fifteen degrees.