Carpal Tunnel Syndrome: Nerves, Bones, Tendons, and Key Structures Explained

The carpal tunnel is a narrow space in the wrist, formed by wrist bones (carpals) and the transverse carpal ligament. It houses important nerves and tendons, and its compression leads to carpal tunnel syndrome, causing pain, numbness, and muscle weakness in the hand. Understanding the structures passing through carpal tunnel is essential for clinicians assessing the carpal tunnel pain location.

What Are the Carpels in Hand and How Do They Form the Carpal Tunnel?

The carpels are the eight small bones that make up the wrist. They form the floor and sides of the carpal tunnel, creating a rigid but flexible structure. These bones work together to allow wrist movement and provide stability. Their arrangement shapes the tunnel’s boundaries, protecting the median nerve and tendons passing through. The carpels’ positioning is crucial for both wrist flexibility and maintaining the carpal tunnel’s integrity. The carpels’ positioning is crucial for both wrist flexibility and maintaining the carpal tunnel contents’ integrity. Knowledge of a carpal tunnel contents mnemonic can help memorise these structures effectively.

Carpal Tunnel Boundaries and Transverse Carpal Ligament

The carpal tunnel is bounded medially and laterally by the carpal bones, forming the floor and sides. The transverse carpal ligament forms the roof, creating a tight passageway for nerves and tendons. This ligament is key in maintaining tunnel shape, but can compress the median nerve in carpal tunnel syndrome. Surgically, releasing this ligament is a common decompression method to relieve nerve pressure and symptoms, while also protecting the structures passing through the carpal tunnel.

Which Bones Form the Carpal Tunnel?

The carpal tunnel is formed by the concave arrangement of specific carpal bones: the scaphoid and trapezium on the lateral side, and the pisiform and hamate on the medial side. This curved bony structure creates a protective, rigid floor and walls for the tunnel, allowing passage of nerves and tendons while maintaining wrist flexibility. Familiarity with carpels in hand and the wrist carpals helps explain the carpal tunnel pain location.

Carpal Tunnel Contents: Key Structures and Their Functions

Contains the median nerve and nine flexor tendons that control finger movement and sensation in the hand and wrist.

What Structures Pass Through the Carpal Tunnel?

The carpal tunnel contains the median nerve, which provides sensation and motor control to parts of the hand. It also houses nine flexor tendons: the flexor pollicis longus tendon (for thumb movement), four tendons of the flexor digitorum superficialis (flex fingers at the middle joints), and four tendons of the flexor digitorum profundus (flex fingers at the fingertips). These structures enable hand and finger function. These structures passing through carpal tunnel enable hand and finger function and are part of the carpal tunnel contents.

Median Nerve: The Primary Carpal Tunnel Nerve

The median nerve is the main nerve passing through the carpal tunnel. It provides sensation to the thumb, index, middle, and part of the ring finger, and controls motor function in some hand muscles. Compression of this nerve within the tunnel causes carpal tunnel syndrome, leading to numbness, tingling, weakness, and sometimes pain in the affected hand.

Carpal Tunnel Syndrome: Which Nerve and Muscles Are Affected?

Carpal Tunnel Syndrome squeezes the median nerve, which can cause pain in the hand muscles that control thumb movement, grip, and finger coordination.

Carpal Tunnel Syndrome and the Median Nerve

Carpal tunnel syndrome primarily affects the median nerve as it passes through the narrow carpal tunnel. Compression disrupts its ability to send sensory signals from the thumb, index, middle, and half of the ring finger. It also impairs motor signals to certain hand muscles, causing numbness, tingling, weakness, and loss of fine motor skills, significantly impacting carpels in hand function.

Muscles Affected by Carpal Tunnel Syndrome

Carpal tunnel syndrome mainly affects the thenar muscles, which control thumb movements like opposition, abduction, and flexion. Weakness or atrophy of these muscles occurs due to median nerve compression, reducing thumb strength and dexterity. This can make gripping and pinching difficult, affecting daily activities such as writing, buttoning clothes, or holding small objects. Knowledge of carpal tunnel contents and using a carpal tunnel contents mnemonic can help explain these effects.

Pain Location in Carpal Tunnel Syndrome

Pain in carpal tunnel syndrome typically affects the thumb, index, middle, and the radial half of the ring finger, where the median nerve provides sensation. Discomfort often includes numbness, tingling, and burning. Pain may radiate proximally up the forearm, worsening with wrist movements or activities that increase pressure within the carpal tunnel, leading to significant functional limitations. Understanding the structures passing through carpal tunnel helps map this pain accurately.

Clinical Features of Carpal Tunnel Syndrome

Carpal tunnel syndrome presents with subjective symptoms like tingling, numbness, and pain, often worsening at night. Patients may experience hand weakness and difficulty with fine motor tasks. Objective signs include thenar muscle atrophy due to nerve compression. Clinical tests such as Phalen’s maneuver (wrist flexion) and Tinel’s sign (tapping over the median nerve) often produce tingling or pain, confirming nerve irritation within the carpal tunnel. These clinical features help identify the carpal tunnel pain location and evaluate the function of the carpal tunnel syndrome nerve.

Diagnostic Tools and Testing

Includes nerve conduction studies, electromyography, ultrasound imaging, and physical tests like Phalen’s and Tinel’s to confirm carpal tunnel syndrome.

Nerve Conduction Studies

Nerve conduction studies measure the speed and strength of electrical signals traveling through the median nerve to confirm compression within the carpal tunnel. These tests compare the median nerve’s responses to those of the ulnar nerve, which is unaffected by carpal tunnel syndrome. Slower or reduced signals in the median nerve indicate nerve impairment and help assess severity. These studies are crucial for monitoring the carpal tunnel syndrome nerve and confirming the carpal tunnel pain location.

Ultrasound and MRI

Ultrasound and MRI imaging visualise the carpal tunnel’s internal structures, including the median nerve and flexor tendons. They help detect anatomical variations, swelling, or space-occupying lesions causing nerve compression. These non-invasive tools assist in diagnosis, treatment planning, and ruling out other wrist pathologies. 

Related Anatomical Variants and Risks

Some individuals have anatomical variations like a bifid median nerve, where the nerve splits into two branches, or a persistent median artery running alongside the nerve. These differences can increase the risk of nerve compression or complicate diagnosis and treatment. Such variants may lead to misdiagnosis or increase the risk of surgical complications during carpal tunnel release, making careful imaging and planning essential for safe, effective care.

When to See a Specialist for Carpal Tunnel Issues

Consult a neurologist or orthopaedic surgeon if symptoms persist despite rest and conservative treatment, or if you experience worsening muscle weakness or visible thenar muscle atrophy. Additionally, seek specialist care when night pain regularly interrupts sleep, affecting quality of life. Early evaluation helps prevent permanent nerve damage and guides decisions about advanced treatments like injections or surgical decompression.

Interdisciplinary Approach to Carpal Tunnel Syndrome

Combines physiotherapy, occupational therapy, medical management, and surgery to provide comprehensive diagnosis, treatment, and rehabilitation for optimal recovery.

Role of Physiotherapy

Physiotherapy plays a crucial role in managing carpal tunnel syndrome by using techniques such as wrist splinting to keep the wrist in a neutral position and reduce nerve compression, especially during sleep. Nerve gliding exercises help improve median nerve mobility and reduce irritation. Ergonomic training educates patients on proper wrist positioning and activity modification to prevent further strain. Together, these methods relieve symptoms, improve hand function, and may reduce the need for surgery. Using a carpal tunnel contents mnemonic during therapy helps track the structures passing through carpal tunnel and monitor the carpal tunnel syndrome nerve.

Role of Occupational Therapy

Occupational therapy focuses on adapting daily activities and the workplace to reduce strain on the wrist and median nerve. Therapists recommend ergonomic modifications such as adjustable desks, supportive keyboards, and optimised tool use. They also provide adaptive devices to assist with tasks, promoting safe hand function and preventing symptom worsening. This holistic approach helps patients maintain productivity while managing carpal tunnel syndrome effectively. Awareness of wrist carpals and the carpal tunnel pain location guides safe activity adaptation and therapy planning.

Surgical and Medical Collaboration

Treatment of carpal tunnel syndrome often involves collaboration between surgeons and medical professionals. Decompression surgery relieves nerve pressure when conservative methods fail. Anti-inflammatory medications reduce swelling and pain. Post-surgical rehabilitation, including physiotherapy, supports recovery by restoring wrist function, strength, and mobility, ensuring the best possible outcomes for patients. Surgery and rehabilitation aim to protect the carpal tunnel nerve, structures passing through carpal tunnel, and carpal tunnel pain location.

Partner with Experts in Wrist and Nerve Health at Physiotattva

At Physiotattva, our specialists deeply understand the complex anatomy and nerve functions involved in wrist health. We collaborate closely with clinicians and patients to provide comprehensive, personalised care for conditions like carpal tunnel syndrome. By combining expert assessment, targeted therapy, and patient education, we optimise treatment outcomes. Trust Physiotattva to guide your recovery journey with specialised knowledge, compassionate support, and advanced techniques tailored to your unique needs for lasting wrist and nerve health.

At Physiotattva physiotherapy clinics in Bangalore and Hyderabad, you receive personalised care tailored to your specific needs, ensuring effective results and comfort throughout your journey to recovery. 

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FAQs

What bones are affected by carpal tunnel syndrome?

Carpal tunnel syndrome involves the carpal bones of the wrist, especially the scaphoid, trapezium, pisiform, and hamate. These bones form the tunnel’s boundaries, and changes or swelling around them can compress the median nerve causing symptoms.

What is the surface anatomy of the carpal tunnel?

The carpal tunnel is located on the palm side of the wrist. It’s bordered by the curved carpal bones forming the floor and sides, and the transverse carpal ligament forming the roof. It appears as a narrow passage beneath the wrist crease.

What structures pass through the carpal tunnel?

The carpal tunnel contains the median nerve and nine flexor tendons: the flexor pollicis longus, four flexor digitorum superficialis tendons, and four flexor digitorum profundus tendons. These enable finger and thumb movement and sensation.

What are the 4 contents of the carpal tunnel?

The four key contents of the carpal tunnel are the median nerve, flexor pollicis longus tendon, flexor digitorum superficialis tendons (4), and flexor digitorum profundus tendons (4). These structures pass through the confined wrist space.

Which bones form the boundary of the carpal tunnel?

The boundaries of the carpal tunnel are formed by the scaphoid and trapezium bones laterally, and the pisiform and hamate bones medially. These carpals create a concave structure that shapes the tunnel floor and sides.