Overview 

The human hand is supplied by terminal branches of three independent nerves, which are the radial, median and ulnar nerves.¹ These nerves are responsible for touch, pressure, pain and temperature sensations. Usually, numbness in the pinky finger is caused by compression of the ulnar nerve. Numbness and tingling in fingers are known to be linked to heart issues such as catecholaminergic polymorphic ventricular tachycardia (CPVT) or heart attack.²

Common causes of numb pinky finger

Ulnar nerve compression

The ulnar nerve is part of the peripheral nervous system (PNS) – the nerves from your brain and spinal cord – and it is responsible for carrying sensory information to and from the brain via the spinal cord. The ulnar nerve is directly linked to the pinky finger and ring finger. Hence, it provides sensations such as touch, pain and temperature.

The ulnar nerve starts from the cervical region (lower neck) of the spinal cord. It then passes through the upper arm to the hand and supplies sensation to the pinky finger and a part of the ring finger. When a stimulus (e.g., high temperature) is detected, sensory receptors in the pinky finger send signals (nerve impulses) through the sensory fibres to the ulnar nerve, which then travels up the arm via the spinal cord to the brain, initiating action.

The neuropathy (nerve condition) of the ulnar nerve is known to cause symptoms such as numbness and tingling, which is caused by the compression or irritation of the nerve, especially in the elbow.³

Cubital tunnel syndrome

Cubital tunnel syndrome is a type of peripheral neuropathy which specifically affects the upper limb.^3,4 This condition occurs when the ulnar nerve that vulnerably passes behind the inner elbow (medial epicondyle) is entrapped in the elbow area. When the elbow is bent and compressed on a hard surface, the ulnar nerve experiences pressure against it and hence leads to cubital tunnel syndrome.

Elbow-bending activities such as phone use, athletic activities, and bending of the elbow cause the feeling of tingling, numbness, and pins and needles (paraesthesia). Many individuals who sleep with their elbow in a bent position may also experience these symptoms.

The chronic cubital tunnel syndrome affects the pinky and ring fingers the most, where individuals may experience difficulty in their motor skills, such as opening jars and using a pen.⁵

Other causes

Carpal tunnel syndrome is another type of peripheral nerve entrapment. The median nerves that pass through the carpal tunnel in the wrist get compressed from repetitive hand movements (e.g., typing) and injured from the pressure exerted by the fluids within the carpal tunnel.⁶ However, paraesthesia is less likely in the pinky finger. 

Due to the pressure, other complications occur within the median nerve, such as restricted blood supply (ischaemia) and demyelination of median nerve fibres. Furthermore, this syndrome is often related to conditions like diabetes, pregnancy, and obesity.

When numb pinky finger could be related to a heart attack

Referred pain and symptoms

Acute myocardial infarction (AMI) poses symptoms like chest pain that radiates to other parts of the body, such as the arms, neck, back, and jaw. Sensations of discomfort, for example, pain, pressure, and squeezing, are experienced by individuals who suffer from AMI.⁷

Signs of a heart attack

Common signs of heart attacks include:⁸ 

• Pressure and tightness in the chest
• Pain behind the breastbone (burning sensation) 
• Pain which spreads to the left or right arm, neck, the back and belly
• Stress 
• Upper body pain or numbness that spreads to the front, back, shoulders, neck, and jaw

Distinguishing between nerve issues and heart attacks

Duration and type of numbness

The pain characteristics in nerve issues and heart attacks differ:

Nerve issue

• Pain type: burning and sharp sensation
• Location: chest, legs, arms, or back 
• Length of time: can be chronic or intermediate 
• Ease of pain: by changing positions or by applying pressure on the affected area can ease /relieve the pain

Associated symptoms include:⁹

• Numbness or tingling 
• Weakening of the muscles 

Heart attack

• Pain type: squeezing or pressure pain 
• Location: left side or centre of the chest 
• Length of time: frequent pain or going away and occurring again 
• Ease of pain: this type of pain is not associated with changing position or resting

Associated symptoms include:¹⁰

• Vomiting and nausea 
• Sweating 
• Shortness of breath
• Sweating 
• Irregular heartbeats 
• Fatigue 
• Dizziness

What to do if you experience numbness

When to seek immediate medical help

• Sudden numbness on one side of the body along with other symptoms like difficulty in speaking, weakness and confusion is one of the signs of stroke
• After an injury to the head or spine, if numbness occurs, it could mean there is damage to the nerve or compression
• If the numbness is followed by shortness of breath or chest pain, it could be a heart attack

If any of these symptoms occur, you must contact the emergency services. 

When to consult a doctor

If the numbness persists or doesn't go away, you should consult a doctor. A medical expert can identify the underlying reason and suggest the best course of action. The following are some potential reasons for ongoing or persistent numbness.

• Nerve damage (Neuropathy): diabetes and other conditions can result in peripheral neuropathy, which causes numbness in the limbs
• Pinched nerve: ulnar nerve compression, cubital tunnel syndrome, or carpal tunnel syndrome can result from the compression of nerves causing numbness and pain
• Multiple sclerosis: if the numbness is accompanied by other neurological symptoms such as balance or visual problems, it may be an early indicator of multiple sclerosis (MS)
• Vitamin deficiency: nerve injury and numbness can result from vitamin deficiencies, such as B12. Tests on the blood can be used to detect these deficits

For ongoing numbness without additional symptoms, schedule a visit with a healthcare provider to rule out nerve or other health issues.

Summary 

While a numb pinky finger can be worrisome, heart attacks are less likely to be the cause of it than nerve problems like ulnar nerve, cubital tunnel syndrome, and carpal tunnel syndrome or pinched nerves. Nerve-related numbness is typically exacerbated by particular motions or positions and frequently comes with tingling, weakness, or discomfort. But it's also important to recognise the more general symptoms of a heart attack, which might include discomfort spreading to the arm or jaw, perspiration, shortness of breath, and chest pain. Get medical help right away if you experience any of these symptoms, especially if you also have numbness. Always visit a healthcare practitioner if you're unclear or concerned.