Views: 0 Author: Site Editor Publish Time: 2026-07-28 Origin: Site
Introduction
Many patients are surprised when they experience significant shoulder pain after surgery involving the chest, abdomen, or pelvis. Although the surgical site may be far away from the shoulder, postoperative shoulder pain is actually a well-recognized clinical phenomenon.
Studies have reported that:
Up to 97% of patients undergoing thoracic surgery may experience postoperative shoulder pain.
Approximately 35%–63% of patients after abdominal surgery develop shoulder discomfort.
Around 71.4% of patients undergoing laparoscopic procedures experience shoulder pain caused by diaphragmatic irritation.
Approximately 40% of women after cesarean section report postoperative shoulder pain.
This phenomenon is not caused by direct injury to the shoulder joint or muscles. Instead, it is mainly related to referred pain transmitted through the phrenic nerve, a key nerve connecting the diaphragm and cervical spinal nerves.
Understanding the relationship between the diaphragm, phrenic nerve, and shoulder region helps clinicians better diagnose and manage this frequently overlooked postoperative symptom.
Shoulder pain is not always generated from the shoulder itself.
The human nervous system shares sensory pathways between different anatomical regions. When an internal organ is irritated, the brain may incorrectly interpret the incoming pain signal as originating from another area.
This phenomenon is called referred pain.
A classic example is:
Heart disease → pain in the left shoulder or arm
Gallbladder disease → right shoulder pain
Diaphragm irritation → shoulder pain
After thoracic or abdominal surgery, the diaphragm and surrounding tissues become irritated. Because the diaphragm shares nerve pathways with the shoulder region, patients may perceive pain in the shoulder despite the shoulder joint being completely normal.
The phrenic nerve is the primary nerve responsible for diaphragm function.
It originates from:
Cervical spinal nerve roots C3
C4
C5
A common anatomical description is:
“C3, C4, and C5 keep the diaphragm alive.”
After originating from the cervical spine, the phrenic nerve travels downward through the neck and thorax before reaching the diaphragm.
Its functions include:
The phrenic nerve controls:
Diaphragmatic contraction
Breathing movements
Respiratory mechanics
The phrenic nerve also carries sensory information from:
Diaphragm
Diaphragmatic pleura
Mediastinal pleura
Pericardium
Upper abdominal peritoneum
Because these structures are connected to the same neural pathway, irritation in these areas can produce pain perceived around the shoulder.
The mechanism involves the convergence of sensory pathways in the cervical spinal cord.
The phrenic nerve sends sensory signals to spinal cord segments:
C3
C4
C5
These spinal levels are also associated with sensory input from the shoulder region.
Therefore, when the diaphragm becomes irritated:
Surgical manipulation stimulates diaphragmatic tissues.
Pain signals travel through the phrenic nerve.
Signals enter cervical spinal cord segments.
The brain misinterprets the origin of pain.
The patient feels pain in the shoulder.
This explains why a patient may complain of shoulder pain after surgery even though the shoulder itself was never operated on.
Although the phrenic nerve and brachial plexus are traditionally considered separate neural structures, anatomical studies have demonstrated that they are not completely independent.
The phrenic nerve originates from the cervical nerve roots (C3–C5), which are located close to the cervical plexus and brachial plexus structures.
Previous anatomical studies have shown that communication branches may exist between:
Phrenic nerve
Brachial plexus
Suprascapular nerve
Long thoracic nerve
Musculocutaneous nerve
Approximately 20% of phrenic nerves may have anatomical connections with branches of the brachial plexus.
These connections provide a possible explanation for why irritation of the diaphragm can produce pain sensations around:
Shoulder tip
Upper trapezius region
Scapular area
The nervous system does not always localize pain accurately. Because the diaphragm and shoulder share overlapping cervical nerve segments, the brain may interpret visceral pain signals as coming from the shoulder.
In addition to the main phrenic nerve, some individuals also have an accessory phrenic nerve.
Studies have suggested that more than one-third of people may possess accessory phrenic nerve pathways.
The accessory phrenic nerve may originate from:
Ansa cervicalis (cervical loop)
Subclavian nerve
The presence of accessory pathways may explain why postoperative shoulder pain varies significantly between patients.
Some patients experience severe shoulder pain after minor abdominal procedures, while others have minimal discomfort after major surgery.
Individual differences in:
Neural anatomy
Diaphragm sensitivity
Inflammatory response
Surgical manipulation
may all influence symptom severity.
One of the most common situations associated with postoperative shoulder pain is laparoscopic surgery.
During laparoscopic procedures, surgeons typically introduce carbon dioxide (CO₂) into the abdominal cavity to create working space.
Although this technique greatly improves surgical visualization and reduces tissue damage, residual CO₂ after surgery can irritate the diaphragm.
The mechanism includes:
The increased intra-abdominal pressure pushes the diaphragm upward.
This causes:
Diaphragmatic tension
Mechanical stimulation of sensory nerve endings
Phrenic nerve activation
CO₂ can dissolve into carbonic acid after contact with tissues.
This may result in:
Local pH reduction
Peritoneal irritation
Increased inflammatory response
Remaining CO₂ beneath the diaphragm stimulates diaphragmatic sensory receptors.
Pain signals are transmitted through:
Diaphragm → Phrenic nerve → C3–C5 spinal segments → Brain
The brain then interprets these signals as shoulder pain.
The diaphragm is not an isolated structure.
It is closely connected with:
Thoracic cavity
Abdominal cavity
Peritoneum
Pleura
Pericardium
During surgery, these tissues may experience:
Direct manipulation
Stretching
Inflammation
Fluid accumulation
Gas exposure
Examples include:
Procedures such as:
Lung surgery
Mediastinal surgery
Chest wall surgery
may stimulate:
Diaphragmatic pleura
Mediastinal tissues
Phrenic nerve endings
Procedures including:
Gallbladder surgery
Gastric surgery
Liver surgery
Colorectal surgery
may irritate the upper abdominal peritoneum, which receives sensory information through the phrenic nerve.
After cesarean delivery, shoulder pain may occur because:
Abdominal tissues are stretched
The diaphragm may be displaced
Peritoneal irritation occurs
Postoperative inflammatory mediators activate sensory pathways
Recognizing the characteristics of referred shoulder pain helps distinguish it from true shoulder disorders.
Typical features include:
Patients often describe:
Pain at the top of the shoulder
Pain near the trapezius muscle
Pain around the scapular region
The pain is usually not located directly inside the shoulder joint.
The pain often appears:
Several hours after surgery
During the first postoperative day
After laparoscopic procedures when anesthesia effects disappear
Unlike rotator cuff injury or shoulder arthritis:
Phrenic nerve-related pain usually:
Does not significantly worsen with shoulder movement
Does not cause weakness
Does not reduce shoulder range of motion
Some patients may also experience:
Abdominal discomfort
Chest discomfort
Difficulty taking deep breaths
Diaphragmatic tightness
A comprehensive assessment should exclude common shoulder disorders first.
Evaluation may include:
Important questions include:
Did the pain begin after abdominal or thoracic surgery?
Was laparoscopic surgery performed?
Is shoulder movement normal?
Is there associated abdominal or chest discomfort?
Clinicians may assess:
Cervical spine mobility
Neural tension
Shoulder joint function
Breathing-related symptom changes
Some physical therapists use nerve mobility tests to evaluate possible involvement of:
C3–C5 nerve roots
Phrenic nerve pathway
Cervical soft tissues
Possible contributing areas include:
Cervical foramina (C3–C5)
Anterior scalene muscle
Sternocleidomastoid muscle
Thoracic outlet region
Diaphragm and visceral fascia
Most postoperative phrenic nerve-related shoulder pain is temporary and improves naturally.
Treatment focuses on reducing irritation and improving mobility.
Changing body position may help redistribute residual gas after laparoscopy.
Common strategies include:
Early mobilization
Walking after surgery when allowed
Avoiding prolonged bed rest
Appropriate analgesia can reduce:
Muscle guarding
Breathing limitation
Secondary stiffness
Under professional guidance, techniques may include:
Diaphragmatic breathing exercises
Rib cage mobility training
Gentle soft tissue techniques
The goal is to reduce excessive tension around:
Diaphragm
Lower ribs
Thoracic fascia
Because the phrenic nerve originates from C3–C5, treatment may include:
Cervical posture correction
Gentle cervical mobility
Neural gliding exercises
Commonly addressed muscles include:
Anterior scalene
Sternocleidomastoid
Upper trapezius
Postoperative shoulder pain has been widely investigated, especially after laparoscopic surgery.
A systematic review published in 2020 analyzed the relationship between visceral surgery and postoperative shoulder pain. The review concluded that phrenic nerve irritation is one of the most important mechanisms responsible for referred shoulder pain after abdominal and thoracic procedures.
The evidence suggests that postoperative shoulder pain is not simply caused by surgical trauma but results from a complex interaction involving:
Diaphragmatic irritation
Peritoneal inflammation
Carbon dioxide retention
Neural transmission through the phrenic nerve
Central nervous system interpretation of pain signals
The occurrence of shoulder pain varies depending on the type of surgery.
Reported incidence includes:
Surgical Procedure | Incidence of Shoulder Pain |
|---|---|
Thoracic surgery | Up to 97% |
Abdominal surgery | 35%–63% |
Laparoscopic surgery | Approximately 70% |
Cesarean section | Around 40% |
The high incidence after laparoscopic surgery is particularly related to CO₂ pneumoperitoneum.
Several factors may increase the likelihood or severity of postoperative shoulder pain:
Higher pneumoperitoneum pressure causes:
Greater diaphragmatic elevation
Increased stretching of the diaphragm
Stronger phrenic nerve stimulation
The remaining CO₂ beneath the diaphragm after surgery may prolong irritation.
The longer gas remains in the abdominal cavity, the longer patients may experience referred shoulder pain.
Longer procedures usually involve:
Longer exposure to pneumoperitoneum
Greater tissue manipulation
More inflammatory response
Because the phrenic nerve and accessory pathways vary between individuals, pain sensitivity differs significantly.
Some patients may experience severe symptoms despite minimally invasive procedures, while others recover with little discomfort.
Although postoperative shoulder pain cannot always be completely prevented, several strategies may reduce its severity.
Using the lowest effective pneumoperitoneum pressure may reduce:
Diaphragm stretching
Phrenic nerve stimulation
Postoperative pain intensity
At the end of laparoscopic surgery, surgeons may attempt to evacuate residual gas.
Methods include:
Gentle abdominal compression
Pulmonary recruitment maneuvers
Gas removal techniques
These approaches aim to decrease the amount of CO₂ remaining beneath the diaphragm.
Early movement is one of the simplest strategies.
Walking and changing position may help:
Accelerate CO₂ absorption
Improve diaphragmatic mobility
Reduce stiffness
Patients should follow the surgeon’s instructions regarding activity level.
Deep breathing exercises can help restore normal diaphragm movement.
Examples include:
Place one hand on the abdomen.
Slowly inhale through the nose.
Allow the abdomen to expand.
Slowly exhale.
This encourages:
Diaphragm relaxation
Improved ventilation
Reduced protective muscle tension
In most cases, phrenic nerve-related shoulder pain is temporary and benign.
It usually improves within:
Several hours
A few days
Occasionally one week or longer
However, not all postoperative shoulder pain should automatically be considered referred pain.
Patients should seek medical evaluation if they experience:
Severe worsening pain
Fever
Chest pain
Shortness of breath
Shoulder weakness
Loss of movement
New neurological symptoms
These symptoms may indicate:
Infection
Blood clot
Lung complications
Nerve injury
True shoulder pathology
Shoulder pain after laparoscopy is mainly caused by irritation of the diaphragm by residual carbon dioxide gas. The irritated diaphragm sends pain signals through the phrenic nerve, and the brain interprets these signals as coming from the shoulder.
Usually not.
The shoulder joint itself is often normal. The pain is a type of referred pain, meaning the source of pain is located elsewhere but perceived in the shoulder area.
Most patients improve within 2–3 days.
Some individuals may experience discomfort for one week or slightly longer depending on:
Amount of residual gas
Surgical complexity
Individual sensitivity
Yes.
Early walking may help:
Promote gas absorption
Improve circulation
Reduce diaphragmatic irritation
However, activity should always follow postoperative restrictions.
Gentle relaxation techniques may help reduce muscle tension around:
Neck
Shoulder girdle
Chest wall
However, direct aggressive massage is usually unnecessary because the pain source is not the shoulder muscle itself.
No.
In most cases, the phrenic nerve is not injured.
The pain results from temporary stimulation or irritation of the nerve pathway rather than permanent nerve damage.
The human body is an interconnected network.
Traditional approaches often consider:
Shoulder
Spine
Internal organs
as separate systems.
However, neuroanatomical connections demonstrate that distant tissues can influence each other through:
Peripheral nerves
Spinal cord pathways
Fascial connections
Visceral sensory pathways
The phrenic nerve represents an important bridge between:
Cervical spine
Diaphragm
Thoracic cavity
Abdominal cavity
Shoulder region
Understanding these connections allows clinicians to provide more comprehensive evaluation and treatment.
Shoulder pain after thoracic surgery, abdominal surgery, or laparoscopic procedures is a common but often misunderstood clinical problem.
The pain usually does not originate from the shoulder joint itself. Instead, irritation of the diaphragm activates sensory signals transmitted through the phrenic nerve, which shares cervical spinal pathways with the shoulder region.
The major mechanisms include:
Diaphragm irritation
CO₂ pneumoperitoneum after laparoscopy
Peritoneal and pleural inflammation
Communication between phrenic nerve and brachial plexus pathways
Recognizing phrenic nerve-related referred shoulder pain can help avoid unnecessary shoulder examinations and provide more targeted management.
Through appropriate pain control, early mobilization, breathing exercises, and correction of contributing factors, most patients can achieve significant symptom relief.
Future research into the interaction between visceral organs, nerves, and musculoskeletal structures may further improve our understanding of postoperative pain mechanisms and rehabilitation strategies.
Review of postoperative shoulder pain after laparoscopic surgery: mechanisms and management. Systematic review, 2020.
Gray’s Anatomy: The Anatomical Basis of Clinical Practice. Phrenic nerve and diaphragmatic innervation.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy.
Standring S. Gray’s Anatomy: The Anatomical Basis of Clinical Practice.
Studies on accessory phrenic nerve anatomy and communication with cervical plexus structures.
