Bell’s palsy is facial muscle weakness or paralysis that arises from idiopathic damage to the facial nerve. It can occur at any age but is commonly associated with some conditions:
1. pregnancy
2. diabetes
3. upper respiratory ailment
4. GBS
5. Toxins

The common symptoms of Bell’s palsy are:
1. Abnormal corneal reflex as the facial nerve controls the motor aspect of the corneal reflex.
2. The loss of control of facial muscles and eyelids leads to decreased tear production.
3. mild weakness to total paralysis on one side of the face, occurring within hours to days.
4. Bell’s palsy is a lower motor neuron lesion that usually spares the forehead while the upper motor near lesions, like stroke, involves the entire face.
5. The anterior two-thirds of the tongue is supplied by the chorda tympani branch of the facial nerve, thus resulting in loss of taste.
6. Ptosis can be a feature of Bell’s palsy but Bell’s palsy would typically show unilateral symptoms rather than bilateral.

The adrenal medulla comprises chromaffin cells (pheochromocytes), which are functionally equivalent to postganglionic sympathetic neurons. They synthesize, store and release the catecholamines noradrenaline (norepinephrine) and adrenaline (epinephrine) into the venous sinusoids.
The majority of the chromaffin cells synthesize adrenaline.

The inflow of blood from the superior vena cava is directed towards the right atrioventricular orifice. It returns deoxygenated blood from all structures superior to the diaphragm, except the lungs and heart.

There are no valves in the superior vena cava which is why it is relatively easy to insert a CVP line from the internal jugular vein into the right atrium. The brachiocephalic vein is similar as it also has no valves.

The ileocolic artery is the terminal branch of the superior mesenteric artery. It supplies:
1. terminal ileum
2. proximal right colon
3. cecum
4. appendix (via its branch of the appendicular artery)

As veins accompany arteries in the mesentery and are lined by lymphatics, high ligation is the norm in cancer resections—the ileocolic artery branches off the SMA near the duodenum.

The external urethral sphincter functions to provide voluntary control of urine flow from the bladder to the urethra.

It receives its innervation from the branches of the pudendal nerve which originate from S2, S3 and S4.

The heart has two venous drainage systems:
1. Greater venous system – it parallels the coronary arterial circulation and provides 70% venous drainage to the heart
2. Lesser venous system – includes the thebasian veins and provides up to 30% of the venous drainage to the heart

Thebasian veins (also called venae cordis minimae) are the smallest coronary veins and run in the myocardial layer of the heart. They serve to drain the myocardium and are present in all four heart chambers. They are more abundant on the right side of the heart and, more specifically, are most abundant in the right atrium. Thebesian veins drain the subendocardial myocardium either directly, via connecting intramural arteries and veins, or indirectly, via subendocardial sinusoidal spaces.

The left marginal artery comes off the left circumflex artery, and runs alongside the heart.

The left circumflex artery is one of the bifurcations of the left coronary artery, and eventually forms the left marginal artery.

An occlusion in the left circumflex artery often results in a lateral MI.

The right marginal artery originates from the right coronary artery.

The left anterior descending artery (LAD) is another bifurcation of the left coronary artery. An occlusion in the LAD would often result in an anteroseptal MI as is diagnosed on ECG by noting changes in leads V1-V4.

The right coronary artery originates from the right aortic sinus of the ascending aorta, and bifurcates to give rise to many branches, including the sinoatrial artery which supplies the sinoatrial (SA) node in 50-70% of cases, the artery of the atrioventricular (AV) node in 50-60% of cases, the right acute marginal artery which supplies the right ventricle. It also supplies the right atrium, interatrial septum and the posterior inferior third of the interventricular septum.

Arrhythmias and inferior MI often occurs as a result of an occlusion in the right coronary artery, and can be diagnosed by ECG changes in leads II, III and aVF.

The sternocleidomastoid muscle divides the neck into anterior and posterior triangles on both sides of the neck.

The posterior triangle has the following boundaries:
anteriorly – sternocleidomastoid muscle
posteriorly – trapezius
roof – investing layer of deep cervical fascia
floor – prevertebral fascia overlying splenius capitis, levator scapulae, and the scalene muscles

The contents of the posterior triangle are:
1. fat
2. lymph nodes (level V)
3. accessory nerve
4. cutaneous branches of the cervical plexus – greater auricular nerve, transverse cervical nerve, lesser occipital nerve, supraclavicular nerve (A major branch of this plexus is the phrenic nerve, which arises from the anterior divisions of spinal nerves C3-C5)
5. inferior belly of omohyoid
6. branches of the thyrocervical trunk (transverse cervical and suprascapular arteries)
7. third part of the subclavian artery
8. external jugular vein

The first rib is an atypical rib. It is short, wide, and flattened and lies in an oblique plane.

It has a small scalene tubercle on its medial border which marks the point of attachment of scalenus anterior. The lower surface lies on the pleura and is smooth.

The tubercle on the upper surface separates an anterior groove for the subclavian vein and a posterior groove for the subclavian artery and lower trunk of the brachial plexus.

Scalenus medius is attached to a roughened area posterior to the groove for the subclavian artery.

The upper surface gives attachment anteriorly to the subclavius muscle and costoclavicular ligament.

The posterior tibial nerve lies on the posterior surface of the tibialis posterior and, lower down the leg, on the posterior surface of the tibia. The nerve accompanies the posterior tibial artery and lies at first on its medial side, then crosses posterior to it, and finally lies on its lateral side. The nerve, with the artery, passes behind the medial malleolus, between the tendons of the flexor digitorum longus and the flexor hallucis longus.

It gives off muscular branches to the soleus, flexor digitorum longus, flexor hallucis longus, and tibialis posterior. A medial calcaneal branches off to supply the skin over the medial surface of the heel, and an articular nerve to supply the ankle joint. Finally, it terminates to become the medial and lateral plantar nerves.

The saphenous nerve is a branch of the femoral nerve that gives off branches that supply the skin on the posteromedial surface of the leg.

The sural nerve is a branch of the tibial nerve that supplies the skin on the lower part of the posterolateral surface of the leg.

The superficial peroneal nerve is one of the terminal branches of the common peroneal nerve. It arises in the substance of the peroneus longus muscle on the lateral side of the neck of the fibular. It ascends between the peroneus longus and brevis muscles, and in the lower part of the leg it becomes cutaneous. Muscular branches of the superficial peroneal nerve supply the peroneus longus and brevis muscles, while medial and lateral cutaneous branches are distributed to the skin on the lower part of the leg and dorsum of the foot. In addition, the cutaneous branches supply the dorsal surfaces of the skin of all the toes, except the adjacent sides of the first and second toes and the lateral side of the little toe.

The superficial peroneal, sural and saphenous nerves cannot be used to assess neuromuscular blocks since they are sensory nerves.

The deep peroneal nerve enters the dorsum of the foot by passing deep to the extensor retinacula on the lateral side of the dorsalis pedis artery. It divides into terminal, medial, and lateral branches. The medial branch supplies the skin of the adjacent sides of the big and second toes. The lateral branch supplies the extensor digitorum brevis muscle. Both terminal branches give articular branches to the joints of the foot. This nerve is too deep to use for neuromuscular blockade assessment